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Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 1
ANDHRA UNIVERSITY
INDUSTRIAL TRANING REPORT OF A STUDY ON
ENGINEERING SHOPS AND FOUNDRY VISAKHAPATNAM STEEL PLANT
A mini project report submitted in partial fulfillment of the requirement for the award of
degree of
BACHELOR OF ENGINEERING
IN
MECHANICAL ENGINEERING
Submitted by
B UDAY BASHKAR MURTHY ndash 311129520002 BMANOJ KUMARndash 311129520003
GLAKSHMAN LUMAR ndash 311129520012 K CHAITANAYAndash 311129520017
O HARI KIRAN ndash 311129520022
WELLFARE INSTITUTE OF SCIENCE TECHNOLOGY ampMANAGEMENT
Affiliated to ANDHRA UNIVERSITY
VISAKHAPATNAM
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 2
AN OVER VIEW OF VISAKHAPATNAM STEEL PLANT Visakhapatnam is popularly called as the Steel City of India and credit
was because of the Vi zag Stee l P lant ndash a venture of Ispat Nigam
VSP i s the f i rs t coasta l based s tee l p lant o f India and i s located
16 km south west o f c i ty o f destiny VSP has an installed capacity of 3
million Tons per annum of liquid s tee l and 2 656 mi l l ion tons o f
sa leable s teel VSP products meet exa l t ing international quality
standards such as JIS DIN BIS BS etcVSP has the distinction to be the first
integrated steel plant in India to becomea ful l y ISO-
9002 cer t i f ied company The cer t i f i cate covers qual i ty systems tr
aining and marketing functions spreading over 4 regional marketing officer
20branch offices and 22 stockyards located all over the country VSP successfully
installing and operating efficiently Rs 460 cores worth of pollution
control and environment control equipment and converting the barren
land scape by planting more than 3 million plants has made the steel plant steel
township a greener cleaner place which can boas of 3 to 40C lesser temperature
even in the peak summer compared to Visakhapatnam City
Exports qual i ty p ig i ron and stee l pro jects to Sr i Lanka
Myanmar Nepal Middle East USA amp South East Asia (Pig Iron) RINL VSP was
awarded ldquoState Trading Houserdquo status during 1997-2000Besides these a captive
power plant with a capacity of 2475 MW Oxygen plant Acetylene plant
compressed iron plant extensive repair maintenance facilities form part of
facilities available at VSP VSP has sufficient infrastructure to expand the plant to
10 Million tons per annum of liquid steel capacity
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 3
MAJOR PLANT FACILITIES VSP has the following major production facilities bull 4 coke oven batteries of 67 ovens each having 416 M3 Volume bull 2 Sinter machines of 312 M3 area bull 3 Blast furnace of 3200 M3 useful volume bull Steel Melts Shop with three LD converters of 150 Tons capacity each and 6 N0sof 4 standard continuous bloom casters bull Light and Medium Merchant Mill of 710000 Tons per year capacity bull Wire rod mill of 850000 tons per year capacity bull Medium Merchant amp Structural Mill of 850000 tons per year capacity Besides these a capacity power plant site a capacity of 2865 MW Oxygen Plant Acetylene plant with Air plant extensive repair maintenance facilities form Part of the facilities available at VSP Number of ovens in series one after the other form a coke oven Battery At VSP there Coke oven Batteries 7 Meter tall and having 67 Ovens each Each oven Is having a volume of 416 m3 amp can hold up 316 Tons of dry coal charge
MINOR DEPARTMENTS Power generation and distribution Water management
Traffic department
Engineering shops and foundry Utilities department
Quality assurance and technology development department
Calcining and refractory material plant
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 4
ENGINEERING SHOPS amp FOUNDRY
INTRODUCTION-
Engineering shops are set up to meet the requirements of ferrous and
non-ferrous spares of different departments in VSP The engineering shops manufacture
and repair the needed spare parts of equipment and tools according to the order of the
certain dept which is called as customer dept
Engineering shops amp foundry is set up to meet the requirements of Ferrous amp nonferrous spares of different departments Engineering shops amp Foundry is divided into 5 shops
1 Central Machine Shop 2 Forge Shop 3 Steel Structural Shop 4 Foundry 5 Utility equipment repair shop
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 5
CENTRAL MACHINE SHOP
CMS is designed to carry the following manufacturing and repairing
activities
1) Manufacturing and finishing of castings forgings fabricated and
rolled sections
2) Heat treatment and reconditioning of parts
3) Tool room work including manufacturing and repair of jigs and
fixtures regrinding and sharpening of cutting tools
4) Dismantling repair and assembling of worn out machinery and
equipment
This shop has four longitudinal bays and one cross bay Heavy and medium
duty machines are located in the first two bays The third bay has light
machines for material preparation and tool room The forth bay houses the
heat treatment and thermal surfacing sections Cross bay connecting other
four bays is the fitting and assembly bay and also houses some of heavy
machine tools Each bay is provided with three EOT cranes with adequate
capacity
INPUTS Iron ampSteel castings forgings rolled sections repair and rectification
Parts nonferrous castings fabrication structures
PRODUCTS AND SERVICE shafts pinions Gears crane Wheels Rollers
Machining of various fabrication jobs done in SSS Repair ampreconditioning of
various assembly jobs like LampT housing To stands pulleys previsioning facing and
centering machines hacksaws and gas cutting facilities are provided The
machining section has over 100 major machine including lathes milling boring and
planning slotting shaping grinding and other machines The assembly section
undertakes medium repair and general overhauling of mechanical equipment
Horizontal and vertical presses washing tanks oil berths etc are provided The tool
room has facilities for manufacture of special tools jigs and fixtures re-grinding of
tools and brazing of tipped tools The heat treatment section is provided with
annealing normalizing heat treatment furnaces carbonizing furnaces heat
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 6
treatment furnace with protective gas atmospheres high frequency hardening
machine quenching tanks with oil cooling arrangements welding generator and
transformers for normal welding sub-merged arc welding machine etc Facilities
for surface grinding pipe bending and threading are provided
MAJOR JOBS OF CMS
Repairing and reconditioning of TK stands of continuous casting
machine
Manufacturing and repairing of different types of gears and
couplings
Reconditioning of single roll crusher rotor assembly and spiral
classifier assembly
Repair of machining of cooling plates carbon blocks
Fitting amp assembly
section
Central Machine Shop
Machining Maintenance
Assembly amp repair
work
Reclamation
work
Machining Gear cutting
Heat
treatment
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 7
EQUIPMENT IN CMS
Plano milling machine
Heavy lathes
Horizontal boring machine
Vertical turret boring machine
Grinding machine
Slotting machine
Milling machine
Planning machine
Drilling machine
Gear hobbing machine
Gear shaper
Bevel gear generator
Balancing machine
Shot blasting machine
Submerged arc welding
Induction gear hardening machine
HEAVY LATHE
The HEC LC 100 LC 125 type center lathes are heavy duty lathe machines
using in CMS These are fully satisfying the claims modern technology Their rigid
structure permits roughing and also precision finishing work It uses cemented
carbide tipped tools and high speed steel tools
Working range specifications LC100 LC125
Swing over bed mm 1000 1250
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 8
Swing over carriage mm 710 900
Height of bed above carriage mm 500 630
Distance between centers mm 3000 12000
Max Torque kgm 2500 3150
Max Weight kg 10000 14000
Spindle speeds in 36 steps
First range rpm 18-90 14-71
second range rpm 8-400 63-315
Dia of taper in spindle mm 80110
Main motor speed rpm 1460 kW 40
Longitudinal feeds in 36 steps
First range mmrev 0125 to 6
Second range mmrev 1 to 48
Movement of
Cross slide mm 530 650
Compound rest mm 360
Tool post mm 110
Max Cross section of tool for 4way
Tool post mm 50times50
Long Rapid transverse mmmin 3600
Motor for Long Rapid transverse rpm 1400 kW 11
Dia of sleeve of tail stock mm 170
Dia of taper in sleeve mm 80110
Rate of travel tail stock mmmin 2150
Offsetting of tail stock mm +-10
Motor of tailstock rpm 1400 kW 005
Pitch of lead screw inch frac12 Motor for lubricating oil pump kW 018
The main parts of a lathe are
1) Bed
2) Head stock
3) Tail stock
4) Carriage
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 9
BED It forms the base of the machine On the bed racks for carriage tail stock head
stock and bearings for feed rod and lead screw are fixed
The bed is provided with 3 transverse holes for lifting It also act as reservoir for
lubricating oil
HEADSTOCK It is on the left side of the lathe bed It contains the lathe spindle and
spindle driving mechanism The spindle is hollow throughout its length to allow bar
stock to pass through It is located and runs in precision anti friction bearings in head
stock housing The spur gear attached to the left end of the spindle drives the trains
gear to provide motion and direction to the feed rod quick change gear box and
thread cutting mechanism This lathe is driven by constant speed motor Change of
spindle speeds are obtained by a series of gear combinations by shifting two or three
levers in different positions The main motor is housed in head stock
CLUTCH and BRAKE The brake serves to reduce the costing of machine to the
maximum It applies automatically as soon as the main motor is switched off and is
released again when the main motor is started The clutch id of centrifugal type
which permits a soft starting and the full torque is gradually built up starting load
being less starting current of motor is less
CARRIAGE It controls the movement of cutting tool either parallel or
perpendicular to lathe axis It moves on the guide ways of the bed It again consists
of
saddle
compound rest
tool post
Saddle is mounted on the guide ways carriage and supports the cross slide
Compound rest is mounted on the guide ways of the saddle and supports the tool
post The base of the compound rest can be swiveled to any angle between 0-360o
and mainly used during taper turning operation
Tool post its main purpose is to hold the tool during operation There are two types
of tool posts
standard tool post
four way tool post
The LC100125 lathes use the four way tool posts
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 2
AN OVER VIEW OF VISAKHAPATNAM STEEL PLANT Visakhapatnam is popularly called as the Steel City of India and credit
was because of the Vi zag Stee l P lant ndash a venture of Ispat Nigam
VSP i s the f i rs t coasta l based s tee l p lant o f India and i s located
16 km south west o f c i ty o f destiny VSP has an installed capacity of 3
million Tons per annum of liquid s tee l and 2 656 mi l l ion tons o f
sa leable s teel VSP products meet exa l t ing international quality
standards such as JIS DIN BIS BS etcVSP has the distinction to be the first
integrated steel plant in India to becomea ful l y ISO-
9002 cer t i f ied company The cer t i f i cate covers qual i ty systems tr
aining and marketing functions spreading over 4 regional marketing officer
20branch offices and 22 stockyards located all over the country VSP successfully
installing and operating efficiently Rs 460 cores worth of pollution
control and environment control equipment and converting the barren
land scape by planting more than 3 million plants has made the steel plant steel
township a greener cleaner place which can boas of 3 to 40C lesser temperature
even in the peak summer compared to Visakhapatnam City
Exports qual i ty p ig i ron and stee l pro jects to Sr i Lanka
Myanmar Nepal Middle East USA amp South East Asia (Pig Iron) RINL VSP was
awarded ldquoState Trading Houserdquo status during 1997-2000Besides these a captive
power plant with a capacity of 2475 MW Oxygen plant Acetylene plant
compressed iron plant extensive repair maintenance facilities form part of
facilities available at VSP VSP has sufficient infrastructure to expand the plant to
10 Million tons per annum of liquid steel capacity
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 3
MAJOR PLANT FACILITIES VSP has the following major production facilities bull 4 coke oven batteries of 67 ovens each having 416 M3 Volume bull 2 Sinter machines of 312 M3 area bull 3 Blast furnace of 3200 M3 useful volume bull Steel Melts Shop with three LD converters of 150 Tons capacity each and 6 N0sof 4 standard continuous bloom casters bull Light and Medium Merchant Mill of 710000 Tons per year capacity bull Wire rod mill of 850000 tons per year capacity bull Medium Merchant amp Structural Mill of 850000 tons per year capacity Besides these a capacity power plant site a capacity of 2865 MW Oxygen Plant Acetylene plant with Air plant extensive repair maintenance facilities form Part of the facilities available at VSP Number of ovens in series one after the other form a coke oven Battery At VSP there Coke oven Batteries 7 Meter tall and having 67 Ovens each Each oven Is having a volume of 416 m3 amp can hold up 316 Tons of dry coal charge
MINOR DEPARTMENTS Power generation and distribution Water management
Traffic department
Engineering shops and foundry Utilities department
Quality assurance and technology development department
Calcining and refractory material plant
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 4
ENGINEERING SHOPS amp FOUNDRY
INTRODUCTION-
Engineering shops are set up to meet the requirements of ferrous and
non-ferrous spares of different departments in VSP The engineering shops manufacture
and repair the needed spare parts of equipment and tools according to the order of the
certain dept which is called as customer dept
Engineering shops amp foundry is set up to meet the requirements of Ferrous amp nonferrous spares of different departments Engineering shops amp Foundry is divided into 5 shops
1 Central Machine Shop 2 Forge Shop 3 Steel Structural Shop 4 Foundry 5 Utility equipment repair shop
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 5
CENTRAL MACHINE SHOP
CMS is designed to carry the following manufacturing and repairing
activities
1) Manufacturing and finishing of castings forgings fabricated and
rolled sections
2) Heat treatment and reconditioning of parts
3) Tool room work including manufacturing and repair of jigs and
fixtures regrinding and sharpening of cutting tools
4) Dismantling repair and assembling of worn out machinery and
equipment
This shop has four longitudinal bays and one cross bay Heavy and medium
duty machines are located in the first two bays The third bay has light
machines for material preparation and tool room The forth bay houses the
heat treatment and thermal surfacing sections Cross bay connecting other
four bays is the fitting and assembly bay and also houses some of heavy
machine tools Each bay is provided with three EOT cranes with adequate
capacity
INPUTS Iron ampSteel castings forgings rolled sections repair and rectification
Parts nonferrous castings fabrication structures
PRODUCTS AND SERVICE shafts pinions Gears crane Wheels Rollers
Machining of various fabrication jobs done in SSS Repair ampreconditioning of
various assembly jobs like LampT housing To stands pulleys previsioning facing and
centering machines hacksaws and gas cutting facilities are provided The
machining section has over 100 major machine including lathes milling boring and
planning slotting shaping grinding and other machines The assembly section
undertakes medium repair and general overhauling of mechanical equipment
Horizontal and vertical presses washing tanks oil berths etc are provided The tool
room has facilities for manufacture of special tools jigs and fixtures re-grinding of
tools and brazing of tipped tools The heat treatment section is provided with
annealing normalizing heat treatment furnaces carbonizing furnaces heat
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 6
treatment furnace with protective gas atmospheres high frequency hardening
machine quenching tanks with oil cooling arrangements welding generator and
transformers for normal welding sub-merged arc welding machine etc Facilities
for surface grinding pipe bending and threading are provided
MAJOR JOBS OF CMS
Repairing and reconditioning of TK stands of continuous casting
machine
Manufacturing and repairing of different types of gears and
couplings
Reconditioning of single roll crusher rotor assembly and spiral
classifier assembly
Repair of machining of cooling plates carbon blocks
Fitting amp assembly
section
Central Machine Shop
Machining Maintenance
Assembly amp repair
work
Reclamation
work
Machining Gear cutting
Heat
treatment
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 7
EQUIPMENT IN CMS
Plano milling machine
Heavy lathes
Horizontal boring machine
Vertical turret boring machine
Grinding machine
Slotting machine
Milling machine
Planning machine
Drilling machine
Gear hobbing machine
Gear shaper
Bevel gear generator
Balancing machine
Shot blasting machine
Submerged arc welding
Induction gear hardening machine
HEAVY LATHE
The HEC LC 100 LC 125 type center lathes are heavy duty lathe machines
using in CMS These are fully satisfying the claims modern technology Their rigid
structure permits roughing and also precision finishing work It uses cemented
carbide tipped tools and high speed steel tools
Working range specifications LC100 LC125
Swing over bed mm 1000 1250
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 8
Swing over carriage mm 710 900
Height of bed above carriage mm 500 630
Distance between centers mm 3000 12000
Max Torque kgm 2500 3150
Max Weight kg 10000 14000
Spindle speeds in 36 steps
First range rpm 18-90 14-71
second range rpm 8-400 63-315
Dia of taper in spindle mm 80110
Main motor speed rpm 1460 kW 40
Longitudinal feeds in 36 steps
First range mmrev 0125 to 6
Second range mmrev 1 to 48
Movement of
Cross slide mm 530 650
Compound rest mm 360
Tool post mm 110
Max Cross section of tool for 4way
Tool post mm 50times50
Long Rapid transverse mmmin 3600
Motor for Long Rapid transverse rpm 1400 kW 11
Dia of sleeve of tail stock mm 170
Dia of taper in sleeve mm 80110
Rate of travel tail stock mmmin 2150
Offsetting of tail stock mm +-10
Motor of tailstock rpm 1400 kW 005
Pitch of lead screw inch frac12 Motor for lubricating oil pump kW 018
The main parts of a lathe are
1) Bed
2) Head stock
3) Tail stock
4) Carriage
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 9
BED It forms the base of the machine On the bed racks for carriage tail stock head
stock and bearings for feed rod and lead screw are fixed
The bed is provided with 3 transverse holes for lifting It also act as reservoir for
lubricating oil
HEADSTOCK It is on the left side of the lathe bed It contains the lathe spindle and
spindle driving mechanism The spindle is hollow throughout its length to allow bar
stock to pass through It is located and runs in precision anti friction bearings in head
stock housing The spur gear attached to the left end of the spindle drives the trains
gear to provide motion and direction to the feed rod quick change gear box and
thread cutting mechanism This lathe is driven by constant speed motor Change of
spindle speeds are obtained by a series of gear combinations by shifting two or three
levers in different positions The main motor is housed in head stock
CLUTCH and BRAKE The brake serves to reduce the costing of machine to the
maximum It applies automatically as soon as the main motor is switched off and is
released again when the main motor is started The clutch id of centrifugal type
which permits a soft starting and the full torque is gradually built up starting load
being less starting current of motor is less
CARRIAGE It controls the movement of cutting tool either parallel or
perpendicular to lathe axis It moves on the guide ways of the bed It again consists
of
saddle
compound rest
tool post
Saddle is mounted on the guide ways carriage and supports the cross slide
Compound rest is mounted on the guide ways of the saddle and supports the tool
post The base of the compound rest can be swiveled to any angle between 0-360o
and mainly used during taper turning operation
Tool post its main purpose is to hold the tool during operation There are two types
of tool posts
standard tool post
four way tool post
The LC100125 lathes use the four way tool posts
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 3
MAJOR PLANT FACILITIES VSP has the following major production facilities bull 4 coke oven batteries of 67 ovens each having 416 M3 Volume bull 2 Sinter machines of 312 M3 area bull 3 Blast furnace of 3200 M3 useful volume bull Steel Melts Shop with three LD converters of 150 Tons capacity each and 6 N0sof 4 standard continuous bloom casters bull Light and Medium Merchant Mill of 710000 Tons per year capacity bull Wire rod mill of 850000 tons per year capacity bull Medium Merchant amp Structural Mill of 850000 tons per year capacity Besides these a capacity power plant site a capacity of 2865 MW Oxygen Plant Acetylene plant with Air plant extensive repair maintenance facilities form Part of the facilities available at VSP Number of ovens in series one after the other form a coke oven Battery At VSP there Coke oven Batteries 7 Meter tall and having 67 Ovens each Each oven Is having a volume of 416 m3 amp can hold up 316 Tons of dry coal charge
MINOR DEPARTMENTS Power generation and distribution Water management
Traffic department
Engineering shops and foundry Utilities department
Quality assurance and technology development department
Calcining and refractory material plant
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 4
ENGINEERING SHOPS amp FOUNDRY
INTRODUCTION-
Engineering shops are set up to meet the requirements of ferrous and
non-ferrous spares of different departments in VSP The engineering shops manufacture
and repair the needed spare parts of equipment and tools according to the order of the
certain dept which is called as customer dept
Engineering shops amp foundry is set up to meet the requirements of Ferrous amp nonferrous spares of different departments Engineering shops amp Foundry is divided into 5 shops
1 Central Machine Shop 2 Forge Shop 3 Steel Structural Shop 4 Foundry 5 Utility equipment repair shop
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 5
CENTRAL MACHINE SHOP
CMS is designed to carry the following manufacturing and repairing
activities
1) Manufacturing and finishing of castings forgings fabricated and
rolled sections
2) Heat treatment and reconditioning of parts
3) Tool room work including manufacturing and repair of jigs and
fixtures regrinding and sharpening of cutting tools
4) Dismantling repair and assembling of worn out machinery and
equipment
This shop has four longitudinal bays and one cross bay Heavy and medium
duty machines are located in the first two bays The third bay has light
machines for material preparation and tool room The forth bay houses the
heat treatment and thermal surfacing sections Cross bay connecting other
four bays is the fitting and assembly bay and also houses some of heavy
machine tools Each bay is provided with three EOT cranes with adequate
capacity
INPUTS Iron ampSteel castings forgings rolled sections repair and rectification
Parts nonferrous castings fabrication structures
PRODUCTS AND SERVICE shafts pinions Gears crane Wheels Rollers
Machining of various fabrication jobs done in SSS Repair ampreconditioning of
various assembly jobs like LampT housing To stands pulleys previsioning facing and
centering machines hacksaws and gas cutting facilities are provided The
machining section has over 100 major machine including lathes milling boring and
planning slotting shaping grinding and other machines The assembly section
undertakes medium repair and general overhauling of mechanical equipment
Horizontal and vertical presses washing tanks oil berths etc are provided The tool
room has facilities for manufacture of special tools jigs and fixtures re-grinding of
tools and brazing of tipped tools The heat treatment section is provided with
annealing normalizing heat treatment furnaces carbonizing furnaces heat
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 6
treatment furnace with protective gas atmospheres high frequency hardening
machine quenching tanks with oil cooling arrangements welding generator and
transformers for normal welding sub-merged arc welding machine etc Facilities
for surface grinding pipe bending and threading are provided
MAJOR JOBS OF CMS
Repairing and reconditioning of TK stands of continuous casting
machine
Manufacturing and repairing of different types of gears and
couplings
Reconditioning of single roll crusher rotor assembly and spiral
classifier assembly
Repair of machining of cooling plates carbon blocks
Fitting amp assembly
section
Central Machine Shop
Machining Maintenance
Assembly amp repair
work
Reclamation
work
Machining Gear cutting
Heat
treatment
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 7
EQUIPMENT IN CMS
Plano milling machine
Heavy lathes
Horizontal boring machine
Vertical turret boring machine
Grinding machine
Slotting machine
Milling machine
Planning machine
Drilling machine
Gear hobbing machine
Gear shaper
Bevel gear generator
Balancing machine
Shot blasting machine
Submerged arc welding
Induction gear hardening machine
HEAVY LATHE
The HEC LC 100 LC 125 type center lathes are heavy duty lathe machines
using in CMS These are fully satisfying the claims modern technology Their rigid
structure permits roughing and also precision finishing work It uses cemented
carbide tipped tools and high speed steel tools
Working range specifications LC100 LC125
Swing over bed mm 1000 1250
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 8
Swing over carriage mm 710 900
Height of bed above carriage mm 500 630
Distance between centers mm 3000 12000
Max Torque kgm 2500 3150
Max Weight kg 10000 14000
Spindle speeds in 36 steps
First range rpm 18-90 14-71
second range rpm 8-400 63-315
Dia of taper in spindle mm 80110
Main motor speed rpm 1460 kW 40
Longitudinal feeds in 36 steps
First range mmrev 0125 to 6
Second range mmrev 1 to 48
Movement of
Cross slide mm 530 650
Compound rest mm 360
Tool post mm 110
Max Cross section of tool for 4way
Tool post mm 50times50
Long Rapid transverse mmmin 3600
Motor for Long Rapid transverse rpm 1400 kW 11
Dia of sleeve of tail stock mm 170
Dia of taper in sleeve mm 80110
Rate of travel tail stock mmmin 2150
Offsetting of tail stock mm +-10
Motor of tailstock rpm 1400 kW 005
Pitch of lead screw inch frac12 Motor for lubricating oil pump kW 018
The main parts of a lathe are
1) Bed
2) Head stock
3) Tail stock
4) Carriage
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 9
BED It forms the base of the machine On the bed racks for carriage tail stock head
stock and bearings for feed rod and lead screw are fixed
The bed is provided with 3 transverse holes for lifting It also act as reservoir for
lubricating oil
HEADSTOCK It is on the left side of the lathe bed It contains the lathe spindle and
spindle driving mechanism The spindle is hollow throughout its length to allow bar
stock to pass through It is located and runs in precision anti friction bearings in head
stock housing The spur gear attached to the left end of the spindle drives the trains
gear to provide motion and direction to the feed rod quick change gear box and
thread cutting mechanism This lathe is driven by constant speed motor Change of
spindle speeds are obtained by a series of gear combinations by shifting two or three
levers in different positions The main motor is housed in head stock
CLUTCH and BRAKE The brake serves to reduce the costing of machine to the
maximum It applies automatically as soon as the main motor is switched off and is
released again when the main motor is started The clutch id of centrifugal type
which permits a soft starting and the full torque is gradually built up starting load
being less starting current of motor is less
CARRIAGE It controls the movement of cutting tool either parallel or
perpendicular to lathe axis It moves on the guide ways of the bed It again consists
of
saddle
compound rest
tool post
Saddle is mounted on the guide ways carriage and supports the cross slide
Compound rest is mounted on the guide ways of the saddle and supports the tool
post The base of the compound rest can be swiveled to any angle between 0-360o
and mainly used during taper turning operation
Tool post its main purpose is to hold the tool during operation There are two types
of tool posts
standard tool post
four way tool post
The LC100125 lathes use the four way tool posts
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 4
ENGINEERING SHOPS amp FOUNDRY
INTRODUCTION-
Engineering shops are set up to meet the requirements of ferrous and
non-ferrous spares of different departments in VSP The engineering shops manufacture
and repair the needed spare parts of equipment and tools according to the order of the
certain dept which is called as customer dept
Engineering shops amp foundry is set up to meet the requirements of Ferrous amp nonferrous spares of different departments Engineering shops amp Foundry is divided into 5 shops
1 Central Machine Shop 2 Forge Shop 3 Steel Structural Shop 4 Foundry 5 Utility equipment repair shop
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 5
CENTRAL MACHINE SHOP
CMS is designed to carry the following manufacturing and repairing
activities
1) Manufacturing and finishing of castings forgings fabricated and
rolled sections
2) Heat treatment and reconditioning of parts
3) Tool room work including manufacturing and repair of jigs and
fixtures regrinding and sharpening of cutting tools
4) Dismantling repair and assembling of worn out machinery and
equipment
This shop has four longitudinal bays and one cross bay Heavy and medium
duty machines are located in the first two bays The third bay has light
machines for material preparation and tool room The forth bay houses the
heat treatment and thermal surfacing sections Cross bay connecting other
four bays is the fitting and assembly bay and also houses some of heavy
machine tools Each bay is provided with three EOT cranes with adequate
capacity
INPUTS Iron ampSteel castings forgings rolled sections repair and rectification
Parts nonferrous castings fabrication structures
PRODUCTS AND SERVICE shafts pinions Gears crane Wheels Rollers
Machining of various fabrication jobs done in SSS Repair ampreconditioning of
various assembly jobs like LampT housing To stands pulleys previsioning facing and
centering machines hacksaws and gas cutting facilities are provided The
machining section has over 100 major machine including lathes milling boring and
planning slotting shaping grinding and other machines The assembly section
undertakes medium repair and general overhauling of mechanical equipment
Horizontal and vertical presses washing tanks oil berths etc are provided The tool
room has facilities for manufacture of special tools jigs and fixtures re-grinding of
tools and brazing of tipped tools The heat treatment section is provided with
annealing normalizing heat treatment furnaces carbonizing furnaces heat
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 6
treatment furnace with protective gas atmospheres high frequency hardening
machine quenching tanks with oil cooling arrangements welding generator and
transformers for normal welding sub-merged arc welding machine etc Facilities
for surface grinding pipe bending and threading are provided
MAJOR JOBS OF CMS
Repairing and reconditioning of TK stands of continuous casting
machine
Manufacturing and repairing of different types of gears and
couplings
Reconditioning of single roll crusher rotor assembly and spiral
classifier assembly
Repair of machining of cooling plates carbon blocks
Fitting amp assembly
section
Central Machine Shop
Machining Maintenance
Assembly amp repair
work
Reclamation
work
Machining Gear cutting
Heat
treatment
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 7
EQUIPMENT IN CMS
Plano milling machine
Heavy lathes
Horizontal boring machine
Vertical turret boring machine
Grinding machine
Slotting machine
Milling machine
Planning machine
Drilling machine
Gear hobbing machine
Gear shaper
Bevel gear generator
Balancing machine
Shot blasting machine
Submerged arc welding
Induction gear hardening machine
HEAVY LATHE
The HEC LC 100 LC 125 type center lathes are heavy duty lathe machines
using in CMS These are fully satisfying the claims modern technology Their rigid
structure permits roughing and also precision finishing work It uses cemented
carbide tipped tools and high speed steel tools
Working range specifications LC100 LC125
Swing over bed mm 1000 1250
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 8
Swing over carriage mm 710 900
Height of bed above carriage mm 500 630
Distance between centers mm 3000 12000
Max Torque kgm 2500 3150
Max Weight kg 10000 14000
Spindle speeds in 36 steps
First range rpm 18-90 14-71
second range rpm 8-400 63-315
Dia of taper in spindle mm 80110
Main motor speed rpm 1460 kW 40
Longitudinal feeds in 36 steps
First range mmrev 0125 to 6
Second range mmrev 1 to 48
Movement of
Cross slide mm 530 650
Compound rest mm 360
Tool post mm 110
Max Cross section of tool for 4way
Tool post mm 50times50
Long Rapid transverse mmmin 3600
Motor for Long Rapid transverse rpm 1400 kW 11
Dia of sleeve of tail stock mm 170
Dia of taper in sleeve mm 80110
Rate of travel tail stock mmmin 2150
Offsetting of tail stock mm +-10
Motor of tailstock rpm 1400 kW 005
Pitch of lead screw inch frac12 Motor for lubricating oil pump kW 018
The main parts of a lathe are
1) Bed
2) Head stock
3) Tail stock
4) Carriage
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 9
BED It forms the base of the machine On the bed racks for carriage tail stock head
stock and bearings for feed rod and lead screw are fixed
The bed is provided with 3 transverse holes for lifting It also act as reservoir for
lubricating oil
HEADSTOCK It is on the left side of the lathe bed It contains the lathe spindle and
spindle driving mechanism The spindle is hollow throughout its length to allow bar
stock to pass through It is located and runs in precision anti friction bearings in head
stock housing The spur gear attached to the left end of the spindle drives the trains
gear to provide motion and direction to the feed rod quick change gear box and
thread cutting mechanism This lathe is driven by constant speed motor Change of
spindle speeds are obtained by a series of gear combinations by shifting two or three
levers in different positions The main motor is housed in head stock
CLUTCH and BRAKE The brake serves to reduce the costing of machine to the
maximum It applies automatically as soon as the main motor is switched off and is
released again when the main motor is started The clutch id of centrifugal type
which permits a soft starting and the full torque is gradually built up starting load
being less starting current of motor is less
CARRIAGE It controls the movement of cutting tool either parallel or
perpendicular to lathe axis It moves on the guide ways of the bed It again consists
of
saddle
compound rest
tool post
Saddle is mounted on the guide ways carriage and supports the cross slide
Compound rest is mounted on the guide ways of the saddle and supports the tool
post The base of the compound rest can be swiveled to any angle between 0-360o
and mainly used during taper turning operation
Tool post its main purpose is to hold the tool during operation There are two types
of tool posts
standard tool post
four way tool post
The LC100125 lathes use the four way tool posts
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 5
CENTRAL MACHINE SHOP
CMS is designed to carry the following manufacturing and repairing
activities
1) Manufacturing and finishing of castings forgings fabricated and
rolled sections
2) Heat treatment and reconditioning of parts
3) Tool room work including manufacturing and repair of jigs and
fixtures regrinding and sharpening of cutting tools
4) Dismantling repair and assembling of worn out machinery and
equipment
This shop has four longitudinal bays and one cross bay Heavy and medium
duty machines are located in the first two bays The third bay has light
machines for material preparation and tool room The forth bay houses the
heat treatment and thermal surfacing sections Cross bay connecting other
four bays is the fitting and assembly bay and also houses some of heavy
machine tools Each bay is provided with three EOT cranes with adequate
capacity
INPUTS Iron ampSteel castings forgings rolled sections repair and rectification
Parts nonferrous castings fabrication structures
PRODUCTS AND SERVICE shafts pinions Gears crane Wheels Rollers
Machining of various fabrication jobs done in SSS Repair ampreconditioning of
various assembly jobs like LampT housing To stands pulleys previsioning facing and
centering machines hacksaws and gas cutting facilities are provided The
machining section has over 100 major machine including lathes milling boring and
planning slotting shaping grinding and other machines The assembly section
undertakes medium repair and general overhauling of mechanical equipment
Horizontal and vertical presses washing tanks oil berths etc are provided The tool
room has facilities for manufacture of special tools jigs and fixtures re-grinding of
tools and brazing of tipped tools The heat treatment section is provided with
annealing normalizing heat treatment furnaces carbonizing furnaces heat
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 6
treatment furnace with protective gas atmospheres high frequency hardening
machine quenching tanks with oil cooling arrangements welding generator and
transformers for normal welding sub-merged arc welding machine etc Facilities
for surface grinding pipe bending and threading are provided
MAJOR JOBS OF CMS
Repairing and reconditioning of TK stands of continuous casting
machine
Manufacturing and repairing of different types of gears and
couplings
Reconditioning of single roll crusher rotor assembly and spiral
classifier assembly
Repair of machining of cooling plates carbon blocks
Fitting amp assembly
section
Central Machine Shop
Machining Maintenance
Assembly amp repair
work
Reclamation
work
Machining Gear cutting
Heat
treatment
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 7
EQUIPMENT IN CMS
Plano milling machine
Heavy lathes
Horizontal boring machine
Vertical turret boring machine
Grinding machine
Slotting machine
Milling machine
Planning machine
Drilling machine
Gear hobbing machine
Gear shaper
Bevel gear generator
Balancing machine
Shot blasting machine
Submerged arc welding
Induction gear hardening machine
HEAVY LATHE
The HEC LC 100 LC 125 type center lathes are heavy duty lathe machines
using in CMS These are fully satisfying the claims modern technology Their rigid
structure permits roughing and also precision finishing work It uses cemented
carbide tipped tools and high speed steel tools
Working range specifications LC100 LC125
Swing over bed mm 1000 1250
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 8
Swing over carriage mm 710 900
Height of bed above carriage mm 500 630
Distance between centers mm 3000 12000
Max Torque kgm 2500 3150
Max Weight kg 10000 14000
Spindle speeds in 36 steps
First range rpm 18-90 14-71
second range rpm 8-400 63-315
Dia of taper in spindle mm 80110
Main motor speed rpm 1460 kW 40
Longitudinal feeds in 36 steps
First range mmrev 0125 to 6
Second range mmrev 1 to 48
Movement of
Cross slide mm 530 650
Compound rest mm 360
Tool post mm 110
Max Cross section of tool for 4way
Tool post mm 50times50
Long Rapid transverse mmmin 3600
Motor for Long Rapid transverse rpm 1400 kW 11
Dia of sleeve of tail stock mm 170
Dia of taper in sleeve mm 80110
Rate of travel tail stock mmmin 2150
Offsetting of tail stock mm +-10
Motor of tailstock rpm 1400 kW 005
Pitch of lead screw inch frac12 Motor for lubricating oil pump kW 018
The main parts of a lathe are
1) Bed
2) Head stock
3) Tail stock
4) Carriage
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 9
BED It forms the base of the machine On the bed racks for carriage tail stock head
stock and bearings for feed rod and lead screw are fixed
The bed is provided with 3 transverse holes for lifting It also act as reservoir for
lubricating oil
HEADSTOCK It is on the left side of the lathe bed It contains the lathe spindle and
spindle driving mechanism The spindle is hollow throughout its length to allow bar
stock to pass through It is located and runs in precision anti friction bearings in head
stock housing The spur gear attached to the left end of the spindle drives the trains
gear to provide motion and direction to the feed rod quick change gear box and
thread cutting mechanism This lathe is driven by constant speed motor Change of
spindle speeds are obtained by a series of gear combinations by shifting two or three
levers in different positions The main motor is housed in head stock
CLUTCH and BRAKE The brake serves to reduce the costing of machine to the
maximum It applies automatically as soon as the main motor is switched off and is
released again when the main motor is started The clutch id of centrifugal type
which permits a soft starting and the full torque is gradually built up starting load
being less starting current of motor is less
CARRIAGE It controls the movement of cutting tool either parallel or
perpendicular to lathe axis It moves on the guide ways of the bed It again consists
of
saddle
compound rest
tool post
Saddle is mounted on the guide ways carriage and supports the cross slide
Compound rest is mounted on the guide ways of the saddle and supports the tool
post The base of the compound rest can be swiveled to any angle between 0-360o
and mainly used during taper turning operation
Tool post its main purpose is to hold the tool during operation There are two types
of tool posts
standard tool post
four way tool post
The LC100125 lathes use the four way tool posts
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 6
treatment furnace with protective gas atmospheres high frequency hardening
machine quenching tanks with oil cooling arrangements welding generator and
transformers for normal welding sub-merged arc welding machine etc Facilities
for surface grinding pipe bending and threading are provided
MAJOR JOBS OF CMS
Repairing and reconditioning of TK stands of continuous casting
machine
Manufacturing and repairing of different types of gears and
couplings
Reconditioning of single roll crusher rotor assembly and spiral
classifier assembly
Repair of machining of cooling plates carbon blocks
Fitting amp assembly
section
Central Machine Shop
Machining Maintenance
Assembly amp repair
work
Reclamation
work
Machining Gear cutting
Heat
treatment
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 7
EQUIPMENT IN CMS
Plano milling machine
Heavy lathes
Horizontal boring machine
Vertical turret boring machine
Grinding machine
Slotting machine
Milling machine
Planning machine
Drilling machine
Gear hobbing machine
Gear shaper
Bevel gear generator
Balancing machine
Shot blasting machine
Submerged arc welding
Induction gear hardening machine
HEAVY LATHE
The HEC LC 100 LC 125 type center lathes are heavy duty lathe machines
using in CMS These are fully satisfying the claims modern technology Their rigid
structure permits roughing and also precision finishing work It uses cemented
carbide tipped tools and high speed steel tools
Working range specifications LC100 LC125
Swing over bed mm 1000 1250
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 8
Swing over carriage mm 710 900
Height of bed above carriage mm 500 630
Distance between centers mm 3000 12000
Max Torque kgm 2500 3150
Max Weight kg 10000 14000
Spindle speeds in 36 steps
First range rpm 18-90 14-71
second range rpm 8-400 63-315
Dia of taper in spindle mm 80110
Main motor speed rpm 1460 kW 40
Longitudinal feeds in 36 steps
First range mmrev 0125 to 6
Second range mmrev 1 to 48
Movement of
Cross slide mm 530 650
Compound rest mm 360
Tool post mm 110
Max Cross section of tool for 4way
Tool post mm 50times50
Long Rapid transverse mmmin 3600
Motor for Long Rapid transverse rpm 1400 kW 11
Dia of sleeve of tail stock mm 170
Dia of taper in sleeve mm 80110
Rate of travel tail stock mmmin 2150
Offsetting of tail stock mm +-10
Motor of tailstock rpm 1400 kW 005
Pitch of lead screw inch frac12 Motor for lubricating oil pump kW 018
The main parts of a lathe are
1) Bed
2) Head stock
3) Tail stock
4) Carriage
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 9
BED It forms the base of the machine On the bed racks for carriage tail stock head
stock and bearings for feed rod and lead screw are fixed
The bed is provided with 3 transverse holes for lifting It also act as reservoir for
lubricating oil
HEADSTOCK It is on the left side of the lathe bed It contains the lathe spindle and
spindle driving mechanism The spindle is hollow throughout its length to allow bar
stock to pass through It is located and runs in precision anti friction bearings in head
stock housing The spur gear attached to the left end of the spindle drives the trains
gear to provide motion and direction to the feed rod quick change gear box and
thread cutting mechanism This lathe is driven by constant speed motor Change of
spindle speeds are obtained by a series of gear combinations by shifting two or three
levers in different positions The main motor is housed in head stock
CLUTCH and BRAKE The brake serves to reduce the costing of machine to the
maximum It applies automatically as soon as the main motor is switched off and is
released again when the main motor is started The clutch id of centrifugal type
which permits a soft starting and the full torque is gradually built up starting load
being less starting current of motor is less
CARRIAGE It controls the movement of cutting tool either parallel or
perpendicular to lathe axis It moves on the guide ways of the bed It again consists
of
saddle
compound rest
tool post
Saddle is mounted on the guide ways carriage and supports the cross slide
Compound rest is mounted on the guide ways of the saddle and supports the tool
post The base of the compound rest can be swiveled to any angle between 0-360o
and mainly used during taper turning operation
Tool post its main purpose is to hold the tool during operation There are two types
of tool posts
standard tool post
four way tool post
The LC100125 lathes use the four way tool posts
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 7
EQUIPMENT IN CMS
Plano milling machine
Heavy lathes
Horizontal boring machine
Vertical turret boring machine
Grinding machine
Slotting machine
Milling machine
Planning machine
Drilling machine
Gear hobbing machine
Gear shaper
Bevel gear generator
Balancing machine
Shot blasting machine
Submerged arc welding
Induction gear hardening machine
HEAVY LATHE
The HEC LC 100 LC 125 type center lathes are heavy duty lathe machines
using in CMS These are fully satisfying the claims modern technology Their rigid
structure permits roughing and also precision finishing work It uses cemented
carbide tipped tools and high speed steel tools
Working range specifications LC100 LC125
Swing over bed mm 1000 1250
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 8
Swing over carriage mm 710 900
Height of bed above carriage mm 500 630
Distance between centers mm 3000 12000
Max Torque kgm 2500 3150
Max Weight kg 10000 14000
Spindle speeds in 36 steps
First range rpm 18-90 14-71
second range rpm 8-400 63-315
Dia of taper in spindle mm 80110
Main motor speed rpm 1460 kW 40
Longitudinal feeds in 36 steps
First range mmrev 0125 to 6
Second range mmrev 1 to 48
Movement of
Cross slide mm 530 650
Compound rest mm 360
Tool post mm 110
Max Cross section of tool for 4way
Tool post mm 50times50
Long Rapid transverse mmmin 3600
Motor for Long Rapid transverse rpm 1400 kW 11
Dia of sleeve of tail stock mm 170
Dia of taper in sleeve mm 80110
Rate of travel tail stock mmmin 2150
Offsetting of tail stock mm +-10
Motor of tailstock rpm 1400 kW 005
Pitch of lead screw inch frac12 Motor for lubricating oil pump kW 018
The main parts of a lathe are
1) Bed
2) Head stock
3) Tail stock
4) Carriage
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 9
BED It forms the base of the machine On the bed racks for carriage tail stock head
stock and bearings for feed rod and lead screw are fixed
The bed is provided with 3 transverse holes for lifting It also act as reservoir for
lubricating oil
HEADSTOCK It is on the left side of the lathe bed It contains the lathe spindle and
spindle driving mechanism The spindle is hollow throughout its length to allow bar
stock to pass through It is located and runs in precision anti friction bearings in head
stock housing The spur gear attached to the left end of the spindle drives the trains
gear to provide motion and direction to the feed rod quick change gear box and
thread cutting mechanism This lathe is driven by constant speed motor Change of
spindle speeds are obtained by a series of gear combinations by shifting two or three
levers in different positions The main motor is housed in head stock
CLUTCH and BRAKE The brake serves to reduce the costing of machine to the
maximum It applies automatically as soon as the main motor is switched off and is
released again when the main motor is started The clutch id of centrifugal type
which permits a soft starting and the full torque is gradually built up starting load
being less starting current of motor is less
CARRIAGE It controls the movement of cutting tool either parallel or
perpendicular to lathe axis It moves on the guide ways of the bed It again consists
of
saddle
compound rest
tool post
Saddle is mounted on the guide ways carriage and supports the cross slide
Compound rest is mounted on the guide ways of the saddle and supports the tool
post The base of the compound rest can be swiveled to any angle between 0-360o
and mainly used during taper turning operation
Tool post its main purpose is to hold the tool during operation There are two types
of tool posts
standard tool post
four way tool post
The LC100125 lathes use the four way tool posts
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 8
Swing over carriage mm 710 900
Height of bed above carriage mm 500 630
Distance between centers mm 3000 12000
Max Torque kgm 2500 3150
Max Weight kg 10000 14000
Spindle speeds in 36 steps
First range rpm 18-90 14-71
second range rpm 8-400 63-315
Dia of taper in spindle mm 80110
Main motor speed rpm 1460 kW 40
Longitudinal feeds in 36 steps
First range mmrev 0125 to 6
Second range mmrev 1 to 48
Movement of
Cross slide mm 530 650
Compound rest mm 360
Tool post mm 110
Max Cross section of tool for 4way
Tool post mm 50times50
Long Rapid transverse mmmin 3600
Motor for Long Rapid transverse rpm 1400 kW 11
Dia of sleeve of tail stock mm 170
Dia of taper in sleeve mm 80110
Rate of travel tail stock mmmin 2150
Offsetting of tail stock mm +-10
Motor of tailstock rpm 1400 kW 005
Pitch of lead screw inch frac12 Motor for lubricating oil pump kW 018
The main parts of a lathe are
1) Bed
2) Head stock
3) Tail stock
4) Carriage
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 9
BED It forms the base of the machine On the bed racks for carriage tail stock head
stock and bearings for feed rod and lead screw are fixed
The bed is provided with 3 transverse holes for lifting It also act as reservoir for
lubricating oil
HEADSTOCK It is on the left side of the lathe bed It contains the lathe spindle and
spindle driving mechanism The spindle is hollow throughout its length to allow bar
stock to pass through It is located and runs in precision anti friction bearings in head
stock housing The spur gear attached to the left end of the spindle drives the trains
gear to provide motion and direction to the feed rod quick change gear box and
thread cutting mechanism This lathe is driven by constant speed motor Change of
spindle speeds are obtained by a series of gear combinations by shifting two or three
levers in different positions The main motor is housed in head stock
CLUTCH and BRAKE The brake serves to reduce the costing of machine to the
maximum It applies automatically as soon as the main motor is switched off and is
released again when the main motor is started The clutch id of centrifugal type
which permits a soft starting and the full torque is gradually built up starting load
being less starting current of motor is less
CARRIAGE It controls the movement of cutting tool either parallel or
perpendicular to lathe axis It moves on the guide ways of the bed It again consists
of
saddle
compound rest
tool post
Saddle is mounted on the guide ways carriage and supports the cross slide
Compound rest is mounted on the guide ways of the saddle and supports the tool
post The base of the compound rest can be swiveled to any angle between 0-360o
and mainly used during taper turning operation
Tool post its main purpose is to hold the tool during operation There are two types
of tool posts
standard tool post
four way tool post
The LC100125 lathes use the four way tool posts
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 9
BED It forms the base of the machine On the bed racks for carriage tail stock head
stock and bearings for feed rod and lead screw are fixed
The bed is provided with 3 transverse holes for lifting It also act as reservoir for
lubricating oil
HEADSTOCK It is on the left side of the lathe bed It contains the lathe spindle and
spindle driving mechanism The spindle is hollow throughout its length to allow bar
stock to pass through It is located and runs in precision anti friction bearings in head
stock housing The spur gear attached to the left end of the spindle drives the trains
gear to provide motion and direction to the feed rod quick change gear box and
thread cutting mechanism This lathe is driven by constant speed motor Change of
spindle speeds are obtained by a series of gear combinations by shifting two or three
levers in different positions The main motor is housed in head stock
CLUTCH and BRAKE The brake serves to reduce the costing of machine to the
maximum It applies automatically as soon as the main motor is switched off and is
released again when the main motor is started The clutch id of centrifugal type
which permits a soft starting and the full torque is gradually built up starting load
being less starting current of motor is less
CARRIAGE It controls the movement of cutting tool either parallel or
perpendicular to lathe axis It moves on the guide ways of the bed It again consists
of
saddle
compound rest
tool post
Saddle is mounted on the guide ways carriage and supports the cross slide
Compound rest is mounted on the guide ways of the saddle and supports the tool
post The base of the compound rest can be swiveled to any angle between 0-360o
and mainly used during taper turning operation
Tool post its main purpose is to hold the tool during operation There are two types
of tool posts
standard tool post
four way tool post
The LC100125 lathes use the four way tool posts
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 10
TAILSTOCK or loose head stock is located on right side of the bed It is used to
support work piece during rotation and to hold drill or reamer during drilling and
other operations It is provided with set over screw at its base for taper turning
alignment It has a cast iron body with bore to accommodate tail stock spindle and
top portion contains the feed screw hand wheel a spindle lock clamp It slides on
the guide ways of the bed and positioned according to the length of the work In case
of heavy lathes a special motor is provided to move the tailstock on the bed
Hydraulics
The head stock of the lathe houses two hydraulic clutches in the drive system
and one hydraulic brake The clutches and brake operate at pressure of 10kgcm2
The hydraulic system consists of an oil tank fixed to front leg of the machine a
suction strainer the gear pump driven by main motor a relief valve a pressure filter
and a rotary valve
In VSP central machine shop the lathes up to 17m length are belt driven and
lathes of bed length 3m 5m are all geared headstocks
Headstock of NH-22 lathe is designed to give spindle 16 forward speeds or 8 forward
and 8 reverse speeds
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 11
HORIZONTAL BORING MACHINE
The table type of horizontal boring and milling machine has a wide range of
machining possibilities
The details of machine used in VSP CMS
Type BH 100
Version standardspecial
Overall length mm 6000
Overall width mm 2650
Overall height mm 3050
Total weight kg 13550
Supply voltage 4157 A 50 Hz 3Ph AC
The main assemblies of machine are
HEAD STOCK It houses the spindles and main drive The main and hollow
spindles are mounted in the radial two row roller bearings with a tapered hole and
inn the one row ball nearing The thrust bearings take up axial loads
The working spindle has the same revolutions as hollow spindle and is slide
able It is mounted in the bush and in taper bush This is slit alongside The torsion
movement is transferred from hollow spindle to working spindle by wedges The
feed of work spindle is delivered from thread shaft on the axis by means of feeding
nut over the plug to extension bearing of the lib
Die of spindle mm 100
Taper in spindle mm 6
Max boring dia mm 560
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 12
Max boring depth mm 900
FACE PLATE The face plate is solid with main spindle the tool slide sliding nut
in a prismatic guide It is possible to take up the lateral clearance by a correct
setting of the adjusting screws When turning then the position of adjusting wedges
change in relation to prismatic guide in faces plate Thus the lateral clearance of
the tool slide increases or decreases
Dia of face plate mm 600
Centering dia mm 280
Depth of Centering dia mm 8
Max Distance between face plate and back rest mm 2800
COLUMN The cast iron column has a narrow guide on the right side when
viewing from front The position of column in relation to the bed is secured by
taper pins The space inside the stand serves for the counter weight hangs on a
chain leading over the pulleys on the top of the column
BED The sliding surfaces of beds are to be regularly lubricated inspected and
looked after the bed ways The bed must not be used for putting away tools etc
SLIDE and TABLE A lever engages different automatic feeds in the group ldquoslide
and tablerdquo
Clamping the work piece
Work pieces are clamped on the turn table with clamping T-slots The
medium slot intersects the rotation axis The centering dia for fixture centering is
turned on the clamping surface in the rotation axis It is possible to fix
simultaneously by the holder of cooling system with feed piping to this table
The table may be loaded with a work piece of the max weight of 4000kg on
condition of uniform distribution
Clamping surface mm 1250times1250
Centering dia mm 180
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 13
Depth of Centering dia mm 6
Long Travel of table mm 1250 to 1750
Cross travel mm 1250
BACK REST the back rest is provided with an independent asynchronous electric
motor for the vertical adjustment of bearing The direction sense corresponds to the
position of the changeover switch The longitudinal movement of back rest is done
only by hand For this a crank put on the shaft is rotated The back rest is locked at
a particular position by tightening of screws
The working principle of machine consists of a coordinate travel of the
individual working groups vertical feed of head stock longitudinal feed of the slide
and cross feed of table
VERTICAL TURRET BORING MACHINE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 14
It is a special vertical type of lathe machine This is used for a large dia and small
depth jobs
CONSTRUCTION
Vertical turret lathe has a single turret head and a side on right hand upright
This turret head can be moved rightward and leftward on a cross slide ways The
cross slide can be raised and lowered on uprights by lever to accommodate
various depths of work by pulleys and suitable elevating screws In this machine
work is placed on a vertically mounted face plate and held in chuck The job must
be carefully balanced and run at a slow speed owing to vibration caused by the
wear in spindle bearings whereas with work mounted on vertical spindle all the
weight is evenly distributed downward on bearing s so that smooth running
results and heavy cutting is possible The main drive is by the electric motor to a
gear box giving 18 speeds operated by levers and then to a large ring gear fastened
to the table Feeds are available in all directions
OPERATION
The job is rotated on table and the turret head is lowered and set to the top of
the job and downward feed of turret is engaged Depth of cut is given by
rightward feed or leftward movement of tool head If outside of the job is doing
it is turning if inside of job it is boring if it is top of job it is facing the maximum
dia of job is 25m to 3m A pilot bush is fixed in a central hole of table It has a
series of drilled holes in order to facilitate the escape of cuttings down the hollow
spindle to the floor
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 15
PLANO MILLING MACHINE
Plano milling machine is a milling machine but designed to execute certain work
formerly confined to the planer It is a multipurpose machine on which milling
planning drilling boring etc can be done It has a cross rail capable of being
raised or lowered carrying the cutters their heads and the saddles all supported
by stout uprights There may be multiple cutter heads on the rail as well as two
heads on the uprights Each cutter head in the Plano-miller is separately driven
The drive of the bed is through hydraulic system
The length of the bed is 8 m and the width of bed is 2 m so that 16 m length
jobs can be done easily This machine is safe on mechanical side using German
technology The electrical power to machine is immediately cut off when over
load or any other interruption like lack of lubricating oil etc is occurred
Therefore the mechanical breakdown doesnrsquot occur and this machine is running
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 16
successfully from 20 years
HORIZONTAL MILLING MACHINE
In horizontal milling machines the cutter is mounted on horizontal arbor by
spacing collars and work is clamped on the table Horizontal milling machine is
generally used for cutting gears by using indexing and for cutting keyways
VERTICAL MILLING MACHINE
In vertical milling machine milling cutter is fixed to the vertical spindle and
work is clamped on the table It is generally employed for producing flat surfaces
Because of its multi-point cutter milling machine is mostly preferred than shaper in
producing flat surfaces
Coolant systems
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 17
Correct cooling and lubrication of cutting tool faces is important Coolant
should have following properties
good cooling effect
good lubrication effect
protection against rust or other chemical influences
Depending upon the requirement of the specific milling operations coolants
may be used
Supply
The milling machine is provided with a coolant pump for the supply of
coolant The sump for the coolant of approximately 35 liters is arranged in the base
of the machine The coolant pump runs as long as spindle runs and is automatically
switched off when spindle stops A separate switch is provided to switch off coolant
independently to the spindle when not required
SHAPER
SHAPER is used for machining flat surfaces Machining on shaper is more
economical with better work setting and cheaper tooling In shaper work is held
stationary on the table and tool reciprocates across the work The tool used on shaper
is of single point cutting tool thus the work on shaper is transferred to milling
machine which is a multi-point cutting tool In shaper material is removed during
forward stroke and return stroke is an idle stroke The quick return mechanism is
employed in shaper to minimize the working time
SLOTTER
SLOTTING machine is used for cutting keyways grooves etc It consists of
ram reciprocates vertically and tool is fed to the work piece on the rotating table In
slotting machine material is removed only during forward stroke amp return is idle
stroke In slotter single point cutting tool is used for the operation Slotter is mainly
used for internal turning
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 18
GEAR HOBBING MACHINE
It is used for machining gears from gear blank In this machine cutting is
carried out by a tool called hob The work is fixed on rotary table and the hob is
rotated by means of an electric motor and work is fed across the hob
Operation
Set the fixture and clamps in the T-slots provided on table Clamp the work
on the table and check the trueness using dial indicator Select the type of hob on the
arbor with a lock nut Set the required helix angle on the hob Start the machine to
cut the teeth on the gear blank
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 19
BALANCING MACHINE
A balancing machine is a measuring tool used for balancing rotating machine
parts such as rotors for electric motors fans turbines disc brakes disc drives
propellers and pumps The machine usually consists of two rigid pedestals with
suspension and bearings on top As the part is rotated the vibration in the
suspension is detected with sensors and that information is used to determine the
amount of unbalance in the part Along with phase information the machine can
determine how much and where to add weights to balance the part
HARD-BEARING VS SOFT-BEARING
There are two main types of balancing machines hard-bearing and soft-bearing
The difference between them however is in the suspension and not the bearings
Hard- and soft-bearing machines can be automated to remove weight automatically
such as by drilling or milling but hard-bearing machines are more robust and
reliable Both machine principles can be integrated into a production line and loaded
by a robot arm or gantry requiring very little human control
Working of machine
With the rotating part resting on the bearings a vibration sensor is attached to the
suspension In most soft-bearing machines a velocity sensor is used This sensor
works by moving a magnet in relation to a fixed coil that generates voltage
proportional to the velocity of the vibration Accelerometers which measure
acceleration of the vibration can also be used
A photocell (sometimes called a phase) proximity sensor or encoder is used to
determine the rotational speed as well as the relative phase of the rotating part This
phase information is then used to filter the vibration information to determine the
amount of movement or force in one rotation of the part Also the time difference
between the phase and the vibration peak gives the angle at which the unbalance
exists Amount of unbalance and angle of unbalance give an unbalance vector
Calibration is performed by adding a known weight at a known angle In a soft-
bearing machine trial weights must be added in correction planes for each part This
is because the location of the correction planes along the rotational axis is unknown
and therefore it is unknown how much a given amount of weight will affect the
balance By using trial weights you are adding a known weight at a known angle
and getting the unbalance vector caused by it This vector is then compared to the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 20
original unbalance vector to find the resultant vector which gives the weight and
angles needed to bring the part into balance In a hard-bearing machine the location
of the correction plane must be given in advance so that the machine always knows
how much a given amount of weight will affect the balance
SUBMERGED ARC WELDING MACHINE
Submerged arc welding machine
Submerged arc welding (SAW) is a common arc welding process originally
devolved by the Linde - Union Carbide Company
It requires a continuously fed consumable solid or tubular (flux cored) electrode
The molten weld and the arc zone are protected from atmospheric contamination
by being ldquosubmergedrdquo under a blanket of granular fusible flux consisting of lime
silica manganese oxide calcium fluoride and other compounds When molten the
flux becomes conductive and provides a current path between the electrode and
the work This thick layer of flux completely covers the molten metal thus
preventing spatter and sparks as well as suppressing the intense ultraviolet
radiation and fumes that are a part of the SMAW (shielded metal arc welding)
process
SAW is normally operated in the automatic or mechanized mode however semi-
automatic (hand-held) SAW guns with pressurized or gravity flux feed delivery are
available The process is normally limited to the Flat or Horizontal-Fillet welding
positions (although Horizontal Groove position welds have been done with a
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 21
special arrangement to support the flux) Deposition rates approaching 100 lb h
(45 kgh) have been reported mdash this compares to ~10 lb h (5 kgh) (max) for
shielded metal arc welding Although Currents ranging from 300 to 2000 an are
commonly utilized [1] currents of up to 5000 A have also been used (multiple arcs)
Single or multiple (2 to 5) electrode wire variations of the process exist SAW
strip-cladding utilizes a flat strip electrode (eg 60 mm wide x 05 mm thick) DC
or AC power can be used and combinations of DC and AC are common on
multiple electrode systems Constant Voltage welding power supplies are most
commonly used however Constant Current systems in combination with a voltage
sensing wire-feeder are available
Electrode
SAW filler material usually is a standard wire as well as other special forms This
wire normally has a thickness of 116 in to 14 in (16 mm to 6 mm) In certain
circumstances twisted wire can be used to give the arc an oscillating movement
This helps fuse the toe of the weld to the base metal
SHOT BLASTING MACHINE
The major operations of a blast machine are as follows
Cleaning of metals
Sand from the primary foundry process rust paint and powder epoxy or other
coatings may be removed from metals through the process of blast cleaning
Normally the metal is being prepared for another coating process so it is
important to remove all matter that would sacrifice the quality of the surface and
cause a poor finish
Descaling mill products
Mill scale produced in the primary process of manufacturing metals is removed by
blast machines Plate sheet strip wire bars billets and other products can be
descaled
Peening metals
In the peening process a stream of metal particles is applied at a high velocity via
a Rot oblast wheel against the surface of a metal part The contact alters the surface
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 22
of the part and creates a rounded depression where the edges of the depression will
rise slightly above the original surface Aircraft components gears springs and
other critical parts undergo peening operations
BLAST MACHINE OPERATION IN 10 STEPS
Most wheel blast machine systems operate as follows
1 Steel abrasive is conveyed into a hopper which is located in a position that is
toward the middle of the system but higher than the Rot oblast Wheels
2 An abrasive gate located above the wheel controls the abrasive through a feed
spout toward the Rotoblast wheel
3 In the Rotoblast wheel is an impeller that rotates The feed spout directs the
abrasive toward the rotating impeller and the impeller directs the abrasive to an
opening in an impeller case
4 The impeller case then directs the abrasive towards the vanes The vanes are
connected to a runner head which is being driven by an electric motor system
Direct drive motors rotate the runner head at 1800 or 3600 RPM For bearing and
spindle drives the speeds can vary from 2100 to 3200 RPM
5 With the vanes rotating at a high speed by the runner head and the abrasive
being fed onto the vanes centrifugal force hurls the abrasive at high speeds toward
the work to be cleaned
6 The steel on steel contact cleans peens descales or performs other functions
designed into the system
7 After contacting the work the spent abrasive falls into a recovery hopper along
with other non-abrasive materials (sand scale etc) which has been removed from
the work The recovery hopper is located below the work that is being cleaned
8 The recovery hopper has a screw conveyor or oscillating conveyor that conveys
the material toward an elevator belt The elevator belt driven by another electric
motor is equipped with buckets that carry the material to the very top of the
system
9 At the top of the system is a scalping drum or another screw conveyor that
initiates a process where good abrasive is separated from foreign matter The
scalping drum detects larger contaminants compared to the size of the abrasive It
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 23
directs the larger contaminants toward a scrap drum on the floor and sends the
balance of the abrasive toward a separator which detects abrasive that may be worn
due to use
10 The separator discharges the good abrasive into a storage bin and recycles to
the Rotoblastreg wheels The spent and broken abrasive is discharged out of the
system and into a refuse container
HEAT TREATMENT SECTION
It is a post machining operation and is carried out for changing the
structure and properties of metals and alloys by controlled heating and cooling
It is performed to relieve internal stresses refine grain size etc the heat treatment
section in VSP machine shop consists of
3 heating furnaces
Oil bath
Water bath
Induction hardening furnace
Carburizing furnace
Nit riding furnace
INDUCTION HARDENING FURNACE
Induction hardening is a form of heat treatment in which a metal part is heated by
induction heating and then quenched The quenched metal undergoes a martensitic
transformation increasing the hardness and brittleness of the part Induction
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 24
hardening is used to selectively harden areas of a part or assembly without
affecting the properties of the part as a whole
Process
Induction heating is a non-contact heating process which utilizes the principle of
electromagnetic induction to produce heat inside the surface layer of a work-piece
By placing a conductive material into a strong alternating magnetic field electrical
current can be made to flow in the steel thereby creating heat due to the I2R losses
in the material In magnetic materials further heat is generated below the Curie point
due to hysteresis losses The current generated flows predominantly in the surface
layer the depth of this layer being dictated by the frequency of the alternating field
the surface power density the permeability of the material the heat time and the
diameter of the bar or material thickness By quenching this heated layer in water
oil or a polymer based quench the surface layer is altered to form a martensitic
structure which is harder than the base metal
Principal methods
Single shot hardening
In single shot systems the component is held statically or rotated in the coil and the
whole area to be treated is heated simultaneously for a pre-set time followed by
either a flood quench or a drop quench system Single shot is often used in cases
where no other method will achieve the desired result for example for flat face
hardening of hammers edge hardening complex shaped tools or the production of
small gears
Traverse hardening
In traverse hardening systems the work piece is passed through the induction coil
progressively and a following quench spray or ring is utilized Traverse hardening
is used extensively in the production of shaft type components such as axle shafts
excavator bucket pins steering components power tool shafts and drive shafts
The component is fed through a ring type inductor which normally features a
single turn The width of the turn is dictated by the traverse speed the available
power and frequency of the generator This creates a moving band of heat which
when quenched creates the hardened surface layer The quench ring can be either
integral a following arrangement or a combination of both subject to the
requirements of the application By varying speed power etc it is possible to create
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 25
a shaft which is hardened along its whole length or just in specific areas and also to
harden shafts with steps in diameter or spines It is normal when hardening round
shafts to rotate the part during the process to ensure any variations due to
concentricity of the coil and the component are removed
Equipment
Power required
Power supplies for induction hardening vary in power from a few kilowatts to
hundreds of kilowatts dependent of the size of the component to be heated and the
production method employed ie single shot hardening traverse hardening or
submerged hardening
Frequency
Induction heating systems for hardening are available in a variety of different
operating frequencies typically from 1 kHz to 400 kHz Higher and lower
frequencies are available but typically these will be used for specialist applications
The relationship between operating frequency and current penetration depth and
therefore hardness depth is inversely proportional
CARBURISING FURNACE
It is used for case hardening of products are done In this process the heating
is carried out up to 600oC for 4 hours at 150oChr and then holding for half an hour
at 600oCtaken place again heating takes place at the rate of 61oChr to 875oC Thus
the heating cycle is completed and cooling is done by quenching them in the water
bath
The main components which are heat treated in this section are Bull head hammers
of flux crushing plant in the sinter plant gear blanks etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 26
Horizontal Boring Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 27
Radial Drilling Machines-
Universal Drilling Machines
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 28
Milling Machines-
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 29
FORGING SHOP
In forging shop the parts and objects which are needed high strength and hardness
that required to VSP
Forging is one of the oldest hot metal working processes It is defined as the
shaping of a heated metal by hammering and pressing In this process metals are
made plastic by heating them and deformed by hammering while they are hot The
components made b this are called forgings The process is carried out at
recrystallization temperature of metals
INPUTS Ingots from foundry blooms from SMS billets rods from mills etc
PRODUCTION AND SERVICES Raw material for shafts coupling gears pinions Flanges bull head hammers for plant hammer crusher drill rods for blast Furnace v-hooks for SMS straightening of pallet frames of sinter plant The shop is designed for production of shafts coupling - flanges Etc and also of forged shapes such as crusher hammer heads special bolts nuts Etc The repair and testing of chains are also carried out The annual production from the shop is about 2400 tons based On 300 working days per year and two Shifts per day These inputs consisting of ingots billets blooms and flats of various sizes In heavy forging section open die forging of long shafts gear blanks couplings etcis made with the help of 2-ton bridge type pneumatic hammers Each hammer will be provided with thin chamber heating furnaces Floor type manipulator and jib Crane are provided for handling heavy jobs In general forging section 1 ton 500 Kg and 200 Kg hammers with separate heating furnaces are provided A 2 ton drop stamp hammer with a heating furnace trimming press etc is provided for stamping For cutting them to size a cold saw a billet shear and gas cutting facilities are provided For stress relieving bogie type-annealing furnace is provided
HEAVY FORGING BAY
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 30
In this bay the jobs which needed a large deformation and the large jobs
which required high forces to deform are done
General heavy forge jobs
Squares to rounds (shafts)
Round to hexagon
Gear blanks
Stepped shafts(bottom roll shafts)
Bull head hammers etc
Raw materials
Blooms (rectangle) rarr 240 320 mm
Squares rarr 240240 mm
Ingots rarr larger dia 350mm smaller dia 240 mm
Equipment in this bay
Heating furnaces ndash 4
Bogie furnace for heat treatment
2 ton amp 3 ton pneumatic hammers
Manipulators ndash 2 1 T amp 2 T capacity
LIGHT FORGING BAY
In this bay the jobs which need light deformation and smaller in size are done
General light forging jobs
Mud guns (4000 3500 2500 mm length)
Tongs
Squares etc
Equipment
Pneumatic hammers ndash 16 T
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 31
500kg hammers ndash 2norsquos
250kg hammers ndash 1 no
Open hearth furnace ndash 1
Drop stamp hammer
Trimming press
TOOL ROOM
It is provided to cut the shafts billets making holes etc
Equipment
Circular saw
Power hacksaw
Band saw
Drilling machine
Shaping machine
Grinding machine
Billet shearing machine
TYPES OF FORGING
There are many different kinds of forging processes available however they can be
grouped into three main classes
Drawn out length increases cross-section decreases
Upset Length decreases cross-section increases
Squeezed in closed compression dies produces multidirectional flow
Common forging processes include roll forging swaging cogging open-die
forging impression-die forging press forging automatic hot forging and upsetting
OPEN-DIE DROP-HAMMER FORGING
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 32
In open-die forging a hammer comes down and deforms the work piece which is
placed on a stationary anvil The dies (the working surfaces of the forge that contact
the work piece) do not enclose the work piece allowing it to flow except where
contacted by the dies Therefore the operator needs to orient and position the work
piece to get the desired shape
IMPRESSION-DIE DROP-HAMMER FORGING
Impression-die forging is also called closed-die forging In impression-die work
metal is placed in a die resembling a mold which is attached to the anvil The
hammer die is shaped as well The hammer is then dropped on the work piece
causing the metal to flow and fill the die cavities
PRESS FORGING
Press forging is variation of drop-hammer forging
Press forges work slowly by applying continuous pressure or force The amount of
time the dies are in contact with the work piece is measured in seconds (as compared
to the milliseconds of drop-hammer forges) The press forging operation can be done
either cold or hot
UPSET FORGING
Upset forging increases the diameter of the work piece by compressing its length
Engine valves couplings bolts screws and other fasteners
ROLL FORGING
Roll forging is a process where round or flat bar stock is reduced in thickness and
increased in length
HEATING FURNACE
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 33
The furnace is equipment used to provide heat for a process Inn this type of
furnace a room type fixed hearth gas fired heating furnace is used
The pilot burner and main burner in two sets are at roof The coke oven gas is
supplied to burner and is burnt with the air provided from an air blower Different
valves are provided for air and gas controls
Operation of furnace
A starting procedure
2) Informing to gas control department indicating the starting of furnace
3) Observe the lsquowater over flowrsquo condition to ensure that lsquoUrsquo seal is full of water
or not
4) Ensure that there are no any defects in gas line fitting
5) Remove if any lsquoblanksrsquo in gas line
6) Keep the furnace door and damper open
7) Keep the main isolation switch of electrical panel in lsquoonrsquo position
8) Switch on the individual feeders
9) Start the blower after blower discharge valve close and then open the valve
ldquoUrdquo seal dewatering process
a Close the water inlet valve of u seal and open the drain
valve to escape water
b Close the over flow valve line and drain valve after
escaping of water
10) Open the gas valve and check the pressure whether it is 500-600 mm of
water column
11) Energize the solenoid and reset the annunciation
12) Set the required temperature in controller
B Lighting the burner
13) Keep the main burner air valve close while the pilot burner air valve is
partially opened
14) Lit the pilot burner by opening gas valve
15) Open the gas and air valves of main burner
16) Open pilot air valve completely while pilot gas valve is closed
17) Above same procedure is followed for second set of burners
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 34
18) Close the furnace door and check the flame is stable or not
When the furnace room temperature is 900 deg C the jobs are introduced The
forging temperature is up to 1200 deg C
C
19) Inform the gas control dept that furnace is fired off
20) Close the main airline valve and accept the annunciation
21) Close the main burner gas line valves
HEAVY FORGING HAMMER
It is a bridge type pneumatic hammer
Construction
The machine supports on two columns Two columns are joined with an arch which
forms a multi prismatic guide of mono block type cylinder at center A ram is slide
inside the cylinder and the top die is fitted to the ram The bottom die is placed on
an anvil located below top die A stuffing box which houses valve controls is placed
before entrance and exhaust of the cylinder The machine and anvil are installed with
strong and deep basement ie 25to 35 feet to make the machine robust to absorb high
shocks
Operation
The top die is the actual tool which performs the hammering action The die
is operated upwards and downwards in cylinder by air pressure The inlet and
exhaust valves are controlled by a lever which is connected to stuffing box When
upper inlet valve is opened the highly pressurized air is supplied into the top of the
piston from lsquoAir Separation Plant Utilities deptrsquo Then the ram moves downwards
and blows on the job which is placed on the bottom die The air below the ram is
exhausted through lower exhaust valve There is a top pressure buffer cap in cylinder
which inserts the ram safely by an aid cushion at the end of its upward stroke The
cylinder and ram is lubricated with oil for free and smooth movement
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 35
LIGHT FORGING HAMMER It is widely used for the manufacture of medium size forgings The ram is
directly connected to piston working in a steam or air cylinder The capacity of
column hammer is about 500kg
It operates with steam or compressed air As compared to pneumatic bridge
hammer column hammer does not possess built in compressor and therefore
requires additional arrangement for supplying high pressure steam or compressed
air
Pneumatic column hammer
DROP STAMP HAMMER
It is a closed die forging hammer Spanners nuts bolts etc are made by this
method The dies are made for these jobs they can produce at rapid rate
because as fast as the heated lumps of steel are taken out of furnace they can be
put into drop stamp pounded by it with dies to the required shape and then
removed to have the surplus metal cut off
Mechanism and operation of this hammer
This hammer is used the friction lift mechanism This consists of two multi
grooved friction drums fixed to the main shaft A one piece cast lifting arm is fitted
between these two drums and is mounted on anti-friction bearings are carried on
main shaft on the outside of each drum cast steel lifting levers are tied to the lifting
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 36
arm by the tie plate and a cam spindle is carried through arm and levers Frodo-lined
Vee brakes operated on the cam spindle by means of a control lever at one end of
the lifter and engage with the friction drum which is fixed to the revolving main
shaft Thus by a pull on the control lever the stationary lifting arm levers and brakes
are locked with drum and the lifting mechanism is put into the operation The
hammer head is connected to the lifting arm by means of a belt which is guided by
a loosen pulley bushed on to the lifting arm The main shaft carries a fixed winch
around which is a control rope is worked by an operator who by a slight pull can lift
the hammer and hold it at any position in guide rods The drive is by means of an
electric motor placed in a suitable position on the floor engaging by a belt to a heavy
fly wheel driving the main shaft through a single train to accuracy machine cut gears
The process includes providing a super abundance of power over the live
weight which it has to control by lifting mechanism such that the forger can obtain
that sharp elastic lsquosnappyrsquo blow when it is left over the job that immediately the
instantaneously merged together
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 37
MANIPULATORS-
Manipulators are used to hold the heated jobs while the forging operation is doing on heavy forging hammer It has two jaws which can be rotated around 360 deg When maximum flexibility in transport and handling capabilities during the forging process is important a Mobile Forging Manipulator is your first choice The compact design and maneuverability of manipulators from DANGO amp DIENENTHAL allow the transport of work pieces even when space is limited Whether small or very large handling capacities are needed DANGO amp DIENENTHAL offers both standard and customized solutions Our machines offer high reliability as well as great flexibility The sturdy and compact design is adapted to the special operating conditions Ergonomically aspects and hands-on experience are the decisive factors for selecting and arranging control levers switches and buttons Characteristics- Powerful tongs unit with large gripping range Multistage adjustment of closing force Spring systems acting both vertically and horizontally to absorb shock loads High maneuverability due to quick and flexible travelling behavior Semi-automatic working cycles at request Travel steering and tongs motions can be carried out at the same time excellent operators view in all directions air conditioned drivers cabin at requestpumpsdriven by electric motor or diesel engine Emergency functions
BOGIE FURNACE
A bogie furnace is used for heat treatment
of the forged jobs
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 38
BILLET SHEARING MACHINE
Description
The shear is mechanically driven and provided with a fixed blade and vertically
moving top blade The drive is by electric motor via v-belts and fly wheel By the
switch able friction clutch the continuously rotating fly wheel can be connected
with the toothed gear The blade slide with the top blade is driven by the gear via
crank shaft and connecting rod With the clutch disengaged the toothed gear is
connected with shear frame by a single disc brake The blade slide moves in the
re-adjustable guides in the machine frame
The machine frame consists of mainly two steel plates and the blade frame from
cast steel which accommodates the bottom blade and the down holders Top blade
and bottom blade are mounted in special blade accommodations from cast steel
which holds the contact surfaces between machine and blade no wear on frame amp
blade slide is ensured
The down holder is arranged in the front of the shear over the bottom blade The
down holder stroke is made by means of a wedge shaped sliding member which
driving motion is taken off by the eccentric shaft The down holder seats on the
cutting material prior to cutting and clamp during the total cutting operation The
height for adaptation to the cross section is adjusted by means of a spindle gear
The required cutting gap between top amp bottom blades can be achieved by the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 39
Specifications horizontal displacement of the bottom blade accommodations by
means of a wedge
Operation
The billets are placed in the cradle in bundles or separately up to 10
tons It is important that the cradle must be completely lowered to avoid damages in
case of hard placing
An orderly and quantitatively regulated transfer of billets is performed by
lifting the cradle until the first billets are moved into the horizontally moved chute
If the billets are disorderly moved on to the chute it can be lifted until the billets are
arranged amp ejector is adjusted
If the cradle is lowered completely the ejector takes the bottom billet and
ejects it Then the billet in chute moves up to the required length stop regulated
manually and clutch is engaged which cuts the billet into required length Then the
clutch is disengaged
The forged jobs are dispatched to the customers after heat treatment is done
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 40
STEEL STRUCTURAL SHOP
In sss the structural work and mainly fabrication work of steel is done The
repairs of huge parts are also done When used as industrial term fabrication
applies to the building of machine structures and other equipment by cutting
shaping and assembling components made from raw materials
Fabrication (steel structural) shop concentrated on the metal
preparation welding and assembling aspects
INPUTS Sheets of various sizes plates angles channels beams for fabrication
Of jobs PRODUCTION amp SERVICES All types of fabrication jobs repair of slag pots of SMS Mfg And repair of punishes for SMS Mfg Of scrap boxes for SMS for sinter Plant hot metal ladle for SMS 500 meters launder for SMS mfg of KAMAG Body for FMD Repairing of buckets for LMMM WRM The annual production of Fabricated structures are about 4500 tones and the input consisting of sheets Plates channels angles beams etc are about 5100 T For marking cutting to size forming and bending guillotine Shear circular saw plate bender gas cutting unit etc are provided for welding Transformer automatic and semi-automatic machines and submerged arc Welding machines are provided Painting is carried out partly with help of spray
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 41
Guns and partly by hand Wire brush spray guns etc are provided A maintenance Section equipped with lathe shaper drill etc are provided for running Repair of shop equipment
DETAILS OF SHOP
Capacity annual production is 4500 tones and material needed is 5100 tones
Activities and work root
Marking the material on stock
Cutting to prepare material for object
Assembling various parts or plates prepared for an object
Welding the assembled parts to join them
Inspection for the defects
Dispatching to customer after ensuring no defects
Welding techniques used in this shop are
Arc welding
Metal in earth gas welding
Thermite welding
Maintenance of stores
A store is maintained for the new materials spare parts and tools etc
Raw materials for sss
Channels
Sheets
Plates
Beams
Billets
Angles
The raw materials are stored in open bay of the shop
Major and regular jobs
Hot metal ladle (BF)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 42
Tundishes Slag pot (SMS)
Coke bucket (Coke ovens)
Cones (SP)
Ducts (CRMP)
Rakes (Mills)
Hooks (for cranes)
Equipment in sss
Shearing machine
Bending machine
Hydraulic press
Combination shearing machine
Radial drilling machine
CNC gas cutting machine
Tool room
This equipment is located in material preparation bay in shop
In material preparation bay the metal sheets and plates of required
dimensions are prepared by making and cutting on the various machines
Marking is done in required profile by developing the surfaces of final
shape of the object using micrometer steel rule compass etchellip tools
After marking material will be cut and shaped The operation of cutting
may be in the form of shearing bending punching pressing punching
notching etc
SHEARING MACHINE
Shearing (metalworking)
Shearing is a metalworking process which cuts stock without the formation of
chips or the use of burning or melting If the cutting blades are straight the
process is called shearing if the cutting blades are curved then they are
shearing-type operations The most commonly sheared materials are in the
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 43
form of sheet metal or plates however rods can also be sheared Shearing-
type operations include blanking piercing roll slitting and trimming
Principle and working
A punch (or moving blade) is used to push the work piece against the die (or
fixed blade) which is fixed Usually the clearance between the two is 5 to
10 of the thickness of the material but dependent on the material
Clearance is defined as the separation between the blades measured at the
point where the cutting action takes place and perpendicular to the direction
of blade movement It affects the finish of the cut (burr) and the machines
power consumption
This causes the material to experience highly localized shear stresses between
the punch and die
The fracture will begin at the weakest point and progress to the next weakest
point until the entire work piece has been sheared this causes the rough edge
The material will then fail when the punch has moved 15 to 60 the thickness
of the material because the shear stresses are greater than the shear strength
of the material and the remainder of the material is torn
The rough edge can be reduced if the work piece is clamped from the top with
a die cushion Above a certain pressure the fracture zone can be completely
eliminated However the sheared edge of the work piece will usually
experience work hardening and cracking Two distinct sections can be seen
on a sheared work piece the first part being plastic deformation and the
second being fractured
Straight shearing
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 44
Shearing machine Straight shearing is done on sheet metal coils and plates The machine used
is called a squaring shear power shear or guillotine
The machine may be foot powered (or less commonly hand powered) or
mechanically powered It works by first clamping the material with a ram
A moving blade then comes down across a fixed blade to shear the material
For larger shears the moving blade may be set on an angle or rocked in order
to shear the material progressively from one side to the other this angle is
referred to as the shear angle
This decreases the amount of force required but increases the stroke A 5
degree shear angle decreases the force by about 20 The amount of energy
used is still the same
The moving blade may also be inclined 05 to 25deg this angle is called the
rake angle to keep the material from becoming wedged between the blades
however it compromises the square ness of the edge[3] As far as equipment
is concerned the machine consists of a shear table work-holding device
upper and lower blades and a gauging device
The shear table is the part of the machinery that the work piece rests on while
being sheared The work-holding device is used to hold the work piece in
place and keep it from moving or buckling while under stress
The upper and lower blades are the piece of machinery that actually do the
cutting while the gauging device is used to ensure that the work piece is being
cut where it is supposed to be
The design of press tools is an engineering compromise A sharp edge
strength and durability are ideal however a sharp edge is not very strong or
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 45
durable so blades for metal work tend to be square-edged rather than knife-
edged
Typical work piece materials include aluminum brass bronze and mild steel
because of their outstanding shear ability ratings however stainless steel is
not used as much due to its tendencies to work-harden
There are also other types of Geometrical Possibilities besides straight
shearing though These include the Squaring Shear the Angle Shear the Bow-
Tie Shear and the Bar Shear All of these have many different uses and are all
used pretty regularly in certain manufacturing fields
Tool Materials
Low alloy steel is used in low production of materials that range up to 14 in
thick
High-carbon high chromium steel is used in high production of materials that
also range up to 14 in in thickness
Shock-resistant steel is used in materials that are equal to 14 in thick or more
COMBINATION SHEARING MACHINE
It is a multi-purpose machine It is completely mechanically operated Five
types of operations can be done simultaneously on the machine
These operations are
2) Punching it is a purpose of making a desired hole by using a punch and
die (Oslash 35 Oslash32 sq 28 32 )
3) Notching it is a process of cutting out the edges of the strip to obtain the
desired outer contour of the work piece (dimensions of blade
180times180times18)
4) Cropping cutting the square bars and round bars (Oslash63 sq55)
5) Shearing cutting stocks without formation of chips
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 46
The machine consists of individual units for each operation having punches
dies blades which are necessary for the above operations
The punching unit is located in the front of the machine Shearing and
cropping units in the rear side and notching unit is in the middle of the
machine At one side of the machine a fly wheel is located and connected to
motor to balance the machine and also drive all units This machine is used
crank lever mechanism to drive A gear train is mounted to fly wheel shaft
and all drives shafts When the lever of unit is engaged to this gear train that
unit is then starting working All the units of this machine can be operated
simultaneously thus it can be used for mass production
BENDING MACHINE
This is used to bend the plates or sheets in order to form into
cylindrical shape conical shape and other curved shapes as well as to
straighten the curved and abstracted plates or sheets and made them flat
Principle
The plates are fed between top roller and bottom rollers and pressure is
given from bottom to top of the plate and plate is fed to and fro so that it is
gradually bent into required shape
Construction and operation
Bending and straightening machine consists of five rollers one is
mounted at center of upper side of machine and four rollers are inserted in
radial slots at bottom can be lowered and raised radically A reversible
electric motor is connected to each bottom roller to drive them and the main
motor is connected to top roller
The plate is placed on the bottom rollers ensuring that the edges of the
plate and rollers are parallel When the machine is switched on the rollers start
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 47
rotating and slowly raised Then the plate starts bending about the top roller
At the same time the plate is fed to and fro by reversing the motor and bending
progresses to the final shape
For conical sections the plate is bent in different sections a parted equal
space
Bending has to overcome both tensile and compressive stresses When
bending is done the residual stresses make it spring back towards its original
position therefore it should be over bend
For straightening process first two alternate rollers are raised and then
the passed through remaining bottom rollers The raised rollers are lowered
against plate and then the plate is straightened
The capacity of the machine is 25 mm thick ness and 2 m width of the
plate
HYDRAULIC PRESS
It is used to pressing large castings The ram is moved by the pressure of the
fluid Oil is mostly used fluid for this press The pressure of oil is increased
by pump and is transmitted to the cylinder in order to lift the ram of or to force
the ram downwards The capacity of machine is 200 T
CNC GAS CUTTING MACHINE
CNC
In modern CNC systems end-to-end component design is highly automated
using CADCAM programs The programs produce a computer file that is
interpreted to extract the commands needed to operate a particular cutting
operation
The movement of the tool resulted in varying forces on the controls that would
mean a linear output would not result in linear motion of the tool The key
development in this area was the introduction of the servo which produced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 48
highly accurate measurement information Attaching two servos together
produced a selsyn where a remote servos motions was accurately matched
by another Using a variety of mechanical or electrical systems the output of
the selsyn could be read to ensure proper movement had occurred
MIT fit gears to the various hand wheel inputs and drove them with
roller chains connected to motors one for each of the machines three axes (X
Y and Z) The associated controller consisted of five refrigerator-sized
cabinets that together were almost as large as the mill they were connected
to Three of the cabinets contained the motor controllers one controller for
each motor the other two the digital reading system[7]
The MIT design used standard 7-track punch tape for input Three of the tracks
were used to control the different axes of the machine while the other four
encoded various control information[8] The tape was read in a cabinet that
also housed six relay-based hardware registers two for each axis With every
read operation the previously read point was copied into the starting point
register and the newly read one into the ending point[8] The tape was read
continually and the number in the register increased until a stop instruction
four holes in a line was encountered
The final cabinet held a clock that sent pulses through the registers compared
them and generated output pulses that interpolated between the points The
pulses are sent into a summing register in the motor controllers counting up
by the number of pulses every time they were received The summing registers
were connected to a digital to analog converter that output increasing power
to the motors
Once the second point was reached the pulses from the clock would stop and
the motors would eventually drive the mill to the encoded position The speed
of the cut by selecting points that was closer together for slow movements or
further apart for rapid ones
The system was terribly complex including 250 vacuum tubes 175 relays and
numerous moving parts reducing its reliability in a production setting Curves
are as easy to cut as straight lines complex 3-D structures are relatively easy
to produce and the number of machining steps that required human action has
been dramatically reduced
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 49
The standard G-code was adapted for CNC use In turn G-code was
supplanted by STEP-NC a system that was deliberately designed for CNC
rather than grown from an existing plotter standard
G-Code or preparatory code or function are functions in the Numerical
control programming language The G-codes are the codes that position the
tool and do the actual work as opposed to M-codes that manages the
machine T for tool-related codes S and F are tool-Speed and tool-Feed and
finally D-codes for tool compensation
Partial list of M-Codes
M00=Program Stop (non-optional) M01=Optional Stop machine will only
stop if operator selects this option M02=End of Program M03=Spindle on
(CW rotation) M04=Spindle on (CCW rotation) M05=Spindle Stop
M06=Tool Change M07=Coolant on (flood) M08=Coolant on (mist)
M09=Coolant off M10=Pallet clamp on M11=Pallet clamp off
M30=End of programrewind tape (may still be required for older CNC
machines)
Common G Codes
G00 Rapid positioning G01 Linear interpolation G02 CW circular
interpolation G03 CCW circular interpolation G12 CW Circle Cutting G13
CCW Circle Cutting G17 X-Y plane selection G18 X-Z plane selection G19
Y-Z plane selection G20 Programming in inches G21 Programming in mm
G90 Absolute programming G91 Incremental programming
CNC gas cutting machinersquos main parts are
Control panel
Frame
Cutting torch
Nozzles
Gas cylinders
Control panel is the main part of the CNC gas cutting machine which
consists of various buttons to enter the data into the machine It consists of
various controls to regulate the speed of the torch to perform operation
Frame includes the bed for placing the sheet and mild steel frame
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 50
which holds cutting torch and moves according to the given program to cut
the required structure
Torch is made of brass to with stand high temperatures It has two ends
To the one end nozzle is fixed and the other end has the provision to
connect two hoses for oxygen and acetylene
Nozzle in the part of the torch where flame comes out and the cutting
takes place Various sizes of nozzles are provided for various thicknesses
Gas cylinders of oxygen and acetylene are used for gas cutting In
this machine cutting is carried out by using oxy- acetylene
RADIAL DRILLING MACHINE
Radial drilling is used for drilling heavy works and especially for the
jobs where high degree of accuracy is required Its main parts are
Base
Column
Radial arm
Drill head
Spindle
BASE is a rigid cast iron casting which is designed to support column and table It
also contains fluid reservoir for coolant ampfor lubrication
COLUMN is mounted vertically on the base and supports radial arm It also houses
drive mechanism for spindle
RADIAL ARM is supported by column and rotates 360o to provide easy drilling in
heavier works
DRILL HEAD moves on the guide ways of the radial arm and it houses spindle and
speed and feed
SPINDLE is the main part which holds the drill and performs the operation Both
parallel shank and taper shank drills are used in drilling The standard taper of taper
shank drill is called MORSE TAPER
The prepared plates sections in material preparation bay they are transferred to
assembly may for assembling of various parts of a structure The plates are welded
to make a required structure
Welding is process of making a permanent joint by establishing inter atomic bonds
between two or more pieces of metal using heat or heat and pressure
In SSS three types of welding techniques are using They are
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 51
i Arc welding
ii MIG welding
iii Thermite welding
FOUNDRY SHOP
Foundry work deals with manufacture of products from molten metal and obtained
products are called castings
The iron and steel foundry at VSP produces metal castings Meant for internal uses at different departments like SMS sinter plant continuous Casting blast furnace coke ovens etc The raw materials for the foundry are blast furnace pig iron and steel scrap This foundry has excellent facilities to produce Quality castings economically on a large scale The VSP foundry is mainly a captive Foundry because the castings produced by it are used only in VSP and is jobbing in Nature as variety of castings varying in chemistry and weight are being made Recently started executing outside orders for special steel ingots
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 52
SEQUENCE OPERATIONS
1 Pattern Making
2 Mould and Core making
3 Melting and Pouring
4 Fettling
5 Inspection
PATTERN MAKING
Pattern is the replica or full size model of castings to be made It gives its
shape to the mould cavity in which the molten metal solidifies to that desired form
and size
PATTERN ALLOWANCES
A pattern differs from the casting dimensions The size of pattern is slightly larger
than the finished casting by an amount called lsquoallowancersquo
The allowances given to pattern are
1) Shrinkage allowance
When molten liquid metal solidifies the contraction or shrinkage will takes
place ie reduces its original size Therefore the pattern is made larger or
oversized than the required casting dimensions The correction for this is
expressed as a ratio
2) Machining allowance After casting is made machining is done in order to get smooth and clean
finishing Therefore the excess dimensions are given to the pattern
3) Draft allowance
When a pattern is removed from a mould the tendency to tear away the edges
of the mould is reduced if vertical surfaces of the pattern are tapered inwards
4) Rapping allowance
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 53
Due to rapping of the pattern in the mould the size of the mould cavity
increases slightly Therefore lsquoshake or rappingrsquo allowances shall be given
to pattern making it smaller to compensate for rapping
Types of patterns
1) Solid pattern
In this type one side is made flat which serves as a parting surface The
mould cavity will be entirely in the drag
2) Split pattern It is used for intricate and complex shaped casting In two piece pattern one
part producing the mould in drag and the other in cope In three piece pattern
molding box is with these parts Center one is cheek box and remaining are
same
3) Gated pattern The pattern which includes gates and riser for producing castings are called
lsquogated patternrsquo
4) Sweep pattern
It is a template made of wood or metal revolving around a fixed axis in
mould shapes the sand to desired contour
5) Cope and Drag pattern This pattern is made up of two halves which are mounted on different
plates Cope and drag parts are made separately and then assembled
6) Skelton pattern It is used for making large castings in small number This is a wooden frame
out lining the shape of the casting The frame is filled with loam sand and
rammed
7) Segmental pattern It is form of a segment and used for molding circular objects such as rings
wheel rims etc This pattern revolves about center
PATTERN MATERIALS
1) Wood
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 54
2) Metal
3) Steel
4) Thermo coal
5) Plaster of Paris
6) Ceramics
In foundry shop the castings are made that is necessary to VSPrsquos needs
The sand is used for molding as it has high thermal shock absorption
Various types of sands used in Foundry are
Green sand Molding sand containing moisture is called lsquogreen sandrsquo It
consists of silica clay water (5) It can be reused by reconditioning
Dry sand Sand free from moisture is dry sand which is used for large
castings as it having high strength
Parting sand It is used to prevent the moulding sand from sticking to
surfaces It is free from clay
Core sand It is silicon sand mixed with organic compound like oils resins etc
It has high refractive ness used for core making
Silica sand It consists of 98 to 90 silica mixed with clay It is mixed with
coal powder and used for CO2 moulding process
MOULDING PROCESSES
According to method
Bench moulding In this moulding flasks are kept on bench used for small castings
Flour moulding The mould is made on flour It does not required cope box
Pit moulding Mould is made in pit and dug in flour It acts as drag box and the cope
box is used separately
According to material
CO2 process
In this process silica sand is mixed with a small amount of sodium silicate and is
placed in moulding box and rammed After moulding Co2 gas at certain pressure is
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 55
flowed through mould by vent holes As the result of chemical reaction between
CO2 and sodium silicate sodium carbonate is formed Therefore the sand is made
harder and ready for pouring This sand can be used only once and not suitable for
reconditioning
Green sand moulding
It uses moist sand in which clay will be added to with stand the forces Drying is not
necessary and molten metal is poured as soon as the mould is prepared
MELTING
Melting is a process of changing the solid state of iron or steel to liquid state The
molten metal is poured into the mould and then solidifies in order to get required
casting
The furnaces used in this shop are
1) Direct Electric Arc Furnace
2) Induction Furnace
Direct Electric Arc Furnace-
This is used to melt steel and other metals
Charge Steel scrap Limestone Steel scrap is the metal which is used for casting
and lime stone is used as flux which eliminates impurities
Construction it consists of a roof which can be raised and lowered by hydraulic
system three electrodes and big cylinder which houses all these things and furnace
The cylinder is lined with refractory bricks to resist heat and melting of cylinder
Process In this the arc is struck between electrodes and steel scrap At the electrode
points the temperature is about 3600 degree centigrade The steel is heated gradually
and its temperature increases When it is reached to 1570 deg Centigrade oxygen is
injected into furnace This O2 is used to form slag by making oxides with impure
elements like MN O SO2 etc It forms slag and floats over the molten metal and
protects it from atmospheric contaminations and acts as a cover While melting the
metal piece sample is sent for the analysis of required additives and made the
required corrections in composition After sampling the reduction of metal is done
The additives required are added Here lime stone acts as a reducing agent
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 56
After temperature is raised to 1640 deg centigrade the metal is tapped off
through tap hole The furnace is tilted and molten metal is poured into ladle which
is placed underground level beside tap hole The cooling system is arranged in
furnace flows through pipes in order to cool the rotating parts of furnace Generally
water is used as coolant
Electric arc furnace details
Furnace capacity - 8-10tons
Transformer rating - 4000KVA
Secondary voltage - 125-250volts
Water pressure for electrode - 15kgcm2
Control and tilting
Water pressure for cooling - 3kgcm2
Max tilting angle at tapping - 40o
Slagging - 20o
Water for cooling - 6litsec
Power consumption - 492KWHton
Melt down period - 77min
INDUCTION FURNACE-
This furnace is used to melt cast iron
Charge pig iron scrap silica
Construction and process - The charge is placed in a crucible It is surrounded by
primary copper coils The space between the crucible and the coil is packed with
sand or any insulating material The high frequency electric current is passed through
coil and this current produces an intense heat in metal charge This heat is enough
to melt the charge The molten cast iron is tapped off through tap hole and poured
into ladle by tilting the furnace
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 57
The primary coil is cooled by water which flows through a separate pipe
surrounding the primary coil In this furnace the charge pig iron is refined in order
to get molten cast iron
Induction furnace details-
Capacity 53 tons
No Of crucibles 2 norsquos
Furnace voltage 1100 KV
Furnace power 1190 KW
Transformer 1350 KVA
Primary Voltage 11KW 3Oslash 50Hz
Secondary Voltage 1100KW max
Cooling water flow rate 1275 m3 hr
Pressure 4 kg cm2
Inlet temperature 45 deg cg
Outlet temperature 65 deg cg max
POURING
The molten metal from furnace is poured into ladle by tilting the furnace The
ladle is made from steel plate and is lined with fire clay Ladle is used to carry the
molten metal from furnace to mould and pouring the metal into mould The ladle is
kept as heat as in furnace so that the metal doesnrsquot loss heat in traveling These ladles
are carried by overhead cranes
The molten metal is poured into mould from ladle in two ways
1) The ladle is tilted by two hoists of overhead crane and molten metal is poured
from top of ladle into the mould using pouring cups This type of pouring is
used for small and medium castings In this slag inclusions may occur
2) Bottom pouring ladle is used for large castings The molten metal is poured
through bottom hole of ladle which is operated by a graphite stopper The
temperature in ladle is also controlled by the stopper As metal is poured from
bottom slag is not included and gives better pouring than top pouring
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 58
SAND PLANT
Sand for moulding is brought from CHEERALA The sand is of 98 and also
of 90 silica The sand is stored in a pit The sand should be prepared before its use
in order to get required moulding properties
Sand handling equipment
1) Sand mixer
2) Belt conveyor
3) Bucket elevator
4) Sand aerator
5) Sand storage bins
6) Drier
7) Cooler
Sand preparation
The sand is poured into bunker from storage pit by a grab
This sand is dropped on the belt conveyor by a disc feeder which rotates and
drops the sand down by centripetal force
It is traveled up and passed in drier by screw feeder through another bunker
A blower forces the sand into drier and sand is heated by coke oven gas to
eliminate moisture in it
Then it is passed through cooler to cool the sand to room temperature
Then the sand is passed to storage bin by a bucket elevator There the sand is
stored when it is not required
When the gate of storage bin is opened the sand is dropped into mixer by a
vibrating feeder
In mixers the required additives are added and mixed thoroughly The
additives are for one ton of sand
Bentonite ndash 6
Dextrin ndash 2
Molasses ndash 1
Moisture ndash 5
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 59
Mixing cycle time is 6 minutes
The water is added for green sand only Then the sand is ready for moulding
The prepared sand is sent to small storage bins which are at moulding places
by bucket elevators and belt conveyors
A sand aerator is placed before each bin and it is used to crush the small sand
lumps (included in sand) and make it powder
Sand can be dropped in any storage bin in its traveling path with help of a
plough which diverts the sand to sides of conveyor
The used sand is also can be reconditioned as the similar way of sand preparation
and stored in separate bins
The sand plant is operated automatically by control panel in controlling room 10
ton of sand can be prepared in one hour
CORES Cores are specially made sand bodies intended to form holes and
cavities in castings Cores are placed in the mould cavity before pouring to form
interior surface of the casting
CORE MAKING
Cores are made in boxes Core boxes may be a simple solid type or split type made
of wood The two parts of core box is clamped together and kept in vertical position
Wires to provide venting and metal rods to strengthen are reinforced in core The
two halves of box are separated and the core is turned out Then the core is backed
in an oven about 230 deg C
CORE PRINTS
The core rest in the mould in recesses specially made for this purpose These
are made from pattern in the form of projections known as lsquocore printsrsquo
Horizontal Vertical Balanced Cover and hanging core etc types of cores are there
according to their position and orientation
FETTLING-
When the molten metal is completely solidified the casting is to be cleaned and
finished After they are removed from mould they have several unwanted projections
as the shape of runners risers fed gates etc And also sand is sticker to it These all
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 60
waste material should be removed by some means This removal of material is called
lsquoFETTLINGrsquo
For iron these projections are removed by nicking them with a chisel and
snapping them off Nonferrous runners etc are sawn off Steel ones are removed by
oxy acetylene cutting process The core holes should be cleaned out and any fins are
removed with a cold chisel Cores are cleaned up by means of drifts The use of wire
brush on the exterior faces of a casting will remove any sands adhering to it and sand
blasting is also used for this purpose Castings that are not too delicate may be
cleaned by tumbling in rattler and fragile castings are properly filled
As per the norms of requirement for cast spares it was found That 12000 Tons of castings will be required for the steel plant comprising of 5400 T of cast iron spares 6240 T of steel spares and 360 T of non-ferrous spares Keeping the requirements in view various equipment were installed to meet the above targets The capacities of the shop are-
The maximum weight of single casting in steel ndash 10 T
The maximum weight of single casting in iron ndash 10 T
The maximum weight of single casting in non-ferrous ndash 1T Captive foundry was envisaged for the supply of consumables and spares for the Steel plant with an investment of 25 cores followed with the man power of 160 People
The foundry is divided into five bays AB Bay - Raw materials section BC Bay - sand preparation core making CD Bay - Melting mound making casting DE Bay - Fettling and cleaning EF Bay Heat treatment and non-ferrous section
UTILITY EQUIPMENT REPAIR SHOP (UERS)
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc
Industrial training ESampF VISAKHAPATNAM STEELPLANT
pg 61
INPUTS Sheets Plates Channels Angles Beams Billets Rounds from Forge Shop for manufacturing Shafts Steel amp Iron castings
PRODUCTS AND SERVICES- Manufacturing of Impellers to various departments repair of GCP ID Fan Repair of Steam exhausters for SMS supply of Cones and Ducts of Various sizes build up amp machining of various components reclamation jobs like Valve repairs Conveyor Idlers PCM Rollers etc