A

Project report

On

“ADDRESSING CUSTOMER’S REQUIREMENT.”

PROJECT GUIDE

SUBMITTED BY-

Yash Meshram Shubham Joshi

B.tech. Metallurgical engineering and B.tech. Metallurgical and materials engineering

Materials science

IIT BOMBAY NIT JAMSHEDPUR

ACKNOWLEGMENT

It is great pleasure to have this opportunity to express my deep sense of gratitude and whole

hearted thanks to the project guide Mr V.M. Joshi and HR dept., who have always offered their

help whenever we needed it.

I would cherish this experience in my future ahead to work in leading steel industries and to face

the rigorous competition ahead.

INTRODUCTION

When the process starts for the achievement of finished product following semi-finished ladder is

presented:

i. HR slitting

ii. Pickling

iii. Cold rolling

iv. Galvalume/ Galvanizing

v. Colour coating.

For fulfilling customer’s requirement properly, all these processes being present in the process flow

are important. The process flow must be according to demand of the customer. In a production unit

all the process lines are situated far away and hence the process synchronization becomes quite

difficult for the organization. For that purpose a joint organization for the overall management and

the proper synchronization, Production Planning and control (PPC) has been established. Formerly the

PPIC, now PPC, is responsible for the inter-process management that constitutes checking and

ordering of HR coils, checking and verifying the quality reports of output of each process and overview

of the finished product and setting up targets for despatches.

Continuous pickling line

Removal of scale from Hot rolled coil by hot dip process in hydrochloric acid is termed as Pickling. On

HR coils generally scale deposited is in the form of iron oxides. General process flow of pickling

constitutes incoming of HR coil of specific grade as per the customer’s requirement, then it is passed

through the scale breaker and mechanical scale breakage is done, then the coil is washed and passed

through a series of tanks containing hydrochloric acid, then it is passed through hot air dryers and

cascade rinse rolls and though centre position control rolls it is sent for trimming. Oiling is done as the

customer’s requirement. Basically this process is a vivid initiation of the overall process flow but the

major crux of this process is to provide a scale free properly trimmed coil to the next process. There

are total of five acid tanks with increasing concentration ranging from 1-2% (iron: 150 ppm max), 2-

4%, 4-6%, 6-10% (iron: 120 ppm max) and 10-14% (iron: 100 ppm max) v/v HCl acid. Quality assurance

dept. determines the acid concentration and the iron present in the solution.

As mentioned above, the major parameter of this process is width of the coil. Coils are trimmed

according to the grade of input HR coil and mechanical properties of output coil. The tolerances of

width is the important aspect of CPL. For soft coils, more tolerance width has to be left and for soft

less tolerance width has to be left. This width is utilized for next processes and trimmed properly as

per the customer’s requirement. For a particular order, the management person presents a sales order

to PPIC, then PPIC verifies and sets targets for the production. The information regarding the product

is fed into SAP and it’s accessible to each unit of process. PPC generates a process order against each

process of the production ladder. After the pickling process, the output width and other process

details and a batch no is generated, are fed into SAP and the coil moves up the ladder according to

the planning.

Rolling

In metalworking, rolling is a metal forming process in which metal stock is passed through a series of

rolls so as to decrease thickness. Cold rolling occurs with the metal below its crystallization

temperature which increases the strength via strain hardening. Vice-versa is the case with hot rolling.

Commonly cold rolled products include sheets, strips, bars and rods. Only disadvantage of cold rolling

is that it cannot reduce thickness as much as hot rolling. Full-hard rolling reduces thickness by as much

as 50%, while the others involve less of a reduction. Skin passing involves the least amount of

reduction: 0.5-2.0%. Process involves: 1) Loading of coil on entry skid. 2) Putting coil on payoff reel

un-coiler. 3) Feeding coil through threading table. 4) Rolling of coil in specified passes to get required

gauge. 5) Shearing Unrolled part of tail and head end of coil. 6) Ejecting of coil, putting tag &

identification. 7) Entering in SAP/Log book.

Thickness is controlled by Load, Tension and Speed. If more Load is applied, then there is a chance

that width may increase. If more Tension is applied, then width may decrease. To overcome this kind

of uncertainty, there is some tolerance left in width by the Pickling line depending on HR coil’s grade,

hardness, mechanical properties, etc. Customers give full information to Marketing department who

generates Sales order containing process order no., dimensions, mechanical properties, etc. PPC

(PRODUCTION PLANNING AND CONTROL) gives information to pickling line which processes and gives

the output to Rolling mill. Information regarding thickness are given to rolling mill. According to that,

they adjust Load, Tension as well as Speed given to the HR coil. Rolling mill gives processed coil to

Galvanizing line or Galvalume for further processing which are identified by batch no. or dispatches

its finished product. Important thing to note is that rolling mill gives actual thickness less than the

declared thickness.

Galvalume

Galvalume is a process for rust proofing iron and steel by the application of Al-Zn coating with traces

of Silicon. It contains Al (55%), Zn (43.5%) and Si (1.5%). Hot dip galvanizing, electro galvanizing and

Al-Zn spraying are methods for Al-Zn coating. Mostly used process is hot dip galvanizing involving

immersing steel into a bath of molten Al-Zn at 650 degrees to form a metallurgically bonded Al-Zn

alloy. Al-Zn coatings protect the material by providing both a physical barrier and cathodic protection

to the underlying steel. Slight Silicon is present to limit the growth of intermetallic grains. Its corrosion

rate is way less than that of galvanizing. Advantages of Galvalume include Corrosion resistance, Yield

advantage, Formability, high temperature resistant and Thermal reflectivity. Process includes: 1)

uncoiling and welding. 2) washing/rinsing & drying. 3) Chemical processing. 4) Al-Zn coating. 5)

Chromating/Non-chromating. 6) Acrylic coating. 7) Exit section (recoiler).

Four types of coating are done in Galvalume: 40, 70, 100, 150 grams per square meter. Skin-passing

and Tension levelling are done soft grade of HR coil. So, in this process, there is a chance that width

may decrease. It also improves flatness in turn improving Shape and reducing roughness of coil.

Surface cold treatment is a process of chromating which further improves Corrosion resistance and

applying acrylic coatings for anti-fingerprint surface. Customers give full information to Marketing

department who generates Sales order containing process order no., dimensions, mechanical

properties, coating details, etc. PPC (PRODUCTION PLANNING CONTROL) gives information to pickling

line which processes and gives the output to Rolling mill which further process and gives output to

Galvalume line. Coating of Al-Zn depends on nozzle gap, nozzle pressure and speed of coil where the

nozzle contains coatings. Depending on customer’s requirements, they adjust the gap, pressure and

speed which are given to them by PPIC. Galvalume gives processed coil to Colour coating line for

further processing which are identified by batch no. or dispatches its finished product. Actual thickness

is less than that of declared thickness in Galvalume.

Continuous Galvanizing line

As the galvanizing line is a continuous line, the coils are passed through a lopper. Continuous annealing

takes place in an in-line annealing furnace. This cleans the coils and helps achieve the desired

hardness. The temperature of this pre-heating oxidising furnace is between 460 deg Celsius to 480

deg Celsius. After this, the coils are passed through a zinc pot where zinc coating it’s carried out using

a technological advanced hot-dip process. Zinc and antimony of the highest purity are used for coating

the sheets. This operation is performed under precise temperature conditions, with the bath

temperature maintained within a range of 440 deg Celsius to 460 deg Celsius. The coating film contains

about 98% zinc and 1.6 to 2% aluminium. Coating thicknesses available are 90, 120, 180, 275, 350,

450, 550 GSM.

Due care is taken for pre-treatment of the substrate on which the zinc coating takes place, as this

increases the life performance of the galvanized sheets. The percentage aluminium, antimony and tin

in the batch is 2 to 3%, 0.35 to 0.45% and 0.3 to 0.4% respectively. The zinc-coated coils are then

passed through a chromate solution to safeguard the coils against white rusting and other

atmospheric reactions. The chromic acid concentration is 1% to 2.5% v/v, and the temperature is kept

at 40 deg Celsius to 55 deg Celsius. Lastly, the coils are passed through a tension leveller to improve

the shape of product and ensure perfect flatness.

This process undermines the thickness and mechanical properties like yield strength, tensile strength

and hardness. The tolerance thickness is considered while coating. The output of the cold rolling

process is input of this process. The batch no of rolling is input for this. Process order is generated by

PPC against sales order. The data is fed into SAP and it’s accessed by galvanizing unit prior to the

process. And after the process the output along with batch number is fed into SAP for next process

that is colour coating line and the coil is moved further the process ladder.

Colour coating line

Colour Coating is a covering that is applied to the surface of HR coil referred as a substrate for the

purpose of decoration or functional or both. Functional purpose includes wettability, adhesion, wear

resistance or corrosion resistance. Paints have dual uses of protecting the substrate and being

decorative. Types of paints include- R.M.P, S.M.P, S.D.P, P.V.D.F, and epoxy. Galvanized /Galvalume

coils constitute the raw material for the colour coating process. The Colour Coating line incorporates

surface protection, service coating, heating, cooling, prime coating, top coating /printing and guard

film application. Pre cold treatment is applied for better adhesion of paint, with a substrate corrosion

resistant. An oven is provided to bake the surface and attain a peak metal temperature between 210

to 240 degrees Celsius. In the service coating process, paint is applied by a paint coating machine. The

ovens for baking temperature depend on line speed and thickness of coil. A controller is provided to

squeeze the water and control the sheet at centre position. Thereafter, prime coating and top

coating/printing are carried out by the plant coating machine. Finally, Guard film is applied to

safeguard against scratches and other surface defects.

Customers give full information to Marketing department who generates Sales order containing

process order no., dimensions, mechanical properties, coating details, etc. PPC (PRODUCTION

PLANNING CONTROL) gives information to pickling line which processes and gives the output to Rolling

mill which further process and gives output to Galvalume line. They further process and give output

to colour coating line. Coating of Al-Zn depends on speed of coil, retention time, thickness and width.

Depending on customer’s requirements, they adjust them for the required coatings which are given

to them by PPC. Colour coating line gives processed coil to corrugation line for further processing

which are identified by batch no. or dispatches its finished product. Actual thickness is less than that

of declared thickness in Colour coating line or maybe higher according to the tolerance expectations

of the customer.

CONCLUSION

The major crux of producing a finished product is to meet the exact requirements of a customer. PPC

is responsible and maintaining a healthy link between each process line and ensuring customer’s

requirement.

The output of one process line behaves as an input for the next one and accordingly the dimensional

tolerances and quality of the product, processed in one line, is useful for successfully achieving a good

finished product in the next process up the ladder, the customer’s requirements are maintained during

the processing and cross verified by quality assurance before releasing to next process.

Regularly feeding the output and process information for the particular line into SAP and its

accessibility to authorised personnel of each process unit, plays an important part in the proper

synchronization between each process line for successfully achieving the finished product, according

to expectations of the customer .