CH_PRP

DOC No. : ISO/QPO/BF (O)-15/03

BHILAI STEEL PLANT PAGE No. : of 15

BHILAI – 490001 DATE OF ISSUE: 23.07.07

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REVISIONS ARE NOT PERMITTED WITHOUT THE PRIOR APPROVAL OF THE

CONTROLLING AUTHORITY

WORK INSTRUCTIONS ON

CAST HOUSE PREPARATION

AND

OPENING / CLOSING OF TAPPING

REVISION RECORDS

REVISION

NO/

DATE

REVISED

PAGE

NO

BRIEF

DESCRIPTION

OF REVISION

PREPARED

BY

CHECKED

BY

CONTROLLING

AUTHORITY

APPROVED

BY

00

12.09.97

--

ORIGINAL

DOCUMENT

Sd\-

MP SINGH

Sr. Mgr. (O)

Sd\-

B SATYANA-

-RAYANA

AGM (O)

Sd\-

SB SINGH

GM (I)

Sd\-

SB SINGH

GM (I)

01

14.06.02 11

Article

7.9.4

Sd\-

D GUPTA

AGM (O)

BF

Sd\-

BK PRASAD

DGM (O)

BF

Sd\-

S AHMED

HOD (BF)

Sd\-

S AHMED

HOD (BF)

02

05.02.07

04

Article

6.4

Sd/-

RR NAGRE

AGM (O)

Sd/-

PK DWIVEDI

DGM (O)

Sd/-

RAVI KUMAR

HOD (BF)

Sd/-

RAVI KUMAR

HOD (BF)

03

23.07.07

04

Article

6.2

TD GUPTA

Sr.Mgr (O)

PK DWIVEDI

DGM (O)

P GAUTAM

HOD (BF)

P GAUTAM

HOD (BF)




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DISTRIBUTION OF CONTROLLED COPIES _________________________________________________________________________________ COPY NO DISTRIBUTION LOCATION REMARKS _________________________________________________________________________________ 1 MANAGEMENT REP. OFFICE OF THE M R FOR RECORD 2 HEAD OF DEPTT OFFICE OF THE HOD FOR CONTROL BLAST FURNACE BLAST FURNACE AND RECORD 3 I/C FURNACES OFFICE OF THE FOR CONTROL I/C FURNACES 4 SHIFT MGR PRODUCTION CONTROL FOR CONTROL BLAST FURNACE BLAST FURNACE 5 MASTER HEARTHMAN FFCR FOR BF 1 BF 1 IMPLEMENTATION 6 MASTER HEARTHMAN FFCR FOR BF 2 BF 2 IMPLEMENTATION 7 MASTER HEARTHMAN FFCR FOR BF 3 BF 3 IMPLEMENTATION 8 MASTER HEARTHMAN FFCR FOR BF 4 BF 4 IMPLEMENTATION 9 MASTER HEARTHMAN FFCR FOR BF 5 BF 5 IMPLEMENTATION 10 MASTER HEARTHMAN FFCR FOR BF 6 BF 6 IMPLEMENTATION 11 MASTER HEARTHMAN FFCR FOR BF 7 BF 7 IMPLEMENTATION 1.0 INTRODUCTION




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Cast house is an area constructed around the Blast Furnaces at Tap Hole level, in order to facilitate the tapping of hot metal and slag from the furnaces through runners. The runners consist the following parts. 1) Main runner 2) Syphon hole & pit 3) Metal runner 4) Rocking runner 5) Slag runner 6) Perival runner 7) Spouts Apart from the above runners the cast houses have the following critical acquirements. 1 Mudgun 2 Drill Machine 3 Cast House crane 4 Telpher crane 5 Pusher car 6 Rocking runner Cast house can be defined as a network of runners originating from tap hole and acquirements in order to carry out cast house preparation and periodical tapping of hot metal & slag. 2.0 SCOPE This work instruction shall cover the preparation of cast house for tapping and opening / closing of tapping. 3.0 REFERENCE 1 SOP on tapping of furnace DOC NO. ISO/QPP/BF (O)-05/** 4.0 DEFINITIONS/ABBREVIATIONS BF - Blast Furnace TH - Tap Hole IC - Intermediate cooler CH - Cast House HM - Hot Metal MC - Main cooler 5.0 RESPONSIBILITY Master hearth-man (Shift) of the concerned furnace under guidance and control of Furnace shift in-charge shall be responsible for implementing this works instruction. 6.0 PROCEDURE




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6.1 IMPORTANT SAFETY POINTS 1 All runners must be dry to avoid blasting. 2 All hearth men attending tapping must be fully dressed with safety appliances to save them from injury. 3 No water logging in and around tracks where ladles are placed to avoid blasting. 4 Only dry metallic objects are to be inserted in HM pool. 5 Ladle should be filled 200-300 mm below top level. 6.2 SAFETY APPLIANCES 1 Safety shoes 2 Safety helmet 3 Woollen Patti 4 Anklet

5 Flame retardent suit / Canvas coat 03 6 Gloves 7 Face shield / goggles 8 Nose pads 9 Ear plugs 6.3 WORKING PROCEDURE ACTIVITY KEY POINTS 6.4 CAST HOUSE MAKING a)In single taphole furnaces (1-3) main runner,syphon and metal runner is made during monthly schd.shut down by dry ramming mass & periwall has to be opened after every tapping. On requirement & visual inspection runner to be repair to achieve through put life of runner & existing practice is to be used for preparation of cast house as maintained. b)In twin taphole fces (4-7) main runner up to R/R to be made by castable runner mass. After achieving desired through put life, periwall is to be opened for making of trough. However intermediate opening of periwall is to be done for inspection and repair of the trough or in case of shifting of tap hole for prolonged time.

For making of branch runner, R/R and slag runner existing practice to be adopted.

6.4.1

ACTIVITY KEY POINTS

Taphole making 1 Visually observe the tap hole condition. 2 If tap hole is deep by around 4-5" with respect to the plane of TH arch. (Furnace




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shift incharge shall take decision for making in consultation with the Sr. Head Keeper) 3 Arrange frame mass (TH gola) 4 Cool tap hole and then break it and its surrounding mass by chisel rod uniformly. 5 Fix TH gola around the broken tap hole in limited number and ram it with tap hole rammer. 6 Continue the process of. gola fixing and ramming till the tap hole comes to the level of TH area. IMPORTANT - TH gola should be properly rammed so that TH becomes compact and strong. 7 Bring the mudgun to tapping closing position and take the impression of the mudgun nozzle on the rammed mass slowly. 8 Again ram the surrounding area and take final impression. 9 Cover the area around arch by thin layer of water bonded clay and cut the TH upto the old clay. 10 Fire the TH with coke oven gas for 1-1/2 hrs with oxygen. 11 The tap hole is ready for tapping. NOTE 1 : Where hydraulic drilling machine has been provided, check the centering by fixing a drill rod. It should co-incide with the dug up hole, otherwise get necessary adjustment. NOTE 2 : Mud gun centering shall be checked after breaking the TH. IMPORTANT : After the TH is broken the Furnace shift incharge will observe the condition of arch bricks, any major gas leakages etc. and will log it in log book. He must inform the concerned Furnace I/C / Shift Manager before fixing clay, if there is any abnormality.




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6.4.2 ACTIVITY KEY POINTS Main runner making 1 Main runner is divided into three parts to facilitate easy and quick making. 1. 1st Half 2. 2nd Half 3. Syphon and pit 2 The Fce shift incharge takes decision of making the runner by seeing the metal pool (depth of jam) and side erosion of runners. 3 Demand and arrange special runner mass. 4 The hearthmen under guidance of Sr. Head Keeper will do the making. Decant the slag and put bari in metal pool. Pour water immediately to get the bari welded with the metal jam. 5 Clean the muck of the runner, expose the jam, pull the bari with the help of CH crane to take out the jam. 6 If the rod comes out without jam due to ineffective cooling or some other problem, make groove by oxygen lancing. Fasten the CH crane hook and pull out the jam. 7 Clean the loose held material and muck. 8 Add special runner mass and spread uniformly to have slope gradient. 9 Ram adequately by hand rammer or electric vibro rammer. 10 Dry the required portion with CO gas for 1 hr. to 1 1/2 hrs. depending upon depth of powder added. 11 Runner is ready for tapping 6.4.3 ACTIVITY KEY POINTS

Syphon hole making




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1 Arrange water bonded clay 2 If syphon hole gets eroded slag starts going towards metal side. 3 Scrub of the old & burnt clay from the skimmer plate and clean it. 4 Place the format below the skimmer plate. 5 Start adding clay around the mould/format and skimmer plate. 6 Compact the clay by ramming after adding dry sand. 7 Remove the format and ram further around the hole. 8 Start drying by coke oven gas immediately otherwise clay will fall down. Dry for an hour. 9 The syphon hole is ready for tapping. 6.4.4

ACTIVITY KEY POINTS

Syphon pit making 1 If there is a metal pool in the pit it is to be made. 2 Insert bari after decanting slag and cool it with water. 3 Take out the jam as in 9.1.2. 4 Clean and add special RMP. 5 Ram it properly and maintain slope for full drainage. 6 Dry it with coke oven gas for about 1 hour. 7 Pit is ready for tapping. IMPORTANT Furnace shift incharge shall check the runner after cleaning, for any damage of side wall / bottom bricks dislodged during jam removal. He shall inform shift manager /furnace incharge for necessary action and log in the furnace log book for future reference.




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6.4.5

ACTIVITY KEY POINTS Metal runner making

1 Cool the runner by water spraying water. 2 Remove solidified metal jams manually or with the help of CH crane. NOTE 3: Bari can be inserted if metal pool is more. 3 Clean the runner and add ordinary or special runner mass. 4 Spread it properly for maintaining slope and ram it. 5 Dry it properly. 6 Runner is ready for tapping. 6.4.6

ACTIVITY KEY POINTS

Rocking runner 1 Insert rod after decanting slag if any. Cool it properly by adding water. 2 Remove the jam with the help of telpher crane and clean properly. 3 Make the spouts with sic water bond clay. 4 Add special RMP, level and raw it properly to give the correct shape. 5 Dry with coke oven gas for 1 1/2 hrs.to 2 hrs. depending upon the depth of jam. NOTE 4: In any above runners if the metal pool is high and lot of water has been added. Dry the naked runner first before adding special RMP to avoid boiling. IMPORTANT While making rocking runner special care shall be taken to keep sufficient clearance between rocking runner side and metal spout. 6.4.7




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ACTIVITY KEY POINTS

Slag runner making 1 Clean the runner after removing slag jams and metal jams if any. 2 Add ordinary runner mass. Level it to give a slope. 3 Ram it properly. No need of heating. 6.4.8

ACTIVITY KEY POINTS

Making of spouts 1. Check the spouts after each cast and, if 1. Metal spout needed, repair/make it. 2. RR spout 3. Slag spout 2. Clean and make with SiC hydrous clay. 4. Periwal runner spout 3. Above this add spl./ordinary RMP. 4. Dry metal spout before tapping to avoid boiling. IMPORTANT SAFETY FACTOR: While inserting bari for taking out metallic jam in any runner, ensure that the bari/rod is dry and warm to avoid explosion and accident. 6.5

ACTIVITY KEY POINTS

Cast house preparation (Without making) 1. Check the TH condition. TH ring should be clear and distinct. 2. Remove the jam in & around TH and main runner. 3. Dress the runner with sand. 4. Remove jam of slag head, perival exit and perival runner.




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5. Close the perival by runner sand. 6. Check the height of metal & slag head. Keep slag head 100-150mm above metal head. 7. Clean the slag runner and close cutters if provided. Make a sand dam in slag head. 8. Remove the jam of metal runner and close cutters if provided. 9. Fill the mudgun and check that adequate clay is coming out of nozzle. See there is no leakage from nose reducer interface or reducer-barrel interface. Cover the reducer hinge with M/G clay to avoid jamming. 10. Check all the movements of M/G, Drill machine, rocking runners & pusher cars, check all coupling bolts. In case of any problem inform concerned maintenance shift I/C and shift manager. 11. Keep nose sleeve and asbestos rope for emergency purposes. 12. The cast house is ready for tapping. NOTE 5 : Drilling machine shall be checked just after closing TH. 6.6

ACTIVITY KEY POINTS

Checking of

hydraulic drilling machine & mud gun 1. Check that required air pressure for drill operation is there. 2. Check that air is coming through the drill rod and drill machine is working normally in both rotation and percussion mode. 3. Check that air compressor is working. 4. Check that hydraulic pressure is perfect and pumps are working normally.




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5. Check the centering of drill machine. 6. The furnace shift incharge shall check/get checked the equipments. 6.7

ACTIVITY KEY POINTS Opening of

tapping 1. Ensure that the CH is ready 2. Check that metal ladles and slag ladles are properly placed below spouts, where pusher cars are provided. Ladles must be coupled properly. 3. If slag is taken in SGP, check runner & spout and inform SGP personnel. 4. Ask electrician to attend tapping. The furnace shift incharge will check the schedule and if it is due will ask his Sr. Head Keeper and crew to open tapping. 5. Turn the drill machine to drilling position. 6. The Sr. Head Keeper will position the drill at the centre of TH with the help of hearthmen and drill the TH to the maximum possible extent without damaging the drill machine. Remove the drill machine. 7. If tapping does not open, connect 1/4" lancing pipe with oxygen hose and start lancing till it softens or opens. NOTE 6 : Lancing should be straight to the drilled TH and also in drilling direction. 8. Poke the TH manually with poking rod or percussion rod (for hydraulic drill machine) to normalise the flow. 9. Switch on "TAPPING" signal. 6.8

ACTIVITY KEY POINTS




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Sampling

1. Take sample of metal and slag with the help of dry & heated sample spoon and mould. Take sample after 20-30 minutes of slag flowing. 2. Send to sample to R&C Laboratory for analysis. NOTE 7 : The Sr. Head Keeper and his crew will remain alert during tapping to face any eventuality. 6.9

ACTIVITY KEY POINTS Closing of

tapping 1 Once the furnace is dry close tapping. 2 Check the TH ring, it should be intact. 3 Check that adequate clay is coming out of mudgun nozzle by pushing out some clay. 4 Turn the mudgun to the taphole in closing position, holding the nozzle over the taphole. Push adequate clay to get the required TH length (Fce 1 - 3 = 2.0 m and 4 - 7 = 2.2 m) 5 Check the ladle in perival spout position and open perival. Poke it to drain fully. 6 Switch off the tapping signal and inform production control. Log the same in FFCR log book. IMPORTANT 1 If the TH ring is not proper and damaged, M/G will not sit properly reduce blast and close tapping. In case of non-closure, take the M/G in parking position, reduce blast. Wrap the nose with asbestos rope and put hydrous clay. Close the tapping. 2 If nose has burnt due to any reason push clay first, insert the nose sleeve and close




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tapping. 3 Inform shift manager and arrange for sufficient number of metal /slag ladles to avoid falling of metal / slag on the track. 6.10

ACTIVITY KEY POINTS

Perival holding 1 In BF 4, 5, 6 & 7 perival shall not be opened after each cast in castable runners. In such case perival shall be hold. 2 After closing of tapping put paddy husk in main runner and syphon pit to keep the slag & metal liquid at top surface. 3 Clean the TH area properly. Before opening the cast check that the upper layer of metal & slag is liquid and there is proper connection when tapping is opened. 4 Keep one metal ladle empty below the perival spout which will take care of accidental self opening of perival. 6.11

ACTIVITY KEY POINTS Tap hole

changing Where two tapholes are provided change tap hole for the following reasons. 1 Break down of any equipment viz M/G, drill machine or SGP in some cases. 2 Cast house preparation is in progress in one tap hole. 3 Scheduled opening. The furnace shift incharge shall take decision in consultation with the Shift Manager/Furnace Incharge.




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6.12

ACTIVITY KEY POINTS Flushing of top

slag through monkey Flushing of top slag shall be done as per requirement of furnace operation in single tap hole furnaces and in emergency in other furnaces. 1 Remove the stopper and clean the monkey hole. 2 Check the stopper alignment ( it should freely go into monkey and sit in the centre of monkey). 3 Make the hole with hydrous clay and patch clay around IC and MC to protect these from damage. 4 Check the runner slag is cleaned and ladle is in position. 5 Open the monkey by poking or lancing as per requirement. 6 When monkey starts blowing or the ladles are filled, close the monkey by lowering stopper into monkey. NOTE 8 : If monkey burns during flushing, close monkey at the earliest. NOTE 9 : If monkey does not close 1 if monkey is not burnt, clean the monkey hole area so that stopper goes freely into monkey, reduce blast pressure and close monkey. 2 if monkey is burnt, reduce water so that foaming of slag is reduced, clean the monkey hole area, close monkey and increase monkey water. NOTE 10 : If monkey stopper is burnt, close monkey with hand stopper after reducing blast pressure.




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6.13 IMPORTANT

PROBLEMS USUALLY FACED DURING TAPPING

Short or Weak Taphole - If the taphole is short and flow of metal & slag is very fast, reduce blast immediately taking care of the furnace and seeing tuyere condition. Timely blast reduction will help in avoiding coke rush also. If the taphole is weak and tapping is continuing with splashes of metal and slag which may create drainage problem, reduce blast in ratio of tap hole length/flow of metal. 6.13.1 DOUBLE STREAM If the during tapping metal & slag starts coming in two or more stream, poke immediately to make single stream. If double stream continues, tapping shall be closed at the earliest. 6.13.2 SPILLAGE OF METAL & SLAG AND COKE RUSH If due to any reason there is spillage of metal and slag in the CH or below the track which can create hindrance to further tapping or can cause closing problem, reduce blast and close tapping immediately even in not dry condition. If there is a tendency of coke rush adjust blast regime and top pressure to tackle it. 7.0 RECORDS Parameters related to taphole condition, tapping details shall be logged in furnace log book.

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