Elimination of Biting problem in Blooming Millrmoc.tksranchi.in/rmoc52/Presentations/JSW - SALEM...
Transcript of Elimination of Biting problem in Blooming Millrmoc.tksranchi.in/rmoc52/Presentations/JSW - SALEM...
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52ndRMOC
Rolling Mill Operating Committee MeetingBokaro Steel City
Better everyday
Elimination of Biting problem in Blooming Mill
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Better EverydayA. Aerial View of JSW Salem Unit
JSW SALEM VISIONTo become the preferred supplier of special steel long products for domestic
and global end users
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Plant located at Pottaneri, MecheriFrom Salem : 40 KMs towards Metturdam 2 of 17
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Better EverydayA.JSW Steel Ltd, Salem Works Tamilnadu
JSW Salem , part of USD 12 Billion JSW Group, is India’s largest integrated special steel plant located in
Salem Tamilnadu with installed capacity of 1 Million Tonnes Per Annum (MTPA)Salem, Tamilnadu with installed capacity of 1 Million Tonnes Per Annum (MTPA).
MANAGEMENT SYSTEMS
ISO ISO OHSAS IATF AS 9100ISO 9001
ISO 14001
OHSAS 18001
IATF 16949
AS 9100 Rev.D
ISO - International Organization for Standardization / Technical Specifications
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OHSAS - Occupational Health and Safety Assessment Series
AS 9100D - International standard for manufacturers of Aerospace product
IATF - International Automotive Task Force 3 of 19
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Bill t /Bl 250
Product Profile based on shape and sizeBillets /Blooms- 250,
280x370mm,340x400 mm square.Rounds – 180 mm to 310 mm
As Cast
Coils - 5.5 to 32 mmRound Bars- 20.5 to 60 mmFlats- 60 x 7 to 101 x 38 mm Hexagon -20.5 and 32.5 mm
Rolled
Bar And Rod Mill
Product
Round Blooms-60 to 200 mm ɸ *RCS - 55 to 240 mm SquareBlooming
Mill
* Round cornered squares (RCS)
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Better EverydayJSW Steels Limited, Salem
Process Flow ChartIRON COMPLEX STEEL MELT SHOP
PCI*
Hot
Iron ore
CoalCoke
pple
r
Coke Oven plant Hot Metal
Iron ore fines Sinter
Wag
on T
ip
Sinter Plant
Blast Furnace Energy Optimizing Furnace
Ladle Refining Furnace
Continuous Casting Machine
-Bars-Coils
Annealing
ROLLING MILLS
Billets
Bar and Rod Mill
-RR *-RCS*
g-Flats
Blooms
CUSTOMERS
Blooming MillFinal Inspection and Dispatch * -Rolled Round(RR)
-Round Cornered Square(RCS)-Pulverized Coal Injection(PCI) 5 of 19
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Better EverydayBLOOMING MILL - ROLLING PROCESS
Reheating Descaler Roughing Finishing Hot Saw Cooling furnace Descaler Mill Mill Hot Saw Bed
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Better EverydayBlooming Mill – Process Flow DiagramReceiving blooms from START gSteel Melt Shop •250 mm x 250 mm RCS•340 mm x 400 mm RCS
•310 mm RND
Cutting in Hot Saws Bundling
START
Charging of blooms in to Reheating
FurnaceRolling in
Continuous Mill Quality inspectionFurnace
Despatch
Heating of blooms (~1240°C) Front end cutting
•RND – 60 mm to 200 mm
•RCS – 55 mm to 300 mm
END
Descaling Rough rolling in Reversible Mill
Project taken RCS ROUND7 of 18
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Better EverydayProcess of Blooming Mill – Hot Rolling
• The Cast blooms from Steel Melting Shop is Reheated in BF gas fired Reheating Furnace
• Then the bar is descaled and Rough Rolled in Reversible Mill (Stand #1)g ( )
• The uneven front end of the rough rolled bar is removed by Gas cutting
• Then the bar is transferred to Finishing mill, which is an 8 stand continuous mill (Stand #2V to Stand #9H)
• The bar is rolled to customer required shape and dimensions in the finishing millq p g
• Hot bars of temperature about 900 °C rolled in series of 4 Vertical and 4 Horizontal stands. Entry and Exit guides are used in each stand to guide the bar work roll groove.
• The work rolls are made of SG iron and used to for a defined life (based on rolling quantity). Then the work rolls are machined in Lathes to remove the roughness formed on the surface during usage
• After finishing rolling, the bars are cut into customer required size, cooled and sent for inspection8 of 18
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Better EverydayProblem and Goal
Problem Statement:• When the rough rolled bars are fed into the first stand of continuous mill (Stand #2V), the bars are not
entering into the work roll groove due to slippage. This is called Biting problem. This happens frequentlyentering into the work roll groove due to slippage. This is called Biting problem. This happens frequently when stand #2V is changed.
• Biting problem in Stand #2V causes delay of 303 minutes/month in average.
• This leads to production loss of more than 200 MT/Month.
Goals/Objective(s):R d i d l d t biti bl f 303 i t / th t 50 i t / th• Reducing delays due to biting problem from 303 minutes/month to
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Action Plan
Counter measures are:Counter measures are:
• Increasing the First bloom HV Mill entry temperature
• Introducing Metal coating on Stand #2 Work Rolls
M dif i bl f t d tti• Modifying bloom front end cutting
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Better EverydayImplementation of Actions based on DOE
S.NO What ? How?
1 Increasing the First bloom HV Mill t t tBy changing the minimum required t t f fi t bl t 930 °Centry temperature temperature for first blooms to 930 °C
2 Introducing Metal coating on Stand #2 Work RollsBy procuring metal coating device and coating on the machined rolls in roll shop.
3 Modifying bloom front end cutting Training the gas cutters and introducing new procedure for front end cuttingy g g new procedure for front end cutting
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Better EverydayImplementation of Actions
Arc Spraying on Work Rollp y g
Metal Coated Work Roll12 of 18
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Better EverydayImplementation of action
Finishing MillMill
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Better EverydaySide Effect Verification
Action : Introducing Metal coating on Stand #2 Work RollsEffect: Roughness in rolled productTest: Visual InspectionTest: Visual Inspection
Result:Result: Since no roughness found on the rolled bars during trial implementation,
this action can be implemented14 of 18
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Better EverydayImplementation of Actions
Front End Taper CuttingFront End Taper Cutting
Inference: New cutting shape in front end of the bar is introducedInference: New cutting shape in front end of the bar is introduced
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Project Results
350Reduction in Biting Delay
303
250
300h
150
200
nute
s/m
onth
3050
100
Min
30
0
50
Before AfterAchieved Target Linear (Achieved)c e ed a get ea ( c e ed)
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Conclusion
• Delays due to biting problem in continuous mill is reduced from 303 minutes / month to 30 minutes/month in average
• Total time saved – 273 Minutes/month
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THANK YOU
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