Steel Melting Shop Presentation With EAF_LRF_CCM Route

Steel Melting Shop

STEEL MELTING SHOP -II Introduction:Jindal Steel & Power Ltd. Has got a sophisticated STEEL MELTING SHOP with a capacity of 2.4 million tones/annum. The main units installed in SMS – II are:1. Ultra high power EAF’S (EBT type) : 2nos. 2. Ladle refining furnace : 03nos 3. Tank Degasser : 01nos 4. R-H Degasser : 01nos 5. Combi caster : 01nos 6. Billet caster : 01nos 7. Slab caster : 01nos main products are:1.Beam Blanks 2.Blooms 3.Billets 4.Rounds 5.Slabs

Process Flow Diagram Steel Melt Shop II Continuous feeding of DRI from DRI Plant

Hot metal ladle

Hot Metal Pouring to EAF

EAF Bucket charging

Beam Blank, Bloom ,Round Combi caster

Billet ,Round

Billet caster Ladle refining Furnace

Slab Vacuum Degassing

Slab caster

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Two ultra high power Electric Arc Furnace Make : SMS DEMAG Capacity : 100 mT Furnace transformer rating : 100 MVA Electrode dia : 24"(600 mm) No of VLB(for Oxygen lancing) : 4 Furnace lining : Magnesia Carbon bricks. Tap Hole : EBT Type Average production 52heats/day SMS –II produced 1.76 MTPA of steel last year 2010

Electric Arc Furnace •

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• • • • • •

Furnace body – shell, hearth, walls, spout, doors etc. Gears for furnace body movement . Roof and roof-lift arrangements. 3 graphite Electrodes, there holders . Electrical equipments – transformer , cables electrode control mechanism etc. Water cooled panels tube -to-tube design(steel and copper tubes) Cu –blocks in lining Manipulator for – 2 oxygen lances, 1 carbon lance Manipulator for sampling and temperature taking TOPARC (arc stability measurement) Water spray cooled roof

Steel Melting shop Inputs for EAF  Metallic inputs:  Hot metal from blast furnace(50 to 55%). %C : 3.8 to 4.2% %Si : 0.7 % max %P : 0.13 max Temp : 1280 deg min  DRI (Lumps +Fines) from DRI Plant (40 to 49%). %C : 0.1 max %Fe(met) : 81 min %SiO2 : 3.5  Scrap(1-5%)  Flux:  Lime from LDP (Lime and Dololime Plant)  Burned dolomite from LDP

 Other inputs:  Oxygen from Oxygen plant.  CPC (Calcined petroleum coke)  HSD (High speed Diesel)

Functions of EAF: 1.Melting of Solid inputs and homogenization of steel bath. 2.Raising the temperature of the melt to ≈1620 C for tapping. 3.Decarburisation. 4.Dephosphurisation. 5.Slag free and compact stream tapping 6.Flexibility to produce a variety of grades of steel ADVANTAGE: 1.Relatively small in size 2.cleaner environment 3.Flexibilty to produce a variety of grades of steel 4.Precise control

Heat cycle: Tap to tap time EBT filling time Slag pot changing/ pit cleaning time Hot metal pouring time Arc time Tapping time

: : : : : :

48 min 3 min 8 min 5 min 29 min 3 min

: :

70 to 75 MW 120 Nm3/min

: : : :

0.05 0.010 Trace 1620°C

Control parameters: Power in put Oxygen input Tap Chemistry %C %P % Other elements Taping Temperature

Most important chemical reactions: •

Decarburization : [c] + o = co

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Manganese reaction : [Mn] + o =(MnO) Desiliconizing : [Si] + O = (SiO2) (SiO2) + (CaO) = (2Cao.SiO2)

•

Dephosphorization : [P] + O = (P2O5) (P2O5)+ (CaO) = (3 CaO.P2O5)

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Iron Combustion : [Fe] + O = (FeO) Desulphurization : [S] + (CaO) = (CaS) + O

•

[] in steel bath, () in slag

Average Slag composition in JSPL All are in percentage • • • • •

SiO2 16.75 FeO 31.06 CaO 28.52 MgO 12.70 Al2O3 8.77

Basicity 1.70

FOAMY SLAG •

Principle of foamy slag – emulsion of metal droplets and gas bubbles in slag

• First step C(Steel)+ O =CO –bubbles Gives energy

• Second step •

Feo(slag) + C = Fe(back to steel) + CO- bubbles Costs energy

• Third Step • •

C(slag) + O = CO – bubbles Fe + O= FeO Gives energy

Advantage of modern development in EAF Advantage of Foamy slag practice • • • • •

Decrease electrical energy consumption Increase refractory life and panel life Reduce nitrogen problem by shielding effect Decrease electrode consumption Increase productivity

Advantage of UHP • Enables Faster melting of solid charge • Decrease tap to tap time hence increase productivity Advantage of oxygen lancing • Faster removal of carbon & other impurities • Faster generation of foamy slag

Ladle refining Furnace(LRF) No of LRF : Make : Capacity : Transformer rating LRF I : LRF II & III :

3 SMS DEMAG 100T each

10 MVA 18 MVA

Main function of LRF: 1.Refining of steel 2.Achieving desired chemistry as per the requirement by adding various Ferro alloys. 3.Thermal and Chemical homogenization of the bath by argon purging. 4.Attaining the lifting Temperature of the steel to maintain the desired super heat.

Vacuum Degasser

VACUUM DEGASSER • •

Design, Engg and Supply : Danieli ,Italy Vacuum degassing mainly based on siverts law

• Salient Features • • •

•

Suction Capacity Pump down time Vacuum System

: : :

350 Kg/hr at 0.5 torr 5 minutes at 0.5 torr 9 Steam ejectors 3+1 condensers works on successive compression of off-gas in a series of stream ejectors. Argon Stirring : Continuous 14 Nm3/hrs

Functions • remove gaseous element, non-metallic inclusion and sulphur from the steel

RH-Degasser Process -Vacuum evacuation of main chamber. -Steel is raising in to lower vessel equivalent to Ferro static pressure. -Circulation effect is produced by bubbling Ar in the inlet snorkel. -Dissolved gasses and Ar released into the vacuum. -Steel accelerates through the inlet snorkel ( ̴ 1.5m/sec or ̴ 1mt/min). -Steel returns to ladle through 2 chamber vacuum-lock and alloy chute. -Temperature loss is low (RH-vessel preheated). Advantages: -Shortening of the primary metallurgy process short treatment -> high availability. -Achievable metallurgical results: ̴ 1.5 ppm H, ̴ 15 ppm C, ̴ 1 ppm O -High alloy recovery yields. - Homogenization, improved cleanliness.

Steel Melt Shop II No of caster : 3 1.Four strand Combi caster. 2.Six strand Billet caster. 3.Single strand Slab caster.

Continuous Casting Machine 1.Four strand combi caster: 

Products

:

420x480x120 mm Beam blank, 355x280x90 mm Beam blank, 285x390 mm 250x250 mm, 305,280,255 mm Round.

Continuous Casting Machine 2.Six strand Billet caster: 

Products

:

142 mm,162 mm, 200 mm, 220 mm Round , 130x130 mm ,150x150 mm , 200x200 mm

Continuous Casting Machine 3.Single strand slab caster: Products

:

Width 1300 mm to 2600 mm Thickness 215 mm, 250 mm and 280 mm

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