Steel Melting ShopSteel Melting Shop

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 : 03nos3. Tank Degasser : 01nos4. R-H Degasser : 01nos5. Combi caster : 01nos6. Billet caster : 01nos7. Slab caster : 01nos

main products are:-1.Beam Blanks2.Blooms3.Billets4.Rounds5.Slabs

STEEL MELTING SHOP -II

EAFBucket chargi

ng

Hot Metal Pouring to EAF

Ladle refining Furnace

Hot metal ladle

Process Flow Diagram Steel Melt Shop IIProcess Flow Diagram Steel Melt Shop II

Vacuum Degassing

Combi caster

Billet caster

Slab caster

Beam Blank,Bloom ,Round

Billet ,Round

Slab

Continuous feeding of DRI from DRI Plant

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

• 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 shopSteel Melting shop

Inputs for EAFInputs 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 maxTemp : 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 : 48 minEBT filling time : 3 minSlag pot changing/ pit cleaning time : 8 minHot metal pouring time : 5 minArc time : 29 minTapping time : 3 min

Control parameters:

Power in put : 70 to 75 MW Oxygen input : 120 Nm3/minTap Chemistry

%C : 0.05 %P : 0.010% Other elements : Trace

Taping Temperature : 1620°C

Most important chemical reactions: 

• Decarburization : [c] + o = co

• Manganese reaction : [Mn] + o =(MnO)

• Desiliconizing : [Si] + O = (SiO2)

(SiO2) + (CaO) = (2Cao.SiO2)

• Dephosphorization : [P] + O = (P2O5)

(P2O5)+ (CaO) = (3 CaO.P2O5)

• 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 developmentin 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)Ladle refining Furnace(LRF)No of LRF : 3Make : SMS DEMAGCapacity : 100T eachTransformer ratingLRF I : 10 MVALRF II & III : 18 MVA

Main function of LRF:

1.Refining of steel2.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 DegasserVacuum Degasser

VACUUM DEGASSER• Design, Engg and Supply : Danieli ,Italy

• Vacuum degassing mainly based on siverts law

• Salient Features• Suction Capacity : 350 Kg/hr at 0.5 torr

• Pump down time : 5 minutes at 0.5 torr

• Vacuum System : 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

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 ( 3 1.5m/sec or 3 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.

RH-DegasserRH-Degasser

Steel Melt Shop II Steel Melt Shop II No of casterNo of caster : :

331.Four strand Combi 1.Four strand Combi

caster.caster.2.Six strand Billet caster.2.Six strand Billet caster.3.Single strand Slab caster.3.Single strand Slab caster.

Continuous Casting MachineContinuous Casting Machine1.Four strand combi caster: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 MachineContinuous Casting Machine2.Six strand Billet caster:2.Six strand Billet caster: Products : 142 mm,162 mm, 200 mm, 220 mm Round , 130x130

mm ,150x150 mm , 200x200 mm

Continuous Casting MachineContinuous Casting Machine3.Single strand slab caster:3.Single strand slab caster:Products : Width 1300 mm to 2600 mm

Thickness 215 mm, 250 mm and 280 mm

Thank YouThank You