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PROCESS FOR M.S. BILLET MANUFACTURING
Grades Manufactured
Mild Steel, En-8, En-9, CK-45, 16 Mn Cr5, 20 Mn Cr5, En-31, En-45, En-45 A, 55 Si 7, 65 Si 7, Corrosion Resistant Steel for TMT application.
Process
i. Scrap Yard
Incoming scrap is analyzed for chemical composition during unloading of truck. The unloaded scrap is then segregated for unwanted material like Cast Iron, non-metallic, non-ferrous, etc.
The selected scrap is then weighed and then transferred to Induction Furnace for melting.
ii. Induction Furnace
Selected scrap and Sponge Iron (In-house production) is melted in Induction Furnace. Slag is removed at regular intervals and a sample is taken 2-3 times during melting for Spectrometer Analysis.
Once we achieve the required Carbon level then de-oxidation is carried out and alloy additions done as required.
The liquid metal is then tapped into Ladle with purging arrangement and transported to Plasma Ladle Refining Furnace.
iii. Plasma Ladle Refining Furnace
Secondary refining is done in PLRF.
Following is carried out in PLRF:
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Raising or maintaining of Temperature |
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Sulphur Removal |
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Micro alloying of elements |
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Homogenization of temperature |
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Homogenization of chemical composition |
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Inclusion removal |
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Holding for sequence casting. |
iv. Continuous Casting Machine
Liquid metal from PLRF is brought to CCM for casting into required size of Billets. The CCM is fully PLC controlled for controlling all Casting parameters.
The sizes available in Electrotherm are:
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100 x 100 mm2 |
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110 x 110 mm2 |
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130 x 130 mm2 |
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160 x 160 mm2 |
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200 x 200 mm2 |
v. Billet Yard
After inspection and surface grinding, wherever required the billets are sent to either market or to Rolling mills in the required lengths.
List of Equipments
| 1. |
2 x 20 MT, 7500 Kw Induction Furnace (Electrotherm make) |
| 2. |
1 x 25 MT, 4200 Kw Plasma Ladle Refining Furnace |
| 3. |
6 x 11 – 2 nos. Continuous Casting Machine |
| 4. |
Shimadzu-PDA-7000 – 18 Channel Spectrometer |
| 5. |
ARL-4460 – 27 Channel Spectrometer |
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Spectra Max- Type-LLM-04BT-32 Channel Spectrometer |
| 7. |
Vertical Ladle Preheating System |
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Horizontal Ladle Preheating System |
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30 MT AOD Converter with Gas Mixing Station |
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600 m3 / hr Cryogenic Oxygen plant |
| 11. |
70 MT EOT Crane |
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2 x 50 MT EOT Crane |
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4 x 20 MT EOT Magnet Crane for SMS Shop |
| 14. |
5 x 15 MT and 2 x 25 MT Magnet Crane for Billet Yard and Scrap Yard |
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Cutting Torches with Iron Powder Dispensing Units |
| 16. |
Double Strand Wire Injection System |
| 17. |
2 nos. Sintering Panels for Induction Furnace (Electrotherm make) |
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PROCESS FOR STAINLESS STEEL BILLET MANUFACTURING
Grades Manufactured
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300 series
AISI 304, AISI 304L, AISI 316, AISI 316L, AISI 302, AISI 303, AISI 321 |
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400 series
AISI 410, AISI 420, AISI 430 |
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200 series
Full Range starting from 0.30% Ni to 6.0% Ni for Utensil and Wire Rods Application. |
Process
i. Scrap Yard
Selected scrap free from oil, grease, cast iron is used for manufacturing of Stainless Steel. The scrap and Sponge Iron is weighed and transferred to Induction Furnace for melting.
ii. Induction Furnace
Scrap and Sponge Iron received from Scrap Yard is melted in Induction Furnace. After complete melting of Scrap and Sponge Iron as per calculation H.C.Fe Cr is added in Induction Furnace. This liquid metal is then poured into transfer ladle and after weightment is poured into AOD Converter.
iii. AOD Converter
Argon Oxygen Decarbonisation in Converter is a process which utilizes cheaper high carbon Ferro Alloys for Stainless Steel manufacturing.
In AOD Converter Carbon is brought down to desired level by injecting Oxygen and Argon / Nitrogen in various proportion to achieve a very low carbon content of the liquid metal.
After achieving the carbon level the melt is subjected to deoxidation and reversal of chromium and manganese from the slag.
The slag after deoxidation is removed and the process is called Slag-off. After addition of balancing elements the liquid metal is tapped into Ladles with bottom purging and is transferred to Continuous Casting Machine. Spectrometer samples are taken from Induction Furnace and AOD at various stages for checking of chemical composition.
Continuous Casting Machine
The liquid Stainless Steel is then cast into required Billet sizes through Close Casting technique by which liquid stream does not come into contact of atmospheric air.
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