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Method for smelting ultra-low carbon steel

An ultra-low carbon steel and converter smelting technology, applied in the field of smelting ultra-low carbon steel, can solve the problems of reducing slag oxidation, unfavorable, and molten steel dissolved oxygen, etc., to reduce production costs, increase production costs, and reduce oxidation Effect

Active Publication Date: 2012-10-10
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there is a problem in all current technologies in this area, that is, the reduction of slag oxidation will inevitably lead to the reduction of dissolved oxygen in molten steel, which is not conducive to the subsequent RH vacuum decarburization treatment.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Smelting ultra-low carbon IF steel, the adopted process route is: molten iron pretreatment desulfurization-260t converter blowing-RH vacuum refining-slab continuous casting.

[0018] Hot metal pretreatment and desulfurization: use magnesium powder + lime powder for desulfurization, and after desulfurization, carry out slag removal operation to ensure the effect of slag removal. The sulfur content in molten iron after desulfurization is 0.0030%.

[0019] Converter smelting: the scrap steel is put into the converter and then mixed with molten iron, the oxygen blowing time of converter smelting is controlled at 13min, and the oxygen blowing flow rate of the oxygen lance is controlled at 40000~59000m 3 / h, the bottom blowing intensity is controlled at 7-8m in the first 1-9min 3 / min, the bottom blowing intensity is controlled at 8-12m after 9min of blowing to the end of blowing 3 / min; control the quality of slag-forming materials such as lime and lightly burned dolomite e...

Embodiment 2

[0025] Smelting ultra-low carbon IF steel, the adopted process route is: molten iron pretreatment desulfurization-260t converter blowing-RH vacuum refining-slab continuous casting.

[0026] Hot metal pretreatment and desulfurization: use magnesium powder injection + lime powder for desulfurization, and then carry out slag removal operation after desulfurization. The sulfur content in molten iron after desulfurization is 0.0026%.

[0027] Converter smelting: the scrap steel is put into the converter and then mixed with molten iron, the oxygen blowing time of converter smelting is controlled at 13min, and the oxygen blowing flow rate of the oxygen lance is controlled at 40000~59000m 3 / h, the bottom blowing intensity is controlled at 7-8m in the first 1-9min 3 / min, the bottom blowing intensity is controlled at 8-12m after 9min of blowing to the end of blowing 3 / min; control the quality of slag-forming materials such as lime and lightly burned dolomite entering the converter, ...

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Abstract

The invention provides a method for melting ultra-low carbon steel. The method adopts a desulfuration of molten iron-converter-RH-continuous casting process, wherein a sulfur content in the molten iron is 0.002%-0.006% after desulphurization; converter smelting controls oxygen blowing time, an oxygen gun flow, a bottom-blowing intensity and a smelting period, adopts slag-stopping tapping, steel tapping with a content of C being 0.06%-0.08% and with a temperature of 1650-1680 DEG C, and an oxygen content in the molten iron is 0.03%-0.05%; an RH adopts forced decarburization with a highest vacuum degree of 67-100 MPa and decarburization time of 15-27 min, and a carbon content in the molten iron is 0.0010%-0.0020% and a dissolved oxygen content in the molten iron is 0.025%-0.040% after the decarburization; the molten iron is recycled for 3-5 min after deoxidation by adding aluminium and recycled for another 3-5 min after adding other alloys; a nitrogen content in the molten iron is 0.0015%-0.0035%, and the temperature is 1590-1640 DEG C; and killed steel treatment is carried out for 10-30 min. The method adopts converter tapping with a high carbon and low oxygen content, can use less or not use slag modified agents during the tapping process, accelerates the production rhythm, makes the molten steel cleaner, and reduces the production cost.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, and relates to a method for smelting ultra-low carbon steel, in particular to a method for stably controlling molten steel carbon, oxygen content, molten steel temperature and molten steel cleanliness when smelting ultra-low carbon steel. Background technique [0002] Ultra-low carbon steel refers to the steel with carbon content below 0.010%. At present, there are two conventional processes for ultra-low carbon steel smelting: one is converter blowing-RH vacuum treatment-continuous casting process. The biggest difficulty in this process is the control of molten steel cleanliness. Due to the high dissolved oxygen content in molten steel during the converter tapping process, The slag has a strong oxidizing property, and it is inevitable for the converter slag to enter the ladle. Therefore, during the RH vacuum treatment process, the top slag with high oxidizing property will continue to oxidiz...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/28C21C7/00C22C33/04
CPCY02P10/20
Inventor 赵成林李广帮廖相巍张维维王丽娟
Owner ANGANG STEEL CO LTD
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