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Molten steel refining and continuous casting method for reducing subsurface bubbles of low-silicon low-aluminum oxygen-containing steel casting blank

A molten steel and steel casting technology, applied in the field of iron and steel metallurgy, can solve the problems of affecting the surface quality of steel, easy generation of subcutaneous bubbles in billets, low content of Si and Al, etc.

Active Publication Date: 2020-01-14
SGIS SONGSHAN CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Low-silicon and low-aluminum oxygen-containing steel has high dissolved oxygen and low Si and Al content in the steel. [O] precipitated during solidification of molten steel mainly reacts with [C] to form CO, which leads to subcutaneous air bubbles in the cast billet, which ultimately affects Steel Surface Quality

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] This embodiment provides a method for refining molten steel for reducing subcutaneous air bubbles of a low-silicon, low-alumina, oxygen-containing steel slab, which includes the following steps:

[0056](1) Steps in the converter: use a 120t converter to smelt 1215 low-carbon high-sulfur free-cutting steel (C content is 0.04% to 0.08%, Si content is 0.015 to 0.05%, Al content is ≤0.005%), and the converter adds scrap steel 24.3 t, molten iron 104.2t, end point C content is 0.036%, a [O] It is 752ppm. 1500Kg of low-carbon ferromanganese, 450Kg of manganese ferrosilicon, 980Kg of ferrosulfur, 230Kg of ferrophosphorus, 118Kg of ferroaluminum are added to the converter tapping process for deoxidation alloying; argon is blown at the bottom of the ladle, and 500Kg of lime is added for slag washing.

[0057] (2) Steps in the argon station: After blowing argon for 3 minutes, the oxygen value is fixed at 98ppm, and the aluminum wire is fed to 48m. The Si content of the sample a...

Embodiment 2

[0061] This embodiment provides a method for refining molten steel for reducing subcutaneous air bubbles of a low-silicon, low-alumina, oxygen-containing steel slab, which includes the following steps:

[0062] (1) Steps in the converter: use a 120t converter to smelt 1215 low-carbon high-sulfur free-cutting steel, add 26.1t of scrap steel to the converter, 103.5t of molten iron, and the C content at the end point is 0.032%, a [O] It is 786ppm. 1495Kg of low-carbon ferromanganese, 500Kg of ferromanganese, 500Kg of ferromanganese, 900Kg of ferrosulfur, 100Kg of ferrophosphorus, and 120Kg of ferroaluminum are added to the converter tapping process for deoxidation alloying; argon is blown at the bottom of the ladle, and 500Kg of lime is added for slag washing.

[0063] (2) Steps in the argon station: After blowing argon for 3 minutes in the molten steel at the argon station, the oxygen value is fixed at 69ppm, and the aluminum wire is fed to 20m. The Si content of the sample at t...

Embodiment 3

[0067] This embodiment provides a method for refining molten steel for reducing subcutaneous air bubbles of a low-silicon, low-alumina, oxygen-containing steel slab, which includes the following steps:

[0068] (1) Steps in the converter: Use a 120t converter to smelt 1215 low-carbon high-sulfur free-cutting steel. The converter adds 26.8t of scrap steel and 102.9t of molten iron. The C content at the end point is 0.049%, a [O] It is 551ppm. 1510Kg of low-carbon ferromanganese, 480Kg of ferromanganese, 480Kg of ferrosilicon, 100Kg of ferrosulfur, 50Kg of ferrophosphorus, and 135Kg of ferroaluminum are added in the tapping process of the converter for deoxidation alloying; argon is blown at the bottom of the ladle, and 500Kg of lime is added for slag washing.

[0069] (2) Steps in the argon station: After the molten steel in the argon station blows argon for 3 minutes, the oxygen value is fixed at 37ppm, the Si content of the sample in the argon station is 0.053%, and the Si co...

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PUM

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Abstract

The embodiment of the invention provides a molten steel refining and continuous casting method for reducing subsurface bubbles of a low-silicon low-aluminum oxygen-containing steel casting blank and relates to the technical field of ferrous metallurgy. The molten steel refining method mainly comprises the steps that molten steel passes through a rotating furnace and an argon station and is subjected to LF refining in sequence, and a step control method is adopted for controlling the content of dissolved oxygen and Si in the molten steel and the content of MnO in refining slag. The method comprises the specific steps that the content of Si in the molten steel in the early period of LF refining is controlled to be 0.04-0.06%; 5-8 minutes before LF refining is ended, silicone and iron are added for increasing the content of Si in the molten steel to 0.015-0.035%. By controlling the content of dissolved oxygen and Si in the molten steel and the oxidability of the refining slag step by step, the content of the dissolved oxygen of the refined molten steel is 35-60 ppm, the content of Si of the refined molten steel is 0.015-0.035%, and the content of MnO of the refining slag is lower than10%. The low-silicon low-aluminum oxygen-containing steel casting blank produced by adopting the molten steel has good surface quality and does not have subsurface bubbles or needle hole defects.

Description

technical field [0001] The application relates to the technical field of iron and steel metallurgy, in particular to a molten steel refining and continuous casting method for reducing subcutaneous air bubbles in low-silicon, low-aluminum, oxygen-containing steel slabs. Background technique [0002] Low-silicon and low-aluminum oxygen-containing steel has high dissolved oxygen and low Si and Al content in the steel. [O] precipitated during solidification of molten steel mainly reacts with [C] to form CO, which leads to subcutaneous air bubbles in the cast billet, which ultimately affects Steel surface quality. [0003] Chinese patent application "A method for reducing subcutaneous air bubbles in ultra-low carbon steel slabs", its production method and parameters: end point carbon control 0.040~0.065%, a [O] 0.035~0.060%, the target temperature of tapping is 1680~1700℃, no pre-deoxidation is required for tapping; after adding aluminum pellets for deoxidation in RH furnace, th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/00C21C7/06B22D11/116
CPCB22D11/116C21C7/0006C21C7/0056C21C7/0087C21C7/06
Inventor 张志明谢杰智寻忠忠万翔刘志龙李成良刘春林郭俊宇敖永明唐梦飞周楠
Owner SGIS SONGSHAN CO LTD