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Method for controlling nitrogen content in Al deoxidization steel by converter process

An aluminum deoxidizing steel nitrogen and converter technology, applied in the field of iron and steel metallurgy, can solve problems such as nitrogen increase, and achieve the effect of reducing the nitrogen content of the slab and preventing nitrogen increase

Active Publication Date: 2009-06-17
PANGANG GROUP RESEARCH INSTITUTE CO LTD +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0016] The technical problem solved by the present invention is to prevent the nitrogen increase of aluminum deoxidized steel produced by the converter process

Method used

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  • Method for controlling nitrogen content in Al deoxidization steel by converter process
  • Method for controlling nitrogen content in Al deoxidization steel by converter process
  • Method for controlling nitrogen content in Al deoxidization steel by converter process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] The experimental conditions are:

[0039] (1) Nominal 120t top and bottom double blowing converter, after blowing for 10min, the bottom blowing gas is changed from N 2 Converted to Ar gas, the production steel grade is P510L, and the production process flow is LD-LF-CC.

[0040] (2) When the converter is charged, the amount of scrap steel added is 75kg / t steel.

[0041] (3) Using active lime (containing CaO85.0~95.0% by weight, 5%≥MgO>0, 2.5%≥SiO 2 >0, the rest are burn reduction and Al 2 O 3 , P, S and other trace impurities) slag, when the converter starts slagging, the basicity of the converter slag CaO / SiO 2 Control at 5.

[0042] (4) The slag added at the beginning of tapping contains by weight: CaO: 72.2%, SiO 2 : 2.7%, Al 2 O 3 : 3.2%, Na 2 O: 2.8%, CaF 2 : 11.6%, MgO: 3.5%, N: 0.02%, and the rest are trace impurities such as burning and P, S, etc., the addition amount is 7kg / t steel; after adding the slag, add aluminum and other alloys.

[0043] (5) T...

Embodiment 2

[0047] The experimental conditions are:

[0048] (1) Nominal 120t top and bottom double blowing converter, after blowing for 10min, the bottom blowing gas is changed from N 2 Converted to Ar gas, the production steel grade is P510L, and the production process flow is LD-LF-CC.

[0049] (2) When the converter is charged, the amount of scrap steel added is 60kg / t steel.

[0050] (3) Using active lime (containing CaO85.0~95.0% by weight, 5%≥MgO>0, 2.5%≥SiO 2 >0, the rest are burn reduction and Al 2 O 3 , P, S and other trace impurities) slag, when the converter starts slagging, the basicity of the converter slag CaO / SiO 2 Control at 6.

[0051] (4) The slag added at the beginning of tapping contains by weight: CaO: 74.6%, SiO 2 : 1.8%, Al 2 O 3 : 2.6%, Na 2 O: 2.7%, CaF 2 : 9.4%, MgO: 4.4%, N: 0.03%, and the rest are ignition reduction and trace impurities such as P and S. The addition amount is 8kg / t steel; after adding slag, add aluminum and other alloys.

[0052] (5...

Embodiment 3

[0065] The experimental conditions are:

[0066] (1) Nominal 120t top and bottom double blowing converter, after blowing for 10min, the bottom blowing gas is changed from N 2 Converted to Ar gas, the production steel grade is 20CrMoH, and the production process flow is LD—LF—RH—BCC.

[0067] (2) When the converter is charged, the amount of scrap steel added is 0kg / t steel.

[0068] (3) Using active lime (containing CaO85.0~95.0% by weight, 5%≥MgO>0, 2.5%≥SiO 2 >0, the rest are burn reduction and Al 2 O 3 , P, S and other trace impurities) slag, when the converter starts slagging, the basicity of the converter slag CaO / SiO 2 Control at 7.

[0069] (4) The slag added at the beginning of tapping contains CaO: 73.3%, SiO by weight percentage 2 : 2.4%, Al 2 O 3 : 2.7%, Na 2 O: 2.8%, CaF 2: 10.5%, MgO: 4.0%, N: 0.03%, the rest are trace impurities such as burning and P, S, etc., the addition amount is 9kg / t steel; after adding the slag, add aluminum and other alloys.

[0...

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Abstract

The invention belongs to the technical field of ferrous metallurgy, in particular relates to a method for controlling nitrogen content of aluminum killed steel produced in a converter process, and is used for preventing the problem that the nitrogen content increases in the aluminum killed steel produced in the converter process. The technical problem is solved by controlling the nitrogen content of the aluminum killed steel produced in the converter process according to the technical proposal as follows: the alkalinity of converter slag CaO / SiO2 is adjusted to 5-7 when a converter starts to produce the slag, the denitrification rate can be increased in the converter smelting process by controlling the alkalinity of the converter slag, the denitrification rate is increased from 50%-70% to 65%-85%, and the terminal nitrogen content of the molten steel in the converter can be controlled within 15PPm. The alkalinity is controlled, special slag is added, and a seal washer with brim is employed to seal between a steel ladle lower opening and a protection tube before starting continuous casting, thus realizing the stable control that the casting blank nitrogen content is not more than 35PPm by an LD-LF-SCC process and the casting blank nitrogen content is not more than 30PPm by an LD-LF-RH-BCC process.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a method for controlling the nitrogen content of aluminum deoxidized steel produced by a converter process. Background technique [0002] With the development of industry and technology, various industries have more and more stringent requirements on the quality of steel. The nitrogen content in the steel has a great influence on the mechanical properties of the steel, especially in the production of low carbon steel and hard wire steel wire for deep drawing conditions, the adverse effect of nitrogen is particularly obvious. When the molten steel solidifies, the precipitation of gaseous nitrogen dissolved in the steel will cause segregation of elements or produce pores in the steel casting, which will reduce the performance of the steel. Increased nitrogen content in steel increases yield limit, strength limit and hardness, decreases plasticity, dec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C5/30C21C7/076
CPCY02P10/20
Inventor 陈天明杨素波陈永曾建华唐历李清春张均祥李桂军江南红顾武安冯远超邱涛
Owner PANGANG GROUP RESEARCH INSTITUTE CO LTD
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