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: 2011-04-20
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 combined blowing converter, after blowing for 10 minutes, the bottom blowing gas is composed of N 2 Converted to Ar gas, the production steel grade is P510L, and the production process is LD-LF-CC.

[0040] (2) The amount of steel scrap added when charging the converter is 75kg / t steel.

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

[0042] (4) The slag material added at the beginning of tapping contains: 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 ignition loss and P, S, etc., the addition amount is 7kg / t steel; after adding slag, add aluminum and other alloys.

[0043...

Embodiment 2

[0047] The experimental conditions are:

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

[0049] (2) The amount of steel scrap added when charging the converter is 60kg / t steel.

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

[0051] (4) The slag material added at the beginning of tapping contains: 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 trace impurities such as ignition loss and P, S, etc., the addition amount is 8kg / t steel; after adding slag, add aluminum and other alloys.

[0052]...

Embodiment 3

[0065] The experimental conditions are:

[0066] (1) Nominal 120t top and bottom combined blowing converter, after blowing for 10 minutes, the bottom blowing gas is composed of N 2 Converted to Ar gas, the production steel grade is 20CrMoH, and the production process is LD-LF-RH-BCC.

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

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

[0069] (4) The slag material added at the beginning of tapping contains CaO: 73.3%, SiO 2 : 2.4%, Al 2 o 3 : 2.7%, Na 2 O: 2.8%, CaF2 : 10.5%, MgO: 4.0%, N: 0.03%, the rest are trace impurities such as ignition loss and P, S, etc., the addition amount is 9kg / t steel; after adding slag, add aluminum and other alloys.

[0070]...

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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 increasingly stringent requirements on the quality of steel. The nitrogen content in steel has a great influence on the mechanical properties of steel, especially in the production of low carbon steel and hard wire for deep drawing, the adverse effect of nitrogen is particularly obvious. When molten steel solidifies, the precipitation of gaseous nitrogen dissolved in steel will cause segregation of elements or cause pores in steel castings, which will reduce the performance of steel. The nitrogen content in the steel increases, the yield limit, strength limit and hardness increase, the plasticity decreases, the impact toughness decreases, and...

Claims

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Application Information

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Patent Type & Authority Patents(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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