Aluminum deoxidation method for nitrogen-containing super stainless steel

A stainless steel and aluminum deoxidation technology, applied in the field of iron and steel metallurgy, can solve the problems of difficult deoxidation process, accelerated furnace lining erosion, shortened furnace lining life and other problems, and achieves the effect of easy industrialized production, reduced erosion, and improved cleanliness.

Active Publication Date: 2020-12-04
NORTHEASTERN UNIV
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  • Claims
  • Application Information

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Problems solved by technology

Extensive use of fluorite not only pollutes the environment, but also accelerates the erosion of the furnace lining, shortens the life of the furnace lining, and increases costs
[0005] In view of the difficulty in aluminum deoxidation process of nitrogen-containing super stainless steel, silicon deoxidation is still widely used in the production of nitrogen-containing super stainless steel, resulting in high total oxygen content

Method used

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  • Aluminum deoxidation method for nitrogen-containing super stainless steel
  • Aluminum deoxidation method for nitrogen-containing super stainless steel
  • Aluminum deoxidation method for nitrogen-containing super stainless steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] The "EAF smelting + AOD smelting + LF refining + continuous casting" process is used to smelt S32750 super duplex stainless steel with a molten steel volume of 30t. The target steel composition (wt.%) is shown in Table 1:

[0045] Table 1 Target steel composition (wt.%)

[0046]

[0047] Aluminum deoxidation method is as follows:

[0048] (1) Carry out EAF smelting and AOD smelting on nitrogen-containing super stainless steel in sequence, and the smelting process is carried out according to conventional methods; in the process of AOD smelting, decarburization, ferrosilicon reduction of chromium, and nitrogen control by blowing argon and nitrogen mixed gas are carried out;

[0049] (2) After the chromium is reduced, the slag is removed, and the exposed area of ​​the molten steel exceeds 90% after the slag is removed. Add 15kg / t lime (CaO content>95wt.%), 6kg / t fluorite (CaF 2 content>wt.85%) and 2kg / t aluminum block for desulfurization;

[0050] (3) After desulfur...

Embodiment 2

[0061] The "EAF smelting + AOD smelting + LF refining + die casting" process is used to smelt S32707 super duplex stainless steel with a molten steel volume of 30t. The target steel composition (wt.%) is shown in Table 3:

[0062] Table 3 Target steel composition (wt.%)

[0063]

[0064] Aluminum deoxidation method is as follows:

[0065] (1) Carry out EAF smelting and AOD smelting on nitrogen-containing super stainless steel in sequence, and the smelting process is carried out according to conventional methods; in the process of AOD smelting, decarburization, ferrosilicon reduction of chromium, and nitrogen control by blowing argon and nitrogen mixed gas are carried out;

[0066] (2) After the chromium is reduced, the slag is removed, and the exposed area of ​​the molten steel exceeds 90% after the slag is removed. Add 17kg / t lime (CaO content>95wt.%), 7kg / t fluorite (CaF 2 content>wt.85%) and 2.5kg / t aluminum block for desulfurization;

[0067] (3) After desulfurizati...

Embodiment 3

[0078] 254SMO super austenitic stainless steel is smelted by the "EAF+VOD+LF+die casting" process, and the amount of molten steel is 30t. Target steel composition (wt.%) is shown in Table 5:

[0079] Table 5 Target steel composition (wt.%)

[0080]

[0081] Aluminum deoxidation method is as follows:

[0082] (1) Carry out EAF smelting and VOD smelting to nitrogen-containing super stainless steel in sequence, and the smelting process is carried out according to conventional methods; in the process of VOD smelting, decarburization and ferrosilicon reduction of chromium are carried out;

[0083] (2) After the chromium is reduced, the slag is removed, and the exposed area of ​​the molten steel exceeds 90% after the slag is removed. Add 20kg / t lime (CaO content>95wt.%), 8kg / t fluorite (CaF 2 content>wt.85%) and 3kg / t aluminum block for desulfurization;

[0084] (3) After desulfurization for 14 minutes, carry out vacuum degassing, and then blow nitrogen to control nitrogen. ...

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Abstract

The invention belongs to the field of ferrous metallurgy, and particularly relates to an aluminum deoxidation method for nitrogen-containing super stainless steel. The aluminum deoxidation method includes the following steps of: carrying out slagging-off after chromium reduction of the nitrogen-containing super stainless steel, adding lime, fluorite and aluminum blocks into molten steel to make new slag, carrying out desulfurization, and then transferring the molten steel to an LF refining station; mixing aluminum shots and silicon-calcium powder, subsequently dividing the mixture into two equal parts, and adding a first part of deoxidizer to carry out slag surface diffusion deoxidation; afterwards, sequentially adding an aluminum wire and a silicon-calcium wire into the molten steel for precipitation deoxidation and calcium treatment; adding a second part of deoxidizer to continue slag surface diffusion deoxidation; and continuing to carry out soft blowing, carrying out tapping afterthe temperature is qualified, and carrying out die casting or continuous casting. According to the aluminum deoxidation method, the content of aluminum in the nitrogen-containing super stainless steelcan be controlled to be 0.015% to 0.030%, the total oxygen content is controlled to be within 20 ppm, precipitation of aluminum nitride caused by the too high aluminum content in a thermal processingand heat treatment process is avoided, and therefore the cold/hot processing performance and the mechanical properties of the nitrogen-containing super stainless steel are improved.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy, in particular to an aluminum deoxidation method for nitrogen-containing super stainless steel. Background technique [0002] Nitrogen-containing super stainless steel mainly includes super duplex stainless steel (such as S32750 and S32707) and super austenitic stainless steel (such as 254SMO). Super duplex stainless steel and super austenitic stainless steel usually contain high nitrogen, and nitrogen mainly exists in the form of interstitial solid solution. The addition of nitrogen can greatly improve the corrosion resistance and fracture strength of super stainless steel without significantly deteriorating its fracture toughness. In addition, nitrogen, as a cheap and efficient austenite structure stabilizing element, can greatly reduce the production cost by "replacing nickel with nitrogen". Compared with ordinary duplex stainless steel and austenitic stainless steel, in add...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/068C21C7/064C21C7/06C21C7/00
CPCC21C7/0056C21C7/0087C21C7/06C21C7/0645C21C7/0685
Inventor 李花兵郑立春冯浩姜周华张树才王晓璐
Owner NORTHEASTERN UNIV
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