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LF refining method of titanium-containing austenitic stainless steel

A technology of austenitic stainless steel and refining slag, which is applied in the field of LF refining of titanium-containing austenitic stainless steel, can solve problems such as affecting the quality of normal casting products, occupational hazards of silicosis and fluorine, affecting product quality, etc., and achieves suppression of harmful inclusions The formation of magnesia-aluminum spinel, the effect of avoiding occupational hazards and improving product quality

Inactive Publication Date: 2020-04-10
GANSU JIU STEEL GRP HONGXING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Titanium is an easily oxidized element. The biggest problem in the production process is that during the LF refining process, titanium is oxidized into the slag, resulting in low yield of titanium
In addition, in the production process of titanium-containing austenitic stainless steel, problems such as nozzle nodules and crystallizer fish formation may occur in the continuous casting process due to the large amount of Ti nitrides and oxides generated, which will affect the normal casting and subsequent product quality. , eventually lead to quality defects such as inclusions and line scales in the rolling process of stainless steel plates and cold-rolled thin plates, and in severe cases, it will lead to quality accidents such as broken pouring or overall rejection of the coil
[0004] At present, lime, fluorite and CaO-Al are generally added in the LF refining process 2 o 3 slag-based refining slag, but the yield of titanium is low, in addition, production workers exposed to mixed dust containing fluorite, can cause silicosis and occupational hazards of fluorine
Al generated during the production of titanium-containing austenitic stainless steel 2 o 3 -MgO, Al 2 o 3 -MgO-TiO x High melting point, easy to deposit inside the submerged nozzle, causing nozzle blockage, affecting the quality of the final product

Method used

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Examples

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Effect test

Embodiment 1

[0024] The LF refining method of steel grade 321 titanium-containing austenitic stainless steel and titanium-containing austenitic stainless steel includes the following steps:

[0025] 1. Tap the molten steel processed by the AOD furnace to the ladle. Before tapping the AOD furnace, open the bottom of the ladle and blow argon to clean the ladle. The ladle is baked to 700℃. After cleaning, the molten steel is quickly poured from the AOD furnace into the baked ladle at 1640℃. The weight percentage of molten steel composition after treatment is:

[0026] C: 0.015%, Si: 0.50%, Mn: 1.10%, P: 0.03%, Cr: 17.1%, Ni: 9.1%, S: 0.002%, N≤0.01%, the rest is Fe and inevitable impurities;

[0027] 2. Lifting to the slagging station to remove the slag: transport the ladle to the slagging station for slagging treatment, slag thickness: 30mm;

[0028] 3. LF enters the station for aluminum deoxidation and calcium treatment: transport the ladle to the LF furnace, blow argon for 3 minutes after enterin...

Embodiment 2

[0034] The LF refining method of steel grade 321 titanium-containing austenitic stainless steel and titanium-containing austenitic stainless steel includes the following steps:

[0035] 1. Tap the molten steel processed by the AOD furnace to the ladle. Before tapping the AOD furnace, open the bottom of the ladle and blow argon to clean the ladle. The ladle is baked to 900°C. After cleaning, the molten steel is quickly poured from the AOD furnace into the baked ladle at 1680°C. The weight percentage of molten steel composition after treatment is:

[0036] C: 0.025%, Si: 0.60%, Mn: 1.30%, P: 0.027%, Cr: 17.4%, Ni: 9.3%, S: 0.0015%, N: 0.009%, the rest is Fe and unavoidable impurities;

[0037] 2. Lifting to the slagging station to remove the slag: transport the ladle to the slagging station for slagging treatment, slag thickness: 20mm;

[0038] 3. LF enters the station for aluminum deoxidation and calcium treatment: transport the ladle to the LF furnace, blow argon for 5 minutes after ...

Embodiment 3

[0044] The LF refining method of steel grade 321 titanium-containing austenitic stainless steel and titanium-containing austenitic stainless steel includes the following steps:

[0045] 1. Tap the molten steel processed by the AOD furnace to the ladle. Before tapping the AOD furnace, open the bottom of the ladle and blow argon to clean the ladle. The ladle is baked to 800°C. After cleaning, the molten steel is quickly poured from the AOD furnace into the baked ladle at 1660°C. The weight percentage of molten steel composition after treatment is:

[0046] C: 0.022%, Si: 0.54%, Mn: 1.20%, P: 0.025%, Cr: 17.2%, Ni: 9.2%, S: 0.0012%, N: 0.008%, the rest is Fe and unavoidable impurities;

[0047] 2. Lifting to the slagging station to remove the slag: transport the ladle to the slagging station for slagging treatment, slag thickness: 25mm;

[0048] 3. LF enters the station for aluminum deoxidation and calcium treatment: transport the ladle to the LF furnace, blow argon for 4 minutes after ...

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Abstract

The invention discloses an LF refining method of titanium-containing austenitic stainless steel. The LF refining method comprises the following steps: (1) tapping molten steel subjected to AOD treatment to a steel ladle; (2) hoisting the steel ladle to a slagging-off station to remove slag; (3) performing LF pull-in aluminum deoxidation and calcium treatment; (4) performing LF heightened titaniumrefining slag and lime slagging; (5) performing LF titanium alloying; (6) performing LF component and temperature confirming and performing weak blow and pull-out; (7) performing continuous casting. According to the method, the high-titanium refining slag is added in the LF refining process, TiO2 in the slag is saturated in advance, the activity of TiO2 in the slag is improved, and the oxidation reaction of titanium is inhibited. High-titanium refining slag and lime are adopted for slagging, so the slagging speed is high, and occupational hazards caused by fluorite are avoided. Meanwhile, an aluminum deoxidation-calcium treatment-titanium alloying process route is adopted, so formation of high-melting-point inclusions in the production process is prevented or inhibited, and the product quality is improved.

Description

Technical field [0001] The invention belongs to the technical field of stainless steel smelting, and particularly relates to an LF refining method of titanium-containing austenitic stainless steel. Background technique [0002] Titanium-containing austenitic stainless steel is added Ti element on the basis of 304 stainless steel. Due to the high affinity between Ti and C, C in steel first forms TiC with Ti, which inhibits the problem of chromium depletion caused by the formation of chromium carbide by Cr and C. Thereby improving its corrosion resistance. [0003] Titanium-containing austenitic stainless steel is mainly used in high-temperature hydrogen-resistant environment, chemical industry, pressure vessel and other fields. Titanium is an element that is easily oxidized. The biggest problem in the production process is that during the LF refining process, titanium is oxidized into the slag, resulting in a low yield of titanium. In addition, in the production process of titaniu...

Claims

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Application Information

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IPC IPC(8): C21C7/00C21C7/06C21C7/072C22C33/04C22C38/02C22C38/04C22C38/50
CPCC21C7/0006C21C7/0056C21C7/06C21C7/072C22C33/04C22C38/02C22C38/04C22C38/50
Inventor 陈兴润潘吉祥刘国平胡桓彰
Owner GANSU JIU STEEL GRP HONGXING IRON & STEEL CO LTD
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