Method for producing ultralow-sulfur steel under high vacuum

A high-vacuum, ultra-low-sulfur technology, applied in the manufacture of converters, etc., can solve the problems of nitrogen content and inclusion increase, and achieve the effects of improving quality pass rate, increasing slag capacity, and avoiding large-scale turnover

Inactive Publication Date: 2012-11-21
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a method that can effectively solve the problem of increased nitrogen content and inclusions caused by the forced desulfurization process of the LF furnace, so that the sulfur content of the finished product can be controlled to less than 0.005% to produce ultra-low sulfur under high vacuum conditions. steel method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] 1. During the converter smelting process, the sulfur weight percentage content of the steel is controlled at 0.009% through measures such as molten iron desulfurization and slag removal, converter slagging and other measures.

[0019] 2. During the refining process of LF furnace, high alkalinity slag is produced by adding lime, and the flow rate of weak argon blowing is 150Nl / min, and the weight percentage of sulfur in steel is controlled at 0.0055%.

[0020] 3. In the late stage of LF furnace refining treatment, the slag basicity is controlled at about 3.0.

[0021] According to the ratio of lime granules: lightly burned dolomite: aluminum slagging balls: fluorite=4:0.5:1.3:2, add 462 kg of lime granules to control CaO, add 58 kg of lightly burned dolomite to control MgO, and add aluminum slag balls 150 kg control Al 2 o 3 , Add 230 kg of fluorite to control CaF.

[0022] Control the total amount of slag per ton of steel to 9kg to form CaO-MgO-Al 2 o 3 -CaF slag s...

Embodiment 2

[0026] 1. During the converter smelting process, the sulfur weight percentage content of the steel is controlled at 0.008% through measures such as molten iron desulfurization and slag removal, converter slagging and other measures.

[0027] 2. During the refining process of the LF furnace, the weight percentage of sulfur in the steel is controlled at 0.0067% by adding white ash to create high-basic slag, and the flow rate of weak argon blowing is 200Nl / min.

[0028] 3. In the late stage of LF furnace refining treatment, the slag basicity is controlled at about 4.2.

[0029] According to the ratio of lime particles: lightly burned dolomite: aluminum slag forming ball: fluorite = 4:0.5:1.3:2, add lime small particles to control CaO, add lightly burned dolomite to control MgO, and add aluminum slag forming balls to control Al 2 o 3 , adding fluorite to control CaF.

[0030] Control the total amount of slag per ton of steel to 10kg to form CaO-MgO-Al 2 o 3 -CaF slag system; b...

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Abstract

The invention provides a method for producing an ultralow-sulfur steel under high vacuum, the sulfur content of steel discharged by a converter can be controlled below 0.010%; during the LF furnace refine treatment process, the sulfur content can be controlled at 0.005-0.007%, the slag alkalinity in the later stage can be controlled between 2.0-4.5, thereby a CaO-MgO-Al2O3-CaF slag system is formed, the total slag amount can be controlled at 8.5-10kg/ton steel, the argon flow during the whole process is 150-250N1/min; and a VD furnace high vacuum treatment is carried out by using argon with a flow of 450-550N1/min for mixing. Thereby the molten slag equivalent of slag can be enhanced, great flip of a molten steel surface can be avoided, the addition of the molten steel nitrogen absorption and impurities can be minimized, rapid operation during desulphurization process can be promoted, the sulfur content of the finished product can be controlled below 0.005%, and nitrogen content of the finished product can be controlled below 25ppm, and the qualified rate of ultralow-sulfur steel production can be increased.

Description

technical field [0001] The invention belongs to the technical field of steelmaking technology, and specifically relates to a method for producing ultra-low sulfur steel based on a converter-LF furnace (ladle refining furnace)-VD furnace (vacuum refining furnace) process. Background technique [0002] With the progress of society, the demand for high-precision steel is increasing, and the downstream users of steel production enterprises—the manufacturers have higher and higher requirements for the quality and performance of steel. Therefore, generally high-quality pipeline steel The [S] content of steel types such as container plates and bearing steels is required to be controlled at 0.005%, or even below 0.005%, which is the so-called ultra-low sulfur steel. At present, although the method of pretreatment of molten iron can control the sulfur content in steel to less than 0.002%, due to the limitation of the materials used in the converter and the desulfurization capacity, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/064C21C7/10C21C5/28
Inventor 宁东高立超徐振东
Owner ANGANG STEEL CO LTD
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