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Method for producing ultralow-sulfur steel by using LF and VD duplex technology

A dual process, ultra-low sulfur technology, applied in the field of steelmaking, can solve the problems of high smelting cost, complex process route, and great impact on continuous operation.

Active Publication Date: 2021-06-15
SHOUGANG CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The patented process route is relatively complicated, using two LF furnace refining + two VD vacuum treatment processes, the smelting cost is high, and it has a great impact on the continuous operation of industrial batch production

Method used

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  • Method for producing ultralow-sulfur steel by using LF and VD duplex technology
  • Method for producing ultralow-sulfur steel by using LF and VD duplex technology
  • Method for producing ultralow-sulfur steel by using LF and VD duplex technology

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0061] The steel type is X60MS, and the target sulfur content of the finished product is less than 0.0010%. The process route adopted is: KR desulfurization pretreatment—converter—LF furnace refining—VD refining—continuous casting.

[0062] Step S1, the molten iron is subjected to KR desulfurization pretreatment, the stirring time is controlled at 10 minutes, and then the slag removal pretreatment is carried out (the slag removal bright surface rate is 95%), and the pretreated molten iron with S=0.0015% is obtained;

[0063] Step S2, converter smelting: using low-sulfur steel scrap and auxiliary materials, controlling the sulfur content of the scrap steel to 0.0050%, and the sulfur content of the auxiliary materials to 0.0040%, and controlling the blowing and stirring time in the smelting to 12 minutes to obtain molten steel with an S content of 0.0060%; Aluminum strong deoxidation is used for tapping, and the addition amount is 2.5kg / t steel; after tapping, aluminum particles ...

Embodiment 2

[0068] Steel type Q345R-HIC, the target sulfur content of the finished product is less than 0.0010%, the adopted process route is: KR desulfurization pretreatment-converter-LF furnace refining-refining-continuous casting.

[0069] Step S1, the molten iron is subjected to KR desulfurization pretreatment, the stirring time is controlled at 15 minutes, and then the slag removal pretreatment is carried out (the slag removal bright surface rate is 98%), and the pretreated molten iron with S=0.001% is obtained;

[0070] Step S2, converter smelting: using low-sulfur scrap steel and auxiliary materials, controlling the sulfur content of the scrap steel to 0.0050% and the sulfur content of the auxiliary materials to 0.0030%, and controlling the blowing and stirring time in the smelting to 15 minutes to obtain molten steel with an S content of 0.0050%; Aluminum strong deoxidation is used for tapping, and the addition amount is 1.0kg / t steel; after tapping, aluminum particles are added to...

Embodiment 3

[0075] The steel grade is A516Gr.60-HIC, the target sulfur content of the finished product is less than 0.0010%, and the adopted process route is: KR desulfurization pretreatment—converter—LF furnace refining—VD refining—continuous casting.

[0076] Steel type Q345R-HIC, the target sulfur content of the finished product is less than 0.0010%, and the adopted process route is: KR desulfurization pretreatment—converter—LF furnace refining—VD refining—continuous casting.

[0077] Step S1, the molten iron is subjected to KR desulfurization pretreatment, the stirring time is controlled at 12 minutes, and then the slag removal pretreatment is carried out (the slag removal bright surface rate is 96%), and the pretreated molten iron with S=0.0015% is obtained;

[0078]Step S2, converter smelting: using low-sulfur steel scrap and auxiliary materials, controlling the sulfur content of the scrap steel to 0.0040% and the sulfur content of the auxiliary materials to 0.0040%, and controlling ...

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Abstract

The invention discloses a method for producing ultralow-sulfur steel by using an LF and VD duplex technology. The method comprises the following steps: carrying out desulfurization and slagging-off pretreatment on molten iron to obtain pretreated molten iron; smelting the pretreated molten iron, low-sulfur waste steel and auxiliary materials to obtain smelted molten steel; carrying out tapping of the smelting molten steel to obtain the tapped molten steel; adding refining slag into the tapped molten steel for LF furnace refining to obtain refined molten steel and first refined final slag; controlling the first refining final slag, wherein W (FeO + MnO) is less than or equal to 1.5%, and the binary alkalinity R = CaO / SiO2 = 5.0-8.0; and subjecting he refined molten steel to VD vacuum refining to obtain ultralow-sulfur molten steel and second refined final slag, wherein the vacuum treatment time is 12-20 min, the bottom blowing flow of a steel ladle is 50-150 NL / min, and the vacuum degree is controlled to be less than or equal to 100 Pa; Stable control of ultralow sulfur less than or equal to 0.0010% is achieved by using the LF and VD duplex technology.

Description

technical field [0001] The invention relates to the technical field of steelmaking, in particular to a method for producing ultra-low sulfur steel by adopting LF+VD double process. Background technique [0002] With the increasing demand for high-grade steel grades, the quality requirements for steel are becoming more and more stringent, and sulfur is a harmful element in most steels, which can cause hot embrittlement of steel, and can also damage the steel by forming sulfide inclusions. The mechanical properties are adversely affected, and the sulfur content in the steel is required to be as low as possible, especially for steels that have special inspection requirements for HIC and SSCC, such as hydrogen-induced cracking-resistant pipeline steel and hydrogen-induced cracking-resistant container steel. Generally, the sulfur content is required to be less than 0.0010 %, therefore, whether the stable control of ultra-low sulfur content in steel has become the key to the produ...

Claims

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Application Information

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IPC IPC(8): C21C7/06C21C7/076C21C7/064C21C7/10C21C1/02
CPCC21C7/06C21C7/076C21C7/064C21C7/10C21C1/02Y02P10/20
Inventor 李战军刘金刚初仁生郝宁朱志远朱国森马长文季晨曦高宠光闫占辉谢翠红杨荣光
Owner SHOUGANG CORPORATION
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