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Refining method of reducing slag made by CAS refining furnace for desulfurization

A refining furnace and converter technology, which is applied in the field of metallurgical steelmaking, can solve the problems of no desulfurization function, molten steel returning to the furnace, and steel grade change judgment, etc., to achieve the effect of broadening the refining function and avoiding sulfur return.

Inactive Publication Date: 2011-05-11
HEBEI IRON AND STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The molten steel treated according to the traditional CAS mentioned above has a weak oxidizing atmosphere in the refining process, and the oxygen potential in the slag is relatively high, so it does not have the desulfurization function. The change of steel grade or the return of molten steel to the furnace will seriously affect the production rhythm and economic benefits of the enterprise

Method used

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  • Refining method of reducing slag made by CAS refining furnace for desulfurization

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Experimental program
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Effect test

Embodiment 1

[0021] Embodiment 1: 115t molten steel is tapped from the converter, the sulfur content at the end point of the molten steel is 0.028%, lime is added to the ladle according to the ratio of 3kg / t during the tapping process, aluminum magnesium calcium is added to the ladle according to the ratio of 3kg / t, and the bottom of the ladle is carried out during the tapping process. Argon blowing and stirring, the flow rate is 18M 3 / h, time 2 minutes. After entering CAS, take samples to measure temperature and determine oxygen OXP=25ppm, control molten steel temperature at 1600-1630°C, add calcium carbide in three batches according to 0.8kg / t ratio according to slag color, and divide into three batches according to 0.5kg / t ratio according to steel slag fluidity Add Fluorite in batches. After 20 minutes of lowering the hood and stirring weakly for 5 minutes, the oxygen was fixed at OXP=4.5ppm, and the sulfur content in the tapped steel was 0.021%.

Embodiment 2

[0022] Embodiment 2: 115t of molten steel is tapped from the converter, the sulfur content at the end point of the molten steel is 0.021%, lime is added to the ladle according to the ratio of 3.5kg / t during the tapping process, and aluminum, magnesium and calcium are added to the ladle according to the ratio of 2kg / t, and the ladle is carried out during the tapping process. Bottom blowing argon stirring, flow rate 20M 3 / h, time 1.5 minutes. After entering CAS, take samples to measure temperature and determine oxygen OXP=23ppm, control the temperature of molten steel at 1600-1630 ℃, add calcium carbide in two batches according to the ratio of 0.7Kg / t according to the color of slag, and divide it into two batches according to the ratio of 0.4kg / t according to the fluidity of steel slag Add Fluorite in batches. After 18 minutes of lowering the hood and stirring weakly for 5 minutes, the oxygen was fixed at OXP=3.8ppm, and the sulfur content of the steel was 0.016%.

Embodiment 3

[0023] Embodiment 3: Converter tapping 115t molten steel, the final sulfur content of molten steel is 0.022%, the tapping process adds lime to the ladle according to the ratio of 3.2kg / t, and adds aluminum magnesium calcium to the ladle according to the ratio of 1.5kg / t, and the tapping process proceeds Ladle bottom blowing argon stirring, flow rate 19M 3 / h, time 1.8 minutes. After entering CAS, take samples to measure temperature and determine oxygen OXP=24ppm, control the temperature of molten steel at 1600-1630°C, add calcium carbide at a ratio of 0.5kg / t according to the color of slag, and add fluorite at a ratio of 0.3kg / t according to the fluidity of steel slag. After 19 minutes of lowering the hood and stirring weakly for 5 minutes, the oxygen was fixed at OXP=3.5ppm, and the sulfur content of the steel was 0.019%.

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Abstract

The invention relates to a refining method for reducing slag made by a CAS refining furnace for desulfurization, which belongs to the steel-making technical field and is used for solving the problem of the occurrence of resulfurization after molten steel is refined by CAS. The refining method comprises tow steps of converter tapping and CAS refining and is characterized in that in the converter tapping step, lime is added into a steel ladle according to 3 to 3.5 kg / t proportion; aluminium magnesium calcium is added into the steel ladle according to 1.5-3.0kg / t; in the CAS refining step, the temperature of the molten steel is controlled to be 1600 to 1630 DEG C, calcium carbide is added according to 0.5-0.8 kg / t proportion, and fluorite is added according to 0.3-0.8 kg / t proportion. The refining method realizes the alloying while the reducing slag is made in the CAS furnace for deoxidation and desulphurization; and after the molten steel is refined in the CAS, the sulphur content can continuously reduce. The method widens the refining function of the traditional CAS, and causes the CAS refining furnace to have the desulfurization capability, avoids the resulfurization after the refining of the CAS furnace, and causes the CAS furnace to have the requirements of producing fine-quality low sulfur steel.

Description

technical field [0001] The invention relates to a smelting technology, in particular to a refining method for desulfurizing reducing slag produced by a CAS refining furnace, and belongs to the technical field of metallurgy and steelmaking. Background technique [0002] In recent years, with the rapid development of steelmaking technology, the quality of steel has been continuously improved. High-quality steel has increasingly strict requirements on the S content in steel. Generally, high-quality steel requires that the S content be controlled below 0.020%. The traditional CAS refining furnace is a ladle-type refining under an argon atmosphere, which has functions such as argon blowing, stirring, impurity removal, and alloying. The CAS furnace is refined in an oxidative atmosphere. During the refining process, molten steel is alloyed by dropping the cover and adding alloys. It does not have the function of desulfurization. Its products can meet the production of general types...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C21C7/064
Inventor 刘利国胡志刚顾少伟许红玉王彦祥王义涛宋依新王文才徐学良
Owner HEBEI IRON AND STEEL