Decarburization smelting method of RH vacuum furnace

Abstract

The invention provides an RH vacuum furnace decarburization smelting method which comprises the following steps: before vacuumizing, respectively cutting off communication between a vacuum chamber and a vacuum alloy bin as well as between the vacuum chamber and a vacuum system pipeline, sequentially opening a first-stage water circulating pump and a second-stage water circulating pump, adjusting working current according to the ascending speed of a steel ladle, and pre-vacuumizing the vacuum system pipeline, so that when the steel ladle ascends to a treatment station, the vacuum system pipeline is decarburized; the pressure of a vacuum system pipeline is reduced to 300-450 mbar; and then increasing the current of the second-stage water circulating pump, opening a vacuum main valve, blowing lifting gas to the vacuum chamber, opening a steam pump step by step according to the reduction of the pressure of the vacuum chamber, and gradually increasing the flow of the lifting gas. And when RH decarburization is carried out for 7-9 min, the lifting gas is changed into 60-70% of argon and 30-40% of hydrogen until RH decarburization is finished, the lifting gas is switched into full argon after decarburization is finished, communication between the vacuum chamber and the vacuum alloy bin is opened, alloy in the vacuum alloy bin is added into molten steel for deoxidation alloying, and then net circulation treatment, vacuum breaking and tapping are carried out. By using the method provided by the invention, the carbon content of the molten steel can be reduced to 12 ppm or below within 13 minutes.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy manufacturing, in particular to a RH vacuum furnace decarburization smelting method. Background technique [0002] RH vacuum furnace has a series of functions such as decarburization, degassing, deoxidation, removal of inclusions, adjustment of molten steel temperature and chemical composition, etc. It has a series of advantages such as short processing cycle, large production capacity, and good inclusion removal effect. It is obtained in steelmaking production. It has been widely used, especially in the production of ultra-low carbon steel and high-quality pure steel. [0003] As the market requires lower and lower carbon content in ultra-low carbon steel, the requirement for RH vacuum deep decarburization capability is getting higher and higher. For example, high-grade silicon steel and IF steel have a carbon content of less than 15ppm or even less than 10ppm in the finished pr...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a RH vacuum furnace decarburization smelting method, which can obtain molten steel with ultra-low carbon content in a short time, and solve the problem of blowing gas into molten steel or adding powder that can decompose and generate gas in the prior art. Problems that cause increased production costs

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