Method for inhibiting low-sulfur steel from being subjected to refinement and resulfurization in LF furnace

Abstract

The invention discloses a method for inhibiting low-sulfur steel from being subjected to refinement and resulfurization in an LF furnace. The method comprises the following steps of, desulfurizing molten iron of a steel grade with S content not more than 0.03 wt%; smelting in a converter; refining in an LF furnace; carrying out pouring and subsequent procedures, wherein the time from the end of molten steel pouring to the beginning of pouring refining slag out of a molten steel tank is controlled to be not more than 13 min; and Then loading the smelted low-sulfur molten steel into the molten steel tank, and carrying out conventional refining and subsequent procedures on the sulfur molten steel in the LF furnace. According to the method, by smelting steel with S content not more than 0.03 wt% in one furnace and controlling the alkalinity of the refining slag in the LF furnace to be less than or equal to 1.2 and the sulfur content in the refining slag to be not more than 0.2 wt%, so that the content of sulfur attached in the molten steel tank is reduced; and after the low-sulfur molten steel to be refined is filled into the molten steel tank, the resulfurization of the low-sulfur steel subjected to LF refining is stabilized to be less than or equal to 0.001 wt%, the judgment-changing rate of the low-sulfur steel is reduced to 1.25% from the original 15.78%, and steel material consumption (molten iron slagging-off) is reduced by 2-3 kg / t.

Description

technical field [0001] The invention relates to a method for smelting low-sulfur steel, in particular to a method for suppressing sulfur return of low-sulfur steel during refining in an LF furnace. The invention is suitable for refining low-sulfur steel which does not have desulfurization ability in LF furnace. Background technique [0002] The molten steel tank is used for receiving molten steel and performing pouring operations during the steelmaking process. The molten steel tank is a large tool in the steelmaking process, and it is unlikely to be replaced at any time. During the process of switching steel types, the components between the upper and lower furnaces will interfere. When steel grades with desulfurization conditions (cord steel, spring steel, industrial pure iron) are used, the phenomenon of "resulfurization" will obviously occur when using the molten steel tank, and the sulfur content will increase by 0.0015-0.005wt%, which may lead to unqualified component...

AI Technical Summary

Problems solved by technology

This method makes reducing slag desulfurization by adding aluminum (0.026wt%), so that the amount of desulfurization ≈ the amount of sulfur increase, so as to achieve the effect of no resulfurization, but the requirements for steel types have certain limitations, such as adding This method cannot be used for aluminum or steel types that cannot produce high alkalinity reducing slag

The rest of the articles are to reduce the impact of sulfur return by improving the desulfurization efficiency of the LF furnace and rinsing the RH vacuum chamber, without analyzing and solving the sulfur return of the residue in the molten steel tank