Clean steel-refining slagging method

Abstract

The invention relates to a clean steel-refining slagging method. The clean steel-refining slagging method includes the following steps in sequence: (I) converter end point control: the converter end point oxygen content is more than or equal to 600ppm, ferro-aluminium which is more than or equal to 2.0kg per ton steel is added in a steel ladle along with steel flow in the tapping process of a converter, and the amount of slag tapped from the converter is less than or equal to 9kg per ton steel; (II) in the refining process of the converter or a ladle furnace (LF), more than or equal to 3kg per ton steel of high alumina slag with Al2O3 with mass percentage being equal to or more than 70 percent is added, lime, the total amount of which is 6kg to 7kg per ton steel, is added, and fluorite which is less than or equal to 1.5kg per ton steel is added; (III) in the ladle furnace process, agitation is carried out with argon flow being 500Nl / min or more than 500Nl / min for 5 minutes or more than 5 minutes, and afterwards, the out furnace time is more than or equal to 15 minutes; and the weight percentage of the refining final slag is as follows: 35 to 40 percent of Al2O3, 41 to 45 percent of CaO and 6 percent or less of SiO2. The melting point of the target slag system of the clean steel-refining slagging method is low, and the usage amount of fluorite is less.

Description

technical field [0001] The invention relates to a method for refining slagging of pure steel, specifically a method for refining slagging of pure steel with T[O]≤25ppm. Background technique [0002] At present, the mass percentage ratio of the refining slag system of most manufacturers is: [0003] CaO≥45%, Al 2 o 3 : 20-35%, SiO 2 : 6-12%, using this refining method and slag system, the melting point of the inclusions is relatively high before being refined out of the station and fed to the CaSi line, and it is only fully denatured after the line is fed to make the melting point lower. In this method, the denaturation of inclusions is relatively delayed, and the reduction of inclusions depends more on the feeding line and weak stirring effect, and the control level of inclusions is unstable. Contents of the invention [0004] In order to overcome the above-mentioned shortcomings of the existing pure steel refining slagging method, the present invention provides a pure...

AI Technical Summary

Problems solved by technology

In this method, the denaturation of inclusions is relatively delayed, and the reduction of inclusions depends more on the feeding line and weak stirring effect, and the level of inclusion control is unstable.