Sulfur control method in high-sulfur steel smelting process

Abstract

The invention belongs to the technical field of ferrous metallurgy, and relates to a sulfur control method in a high-sulfur steel smelting process. In the high-sulfur steel smelting process, blast furnace slag is used as synthetic slag so as to be added to a steel ladle along with steel flow, and the addition of the blast furnace slag is 5 to 8 kg per ton of steel. The production cost can be reduced, and the resource utilization rate can be increased.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, in particular, the invention relates to a sulfur control method in the smelting process of high-sulfur steel. Background technique [0002] In the pure steel smelting process, sulfur is a harmful element. When the sulfur content in the steel is too high, it will cause hot embrittlement, cause difficulties in the hot processing of the steel, and deteriorate the mechanical properties of the steel. However, in some steels that require precision cutting, sulfur can improve the cutting performance of such steels. Sulfur and manganese form manganese sulfide inclusions in the steel. Such inclusions can interrupt the continuity of the base metal. Promote chip breaking to form a small and short curl radius, which is easy to remove, reduces tool wear, reduces machined surface roughness, and improves tool life. Generally, the machinability of steel increases with the increase of sulfur co...

AI Technical Summary

Problems solved by technology

[0003] At present, the sulfur content in most sulfur-based free-cutting steels in the world is 0.1-0.4%, which is 10-100 times the sulfur content in normal pure steels. Therefore, the smelting process of sulfur-containing free-cutting steels is significantly different from that of pure steels. In the refining process, low-alkalinity slag needs to be produced, and the alkalinity of the refining slag is W CaO / W SiO2 It is advisable to control the value of 1.0 to 1.5, where W CaO is the mass percentage of CaO in the slag, W SiO2 SiO in slag 2 At present, steel mills are using lime (mainly composed of CaO) and wollastonite (mainly composed of CaSiO) in the slagging material 3 ) to achieve the effect of producing low-alkalinity slag, but because wollastonite is the slag-forming material used to produce neutral slag or acid slag, and the rest of the steel types in the steel plant are made of alkaline slag The refining process requires re-purchase of slag-making materials every time free-cutting steel is produced, which causes a lot of inconvenience to the production arrangement

Moreover, the melting point of lime and wollastonite is relatively high, and the slagging speed in the refining process is slow, and the refining effect is not ideal.