Method for eliminating macro C segregation by performing heat preservation on continuously cast steel billets

Abstract

The invention belongs to the field of metallurgy and in particular relates to a method for eliminating macro C segregation by performing heat preservation on continuously cast steel billets. The method particularly comprises the following steps of: 1.1 determining the heat-preserving temperature of steel grade; 1.2 determining the solid phase change (alpha to gamma) temperature T2 in the heating state of the steel grade according to a Fe-C phase diagram; and 1.3 performing heat preservation on the continuously cast steel billets in a heating furnace at the temperature of 20 DEG C less than the temperature T2 for 40 hours; heating to temperature T1 and preserving heat for 40 hours; and after heat is preserved, cooling along with the furnace. According to thermodynamic calculation, organizational analysis and laboratory experiments, a heat-preserving method is provided, so diffusion homogenization efficiency of C can be efficiently improved. The equipment is readily available and the method is easy to operate and is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the field of metallurgy, in particular to a method for continuously casting steel slabs to keep warm to eliminate macroscopic C segregation. Background technique [0002] Macro segregation refers to the non-uniform chemical composition phenomenon (such as center segregation, R / 2 segregation, black spot, etc.) The quality of the finished product is an internal defect that should be eliminated as much as possible. [0003] At present, the means to reduce the macro-segregation of slabs are mainly concentrated in the continuous casting stage, such as low superheat, optimization of specific water volume, electromagnetic stirring, light reduction, etc. However, it has been proved that it is basically impossible to eliminate macrosegregation in the continuous casting process, so for some steels with extremely strict requirements on macrosegregation (such as high-speed wheel steel), the quality requirements cannot be met. Therefore, ...

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Problems solved by technology

[0004] At present, it is impossible to produce steel billets without segregation in China, so the steel used in some high-tech fields relies on imports

So far, most of the domestic factories are optimized in the continuous casting process. Although there are improvements, they cannot be completely solved.

Later, someone proposed to put the produced billet back into the heating furnace, heat-preserve and diffuse at high temperature, and obtain a billet without segregation, but even after heating for hundreds of hours, the effect is still not obvious

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