A microstructure refining treatment process for low-alloy high-strength steel continuous casting billets

Abstract

The present application relates to the technical field of steel metallurgy medium plate continuous casting billet, and proposes a microstructure refining treatment process for low-alloy high-strength steel continuous casting billet, which comprises the following steps: after the initial continuous casting billet is completely passed through the straightening machine, the surface temperature is controlled to be 780-880 DEG C, online rapid cooling is performed, temperature is returned and buffered, after cutting to the fixed size, gradient cryogenic treatment is performed, and drying is performed to obtain the low-alloy high-strength steel continuous casting billet; the gradient cryogenic treatment comprises first-stage cryogenic treatment and second-stage cryogenic treatment; in the first-stage cryogenic treatment, the initial continuous casting billet is cooled at a cooling rate of 1.0-2.5 DEG C / s to a surface temperature of 200-250 DEG C; in the second-stage cryogenic treatment, the initial continuous casting billet is cooled at a cooling rate of 0.03-0.15 DEG C / s to a surface temperature of 60-80 DEG C; the cooling water temperature for the first-stage cryogenic treatment is 30-50 DEG C, and the cooling water temperature for the second-stage cryogenic treatment is 60-80 DEG C. Through the above technical scheme, the problems of coarse microstructure and serious center segregation of the continuous casting billet in the related art are solved.