Method for continuous casting production of YQ450NQR1 Z-type steel bloom

Abstract

The invention discloses a method for continuous casting production of a YQ450NQR1 Z-type steel bloom in the field of steel metallurgy. The method is mainly improved in the molten steel continuous casting stage, during continuous casting, a tubular crystallizer with the section size consistent with that of a casting blank is utilized, and special continuous casting crystallizer protective slag is used in cooperation, wherein according to physical property index requirements of the protective slag, the viscosity is 1.00-1.02 Pa, the alkalinity 0.83-0.85, the softening temperature is 1130-1136 DEG C, the hemispherical temperature is 1190-1196 DEG C, the flowing temperature is 1200-1202 DEG C, and the slag consumption in the application process is 0.55-0.62 kg of slag per ton of steel. On thebasis, the appropriate crystallizer cooling strength, continuous casting drawing speed, crystallizer electromagnetic stirring parameters and superheat degree control are also utilized so that a billetcan form a blank shell complete in surface and uniform in thickness in the crystallizer, the method particularly has a remarkable effect on controlling cast blank shell quality defects caused by peritectic transformation linear contraction, the problems of rolling and cracking caused by the cast blank shell quality defects are solved, and an important foundation is laid for controlling cracking defects of Z-type steel in the later rolling stage.

Description

technical field [0001] The invention relates to the field of iron and steel metallurgy, in particular to a production method for continuous casting of YQ450NQR1 B-shaped steel blooms. Background technique [0002] As my country's economic development drives railway transportation, railway steel continues to develop. As an important variety of railway steel, YQ450NQR1 high-strength and high-weathering B-shaped steel has high strength and corrosion resistance. It is a special special product for making train car middle beams Section steel is an important guarantee for the heavy load of trains. From the appearance point of view, B-shaped steel is a large-scale asymmetric cross-section profile. Although the cross-section shape is simple, due to the different lengths and thicknesses of the upper and lower legs, there is serious uneven deformation during the rolling process, and the rolled piece bends towards the short leg. At the same time, it has a tendency to reverse relative t...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the deficiencies of existing YQ450NQR1 B-shaped steel blooms with large cross-sections in the production process caused by the shrinkage of the peritectic phase transition line, such as corner cracks, uneven shell thickness, and poor control effect on the depth and width of vibration marks, the present invention The technical problem to be solved is to provide a continuous casting production method capable of improving the overall quality of YQ450NQR1 B-shaped steel blooms