Continuous casting process capable of relieving internal quality defects of bearing steel bloom

Abstract

The invention discloses a continuous casting process capable of relieving internal quality defects of bearing steel boom. The continuous casting process adopts a large chamfering crystallizer, a chamfering angle of the obtained large chamfered continuously cast bloom is 50-75 degrees, and length of a chamfered inclined surface is 60-90 mm. The adopted following pressing-down process is as follows: at a pressed-down start point position, central solid fraction fs is 0.55-0.65, and pressing-down amount is 1.0-2.0 mm; at a second pressing-down roller, central solid fraction fs is 0.65-0.75 and pressing-down amount is 3.0-5.0 mm; at a third pressing-down roller, central solid fraction fs is 0.75-0.85, and pressing-down amount is 2.0-4.0 mm; at a fourth pressing-down roller, central solid fraction fs is 0.85-0.95, and pressing-down amount is 2.0-3.0 mm; and at a fifth pressing-down roller, central solid fraction fs is 0.95-1.0, and pressing-down amount is 0-2.0 mm. The continuous casting process reduces casting, rolling and pressing-down force in a casting blank pressing-down process, and improves pressing-down efficiency, so that the effects of stably controlling quality defects such as center segregation, V-shaped segregation, central loosening and hole shrinkage of the bearing steel boom are achieved.

Description

technical field [0001] The invention relates to a continuous casting process, in particular to a continuous casting process for alleviating internal quality defects of bearing steel blooms. Background technique [0002] CGr15 bearing steel is a high-carbon bearing steel with high carbon content and alloy content. Its solidification process has a wide two-phase zone, and the continuous casting slab is prone to defects such as center segregation, porosity, and shrinkage cavity; Large, the solidification time of the slab is prolonged, and the slab has a greater tendency to produce internal quality defects such as center segregation, V-shaped segregation, center porosity, and center shrinkage cavity. Quality defects such as center segregation, porosity, and shrinkage cavities of bearing steel slabs are difficult to be effectively eliminated in the later heating and rolling process. During hot rolling deformation, carbide enrichment bands are formed, and carbide bands are located...

AI Technical Summary

Problems solved by technology

However, the convex roll reduction process has the following disadvantages: (1) It is difficult to completely solve the problem of deviation of the continuous casting slab under the convex roll reduction, resulting in a large amount of cast slab rejection; (2) The continuous casting slab is extremely Subcutaneous cracks are easy to occur; (3) Convex rollers wear quickly, and the surface of the slab is prone to surface quality defects such as steps and right angles, which will bring greater pressure to the subsequent grinding process, resulting in a substantial increase in costs

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