Industrial Application of Mechanical Reduction on Continuous Casting of Bearing Steel Bloom

Xinghua Chen,Wei Deng,Shuai Niu

doi:10.3390/pr9122280

Abstract

Industrial experiments of mechanical soft reduction in continuous casting were conducted in the present study aiming to improve the internal quality of the bearing steel blooms. Two methods were developed to verify the solidification model for a reliable crater end in the caster, which is provided by SMS CONCAST. The verified solidification model was applied to determine the solidification status of the bloom and provides theoretical reduction region. Several trials were conducted to study the optimization of the reduction rate regarding the V-shaped and centerline segregation of the bloom. The results show an obvious improvement of internal quality in the bearing steel bloom by applying appropriate reduction during casting.

Highlights

The internal quality of the bearing steel bloom has great influence on its reliability and service life due to the inheritance of the defects from the bloom, such as shrinkage porosity, center segregation, and V-shaped segregation to the subsequent rolling product
Coarse equiaxed grain can cause the formation of bridging, and the enriched liquid will be partly sucked from interdendritic areas downwards to compensate the shrinkage at the final stage of solidification, and these compensated regions are the origins of the spot segregation [7,8,9]
Insufficient compensation of the solidification shrinkage between the settling of equiaxed crystals causes the suction of enriched liquid when strand contraction occurs, and the V-shaped segregation is generated [10]

Summary

Introduction

The internal quality of the bearing steel bloom has great influence on its reliability and service life due to the inheritance of the defects from the bloom, such as shrinkage porosity, center segregation, and V-shaped segregation to the subsequent rolling product. Industrial Application of Mechanical Reduction on Continuous Casting of Bearing Steel Bloom. Compared to the methods mentioned above, applying mechanical soft reduction (MSR) in the final stage of solidification of the crater end, which has been successfully applied in continuous cast slab for improving the center segregation and the V-shaped segregation, offers a possible alternative for producing low-segregation-level steel blooms, especially for the high-carbon and large-section steel blooms [11,12].

Results

Conclusion