Numerical and experimental investigation of solidification structure evolution and reduction of centre segregation in continuously cast GCr15 bloom

Abstract

ABSTRACT A CAFE model and SDAS model are established in order to study evolutionary behaviour of macrostructure and secondary dendrites on 220 × 260 mm2 bloom cross-section of GCr15 bearing steel, respectively. Based on numerical simulation and experiments, the effects of process parameters on centre ECR and SDAS are investigated. It is found that increase of centre ECR and decrease of SDAS occur with the decrease of superheat and with the increase of M-EMS. The results reveal that M-EMS and superheat exhibit a significant effect on centre ECR, whereas casting speed evidently affects SDAS than superheat. In addition, casting speed has the obvious influence on solidification end, which is closely related with F-EMS implementation. After less than superheat of 25°C and casting speed of 0.8 m min−1 with optimized M+ F-EMS are adopted, centre ECR increases by 11% and the SDAS is effectively refined. Furthermore, centre segregation gets improved as well.