Processing parameter optimization for continuous casting of 38CrMoAl round bloom based on a prediction model of the equiaxed crystal ratio

Abstract

To control the quality of the continuous casting of 38CrMoAl round bloom, a prediction model combining the criteria of columnar to equiaxed transition, the numerical simulation of heat transfer and measured data is proposed. In this model, the inaccurate selection of heterogeneous nucleation density can be avoided. The accuracy of the numerical simulation is verified by a nail-shooting experiment, and the effects of parameters on equiaxed crystal ratio (ECR) were studied. It is proposed that low superheat and weak secondary cooling intensity increase ECR, while casting speed has little effect on ECR. The effect of strand electromagnetic stirring on the increasing ECR is clear, and it is more effective than superheat in the increasing ECR. When the diameter of the round bloom increases from 500 to 600 mm, the C_et increases from to , where ECR is larger. The suitable continuous casting parameters of ϕ500 mm bloom include a superheat of 30°C and a continuous casting speed of 0.19 m/min, as well as a weak secondary cooling intensity.