Theoretical model for determining optimum soft reduction zone of continuous casting steel

Abstract

A theoretical model for determining the optimum soft reduction zone of continuous casting steel was developed. According to the theoretical analysis of the solute segregation behaviour in the mushy zone with the soft reduction by one pair of pinch rolls, there is an optimum soft reduction position for each element of steel, and all optimum soft reduction positions of different solute elements should be included in order to eliminate the centreline segregation effectively. The theoretical analysis shows that the carbon content has a great effect on the optimum soft reduction zone, and the cooling rate could affect both the optimum soft reduction positions of the segregation prone elements (P, S) and the optimum soft reduction zone of continuous casting steel. Plant trials of steel SWRH82B with soft reduction were carried out to validate the theoretical model, and the results show that the solute element segregation in the centreline of the strand has been improved with the optimum soft reduction zone.