Development and application of an off-line soft reduction model during continuous casting of high-carbon rectangular billet

Abstract

An off-line soft reduction model was developed in order to improve the inner quality of high-carbon rectangular billet, which includes a heat transfer model, cooling water control model and roll-gap calculation model. The distribution of the total reduction amount in each pinch roll is calculated by using a segmented slope method in the reduction zone. The model application results showed that the inner quality of the high-carbon 82B steel with a section size of 180 mm × 240 mm had clearly been improved. It is evident that the formation of V-segregation in a rectangular billet subjected to soft reduction is suppressed and the centerline shrinkage cavity is clearly decreased. The mean center carbon segregation index was reduced from 1.15 to 1.08 with soft reduction. Besides, the soft reduction process improved the compactness and homogeneity of the central equiaxed dendrite zone and decreased the secondary dendrite arm spacing.