Numerical Prediction of Solidification Structure Taking Account of Molten Steel Flow

Abstract

The casting experiment by using vertical type continuous casting machine was performed in order to clarify the effect of electromagnetic stirrer (EMS) on the solidification structure. It has been confirmed that the ratio of equiaxed zone increases and the size of equiaxed crystal and segregated area in the center of billet becomes finer with the application of EMS. The numerical model of columnar to equiaxed transition (CET) was constructed with consideration of molten steel flow to examine the mechanism of the changes in the solidification structure. It has been estimated by the model that the enlargement of undercooled region and the increase of grain density of equiaxed crystal lead to the refinement in solidification structure with the application of EMS. Moreover, the effect of superheat and casting speed on the ratio of equiaxed zone has been analyzed by using the present model and the obtained results show good agreement with experimental ones.