Numerical Simulation of Solidification Behavior and Solute Transport in Slab Continuous Casting with S-EMS

Abstract

A 3D numerical model was built to investigate the transport phenomena in slab continuous casting process with secondary electromagnetic stirring (S-EMS). In the model, the columnar grain grew from strand surface and it should be treated as a porous media. While for the equiaxed zone, the nucleated grain moves with fluid flow in the earlier stage and it was regarded as a slurry. The model was validated by measured strand surface temperature and magnetic induction intensity. The results show that the solidification end near the 1/4 width of slab was postponed, due to the liquid flow from a submerged entry nozzle injected to the strand’s narrow face. As the linear stirring in the same direction is applied, liquid moves from side B to side A and then penetrates deep downward with higher temperature. In the later stage, the solidification end near the side A is postponed and the solute element is concentrated. When linear stirring in the opposite direction is used, the solidification end near the side A moves backward, while that near the side B moves forward. Moreover, it is found that the solute segregation in the side B is deteriorated, but that in the side A is reduced. As rotational stirring mode is applied, the evenness of solidification end profile is improved and the centerline segregation is reduced, especially with higher current intensity. Therefore, it is concluded that the linear stirring mode is not appropriated for slab casting, while the rotational stirring mode is more suitable.