Numerical simulation of macrosegregation in billet continuous casting influenced by electromagnetic stirring

A three-dimensional numerical model coupling the macrosegregation and magnetohydrodynamic simulations was developed to investigate the effects of electromagnetic stirring (EMS) on the macrosegregation. The results show that a significant swirling flow was induced by the in-mold EMS, which further changed the shape of the solidification shell and homogenized the solute elements in mold. However, the effects were only confined to the initial billet shell. The improvement in centerline segregation was observed with the usage of the final EMS (F-EMS), which led to the forced convection at the final solidification stage. The solute elements in the mushy zone were significantly even, with the maximum segregation degree of solute C reducing from 1.311 to 1.237. In addition, the effects of the stirrer positions and currents of F-EMS on the macrosegregation alleviation were numerically studied. Different values of centerline segregation were predicted with various stirrer positions and currents, and there is an optimum stirrer parameter to obtain the best macrosegregation alleviation. In the experimental conditions, the optimum position was about 7 m away from meniscus, and the optimum current was 300 A.