The Gandhi's scaled-frequency FDTD (finite-difference time domain) method for the computation of electromagnetic fields of low frequency is modified, which is adaptable to the numerical computation of soft-contact mould. The computational results for the simplified model agree well with the analytical solutions.

The whole process of the numerical simulation of electromagnetic field in the liquid steel inside the soft-contacting billet mold is presented by FEM (Finite Element Method) and BEM (Boundary Element Method). Whitney edge element FEM based on tetrahedral elements, the discretization of H-Φ equation and boundary integration equation is mainly explained. By connecting FEM and BEM, it needs less work and time to the calculate the electromagnetic field. Numerical simulation program of three-dimensional electromagnetic field is exploited and the solution is proved to coincide with the fact.