Abstract
In the continuous casting process, it is very important to make the dynamic behavior of free surface of molten steel clear, because surface quality of steel is almost decided by conditions of free surface. The conventional MHD calculation, which has been used to design the process, was using only the constant electromagnetic force in the time. Then, we developed new MHD calculation also taking the cyclic electromagnetic force into account, and confirmed that free surface vibrates more intensely than conventional result. Therefore, to make the dynamic behavior of free surface clear, cyclic electromagnetic force must be considered.