For the better understanding of the phenomena in the cold crucible, advanced models for electromagnetic field have been developed for both vertical and horizontal cross sections of the crucible. In the former model, the axi-symmetric steet geometry was assumed and the influence of the number of slits was taken into account by the use of a parameter representing the magnitude of the electromagnetic interaction. In the latter one, the conservation problem of the current density in a finite cell was successfully solved through the introduction of Newton's method for the simultaneous convergence of both scalar and vector potentials. The validity of the models was confirmed through experimental measurements of the magnetic flux density, the coil voltage, and the elevation height of the Al-Cu alloy melts.
Regardless of the number of slits and the shape of the crucible, the induced current on the intenal and the external sheets of the crucible flows on the horizontal path. An increase in the number of slits resulted in the increase of the magnetic flux density. This is mainly explained by the reason that the partition ratio of the induced current into the segmented part of the crucible increases with the number of slits. Since the melt is expected to contact with the internal wall near the slit bottom in the case of the straight type crucible, the solidification is preferable to be completed just above the slit bottom for the improvement of the ingot surface during continuous casting.