1. Changing the dynamics conditions during the solidification process (i.e., mechanical model theory);

2. Changing thermodynamics condition during the solidification process of (i.e., thermal model theory);

3. Improving material migration conditions during the solidification process (to make the components uniform).

The strong electromagnetic stirring force enable the un-solidified molten steel flush the end of the solidification, cut off and corrode the crystal arm of columnar crystal, forming a large number of dendrite fragments as crystal nucleus of equiaxed grain, making the grain multiplied grown, so as to inhibit the growth of dendrites.