In order to reduce center porosity of round billet in horizontal continuous casting, experiments of electromagnetic stirring (EMS) were carried out for two kinds of stainless steel containing Nb and Ti, which had a tendency to enhance center porosity. Combined electromagenetic stirrings in mold (M-EMS), in strand (S-EMS) and in final solidification region (F-EMS) were applied to continuous casting of 263 mmφ round billet.
It has been found that the combined stirrings of M-EMS, S-EMS and F-EMS are most effective to reduce center porosity of the billet. A lack of the stirrings decreases the effect on the reduction of center porosity. S-EMS was proved to have the effect to disperse equiaxed crystals in the molten steel, which were formed in the mold by M-EMS and consequently, enable uniform packing of the equiaxed crystals in the center of billet. F-EMS was proved to be most effective, when it was applied for the liquid core diameter of 40 mm to 80 mm. F-EMS is thought to have the effect to secure the fluidity of mushy zone in the center of billet by the stirring of 15 Hz, but has no influence on solidification structure.
