LAUSR

Electromagnetic stirring (EMS) by means of AC magnetic fields is a valid method for contactless flow control in billet/bloom casters for about 40 years,1–4) where the rotary stirring of the mould flow by means of a rotating magnetic field (RMF) can be considered as an established application. The stirring is supposed to enhance the homogeneity of the molten steel and to improve the quality of the solidified steel strand therefore significantly decreasing the number of casting defects. In particular, it is assumed that non-metallic particles are prevented from becoming entrapped in the solidified shell by the so-called washing effect.5) Particles attached to the growing columnar dendrites are prevented from engulfment by the mushy zone, washed out by the forced flow and transported back into the bulk liquid. In addition, the stirring shall stimulate the agglomeration and the formation of larger particles which rise up more easily towards the free surface. Yamada et al.6) analyzed the size of alumina inclusions in solidified steel. They suggested that the maximum diameter of the clusters remaining in the product corresponds to the EMSinduced velocity of molten steel. On the basis of these data Matsumiya7) concluded that inclusions with a size of 100 μm can be prevented from Experimental Investigations of Rotary Electromagnetic Mould Stirring in Continuous Casting Using a Cold Liquid Metal Model