Improving inner quality in continuously cast billets: comparison between mould electromagnetic stirring and thermal soft reduction

The effect of electromagnetic stirring in the mould (MEMS) and thermal soft reduction (TSR) on V segregates and centreline macrosegregation has been studied. The results of several experiments, both stirred and non-stirred and with different cooling patterns, are presented. Theoretical calculations of centreline macrosegregation and thermal strains are presented. The results show that both MEMS and TSR can improve centreline macrosegregation. The optimal result is obtained if a combination of MEMS and TSR is used. The results also show that MEMS is an easier technique to use than TSR because TSR requires a high degree of knowledge about the solidification process in the actual casting machine. Based on strain calculations and metallographic analysis the formation of macrosegregation and V segregates is discussed