Numerical analysis of role of melting rate on electroslag remelting continuous directional solidification of a die steel

The effect of melting rate on the temperature distribution,velocity field,macrosegregation and dendrite arm spacing during electroslag remelting continuous directional solidification process with a mould of 160 mm in diameter was investigated.The mechanism of solute transport and dendrite growth of austenitic hot-work die steel during electroslag remelting process was proposed.The results showed that a lower melting rate contributed to a higher temperature gradient as well as a shallower liquid metal molten pool.With the increase in the melting rate,the central counterclockwise vortex in the slag and clockwise vortex in the liquid metal molten pool grew,whereas the marginal clockwise vortex in the slag reduced.With increasing melting rate,the macrosegregation of carbon became more serious,whereas the average value of secondary dendrite arm spacing first decreased and then increased.The secondary dendrite arm spacing reached a minimum value at melting rate of 98 kg/h,which indicated that 98 kg/h was a proper melting rate for electroslag remelting continuous directional solidification process with a mould of 160 mm in diameter.