2012 Volume 52 Issue 5 Pages 823-830
A combined cellular automaton-finite difference (CA-FD) model has been developed to simulate solute diffusion controlled solidification in continuous steel casting. Constitutional and curvature undercooling were both solved to determine the equilibrium temperature and growth velocity of the solid/liquid interface. Simulations were firstly performed for both the free dendritic growth from an undercooled melt and the columnar dendritic growth in unidirectional solidification. Finally, competitive dendritic growth and columnar to equiaxed transition (CET) occurring in solidification of continuous casting process were reproduced by the present CA-FD model. The effect of the fragmentation of dendrites due to fluid flow induced by EMS in mould on nuclei was taken into consideration by increasing the grain density. The comparison between the simulated and experimentally observed results shows that the present model can be used to simulate solidification structure formation during the continuous casting process of steel. The influence of superheat on solidification structure was also analyzed, and it was found that increasing superheat increases the columnar dendritic growth and reduces the equiaxed ratio, as it is empirical well known.