Solidification behavior of high-silicon steel based on experimental and 3D-CAFE method

The as-cast structure of high-silicon steel ingots under different cooling conditions was studied in this paper. It is found that the as-cast structure of the ingot is formed mainly by coarse columnar crystals, especially in the water cooling ingot, and the ratio is reaches as 90%. The dendrite tip growth kinetic coefficients and Gauss distribution parameters for 3D-CAFE simulation were determined according to the compositions of high-silicon steel and the results of as-cast structure. Then the solidification process of high-silicon steel under different cooling conditions was simulated by 3D-CAFE method. The results show that the temperature field under air cooling is more uniform, the mushy zone is broader, and it exhibits a transitional solidification pattern, however, which shows a layered solidification pattern under water cooling. The flow field under air cooling is more stable than that under water cooling, there is a remarkable suction region within the feeder head of the air cooling ingot, and this phenomenon is not observed in the water cooling one. The CAFE results including both morphology and grain size show a good agreement with the results from experiments. Moreover, the influence of superheat on the solidification structures was researched to find that the ratio and quantity of equiaxed structures increase with the decrease of the superheat, and the grain size becomes finer.