Nucleation and growth model based on Cellular Automation(CA) incorporated with macro heat transfer calculation was presented to simulate the microstructure of aluminum twin-roll casting. The dynamics model of dendrite tip (KGT model) was amended in view of characteristics of aluminum twin-roll casting. Through the numerical simulation on solidification structure under different casting speeds, it can be seen that when the casting speed is 1.3 m/min, that is, under conditions of conventional roll casting, coarse columnar grains dominate the solidification structure, and equiaxed grains exist in the center of aluminum strip. When the casting speed continuously increases to 8 m/min, that is, under the conditions of thin-gauge high-speed casting, columnar grains in solidification structure all convert into equiaxed grains. Experimental and numerical results agree well.
The microstructures in the solidification process of aluminum twin-roll casting was simulated based on CA(Cellular Automation Method),and the nucleation model based on the normal distribution and KUZR-GIOVANOLS-TRIVEDI(KGT) growth model were used in the calculation. FDM(Finite Difference Method) combined with relative motion was used,and dynamic evolution of microstructures in the process of aluminum twin-roll casting was achieved. Visual Fortran programming language was adopted to calculate and realize the image post-processing. Moreover,the effect of different casting process parameters on the formation of the microstructures was simulated. The results are helpful to explaining the dendritic segregation and size segregation as well as shrinkage-porosity defects. Columnar grains mainly distribute near the casting roller while equiaxed grains distributed far away from the casting roller.
