Numerical simulation of Mo macrosegregation during ingot casting of high-Mo austenitic stainless steel

Mo macrosegregation was studied through the comparison of numerical simulation of the ingot pouring process and experiment on as-cast 500 kg high-Mo austenitic stainless steel ingot. The simulated results showed the evolution of temperature, melt velocity and the patterns of Mo macrosegregation, and revealed the effects of pouring temperature and cooling rate on macrosegregation. The predicted variation of Mo macrosegregation was compared with measurement values from an industrial ingot along the vertical centreline and horizontal direction. Severe normal and gravity segregation were observed. Although a basic agreement was obtained, the lack of a sufficiently fine numerical grid and the neglect of sedimentation for free equiaxed grains in the prediction brought about the absence of A-segregation and V-segregation. Further investigation would be needed to perform this investigation. The predicted results also confirmed that Mo macrosegregation in the ingot could be effectively diminished by improving cooling rate and decreasing pouring temperature.