Numerical study of macrosegregation in a large steel ingot with multiple pouring process

Multiple pouring (MP) process with a higher concentration in the beginning and a lower concentration at the last is generally utilized to reduce macrosegregation in the large steel ingot production. However, it is insufficient to demonstrate the practical efficiency of MP process from the point view of theory. In this paper, the whole filling and solidification processes were investigated to analyze the formation of macrosegregation in a large steel ingot. Firstly, a filling transportation model considering the entire MP process was presented. The carbon concentration variation through the outlet of the tundish at different times was predicted and provided as the boundary conditions for the mold filling and the solidification processes simulation. Secondly, the macrosegregation model was integrated into the filling transportation model to investigate the influence of the MP on the macrosegregation in the ingot through the comparison of the MP and the single pouring process (SP). Finally, the top section of a 438-t steel ingot was cut off and the carbon concentration was measured to validate the numerical results. The results indicated that the MP process has a certain favorable effect on reducing the positive segregation in the top region of the ingot.