Numerical Simulation of Macrosegregation with Solid Deformation During the Solidification of Steel Ingots Using a Single-Phase/Two-Phase Integrated Model

Abstract

Macrosegregation, a serious defect formed during the solidification of steel ingots, impairs the performance of the final components. To predict macrosegregation caused by thermal-solutal convection and solid deformation, a volume-averaged single-phase/two-phase integrated model is developed. During the deformation stage, the two-phase model coupling the solid deformation and liquid flow in the mushy zone is utilized. Before or after the deformation stage, the motion of the solid phase is neglected, and the single-phase model is solved. A 450 kg steel ingot punching test is considered for application. The results show that when the solid shell of the ingot is being punched, the solid phase in the mushy core at punching height is compressed, and a relative liquid flow is induced. This in turn causes a transition of positive segregation to negative segregation in the compressed mushy core of the ingot. According to numerical sensitivity tests of different punching parameters, as the punching start time and punching velocity increase, the effect of punching on macrosegregation will be smaller. It is demonstrated that the single-phase/two-phase integrated model can predict macrosegregation in the steel ingots which are deformed during solidification.