Modeling of Interdendritic Strain and Macrosegregation for Dendritic Solidification Processes: Part II. Computation of Interdendritic Strain and Segregation Fields in Steel Ingots

In Part II of this article, the models are applied to analyze the effects of various cooling conditions on the interdendritic-strain history and macrosegregation patterns. The temperature measurements are used to evaluate the heat-transfer coefficient between the ingot surface and the cooling fluid. The model predictions are compared to temperature measurements and carbon-concentration profiles in ingots, where good agreements are obtained. In examining the fluctuated cooling conditions on the interdendritic strain, the results show that the sudden increase in the heat flux is found to increase the compressive strain in the interdendritic-strain region. The drop in the heat flux shows completely opposite behavior, where the tensile strain generates through the same region. The model demonstrates also that interdendritic strain associated with the fluctuated cooling conditions is a major factor in determining macrosegregation quantitatively and qualitatively. The results show that the tensile interdendritic strain results in a positive segregation, whereas the compressive strain yields a negative one. The segregation level depends mainly on the interdendritic-strain history and its rate value. The mechanism of fluctuated-segregation phenomenon as a function of the interdendritic strain is extensively discussed.