Three-Dimensional Modeling of Segregation Behavior during Solidification of a Sn-6 wt.% Pb Alloy

In this study, a three-dimensional (3D) solidification model was developed that uses a SOLA algorithm to solve momentum equations and accelerate iterative convergence. The macrosegregation behavior of a sand-cast Sn-6 wt.% Pb alloy was numerically investigated by the developed 3D model. The experiment was carried out for a casting with one side in contact with a graphite chill and the other sides in contact with resin sand. The necessary precision of in-house-developed codes was validated by comparisons with experimentally measured cooling curves and lead concentration distribution. The limitations of the model in fitting experimental results well were discussed. A comparative study between simulations in two-dimensional (2D) and 3D cavities showed that although the general distribution pattern of macrosegregation was slightly affected, the details regarding segregation degree, solute composition distribution over the solidifying domain, solidification time and fluid flow pattern were different. For 2D simulations without boundary walls, the convection behavior was less complicated, and the cooling process was slowed down both in the casting and in the mold.