Computer simulation of macrosegregation in directionally solidified circular ingots

The formulation and employment of a computer code designed to simulate the directional solidification of lead-rich Pb-Sn alloys in the form of an ingot with a uniform and circular cross-section are described. The formulation is for steady-state solidification in which convection in the all-liquid zone is ignored. Particular attention was given to designing a code to simulate the effect of a subtle variation of temperature in the radial direction. This is important because a very small temperature difference between the center and the surface of the ingot (e.g., less than 0.5 C ) is enough to cause substantial convection within the mushy-zone when the solidification rate is approximately 0.001 to 0.0001 cm/s.