Numerical Analysis of the Influence of Melting and Application of Electromagnetic Stirring Prior to Solidification on Macrosegregation Formation during Casting of a Binary Alloy

Numerical simulations of macrosegregation formation during horizontal solidification of a hypoeutectic Sn-Pb alloy in a rectangular cavity is presented and compared to experimental results. The experiment involves a melting phase, a holding stage at constant temperature with or without application of electromagnetic stirring, and finally solidification. We simulate all stages of the experiment and study the segregation of Pb throughout the experiment. A two-phase volume-averaged model is used for the numerical simulations, accounting for thermo-solutal convection and assuming perfect microscopic mixing (lever rule). The influence of the melting phase and of the electromagnetic stirring is studied with different cases to illustrate the consequences on the flow pattern and on Pb segregation during melting and during solidification. The numerical simulations are compared to the experimental data and the impact of chemical inhomogeneities prior to solidification on macrosegregation formation is discussed.