Electromagnetically driven convection applied during solidification of Pb-Sn alloys

Many references from the cast metal literature consider the application of sonic vibrations, mechanical or electromagnetic stirring as a tool to promote the formation of fine, equiaxed grains during solidification. In this paper experimental and numerical investigations will be presented concerning the influence of a flow driven by a rotating magnetic field (RMF) on the momentum, heat and mass transfer within binary Sn-Pb alloys solidified directionally.
Our results show that the forced convection influences significantly the concentration as well the temperature profile ahead of the solidification front. The convective transport of solute reduces the thickness of the solutal boundary layer and increases the constitutional supercooling. The RMF-application provokes a distinct grain refinement for all considered alloy compositions and equiaxed growth has shown to be encouraged. A flow effect can be supposed both on the presence of nuclei in the melt and suitable conditions allowing them to grow in competition with the columnar front.