Experimental investigation of the effect of travelling magnetic field on the CET in Sn-10wt.%Pb alloy

Abstract

In order to eliminate internal and surface defects, which appear in the ingots during solidification process of metallic alloys, homogeneous and fine structures are often required. Therefore, when the adjunction of inoculant substances is not possible, the electromagnetic stirring (EMS) process thanks to the use of travelling magnetic fields has technically shown its effectiveness. The present experiments consist to create convective movements in a Sn-10wt.%Pb liquid metal, by the action of an electromagnetic field during its solidification. A significant improvement in the columnar-equiaxed transition (CET) mechanism has been observed and consequently a fine equiaxed grain structure can then be detected. The main goal of this experimental study is to examine the effect of the EMS process on grain structures for that alloy as well as the corresponding segregations. In particular, it included the determination of the optimal experimental parameters to obtain a grain refinement, the characterization of their effect on the solidification and the understanding of the physical mechanisms driving grain refinement.