Control of solidified structure of cast metal by imposing electromagnetic field

In order to improve the quality of cast metal and to control solidification of metals, two new casting processes controlling metal solidification by i mposing electromagnetic field are developed. One is simultaneous imposition of multiple-electromagnetic fields from the outside of a cold-crucible cop per mold during continuous casting of Sn-4.5 mass% Pb alloy, and the other is the imposition of a rotating magnetic field during the unidirectional so lidification to make in situ surface composite with special mechanical and physical properties. The experimental results show that multiple-electromag netic fields can not only eliminate surface defects, but also improve solid ification structure of cast metal. Moreover, a new kind of composite pipe a nd gear of Al-12.6 mass% Si eutectic alloy was made by imposing electromagn etic stirring during unidirectional solidification. This suggests a new met hod of making surface composite with special mechanical and physical proper ties. It is also found that a separated eutectic occurs in the anomalous eu tectic and the separated phase is the leading faceted phase with solution e ntropy over 23 J/mol K.