Effects of the low frequency electromagnetic field on the centerline macrosegregation of 7075 aluminum ingots

The effects of the low frequency electromagnetic field on the macrosegregation of the 7075 aluminum ingots were investigated. The 7075 aluminum ingots with the diameter of 200 mm were prepared by the conventional direct chill casting and the low frequency electromagnetic field casting (LFEC) processes, respectively. The temperature during casting at steady state was measured, and the mushy region was observed from the temperature contour. The concentrations of the alloying elements were measured by the spectrograph. It was found that the transition region was broadened, but the mushy zone became narrower with presence of the low frequency electromagnetic field. The centerline macrosegregation of the ingots was alleviated by the low frequency electromagnetic casting process.