EFFECT OF APPLICATION OF OUT-OF-PHASE ELECTROMAGNETIC FIELD ON HORIZORNTAL DIRECT CHILL CASTING OF 7075 ALUMINUM ALLOY

The effect of application of the out-of-phase electromagnetic field in HDC on the process and the metallurgical quality of 7075 alloy ingots was investigated in detail. The results show that when out-of-phase electromagnetic field was applied, the effect of gravity on the HDC casting process was eliminated effectively, the temperature distribution in the pool became more uniform, the cooling difference between upper and bottom surface and depth of sump were decreased, the sump shape was changed to be more symmetric about geometrical center of the mold, the thickness of segregation layer decreased and the surface quality and the microstructures of the ingots were improved, the area of feathery grains decreased and the area of equiaxed grains increased, the equiaxed grains were refined and the floating grains eliminated so that the quality of the ingots was improved.