Study on the sump and temperature field during low frequency electromagnetic casting a superhigh strength Al–Zn–Mg–Cu alloy

The effects of low frequency electromagnetic field on the sump depth and temperature field of a molten aluminum alloy (Al–Zn–Mg–Cu) were investigated by temperature measurement method. The results showed that during low frequency electromagnetic casting (LFEC) process the temperature field of the whole melt in the hot top is very uniform, and about 6 °C lower than liquidus temperature, which is very helpful to obtain uniform and fine microstructures. It was considered that LFEC process is like a kind of liquidus or near liquidus semi-continuous casting. It was also found that the sump depth during LFEC process is shallower than that of conventional direct chill (DC) casting process.