Effect of low-frequency electromagnetic field on microstructures and macrosegregation of Φ270 mm DC ingots of an Al–Zn–Mg–Cu–Zr alloy

Compared with traditional direct chilling casting (DC) ingot, the edge and center microstructures of Φ270 mm low-frequency electromagnetic casting (LFEC) ingot are fine and uniform; and the macrosegregation is also greatly reduced. When the electromagnetic intensity is kept as 9000 At, with decreasing the frequency, the center microstructures are much finer and the macrosegregation is much lower. In the range of frequency employed in the experiments, the optimum frequency is found to be 15 Hz.