Effect of Low-Frequency Magnetic Fields on Microstructures of Horizontal Direct Chill Cast 2024 Aluminum Alloys

Abstract

The horizontal direct chill (HDC) casting process is a well-established production route for wrought aluminum alloy ingots. However, the ingots may suffer from heterogenous microstructures due to the unbalanced cooling condition and gravitational effect. In order to minimize the casting defects, a low frequency electromagnetic field was applied in the HDC casting process and its influence on solidified microstructure was studied. The results show that the low frequency electromagnetic field can effectively reduce heterogenous microstructures in HDC ingot; and two main parameters of electromagnetic field, i.e., intensity and frequency, significantly affect the microstructures and solute distribution from the center to the periphery of the ingot. In the range of ampere-turns and frequency employed in the experiments, the ampere-turns of 10000 At and frequency of 30 Hz were found to be optimum.