In order to obtain semi-solid aluminum alloy billets of high quality, an investigation was carried out of imposing multiple magnetic fields from the outside of a cold-crucible copper mold in a continuous casting process. AlSi6Mg2 (wt.%) alloy designed for a semi-solid metal (SSM) process was continuously cast through a submerged entry nozzle under various conditions. By means of optimizing the distribution of multiple magnetic fields in the mold, the effect of multiple magnetic fields on both the meniscus motion and billet quality was examined. The experimental results showed that meniscus disturbance could be controlled efficiently and the surface quality of a semi-solid aluminum alloy billet was improved greatly by imposing multiple magnetic fields, and also a uniformly fine, globular microstructure across the transverse section of the billet was achieved by optimizing the distribution of the multiple magnetic field.

Keywords: continuous casting; multiple magnetic field; aluminum alloy; semi-solid; microstructure