Experimental study of molten metal flow and numerical simulation of magnetic field during permanent magnet stirring and its application in continuous casting

Molten metal flow and magnetic field of the permanent magnet stirring (PMS) were investigated by experimental study and numerical simulation, respectively. A laboratory experiment was first performed to study the effects of PMS on the flow velocity of the Sn-20%Pb hypereutectic alloy during solidification. The results showed that the center magnetic flux density and stirring frequency were the two key factors affecting the electromagnetically-driven convection of the molten alloy. The electromagnetic field analysis software Opera-3D was used to develop a materials-saving and highly effective final permanent magnet stirring (FPMS) apparatus comprising a reasonable magnetic field design. Based on the scalar potential formulation, the stationary magnetic fields of the PMS were calculated and the number, arrangement and size of the permanent magnets were optimized. Thereafter, a pair of arc NdFeB permanent magnets with optimally designed geometrical dimensions was developed for industrial use in the FPMS apparatus. Consequently, with the industrial application of the new equipment in continuous casting, an improvement of the macrosegregation and other macro-defects of the rectangular billet were obtained.