Multi-physical fields distribution in billet during helical electromagnetic stirring: A numerical simulation research

Electromagnetic stirring is one of the widely applied techniques to modify the quality of casting billets. Different from conventional rotate stirring, the helical stirring is more professional in assisting multi-dimensional flow of molten metal and eliminating solidification defects. In this study, the single-winding helical stirring (SWHS) was introduced, offering advantages such as smaller volume and lower electromagnetic shielding compared to traditional helical stirring methods. Following a comprehensive numerical simulation, the stirring parameters of SWHS were adjusted to yoke inclination angle of 43 degrees and frequency of 12 Hz. The higher electromagnetic force and flow velocity in drawing direction, as well as the lower temperature gradient induced by the SWHS, are positive factors for homogeneous solidification of billet. The experimental results on Al-8%Si alloy and 0.4%C-1.1%Mn steel demonstrate that compared to rotate stirring, the SWHS process can induce better billet quality and is more effective in accelerating the equiaxed expansion and reducing element segregation. The SWHS process can enhance the equiaxed ratio of the billet by 58.3% and reduce segregation degree of carbon element by 10.97%. Consequently, SWHS holds great promise as a potential approach for improving the quality of continuous casting billets.