<p>A transient two-dimensional axisymmetric Multiphysics-coupled model was developed using COMSOL Multiphysics to simulate the DC casting process of Fe-0.2C-6Cu wt.% alloys. The effects of magnetic field distribution, Lorentz force behavior, melt flow, heat transfer, and solidification characteristics were investigated under four magnetic field configurations: low-frequency magnetic field (LFMF), pulsed magnetic field (PMF), differential-phase low-frequency magnetic field (DLFMF), and differential-phase pulsed magnetic field (DPMF). It was found that both LFMF and PMF generated strong magnetic induction intensities near the billet surface; however, non-uniform field distributions and significant flow fluctuations were observed. In contrast, DLFMF and DPMF resulted in more uniform and stable electromagnetic field distributions due to the superposition of phase-differential magnetic fields, which effectively reduced melt flow pulsation and enhanced electromagnetic stability. Under differential-phase magnetic fields, the axial component of the Lorentz force was significantly enhanced, leading to a synergistic interaction between the radial and axial components and promoting a more stable and complex melt circulation pattern. It has been demonstrated that the intensified forced convection enhances heat transfer efficiency, resulting in a flatter solidification front and a more uniform distribution of the liquid phase fraction. Further analysis revealed that the intensity of the Lorentz force was primarily governed by the current amplitude, followed by the effects of frequency and duty cycle. Due to the dual-phase superposition effect, the differential-phase pulsed magnetic field (DPMF) exhibited a smoother and more uniform Lorentz force distribution. Notably, strong driving capability was maintained under high-frequency and high-duty cycle conditions, indicating superior adaptability to high-frequency operation and enhanced effectiveness in controlling solidification structure.</p>