Effect of different excitation currents on droplet transfer and weld formation of Al-Mg-Si alloy CMT MIX + Synchropulse welded joint

Abstract In this paper, the droplet transfer behavior, molten pool flow and weld formation of Al-Mg-Si alloy CMT MIX + Synchropulse welded joint under different excitation currents were studied. The external magnetic field (EMF) can effectively suppress the porosity and macroscopic pore (＞200 μm), especially at 20 A and 30 A excitation currents level. The EMF significantly reduces the droplet size (0 A → 20 A, 1.6 mm → 1.4 mm), which reduces the droplet heat and the impact force on the molten pool. The EMF changes the impact position of the molten droplet on the molten pool, making the temperature distribution on both sides of the molten pool inconsistent, which finally leads to asymmetrical weld cross-sectional morphology.