Numerical and experimental investigation of metal droplet transfer during pulsed bypass-current plasma-GMAW hybrid arc welding

In this research, AA 5083 aluminum alloy was proposed to be joined by the bypass-current plasma-GMAW hybrid arc welding with pulse current mode. During this hybrid process, three kinds of current work synergistically, including the main current from the welding wire, the bypass current into the copper nozzle, and the welding current into the base metal. Moreover, they have the same waveform due to the same system controlling them. For a deep understanding of the coupled effects of multiple pulse currents on metal droplets, a comprehensive study combining the experiment and the simulation was executed to compare the heat and mass transfer behaviors when the current mode changes. The results show that when the wire feed speed is maintained at 6 m/min, the droplets have a projected transfer mode no matter with which kind of current mode. However, the transfer frequency is increased by approximately double when the pulse waveform is employed. Furthermore, the transfer stability is further enhanced due to the force state getting regulated by the various hybrid electromagnetic fields stimulated by the pulse currents. This investigation offers a deeper understanding and continuous optimization of precise control of metal droplet behaviors in aluminum alloy welding.

Automated summary

This research proposes a method for joining AA 5083 aluminum alloy using pulse current mode in bypass-current plasma-GMAW hybrid arc welding. The effects of multiple pulse currents on metal droplet behaviors were comprehensively studied through experiments and simulations. The results show that the use of pulse waveform increases the transfer frequency and stability of the droplets, providing an optimized method for controlling metal droplet behaviors in aluminum alloy welding.