Metal Transfer Behavior in AA6061 Aluminum Alloy Double-Wire Median Pulsed Gas Metal Arc Welding

An integrated aluminum alloy double-wire pulsed current gas metal arc welding system with a median waveform is developed. A digital oscilloscope acquires the voltage and current waveforms of the front median pulse (FMP) and back median pulse (BMP). At the same time, a high-speed camera records the metal transfer processes of FMP and BMP. The metal transfer behavior is analyzed. The experimental results showed that FMP and BMP could obtain stable voltage and current waveforms in addition to achieving continuous welds. In the case of the FMP, the metal transfer mode is one drop multi-pulse, precisely one drop two-pulse mode. The droplet diameter is large, so droplet collisions are more likely to occur, causing the welding process to splash around severely. In the case of the BMP, one drop per pulse (ODPP), the ideal mode, is achieved. The droplet diameter is small, so the spatter is limited, and the welding process appears more stable than that of FMP. The BMP can promote metal transfer, making it easier to achieve ODPP using the same parameters. In addition, the weld quality of BMP is better than that of FMP, in which the fish-scale ripples are prominent.