Effect of phase shift on arc interference and weld bead formation in aluminum alloy tandem GMAW with a median pulsed waveform

作者:Wu, Kaiyuan; Wang, Yifei; Tao, Taoyuan; Zhan, Jiatong; Hong, Xiaobin*
来源:INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY, 2022, 120(11-12): 8013-8030.
DOI:10.1007/s00170-022-09200-5

摘要

In this study, the effect of phase shift on welding properties in tandem gas metal arc welding (GMAW) with a medium pulsed waveform applied to aluminum (Al) alloy was investigated. The arc profiles obtained with different phase shifts were captured by a high-speed digital camera, and the corresponding voltage and current waveforms were simultaneously recorded using a digital oscilloscope. The influence of phase shift on weld bead formation was also analyzed. The results show obvious double arc interference with a phase shift of 0 degrees. When the phase is shifted by 120 degrees or 240 degrees, the degree of arc interference at the higher current decreases while the degree of arc interference at the lower current increases. Double arc interference changes the angle of arc pressure acting on the surface of the weld pool. Furthermore, the weld penetration deepens with increasing phase shift, thus confirming that weld penetration is positively correlated with the vertical component of arc pressure. The welding process is more stable when the phase is shifted by 120 degrees or 240 degrees, compared with a 0 degrees phase shift, resulting in a smoother and more uniform weld appearance. Finally, trends of decreasing weld width, increasing weld reinforcement, and reducing porosity were observed.