A novel ultrafast-convert hybrid pulse square-wave VP-GTAW process for aluminum alloys

A novel ultrafast-convert hybrid pulse square-wave variable polarity arc welding power source was developed. The variable polarity current which crossed zero with no dead time possessed the ultrafast converting speed and the series of ultrasonic pulse current were superimposed in the positive polarity current duration. A high-efficiency hybrid pulse variable polarity gas tungsten arc welding (HPVP-GTAW) process for aluminum alloys was achieved. With X-ray inspection, microstructure analysis, tensile tests and scanning electron microscopy (SEM) for fracture surface, the square butt welding characteristics of 5A06, 2A14 and 2219 aluminum alloys were tested, respectively. Experimental results show that microstructure and mechanical properties of these aluminum alloy welded joints are influenced significantly by the introduction of ultrasonic pulse current. The weld quality is improved predominantly by the novel HPVP-GTAW process.