Weld appearance of 2219-T87 high strength aluminum alloy produced by HPVP-GTAW process

Based on hybrid ultrahigh frequency pulse variable polarity gas tungsten arc welding (HPVP-GTAW) surfacing process for 2219-T87 high strength aluminum alloy, the effect of pulse current parameters on weld appearance was analyzed. Experimental results show that the weld penetration and weld depth to width was improved significantly by HPVP-GTAW process, compared with the conventional VP-GTAW process. The weld appearance was changed obviously when the pulse current parameters were adjusted. With constant average current at positive polarity duration, the weld penetration and weld depth to width was overall improved with the increase of the pulse frequency, and weld depth to width increased by 60% when the pulse frequency reached up to 60 kHz. Weld depth to width was improved with the increasing of the ratio of the pulse peak current and base current. Weld depth to width was the highest with 20% duty cycle and improved most significantly with the increase pulse current ratio compared with the duty cycle of 50% and 80%.