Al-Mg合金超高频脉冲VP-GTAW电流参数优化

Optimization of ultrahigh-frequency pulsed VP-GTAW (HPVP-GTAW) welding parameters for 5A06 aluminum alloy was carried out. Taguchi method was employed to design the experiment. The microhardness of the fusion zone and heat affected zone (HAZ) was taken as an indicator, and the characteristic welding current parameters of HPVP-GTAW were taken as factors. The experimental results were analyzed by both the range analysis method and the regression analysis method. Results show that the optimal parameters of variable polarity current frequency f _L , pulse frequency f _H and pulsed current proportional coefficient ψ are 1 kHz, 20 kHz and 0.6 (high-frequency background current 75 A, high-frequency peak current 180 A, duty cycle of high-frequency pulse 0.2), respectively. Meanwhile, f _L influences microhardness most significantly, followed by f _H , and the impact extent of ψ on the microhardness is the least. The confirmatory experiment shows that the microhardness, tensile strength, elongation and ratio of reduction with the obtained optimal parameters are 84.7%, 94.3%, 80% and 93.4% of those of the base metal, respectively.