Al-Mg合金超高频脉冲VP-GTAW电流参数优化

Optimization of Ultrahigh-Frequency Pulsed VP-GTAW Welding Parameters for Aluminum-Magnisium Alloy

摘要:

以铝镁系5A06铝合金为对象，开展了复合超高频脉冲变极性钨极气体保护电弧焊（Hybrid Ultrahigh Frequency Pulsed Variable Polarity Gas Tungsten Arc Wending, HPVP-GTAW）电流参数优化研究。利用正交试验方法设计了焊接实验，以接头薄弱区的显微硬度为评价指标，以HPVP-GTAW电流特征参数为影响因素，分别采用极差分析法和回归分析法对实验结果进行分析与讨论。结果表明，变极性电流频率fL、高频脉冲频率fH和脉冲电流比例系数ψ（定义为高频脉冲基值电流Ib、高频脉冲峰值电流Ip和脉冲占空比δ的综合作用）的最优参数匹配依次为1kHz、20kHz和0.6（Ib为75A，Ip为180A，δ为0.2）。fL对显微硬度影响最为显著，fH影响作用次之，ψ对显微硬度影响最弱。最优参数匹配的条件下，接头的显微硬度、抗拉强度、延伸率和断面延伸率分别达到母材性能的84.7%、94.3%、80%和93.4%。

Abstract:

Optimization of ultrahigh frequency pulsed VP-GTAW (HPVP-GTAW) welding parameters on microhardness 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 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 regression analysis method. Results show that the optimal parameters of variable polarity current frequency fL, pulse frequency fH and pulsed current proportional coefficient ψ are 1kHz, 20kHz and 0.6 (high-frequency background current 75A, high-frequency peak current 180A, duty cycle of high-frequency pulse 0.2), respectively. Meanwhile, fL influences on microhardness the most significantly, followed by fH, and the impact extent of ψ on microhardness is the least. The confirmatory experiment shows that the microhardness, tensile strength, percent elongation and ratio of reduction with the obtained optimal parameters are 84.7%、94.3%、80% and 93.4% of those of the base matel, respectively.