超快变换高频变极性方波TIG电弧行为

TIG arc behavior of ultrafast-convert high-frequency variable-polarity square wave

基于一种新型电路变换拓扑实现频率达超音频段且具有超快速电流上升沿和下降沿变化速率的高频变极性方波电流输出,将其用于铝合金TIG焊接过程,研究分析高频变极性TIG电弧行为.结果表明,变极性电流频率和变化速率具有对电弧形态、稳定性及电弧力的控制能力,提高电流极性变换频率,电弧清除氧化膜的能力增强,电弧表现出明显的收缩效应,电弧电压和电弧等效电阻增大,但电弧偏吹作用加剧.在一定频率范围内,增加变极性电流频率,减小负极性电流幅值及其持续时间,可增大焊缝熔透率,有利于提高焊接效率和质量.

Based on a novel main circuit topology of ultrafast-convert power supply,variable polarity current with the ultrafast current rate of rise and fall was achieved,and the arc behavior of high-frequency variable-polarity tungsten inert-gas welding for aluminum alloy was investigated.The experimental results show that with the increase of current frequency,the cleaning action of ultrafast-convert high-frequency variable-polarity arc for surface oxide is significantly enhanced,arc plasma has an obvious pinch effect,arc voltage and arc resistance increase respectively,but arc blow-effect is also enhanced.Increasing the current frequency and decreasing negative polarity current amplitude and its duration in certain ranges can improve weld penetration and reduce the electrode consumption.It is beneficial to improve weld quality and efficiency for aluminum alloys.