铝合金变极性TIG焊接电弧行为

分别采用正弦波变极性和方波变极性氩弧焊对铝合金试板进行了焊接试验,利用高速摄像机和汉诺威分析仪分别对焊接过程中变极性电弧形态及电信号进行采集分析. 结果表明,电弧电压概率密度分布和高速摄像图证实了较小焊接参数条件下正弦波变极性比方波变极性电弧稳定性差的现象. 正弦波变极性TIG电弧随EP(反极性)的增加清理宽度增加,但熔宽未增加,证明此条件下正弦波变极性TIG电弧过于发散;焊接参数较大时,随EP的增加,正弦波变极性熔宽变宽,证实正弦波变极性TIG电弧稳定性随之提高,证明了铝合金变极性TIG焊接过程中EP极性电弧产热大于EN极性电弧能量的本质特征.

Arc behavior during variable polarity TIG welding of aluminum alloy

Variable polarity TIG welding of aluminum alloy was investigated with sine and square wave power supply output, respectively. Arc shape was achieved by high-speed camera. Welding current and arc voltage were acquired by Hannover welding quality analyzer. The experimental results indicate that the arc is less stable with sine waveform output than that with square wave under lower welding parameters based on distribution of voltage probability density and high speed photography. With the increasing time ratio of electrode positive period with sine waveform output, the arc cleaning area became wider, while the weld bead width kept constant since the arc was less concentrated. The weld bead width with both sine and square waveform outputs increased under large welding parameters. The results show that the arc energy was greater in electrode positive period than in electrode negative period.