TIG焊电弧辅助MIG焊引弧过程分析与机理探讨

在TIG-MIG复合焊中，先引燃的TIG焊电弧能够辅助MIG焊实现非接触引弧，且在整个非接触引弧过程中不产生焊接飞溅. 利用电信号与高速摄像同步采集系统获取MIG焊引弧过程的电弧电压、焊接电流和电弧图像，研究了先引燃的TIG焊电弧及其参数变化对MIG焊引弧过程及引弧方式的影响. 结果表明，细长放电通道形成于MIG焊丝末端与TIG焊电弧之间是TIG焊电弧辅助MIG焊实现非接触引弧的关键；TIG焊电弧辅助MIG焊实现非接触引弧对TIG焊接参数的变化具有良好的适应性. 此外，基于气体间隙击穿的流注理论，探讨了细长放电通道的形成过程，揭示了TIG焊电弧辅助MIG焊实现非接触引弧的机理.

Process analysis and mechanism discussion of MIG arc ignition assisted by TIG arc

In the TIG-MIG hybrid welding, the first ignited TIG arc can assist MIG welding to achieve the non-contact arc ignition. And no welding spatter was produced during the whole process of non-contact arc ignition. The arc voltage, welding current and arc images during the process of the MIG arc ignition were acquired by a synchronous acquisition system of electrical signals and high-speed video, then the effect of the first ignited TIG arc and the parameters variation on the MIG arc ignition process and ignition modes was studied. The results showed that the critical point to realize the non-contact ignition of MIG arc with the assistance of the TIG arc was the filamentary discharge channel formed between the MIG wire tip and the TIG arc. The non-contact ignition of MIG arc with the assistance of the TIG arc presented good adaptability to the variation of TIG welding parameters. In addition, based on the streamer theory of gas gap breakdown, the formation of filamentary discharge channel was discussed, and thereby the mechanism of realizing the non-contact ignition of MIG arc with the assistance of the TIG arc was revealed.