铝合金VPPA-MIG复合焊接电弧形态及伏安特性

试验使用VPPA-MIG复合焊方法对铝合金进行对接试验. 通过高速摄像和数据采集系统获取复合电弧形态和伏安特性. 结果表明，由于磁场间的耦合作用，在VPPA正极性阶段电弧相互排斥，反极性阶段相互吸引，采取外加横向交变磁场，电弧摆动幅度明显减小. 由于MIG焊电弧的存在，等离子电弧伏安特性发生了改变. 弧柱气氛更容易电离，使得等离子电弧电压下降. 等离子电流较小时，电弧电压随MIG焊电流的增加而降低；等离子电流较大时，随着MIG焊电流进一步增加，电弧电压降低程度有所减少. 试验结果为实现厚板铝合金高效焊接及其电弧耦合机理研究提供理论依据.

Study of arc shape and voltage-current characteristics in variable polarity plasma arc-MIG hybrid welding of aluminum alloys

Butt weld experiments were performed on aluminum alloys plates using VPPA-MIG hybrid welding method. Arc shape and voltage-current characteristics were obtained by high-speed camera and data acquisition system. The results show that arcs are repellent during VPPA direct current electrode negative period and attractive during direct current electrode positive period as the effect of magnetic field coupling. By applying external transverse alternative magnetic field, arc swing amplitude can be reduced apparently. Due to the existence of MIG arc, voltage-current characteristics of VPPA are changed. Atmosphere is easily ionized in arc column, and the voltage of VPPA decreases. VPPA voltage decreases with increasing MIG current when VPPA current value in low level, and VPPA voltage slightly decreases with increasing MIG current when VPPA current value in high level. Experiments provide theoretical support for high efficiency welding of thick plate aluminum alloys and arc coupling mechanism.