空心钨极同轴填丝焊接丝弧交互作用机制

空心钨极同轴填丝焊接焊丝与电弧(丝-弧)交互过程是决定焊接质量的关键.首先利用高速摄像观察分析了空心钨极电弧与实心钨极电弧形态，及其对焊缝成形特征的影响规律，然后构建了熔丝过程受力模型，系统分析了同轴填丝焊接过程中熔滴形成及过渡过程动力学特征.结果表明，空心钨极电弧表面辐照区域大于实心钨极，在大电流工艺条件下焊缝成形稳定；熔滴形成阶段，焊丝末端熔滴处于静力平衡状态，在较大表面张力作用下，无法自发从焊丝末端直接过渡进入熔池；熔滴过渡阶段，部分电流从焊丝流过，产生电磁收缩力，引起焊丝与熔池之间的熔滴摆动.

Mechanism of wire and arc interaction in hollow tungsten arc welding with coaxial filler wire

The interaction between welding wire and arc (wire-arc) is the key factor to determine the welding quality of hollow tungsten arc welding. Firstly, the shape of hollow tungsten electrode arc and solid tungsten electrode arc, and their influence on the weld forming characteristics are observed and analyzed by high-speed camera. Then the stress model of fuse process is constructed, the dynamic characteristics of droplet formation and transition process in coaxial wire filling welding are systematically analyzed. The research results show that the surface irradiation area of hollow tungsten electrode is larger than that of solid tungsten electrode, and the weld formation is stable under the high welding current. At the stage of droplet formation, the droplet at the end of the welding wire is in static equilibrium, and it cannot spontaneously transition from the end of the welding wire to the molten pool under the action of large surface tension. In droplet transition stage, part of the welding current flows through the welding wire, producing electromagnetic shrinkage force, causing the droplet swing between the welding wire and the molten pool.