SiO_(2)在粉末熔池耦合活性TIG焊熔池表面的过渡行为

Transfer Behavior of SiO_(2) on the Surface of Powder Pool Coupled Activating TIG Welding Pool

针对铝合金交流PPCA-TIG焊(Powder Pool Coupled Activating TIG Welding),研究了活性剂SiO_(2)在熔池表面的过渡行为,这对于活性焊的发展与活性剂开发具有重要意义。通过对比PPCA-TIG焊与TIG焊的焊缝表面成形、斑点行为以及高温焊态电阻,发现SiO_(2)的过渡导致电弧收缩,并且PPCA-TIG焊在EN时段阴极斑点数量增多是导致焊缝表面成形差的重要原因;在EP时段,SiO_(2)的较高高温焊态电阻强制电弧收缩,减小了导电面积,是熔深增加的主要原因。结合骤冷法获得的高温熔池的成分、物相分布与热分析结果,发现SiO_(2)并未直接参与到熔池的冶金反应,且SiO_(2)过渡到熔池表面粘附后并未深入熔池。最终建立了铝合金交流PPCA-TIG焊中SiO_(2)在熔池表面的过渡模型。

For the AC PPCA-TIG welding(Powder Pool Coupled Activating TIG Welding) of aluminum alloys, the transition behavior of the active flux SiO_(2)on the surface of the molten pool is studied, which is of great significance for the development of active welding and the development of active fluxes. In this paper, by comparing the weld surface formation, spot behavior and high temperature resistance of PPCA-TIG welding and TIG welding, it is found that the transition of SiO_(2)leads to arc shrinkage, and the increase in the number of cathode spots of PPCA-TIG welding in EN period is an important reason for poor weld surface formation;during EP period, the high-temperature resistance of SiO_(2)forces the arc to shrink and reduces the conductive area, which is the main reason for the increase of melting depth. Combined with the composition,phase distribution and thermal analysis results of the high-temperature molten pool obtained by rapid cooling method, it is found that SiO_(2)does not directly participate in the metallurgical reaction of the molten pool, and SiO_(2)does not go deep into the molten pool after transitioning to the surface of the molten pool. Finally, a transition model of SiO_(2)on the surface of the molten pool in AC PPCA-TIG welding of aluminum alloy is established.