中文摘要：

通过YB005-01型压力变送器测定相同参数条件下正极性等离子电弧力大于反极性等离子电弧力,并建立了铝合金VPPA焊接穿孔熔池受力模型,分析了在不对称正、反极性等离子电弧力的作用下,穿孔溶池稳定性及其焊缝成形机理。同时进一步分析铝合金VPPA力学特性,掌握了焊接电流和离子气流量等重要焊接参数对其影响。经穿孔焊工艺实验,合理选择正、反极性电流幅值和离子气流量等参数,保持穿孔熔池热和力的平衡,为获取铝合金VPPA焊接稳定的工艺规范提供了理论支持。

英文摘要：

Using YB005-01 pressure transmitter the plasma arc force in positive polarity was greater than that in reverse polarity was measured.The thermal and force models on aluminum alloy variable polarity plasma arc（VPPA） keyhole molten pool were built.The stability of keyhole molten pool and the forming mechanism of weld under the action of thermal and force in asymmetric positive and reverse polarity plasma arc were analyzed.By further analysis of aluminum alloy variable polarity plasma arc mechanical and thermal characteristics,the key welding influence factors on welding current and plasma air flow were mastered.According to the keyhole welding process testing,the reasonably selected positive and reverse polarity current amplitude and plasma air flow which keep thermal and force balance during keyhole welding process provided theoretical support for getting stable technique parameters in aluminum alloy variable polarity plasma arc welding.