建立包括钨极、电弧和阳极的定点活性钨极惰性气体保护(Activating tungsten inert gas，A-TIG)焊电弧熔池交互作用统一数学模型。通过麦克斯韦方程组、连续性方程、动量守恒方程、能量守恒方程和组分输运方程的耦合求解，得到了电弧和熔池的温度、等离子体运动速度、熔池流动速度、电弧压力、电势、电流密度和金属蒸汽分布等结果。因为在A-TIG焊中，熔池的内向流动造成了大量的热被传入到熔池底部，热量的利用率更高，导致焊接熔池的表面温度比TIG焊的表面温度要高，从而引起了金属蒸汽浓度的增加，所以考虑金属蒸汽的A-TIG焊的电弧等温线较考虑金属蒸汽的TIG焊的电弧等温线有一定程度收缩。结果表明，考虑金属蒸汽对A-TIG焊熔深的模拟结果具有一定的影响，熔深减小约6%，该结果与有关试验研究结果吻合良好。

A three-dimensional(3D) numerical analysis model of stationary activating tungsten inert gas welding(A-TIG welding) arc in interaction with the anode material and the tungsten electrode is presented. According to the method,the distributions of temperature field and velocity field of arc plasma and weld pool,metal vapor concentration and current density in the arc plasma are investigated by solving the Maxwell equations,continuity equation,momentum conservation equation,energy conservation equation and the components of the transport equation. As it is different between A-TIG welding and TIG welding about the flow pattern,the temperature on the anode surface material in A-TIG welding is higher than that in TIG welding, then the metal vapor concentration in A-TIG welding is higher, which causing the temperature contour of A-TIG welding shrinks in the end.With the influence of the metal vapor,temperature contour of A-TIG welding also shrinks for the same reason in TIG welding and it shrinks in a bigger degree than TIG welding. It results that the weld depth decreases about 6% with the impact of metal vapor in A-TIG welding.