在模拟计算100 μm超薄不锈钢板脉冲微束等离子弧焊过程的基础上，研究了实际热源动态脉冲加载下的熔池温度场动态过程及脉冲参数对该动态过程的影响机制；研究了脉冲参数对焊缝成形的影响，对模拟计算的结果进行验证，并探讨了脉冲参数和焊接速度的匹配与焊缝成形特征的关系. 结果表明，超薄板脉冲微束等离子弧焊接的温度场变化具有周期性的波动特征和惯性特征，脉冲频率越高或基值电流/峰值电流之比较小，温度场变化的波动幅度也越大，其相对于脉冲电流变化的惯性也越大；脉冲电流下的焊缝成形有连续和不连续两种形式，这与焊接速度、峰值电流作用时的焊缝长度、脉冲频率三者之间的匹配有关；模拟计算的熔池最高温度超过熔点的持续时间与脉冲周期的比值结果较好地解释了试验得到的焊缝成形的连续程度.
Based on the numerical calculation of pulsed microplasma arc welding (P-MPAW) 100 μm ultrathin sheets, dynamic distribution characteristic of weld pool temperature field under dynamically loading the actual heat source and influence of pulse parameters on it were studied. Effect of pulse parameters on weld morphology was investigated and the numerically calculated results were verified. In addition, the relations between the matching of pulse parameters and welding speed with the weld morphology were discussed. The results were as following. Firstly, the dynamic variations of temperature distribution are characterized with cyclical fluctuation and inertia. The higher the pulse frequency or the smaller the ratio of peak current to base current, the stronger the fluctuating amplitude and the more intense the inertia of temperature variation corresponding to the changes of pulsed current are. Secondly, there are two forms of weld morphologies with pulsed current, continuous weld and non-continuous weld morphologies. These two different weld morphologies are attributed to the matching of welding speed, seam length during peak current period and pulse parameters. Finally, the continuity of experimentally obtained weld morphology was well explained by the numerically calculated results about the ratio of pulse period to lasting time when the maximum weld pool temperature is higher than the material melting point.
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