Among the factors that influence welding defects, arc interruption is an important and unavoidable problem. When the welding torch swings during narrow gap pulsed gas metal arc welding (P-GMAW), arc interruption phenomenon always occurs at the same position along the torch trajectory and is therefore governed by some concrete conditions. Prior to arc interruption, the arc exhibits a distinct shape and the voltage signals fluctuate significantly. Internal causes of the distinct arc shape were investigated, and it was found that narrowness of the gap played an important role. As the metal vapor is easily ionized, the arc rises along with the rising vapor plume, expanding beyond the end of the wire and forming an approximately parabolic shape. The effect of narrow grooves on the droplets and weld beads, especially when the torch deviates from the groove center, will be beneficial for the generation and collection of metal vapor. Since the arc will always be prolonged prior to interruption and the voltage will fluctuate, the arc interruption of this kind can be predicted and eliminated, thus improving the welding quality of narrow gap.

中文翻译：

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窄间隙P-GMAW中的电弧中断现象和内部原因

在影响焊接缺陷的因素中，电弧中断是一个重要且不可避免的问题。当焊枪在窄间隙脉冲气体保护电弧焊（P-GMAW）中摆动时，电弧中断现象总是沿着焊枪轨迹在同一位置发生，因此受某些具体条件的影响。在电弧中断之前，电弧呈现出明显的形状，并且电压信号明显波动。研究了产生明显弧形的内部原因，发现间隙的狭窄起着重要的作用。由于金属蒸气易于电离，因此电弧与上升的蒸气羽流一起上升，扩展到金属丝末端之外并形成近似抛物线的形状。窄槽对熔滴和焊道的影响，特别是当割炬偏离凹槽中心时，将有利于金属蒸气的产生和收集。由于在中断之前电弧总是会延长并且电压会波动，因此可以预测并消除这种电弧中断，从而提高了窄缝的焊接质量。