铝合金电阻点焊的熔核形成过程

点焊过程中熔核形成过程对焊接结构的强度和耐用性具有非常重要的影响.文中采用高速摄像技术研究了焊接电流和电极压力对铝合金电阻点焊形核过程的影响.结果表明,铝合金电阻点焊熔核首先在工件/工件接触面中心处形成,然后沿着水平方向生长,同时垂直方向也有少量的生长,一直扩展到电极头端面直径.熔核尺寸在点焊前80 ms时迅速长大,120 ms后基本保持不变,表明过长的焊接时间是没有必要的.随着电极力的增加,工件会经历较大的塑性变形,导致没有熔核形成.因此常规点焊时,不应采用过高的电极压力.

Nugget formation process in aluminum alloy resistance spot welding

The nugget formation process in resistance spot welding plays an important role in controlling the strength and durability of the welded structure. This paper investigated the effects of welding current and electrode force on the nugget formation process during aluminum resistance spot welding by using high-speed camera. The results show that the nugget was initially formed at the center of workpiece/workpiece interface,then extended along the horizontal direction to the width of the tip end while it has slightly grown in the vertical direction. The nugget size rapidly grows up before the welding time of 80 ms and it nearly remains unchanged after the welding time of 120 ms. This indicates that a long welding time is unnecessary. The workpieces will suffer a serious plastic deformation when the electrode force is large. Therefore,too large electrode force should be avoided during resistance spot welding.