不锈钢电阻点焊过程中的动态电阻变化规律分析

Analysis on dynamic resistance in resistance spot welding of stainless steel

对利用自动数据采集技术获取的不锈钢点焊过程中的动态电阻信息进行系统研究。结果表明,不锈钢点焊过程中动态电阻能够灵敏且有规律地反映点焊工艺参数的变化,蕴含着丰富的点焊质量信息。焊接过程中动态电阻变化与熔核生长过程具有明显的对应关系,动态电阻曲线的拐点时间及终点值等特征量分别与熔核出现时间和最终熔核尺寸有很强的相关性。点焊过程喷溅会导致动态电阻骤降,其动态电阻变化率曲线在相应位置出现尖峰,为喷溅的自动识别提供了依据。

The dynamic resistance signal was collected by an automatic data acquisition system. Research indicated that the dynamic resistance signal responded well to the change of welding parameters, and contained plenty of quality information. There was an obvious correspondence between the dynamic resistance signal and the growth process of nugget. The inflexion time and destination value of dynamic resistance curve had strong relativity with the time of nugget appearance and the final size of the nugget respectively. Welding parameters affected the dynamic resistance signal obviously and regularly. When an expulsion occurred, a sharp drop in dynamic resistance curve and a peak in the change rate of dynamic resistance curve can be used to automatically identify the splash.