热镀锌高强钢点焊的电极磨损对焊点质量的影响

Effects of electrode wear on weld quality of hot galvanization steel with high strength in resistance spot welding

试验研究了热镀锌高强钢点焊的电极磨损规律,同非镀层低碳钢相比,热镀锌高强钢点焊的电极寿命低、点蚀磨损特征变化明显.在此基础上分析电极磨损对焊点质量影响,电极磨损初期阶段,热镀锌高强钢点焊的飞溅严重、焊点表面产生微裂纹程度大,导致焊点质量下降.最后根据电极磨损对焊点微裂纹与熔核直径影响的试验结果,以微裂纹长度不超过0.25 mm的电极端面电流密度为标准,确定电流递增工艺方案,以减小严重电极磨损对焊点质量的影响.

Electrode wear characteristics were studied;the electrode life of uncoated steels was much lower and pitting changed more obviously than that of galvanization steels when welding.The effect of electrode wear on weld quality was studied;the expulsion was serious and more micro-cracks were grown at early electrode wear stage,which decreased weld quality greatly.And then based on the experiment results of effect of electrode wear on weld quality,welding technique step-current was established according to the current density that micro-crack degree was less than 0.25 mm to reduce the effect of electrode wear on weld quality.