交流电阻点焊中电极位移波动特征的分析  

Analysis on electrode displacement fluctuation characteristics in AC resistance spot welding

作　　者：王先锋[1] 孟国香[1] 谢文华[1] 冯正进[1] 

机构地区：[1]上海交通大学机械与动力工程学院,上海200240

出　　处：《焊接学报》2010年第11期109-112,共4页Transactions of The China Welding Institution

摘　　要：利用改进的交流电阻点焊监控系统采集电极位移和焊接电流,经分析认为电极位移曲线上的波动是由50 Hz的交流电阻热脉冲引起的.利用电阻点焊中的洋葱环现象分析了电极位移波动特征的机理,认识到电极位移在熔核形成前以热膨胀为主,在熔核形成后以相变膨胀为主,并且都具有波动特征.利用焊接电流曲线提供的晶闸管触发角和导通角依次计算功率因数角、动态电阻和动态电阻热.通过位移波动周波峰值与动态电阻热的对比分析,发现位移波动周波峰值在点焊过程中对热膨胀与相变膨胀有较强的敏感性,能用来反应熔核形成过程的不同阶段.The signals of electrode displacement and welding current were sampled by the improved monitoring system of AC resistance spot welding(RSW).The fluctuation characteristics of the electrode displacement were analyzed,and it was concluded that the displacement fluctuation was caused by 50 Hz AC resistance heat pulse.The mechanism of electrode displacement fluctuation was analyzed by onion phenomenon in RSW,and the results showed that the electrode displacement was mainly caused by thermal expansion before the nugget formation and by phase transition expansion after that,and there were the fluctuation characteristics in both expansion.The power factor angle,dynamic resistance and dynamic resistance heat were calculated with the firing angle and conduction angle provided by the welding current curve.Through the comparative analysis on the peak of the displacement fluctuation cycle and the dynamic resistance heat,it was found that the former was sensitive to the thermal and phase transition expansion,and can be used to reflect the different stages of the nugget formation process.

关 键 词：电阻点焊 电极位移 波动特征 热膨胀 相变膨胀 

分 类 号：TG115.28[金属学及工艺—物理冶金]