铝合金P-MIG焊接过程熔滴过渡行为的结构负载声发射表征

Characterization of metal droplet transfer by structureborne acoustic emission signals during PMIG welding on aluminum alloy

通过在线检测铝合金PMIG焊接过程的结构负载声发射信号,研究熔滴过渡行为的表征,以及熔滴过渡形式变化对声发射信号特征参数的影响.结果表明,焊接过程中检测到的结构负载声发射信号时域波形包含了较多的PMIG焊接过程熔滴过渡特征信息,利用时域波形及其平均振铃计数、平均正峰值等特征参数可以对PMIG焊接过程中的熔滴过渡现象进行表征.当熔滴过渡频率相同时,随着熔滴过渡对液态熔池的冲击作用增大,声发射信号特征参数相应增大;当熔滴过渡频率不同时,熔滴过渡频率越大,熔滴体积越小,对液态熔池的冲击作用越小,声发射信号特征参数相应减小.

The structure-borne acoustic emission( AE)signals during pulse MIG welding on aluminum alloy were detected in real-time and analyzed to study the characteristics of AE signals corresponding to the metal droplet transfer and its influence upon the characteristic parameter of AE signals. The results showed that a mass of information about metal droplet transfer was included in the AE signals collected during PMIG welding process. It was a feasible way to characterize the behavior ofmetal droplet transfer by the time domain waveform and characteristic parameter of AE signals. As the frequency of metal droplet transfer is fixed,the characteristic parameters of AE signals increasee with the ineseasing of impact effect of metal droplet transferred into the molten pool. As the frequency of metal droplet transfer is unfixed,the impact effect of metal droplet to the molten pool decneases with the increasing of the droplet transfer frequency. So,the characteristic parameters of AE signals are decreased.