等离子弧焊小孔行为的反翘电压检测

在穿孔等离子弧焊接过程中，小孔稳定性对焊接过程的稳定和优质的焊缝成形是非常关键的。文中采用无源探针对由等离子弧梯度电压和等离子鞘层电压构成的等离子反翘(等离子云)电压进行检测。根据等离子鞘层理论，随等离子反翘长度和角度变化的反翘电压可以反映小孔的状态信息及其形成、坍塌过程。文中讨论了检测信号的特征，以及材料、探针位置、焊接电流，等离子气流等因素对检测信号的影响。试验证明，该方法可以有效的预测小孔信息和焊缝熔透情况。

Detection of keyhole behavior in keyhole plasma arc welding using plasma cloud voltage

Keyhole stability during plasma arc welding welding process is critical to the process stability and weld quality. A non power supply probe was developed to detect the plasma cloud voltage, which consists of plasma arc voltage gradient and plasma sheath voltage. Based on plasma sheath theory, the keyhole state information, keyhole establishment and collapse could be predicted by the plasma cloud voltage which changes according to the length and angle of plasma cloud. The signal characteristic and the influences of welding materials, probe location, welding current and plasma gas flow on the signal are discussed. Experiments verified the effectiveness of the method for predicting the keyhole information and joint penetration state.