Study on Penetration Sensing Method Based on Pool Oscillation and Arc Voltage during Pulsed GMAW

The internal relations among the oscillation characteristics of the weld pool, the voltage signal curve and the penetration status of the weld joint in pulsed gas metal arc welding were investigated by using high-speed camera and image analysis system to extract characteristics of weld pool oscillation. The results show that the amplitude of weld pool oscillation decreased with decreasing weld penetration. An abrupt change occurred in the frequency components and amplitude of weld pool oscillation, accompanying the transition from partial to full penetration. The voltage signal curve lost the oscillation frequency characteristic of the pool, due to the curvature of the weld pool surface. While similar to the oscillation amplitude, the fluctuation of the voltage signal caused by the weld pool oscillation reflected the penetration of the weld pool. The abrupt transition in the fluctuation amplitude of the voltage signal in the base duration from partial penetration to full penetration may be used to sense the penetration of the weld pool in real time.