On the mechanism and detection of porosity during pulsed TIG welding of aluminum alloys

Abstract

Porosity is the remarkable barrier to realize the high efficient automatic welding of aluminum alloy. The paper provides new insights into the nucleation mechanism of porosity formation during pulsed TIG welding of aluminum alloys. Firstly, the model of bubble’s nucleation based on inclusions is proposed. The calculated pore minimum radius shows large sensitivity to pulse duty cycle as well as welding current. Then a novel method based on spectral analysis to detect porosity is developed. The relationships among the extracted signals and porosity defection are discussed, and the results show that Ar and HI spectral lines can be used as an aid to determine the most likely position of the porosity.