Study of porosity suppression in oscillating laser-MIG hybrid welding of AA6082 aluminum alloy

The AA6082 aluminum alloy was welded by oscillating laser-MIG hybrid welding. By using beam oscillation, the porosity can be effectively suppressed in the range of 100-300 A arc current, especially at low arc current level. Percent porosity decreased greatly with the increase of the oscillating amplitude and frequency. The threshold frequency of porosity-free at different amplitudes were achieved. The effect of beam oscillation on porosity formation and suppression was studied by observing keyhole behavior via a sandwich high-speed video method. It was found that the porosity suppression depended on three reasons. Firstly, high-frequency oscillating keyhole can capture the bubbles or cavities in the molten pool and solidification front. Secondly, high-frequency oscillating keyhole can enlarge the diameter of keyhole and improve keyhole stability. Thirdly, beam oscillation can form stirring effect in molten pool, which can produce turbulence to reduce possibility of bubbles moving to the solidification front.

Automated summary

The use of beam oscillation in oscillating laser-MIG hybrid welding of AA6082 aluminum alloy effectively suppresses porosity, especially at low arc current levels. Increasing the oscillating amplitude and frequency further reduces the percentage of porosity. The formation and suppression of porosity is influenced by the frequency of oscillation, with a threshold frequency for porosity-free welding achieved at different amplitudes.