Laser-MIG hybrid welding process and micro-pores defects of 6082-T6 aluminum alloy

Objective The aim is to solve the problems of poor formation and higher porosity caused by many process parameters and difficulty for reasonable matching in laser-arc hybrid welding of aluminum alloy. Methods Control variable method is adopted to conduct 10 sets of laser-MIG hybrid welding experiments on 6 mm-thick 6082-T6 aluminum alloy sheets under various welding parameters. Characteristic size of weld section and size and proportion of micro-pores are determined via metallographic observation, and influence of welding parameters on weld morphology and micro-pores is analyzed. Results The experimental results show that laser power, welding current and welding speed change cross-sectional morphology of weld by affecting the total welding heat input. Welding heat input has a peak value of 5.4 kJ/m. Before the peak value, as the heat input increases, weld width, penetration, reinforcement and cross-sectional area of weld all increase. After reaching peak value, characteristic values of cross-sectional size show a downward trend. Conclusion When diameter of light spot is 0.8 mm and heat input is 5.45 kJ/m, porosity and average area of pores are the smallest.