Effect of Energy Ratio Coefficient on Pore During Aluminum Alloy Laser-MIG Hybrid Welding

To study the effect of energy ratio coefficient (the ratio of laser power to arc power) on pores during the aluminum alloy laser-MIG hybrid welding process, 6 mm thick 6061 aluminum alloy laser-MIG hybrid welded joints were measured using X-ray nondestructive testing and metallographic microstructure observation. Pores under the energy ratio coefficient of 1.0, 3.5, and 3.1 were analyzed. It was observed that the laser power has a significant effect on the bottom weld width in the cross-setion of the weld and increasing the arc power can effectively deepen the hybrid zone. Under the higher-energy ratio coefficient, the diameter of the pores inside the weld is larger, but the number of pores is smaller, contributing to low porosity. The pores in the weld cross-section arc mainly distributed in the upper part of the weld and less in the lower part. However, when the energy ratio coefficient is reduced to 3.1, the distribution of pores tends to be uniform, the number of pores in the lower part significantly increases, and the number of process pores increases. These results show that increasing the energy ratio of laser power during laser-MIG is beneficial to reduce the porosity.