Effect of power distribution on the temperature evolution in laser-MIG hybrid welding for Q235 Steel

Abstract

Numerical simulation of laser-MIG hybrid welded Q235 steel was conducted using finite element simulation software with a 3D model. The thermal analysis was performed with a combined ellipsoid-Gaussian heat source. Double ellipsoid heat source and Gaussian heat source (Gauss rotating body heat source and Gauss cylinder heat source) were utilized to represent arc and laser heat, respectively. The effects of power distribution on the temperature evolution and the geometry of molten pool were numerically investigated. The simulated temperature field shows that the increase of the power ratio of laser in laser-MIG hybrid welding (LMHW) is more conducive to improve the peak temperature, leading to remelt interlayer and promote interlayer heat accumulation. Meanwhile, the depth-to-width-ratio (DTW) of molten pool increases with the risen laser power. The change of DTW value with [Formula: see text] value is more obvious when the [Formula: see text] value is greater than 1. Comparison of the calculated and validation experiment results suggested that the LMHW process is characterized well by the combined heat source model. Fine weld joint with good shape of molten pool morphology is obtained when the DTW of first pass, second pass and third pass are 0.94, 0.34 and 0.27, respectively.