The influence of energy distribution factor during laser-MIG hybrid welding of Invar alloy

Abstract

In this study, a three-dimensional (3D) finite element model was established to predict the shape of the molten zone and the temperature fields of multi-layer laser–MIG hybrid welding for Fe36Ni Invar alloy. The multi-layer laser–MIG hybrid welding experiments of 19.05-mm-thick Invar plates were conducted to obtain the well-welded joints. The molten zone shapes were compared to the simulated results to figure out the relation between the energy distribution factor and the welding temperature field. A combined heat source model was proposed to describe the interaction between laser heat source and arc heat source. Besides, the empirical formula of energy distribution factor was given. The metallography detection results showed that the increasing ratio of laser power in hybrid welding could increase the weld penetration depth and the increasing ratio of arc power in hybrid welding could increase the weld width. In addition, it was also found that the laser heat source in hybrid welding heat source contributed equiaxed grains, and weld centerlines had rotation, due to different ratios of energy distribution during the multi-layer laser–MIG hybrid welding.