Comparative Analysis of Temperature Field and Stress Field of TC4 Ti-tanium Alloy Joint Between CMT and MIG Welding

A model was used for the cold metal transfer (CMT) welding based on the volume heat flux distribution of double ellipsoids loaded with time intervals. The temperature field and stress field of TC4 titanium alloy were numerically simulated by ANSYS software. The distribution laws of temperature, residual stress and post-weld deformation during CMT and MIG welding were studied and compared. It was found that the maximum temperature of the molten pool in CMT welding was fluctuating and rising during the loading process, while the temperature of the molten pool in MIG welding was rising smoothly and the maximum temperature was higher than that in CMT welding. The welding stress field was analyzed by thermal-stress coupling analysis. The stress distribution simulated based on the MIG welding heat source was similar to CMT welding, but the maximum von Mises stress was greater than that of CMT welding. Due to the cooling shrinkage, both of them would produce angular deformation after welding. And the maximum angular deformation simulated based on the MIG welding heat source was greater than that of CMT welding. It was proved by welding simulation that CMT welding could reduce welding heat input and residual stress and deformation after welding.