Experimental and numerical investigations of welding distortion induced by CO2 gas arc welding in thin-plate bead-on joints

Thin plates are widely used in aerospace, naval, and automobile industries to reduce the weight of component. Welding distortion occurring in thin plate joint or structure is inevitable and often results in loss of dimensional control, structural integrity and manufacturing costs increase due to additional straightening work. In the present study, a computational approach based on finite element method with considering both materials nonlinearity and geometrical nonlinearity was developed to investigate welding distortion and residual stress in low carbon steel thin-plate bead-on joints induced by arc welding process. Besides temperature-dependent thermal physical and mechanical properties and moving heat source model, the weld reinforcement shape was also considered in the finite element model. Meanwhile, experiments were carried out to verify the numerical results. In the experiments, an arc welding robot was used to perform the bead-on welding. The comparison between simulation results and measurements suggests that the developed finite element model can capture the features of welding distortion and residual stress distribution in thin plate welded joints. Moreover, the influences of heat input on buckling propensity were examined numerically. In addition, the mechanisms of out-of-plane deformation formation in the thin-plate bead-on joints were discussed.