Investigation of Distribution of Residual Stress in Swing arc Narrow Gap MAG Welding by Numerical Simulation and Experiments

Thick section steel plates are widely used in many industries, and the main technique for welding steel plates is still the electric arc welding process. In this study, a numerical model of 5-pass weld joint with plate of 20 mm thickness was established, combining finite element transient heat flow analysis with thermodynamic coupling analysis to predict the residual stress distribution on the specimen, comparing the simulation results of swing and non-swing arc as a means of discussing the impact of the calculation time and the distribution of residual stress. The residual stresses of the welded specimen were measured using the blind drill method and the data obtained were compared with the residual stresses predicted by the numerical simulation, two results are in good agreement. The simulation results of the swing and non-swing arcs show that the distribution of residual stress in the three-dimensional direction is basically the same, but the calculation time for the linear motion is much less than swing, which means that in specific cases, the linear heat source can be used instead of the swing heat source to study the distribution of residual stress in thick plate welding, which can save the calculation cost to a great extent.