The effect of heat input on the residual stress distribution in gas-metal arc welding of carbon steel: Simulation and experimental methods

A major challenge in fusion welding is the development of residual stresses and distortions, stemming primarily from non-uniform thermal cycles during welding. These stresses adversely influence fatigue life, corrosion resistance, and dimensional stability of engineering components. Heat input is a crucial parameter governing residual stress formation. Conventional experimental methods for residual stress determination are often time-consuming or destructive, making simulation an efficient alternative for stress prediction. This study assessed the effect of heat input on residual stress in the gas metal arc welding (GMAW) process through integrated simulation and hole-drilling measurements. For this purpose, A516 Gr70 steel plates were welded using the GMAW technique with varying heat inputs, both with and without a back welding. After characterizing microstructure and mechanical properties, residual stresses were quantified via the hole-drilling method. Numerical simulation employed Abaqus with the Goldak double-ellipsoid heat source model and element birth-and-death technique, with results validated against experimental data. The microhardness value of the weld zone produced by the lowest heat input was found to be ∼198 HV, with a microstructure dominated by pearlite and varying morphologies of ferrites. Simulation revealed peak residual stresses in the heat-affected zone (HAZ) and weld center across all heat inputs. The reduction in heat input and applying the back welding resulted in less tensile residual stresses in most areas and slightly increased compressive residual stresses in areas farther from the HAZ. Four-channel thermocouple measurements and numerical simulation provided detailed thermal analysis during welding, with simulated residual stresses showing 96 % agreement with hole-drilling results, validating both methodologies.