Welding process impact on residual stress and distortion

Residual stress and distortion continue to be important issues in shipbuilding and are still subject to large amounts of research. This paper demonstrates how the type of welding process influences the amount of distortion. Many shipyards currently use submerged arc welding (SAW) as their welding process of choice. In this manuscript we compare welds made by SAW with DC gas metal arc welding, pulsed gas metal arc welding, Fronius Cold Metal Transfer (CMT), autogenous laser and laser hybrid welding on butt welds in 4mm thick DH36 ship plate. Laser and laser hybrid welding were found to produce the lowest distortion. Nevertheless a considerable improvement can be achieved with the pulsed gas metal arc welding and CMT processes. The paper seeks to understand the relationship between heat input, fusion area, measured distortion and the residual stress predicted from a simple numerical model, and the residual stresses validated with experimental data.