Welding Residual Stresses in Two Competing Single V-Butt Joints

During fabrication of welded components residual stresses are generated as a result of non-uniform temperature distribution during the welding and particularly the cooling processes. The residual stresses have a major effect on the overall performance of the components in service, especially when hydrogen is involved and the components might become prone to Hydrogen Assisted Cold Cracking (HACC). Up to the present, most of the welding standards and specifications to test the resistance of welds against HACC test are without consideration of the restraint intensity provided by the surrounding structure. This may lead to a misunderstanding of the welding heat treatment procedures, i.e. preheating and interpass temperature, for multi-pass welding of extra high strength steels. The restrained welds might also interact at real components with respect to the stresses and strains produced in the transverse direction. This point has not been addressed within recent years, and in order to elucidate such effects, two competing single v-butt joints in high strength steel with a yield strength level of 1100 MPa are investigated in the present contribution by Finite Element Analyses (FEA). As a specific result, it turned out that the transverse residual stresses increase with the restraint intensity of the surrounding structure. As a consequence of the different restraint intensity during completion of the joints, the stresses are distributed inhomogeneously in the component and special attention has to be paid to such regions with respect to cold cracking.