Evaluations of residual stresses in repair welding of Ni-based IN939 superalloy

The residual stresses (RSs) generated from partial penetration repair welding of a specimen extracted from the 4th stage vane of a gas turbine replace studied. The RSs are maximum in the heat-affected zone, beneath the weld along the weld center at the specimen mid-section. The RS field tends to exhibit over a large volume beneath the weld bead where severe restraint conditions exist in the repair welding. The stress triaxiality field was presented as an assessment tool to find the critical areas of welding RSs. The maximum value of stress triaxiality occurs beneath the weld bead in somewhere different from maximum residual stress locations. This indicates the role of a through-thickness component of RSs in the integrity of repair welds.