Residual stresses in a multi-pass CrMoV low alloy ferritic steel repair weld

A trial part through-section excavation manual metal arc repair weld, designed to minimise residual stresses was prepared using a critical combination of weld metal strength, bead size and deposition pattern. The repair was in a low alloy ferritic CrMoV steel plate, and the weldment was made using a lower strength C–Mn steel weld metal. Residual stresses have been measured to a high spatial resolution across the weldment using the X-ray diffraction technique with CrKα X-radiation. Peak tensile stresses have been identified in the heat affected zone in the parent plate adjacent to the weld metal. Further measurements have been made using the rosette strain gauge centre hole relaxation and deep hole drilling techniques. The measured residual stress profiles are discussed with respect to comparisons between techniques, the range of microstructures within the weldment and predictions of a finite element model for this particular multi-pass repair weld.