Computation of residual stresses for a repair weld case

Abstract

The target of EU FP7 STYLE project “Structural integrity for lifetime management – non-RPV component” was to improve and unify the methods of a structural integrity assessment in the ageing and lifetime management of reactor coolant pressure boundary components. One of the mock-ups in the project was manufactures from two pipes welded together. After completion of the girth weld, a deep weld repair was inserted into the girth weld. As a part of the work, round-robin finite element computations were performed to determine residual stresses after repair welding and the computational results were compared to the deep hole drilling measurements. In this paper, the details and recomputed results of one of the analyses is presented. A part of the input data was generated with in-house codes. Sequential thermal and mechanical analyses were performed with a small strain and displacement formulation. The comparison of computed and measured temperatures and stresses shows good agreement. The computed hoop stress at the repair mid-length was higher than the axial stress. Both stresses were tensile through the wall thickness. Confidence in the results was also gained as the results were compared to those presented in the literature for a repair welding case.