Weld repair simulation for the Mock-up 2 of EU FP7 STYLE Project

The Mock-up under study is fabricated of austenitic stainless steel with additions of vanadium and niobium to increase its high temperature strength. The Mock-up comprises two pipes welded together to produce a pipe section of 600 mm overall length. After completion of the girth weld, deep weld repair was inserted into the girth weld. Abaqus finite element code was utilised in the welding simulation. Part of the input data was generated with in-house codes. Sequential thermal and mechanical analyses were performed with small strain and displacement formulation. In the mechanical analysis, mixed hardening material model and an anneal temperature of 1100°C was assumed. Symmetry conditions were utilised to reduce the size of the model. The comparison of computed and measured temperatures and stresses shows good agreement. The computed hoop stress at the repair mid-length was higher than 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 literature for a repair welding case.