Residual stresses and deformation in dissimilar girth welds: Numerical simulations and experimental verifications
Weld fabrication of dissimilar girth welds made of the austenitic steel X3 CrNiMoN 17-13, the ferritic 9% Cr-steel X10 CrMoVNb 9-1 and a Ni-weld metal was simulated numerically based on the application of the program system SYSWELD+. A three-dimensional (3D) and an axisymmetrical finite element model of the girth weld were established. According to the real dissimilar weld the model is divided into three different material zones, the austenitic, the ferritic and the Ni-weld metal zone neglecting the heat-affected zone in the ferritic base metal. The results obtained in this study are presented in terms of temperature distributions during welding and just after welding. The residual stresses calculated for the dissimilar girth welds are shown both for the axial and the circumferential orientations. The calculated residual stress distributions are compared to residual stresses measured by X-ray diffraction. It is shown that the calculated residual stresses are in good agreement with the residual stresses determined experimentally. Residual stress distributions in dissimilar girth welds are discussed on the basis of variable weld fabrication conditions and different boundary conditions selected for the numerical calculations.