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 S YSWELD+. A three-dimensional (3D) and an axisymmetrical finite element mode l 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 i n the ferritic base metal. The results obtained in this study are presented in terms of temperature distributions during welding and just after weldin g. The residual stresses calculated for the dissimilar girth welds are show n both for the axial and the circumferential orientations. The calculated r esidual 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. Resid ual stress distributions in dissimilar girth welds are discussed on the bas is of variable weld fabrication conditions and different boundary condition s selected for the numerical calculations.