Prediction of residual stresses in a dissimilar metal welded pipe with considering cladding, buttering and post weld heat treatment

摘要

Dissimilar metal weld joints are widely used in the nuclear power plants to connect the ferritic steel components and the austenitic steel piping systems. Because the manufacturing processes are considerably complicated, it is difficult to accurately predict residual stresses in dissimilar metal weld joints by numerical simulation technology. In this study, a simplification methodology has been developed to compute residual stresses in a dissimilar metal pipe joint with considering cladding, buttering, post weld heat treatment (heat treatment after cladding and buttering) and multi-pass welding using a united fashion. The computational procedure based on thermal elastic plastic finite element method is used to simulate the thermo-mechanical behaviors. With using this computational procedure, the variations of stress status at each manufacturing stage are investigated and the influences of cladding, buttering and post weld heat treatment on the final residual stresses after welding are also clarified. In addition, the simulation results are compared with the measured data and the usefulness of present method is verified.