Numerical analysis of residual stress distribution in tubes with spiral weld cladding

Residual stresses and strains in a tube with spiral weld cladding were analyzed by the finite element (FE) method. The objective of this work was to determine the residual stress-strain state in the weld clad tube and verify the developed FE model, which might serve for future parametric sensitivity studies of various welding parameters on residual stresses in such tubes. An axisymmetric FE model was developed to simulate the circumferential weld cladding process of Alloy 625 on SA210 carbon steel tube and to analyze the residual stress-strain state. The analysis was uncoupled in that the thermal and mechanical analyses were conducted in two separate runs. The results show high tensile residual stresses in the weld cladding and at the interface with a gradual transition to compressive stresses at the inner tube surface. A neutron diffraction technique was used to experimentally determine residual elastic strains in the clad tube. Comparison with the FE results shows good overall agreement. The agreement is excellent in radial and axial elastic strain components, whereas the calculated tangential elastic strain overpredicted the measured value. The difference is discussed, and certain conclusions are given. Finally, some attempts on how to prevent or relieve high tensile stresses in more » the weld cladding are presented and discussed in this paper. « less