Abstract: Radial and hoop residual stress value of the welded joint between tube and tube sheet were predicted by the thermal stress analysis module of FEA software ABAQUS. The simulation results showed that the maximum radial stress appears on the heat affected zone (HAZ) between the adjacent welds in the surface of the tube sheet. The maximum value of hoop stress is located in the weld toes, and close to the gaps between tube and tube sheet. The weld toe is directly contacted with heat exchange medium, which is prone to stress corrosion cracking at the connection between the heat exchange tube and the tube plate. The welding residual stress in the heat affected zone of the tube and plate joint are measured by X-ray diffraction method. It is found that the process of expansion before welding reduce the probability of stress corrosion between the tube and tube sheet because not only the gap between the heat exchange tube and tube sheet is reduced, but also welding residual stress value is decreased, even the tensile stress is turned into compressive stress. Comparing the calculated and measured values of the post-weld hoop residual stresses, the trend of both is consistent.

Key words: tube to tube sheet joint, residual stress, numerical simulation, X-ray stress measurement