Abstract: Dissimilar metal welded (DMW) joint is widely used in machinery, chemical industry, electricity and transportation. Due to different material properties of DMW joint, the residual stress distribution induced by welding is very complex. So far, the research on welding residual stress of DMW joints is still inadequate. Based on SYSWELD software, a thermal elastic plastic finite element method is developed to simulate residual stress and deformation for DMW joints. Based on the developed computational approach, the influence of deposition sequence and wall thickness of pipe on welding residual stress and deformation in a tube-plate joint is investigated. In the numerical simulations, different constitutive models are used to simulate the mechanical behavior of different types of steel. Meanwhile, the deformations of welding joint at characteristic positions are measured by using 3D contact coordinate measuring instrument, which verifies the validity of the computational approach. The results show that the residual stress distribution of the tube-plate joint is significantly affected by the deposition sequence, and the deformation distribution pattern is also affected by the deposition sequence to some extent. As the thickness of tube increases, the deformation in the radial direction decreases, and the peak value of the hoop residual stress increases. The numerical simulation method developed is a powerful tool for predicting residual stress and deformation of welding joints of different types of steel and the simulated results obtained by numerical simulation can provide theoretical support for the performance evaluation of welded structure.

Key words: dissimilar steel, numerical simulation, residual stress, welding deformation