Simulation Analysis of Multi-pass Welding of Tube Plate Structure Based on SYSWELD

In order to study the residual stress and local characteristics of welding deformation of large tube plate welding parts, taking single tube plate welding as an example, the numerical simulation of the Q235 tube plate components was carried out by using welding simulation software SYSWELD based on the thermoelastoplastic finite element method. The changes of temperature, stress, displacement and phase transition during welding were obtained. The simulation results show that after cooling, the microstructure of the weld metal is bainite and martensite; the welding residual stress appears near the welding seam and its heat-affected zone, and the transverse residual stress is tensile stress, and the peak value appears in the middle pass, which exceeds the yield limit of the material. The longitudinal residual stress of the weld is lower than the yield limit of the material except the fifth weld. The transverse deformation at the weld is stretched at first and then compressed, and the deformation at the end position is 0.