Abstract: Residual stress distribution of double-sided multi-pass welding in the course of spinning heads welding is studied. The welding process and material property of Q345R material for heads blank is analyzed. And then the multi-pass welding process of the blank is simulated with SYSWELD software. According to the welding simulation, the temperature field, welding deformation and welding residual stress are analyzed. Then, distribution curves of transverse residual stress and longitudinal residual stress on the top and the bottom surface, and along the thick direction are given. It indicates that the distributions of the welding residual stress are complicated, while the residual stress values especially in the weld zone are too large after the Q345R blank welding. The high residual stress in the weld zone can cause cracks in followed spinning process. According to the simulation results, a reasonable heat-treatment process is considered and implemented to relief the residual stress. The experiments of blank welding and spinning verified that the simulation results are valid and reliable. The research method provides an effective measure for the forecast and control of the large heads multi-pass welding and the determination of the manufacturing process of similar products.

Key words: Blank of heads, Multi-pass welding, Numerical simulation, Residual stress