Numerical simulation analysis of residual stress in 45 steel pipe induction welding

Objective Most factories use the submerged arc welding process to weld metal pipes, which often results in a large temperature difference along the wall thickness at the pipe weld, producing large residual stresses at the weld. The paper aims to reduce the residual stress at the pipe weld and increase the quality of the pipe weld. Methods The induction heating process of helical coil is utilized to complete the pipe welding and heat treatment process. The influence of the electric parameters of induction heating and the structural parameters of helical coil on the stress is comprehensively considered. In view of the special characteristics of the structure of helical coil, the residual stress distribution law of weld and heat affected zone of pipe is quantitatively analyzed. Results It is found that the stress of the pipe is the largest at the junction of the weld zone and the heat affected zone, and with the increase of the cooling time, the maximum equivalent residual stress gradually transfers from the surface to the 1/2 along the wall thickness. The cooling time is the longer, the residual stress in the middle layer inside the direction of the wall thickness is the larger. Conclusion Mastering the characteristics and laws of induction heating electric parameters and helicol coil structure parameters on stress distribution can provide theoretical basis for optimizing induction welding process, which is great significance for improving welding quality.