Influence of heat treatment on residual stress of P92 steel pipe girth weld

Firstly, the welding temperature field of P92 steel pipe was measured with thermal imaging system, and the thermal cycles were achieved. Secondly, the finite element method (FEM) was utilized to simulate the welding process of P92 pipe girth weld, and to analyze the distribution of welding temperature in the welded joint. It was found that the simulation results had good agreement with the experimental results. Lastly, the simulated welding temperature field was used to calculate the residual stress of P92 steel pipe girth weld, and the emphasis was focused on the influence of the postweld heat treatment on the residual stress. The results showed that the postweld heat treatment could partially release the residual stress, while the comparatively large residual stress still survived in the weld joint. Therefore, the effect of residual stress must be considered in the life evaluation of P92 pipe.