Effect of welding sequences and welding direction on the residual stress in X80 pipeline steel

In response to the problem of a number of cracking accidents in the application of X80 pipeline steel in recent years. Double ellipsoidal heat source model was used and a V-shaped weld filler used raw and dead cell technology to build a numerical simulation process for welding. A combination of experimentation and simulation was used, the effect of two different welding sequences and four different directions on the weld residual stresses of X80 pipeline steel in multi-layer and multi-pass welding were compared and analyzed. The results show that the welding sequence has a significant impact on the residual stress in the weld zone and HAZ, and the peak residual stress is only 296.4 MPa when using the symmetrical welding sequence is 29.3% lower than the peak stress of the sequential welding sequence. The welding direction on the weld zone and HAZ residual stress was not significant. Numerical calculation results match the experimental results better and the calculation results have some guidance for welding experiments.