Residual stresses in the welding joint of the nozzle-to-head area of a layered high-pressure hydrogen storage tank

•The interlayer gap of the head has an effect on the residual stress in HAZ section.•Peak residual stresses are decreased with preheating temperature increasing.•The welding heat input has little effect on residual stresses.

In this study, a sequentially coupling finite element analysis (FEA) program was utilized to simulate the welding temperature and predict the residual stress in the weld and Heat Affect Zone (HAZ) between the nozzle and the head. The results of a numerical calculation indicated that complex residual stresses were generated and concentrated in the weld and HAZ. Due to the existence of the interlayer gap between the two layers of the head, discontinuous stress distributions occurred. There were several sections where there are stress concentrations because of the discontinuous structure. The influences of welding heat input and preheating temperature were also investigated in this study. When the preheating temperature increased, the peak residual stresses in the structure decreased. The welding heat input had little effect on the residual stresses.