Using FEM to predict residual stresses in girth welding joint of layered cylindrical vessels

• Discontinuous stress in weld is presented between stainless and low alloy steel.
• Large tensile residual stresses are generated in the weld and HAZ.
• Stress distributions in layers are not continuous due to interlayer gaps.

Layered cylindrical vessels are used widely in process industries. During the girth welding of layered-to-layered sections, residual stresses are generated and influence the structure integrity. In this paper, the Finite Element Method (FEM) is used to predict the residual stresses in a layered-to-layered joint. The results of numerical calculation show that large residual stresses are generated in the weld and Heat Affect Zone (HAZ). Due to the material mismatching between inner stainless steel layer and outer low alloy steel layer, discontinuous stress distributions are presented. The gap between discrete layers has a great effect on the residual stress in HAZ. Through the whole vessel thickness of multi-layers, the stress distributions in layers are not continuous.