On residual stress prescriptions for fitness for service assessment of pipe girth welds

• Critically assessed girth weld residual stress profiles in major FFS Codes and Standards.
• Identified deficiencies in relating to pipe geometry, heat input, and axial distance from weld.
• Presented a shell theory based scheme for prescribing full-field residual stress profiles.

This paper aims to provide a detailed assessment of some of the existing residual stress profiles stipulated in widely used fitness-for-service assessment codes and standards, such as BS 7910 Appendix Q and API 579 RP Annex E, by taking advantage of some comprehensive residual stress studies that have recently become available. After presenting a case study on which residual stress measurements are available for validating finite element based residual stress analysis procedure, residual stress profiles stipulated in BS 7910 for pipe girth welds are selected for detailed evaluation by comparing residual stress distribution characteristics shown in parametric finite element results. A shell theory based full-field residual stress profile estimation scheme is then presented to illustrate how an improved estimation of residual stress profiles can be achieved in light of some of the deficiencies in BS 7910 and API 579 identified in this study.