An IIW Compendium for Residual Stress Distributions:
Pipe and Vessel Girth Welds

By P. Dong
Center for Welded Structures Research
BATTELLE
505 King Avenue
Columbus, OH 43201-2693, USA
Email: dongp@battelle.org

Journal Committee: Canadian Welding Association, H.B. Clarke, D.G. Harvey, B.E. James, M.J. Pates

Abstract

This document summarizes residual stress distributions based on ongoing IIW X-XIIIXV joint working group (JWG) round-robin efforts on the compilation of existing residual stress distributions for welded joints, initiated two years ago within the IIW community. The present focus is on the residual stress distributions in pipe and vessel welds, since more rigorous validations are mostly available in these applications in performing structural integrity assessments. Based on submissions from some of the participants in the IIW RSDP joint working group and on publications in open literature to date, residual stress distributions in pipe and vessel welds can be compiled based on two important categories: (a) self-equilibrating dominant type, and (b) bending dominant type. Various available and credible residual stress solutions collected to date are being documented based on such a categorization. To facilitate the interpretation of the residual stress results documented, the author also provided explanations on the underlying mechanics that connect the two important types of residual stress distributions.

Key Governing Parameters

The two types of axial residual stress distributions discussed above represent two extreme cases that bound a continuum within which the residual stress distributions exhibit a varying degree of mixture of bending and self-equilibrating content. Their relative bending and self-equilibrating composition, as well as membrane (negligible for most applications), can be quantified in an equilibrium sense by a residual stress decomposition technique as described in Reference 2. This not only facilitates the fracture-mechanics-based treatment of residual stresses, but also simplifies the development of stress intensity factor solutions. See Reference 2.

Reference 2: Dong, P. and Hong, J.K., “Recommendations for Determining Residual Stresses in Fitness-for-Service Assessment,” WRC Bulletin No. 476, November, 2002, Welding Research Council, New York, New York.

For a complete copy of this document, contact the CCIIW at www.cciiw.org and request IIW Document XV-1143-03.

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