Full Content is available to subscribers

Subscribe/Learn More  >

The Significance of Low Toughness Areas in the Seam Weld of Linepipe

[+] Author Affiliations
Robert M. Andrews, Glyn C. Morgan

Advantica, Loughborough, UK

W. Jack Beattie

TransCanada PipeLines, Calgary, AB, Canada

Paper No. IPC2004-0422, pp. 1833-1842; 10 pages
  • 2004 International Pipeline Conference
  • 2004 International Pipeline Conference, Volumes 1, 2, and 3
  • Calgary, Alberta, Canada, October 4–8, 2004
  • Conference Sponsors: International Petroleum Technology Institute
  • ISBN: 0-7918-4176-6 | eISBN: 0-7918-3737-8
  • Copyright © 2004 by ASME


There are concerns that there may be areas of low toughness in the seam welds of submerged are welded linepipe. These areas are typically associated with the Coarse Grained Heat Affected Zone and manifest themselves through low values obtained in Charpy impact and crack tip opening displacement (CTOD) tests. Although it is possible to locate areas of low toughness in linepipe seam welds, it is not clear if these are structurally significant. If it can be shown that low toughness areas in the seam weld HAZ do not affect the fitness for service of the pipe as a structure, these could be accepted for use. Under funding from PRCI, a study has been carried out to investigate this problem quantitatively. Experience in the offshore structural field, where the similar problem of local brittle zones in weld HAZs has received considerable attention, was reviewed. A constraint based fracture mechanics analysis was developed using the T-stress approach. Cracked body finite element analyses were used to obtain the T-stress for a range of surface breaking and buried defects in typical linepipe geometries. The results from these models were used to develop a constraint modified Failure Assessment Diagram for a fracture analysis. Fracture analyses showed that the structural constraint is low and failure will occur by plastic collapse for practical seam weld defect sizes. This shows that even when the seam weld toughness is very low, the dominant failure mode for the structure will be plastic collapse. Hence the low toughness values obtained in fracture mechanics tests are not structurally significant for practical defect sizes likely to occur in linepipe.

Copyright © 2004 by ASME



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In