0

Full Content is available to subscribers

Subscribe/Learn More  >

Cracking of Non-PWHT’d Carbon Steel Operating at Conditions Immediately Below the Nelson Curve

[+] Author Affiliations
James McLaughlin, Joseph Krynicki, Thomas Bruno

ExxonMobil Research and Engineering Company, Fairfax, VA

Paper No. PVP2010-25455, pp. 919-930; 12 pages
doi:10.1115/PVP2010-25455
From:
  • ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference
  • ASME 2010 Pressure Vessels and Piping Conference: Volume 6, Parts A and B
  • Bellevue, Washington, USA, July 18–22, 2010
  • Conference Sponsors: Pressure Vessels and Piping Division
  • ISBN: 978-0-7918-49255 | eISBN: 978-0-7918-3878-5
  • Copyright © 2010 by ASME

abstract

Cracking was observed in non-PWHT’d carbon steel piping and vessels operating at conditions immediately below the “Nelson” curve. This curve provides a threshold limit for high temperature hydrogen attack as a function of the equipment operating temperature and hydrogen partial pressure. This curve is based on industry experience with steel equipment operating for many years in high temperature high pressure hydrogen service. Our investigation indicated that cracking occurred in 2 stages. Stage 1 or the initial stage of cracking appeared to occur as a result of intergranular “hydrogen assisted” cracking very similar to high temperature hydrogen attack. It appears that Stage 1 cracking is driven by the combined effects of residual welding stresses and “methane pressure” stresses from the decomposition of carbides. The circumstances of the observed cracking indicate that, unlike high temperature hydrogen attack, it occurred over a relatively short period of time after an operating change to a higher hydrogen partial pressure. Stage 2 cracking results from sulfide scale packing the crack during high temperature operation in a sulfidizing environment and causes the Stage 1 cracks to further propagate through wall. Once the sulfide scale filled crack cools down during a shutdown, the surrounding metal contracts around the scale and causes a high load on the crack tip which promotes further crack propagation. The presence of dissolved hydrogen in the steel further promotes Stage 2 crack propagation during shutdown periods.

Copyright © 2010 by ASME

Figures

Tables

Interactive Graphics

Video

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

NOTE:
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