0

Full Content is available to subscribers

Subscribe/Learn More  >

Crack Growth in High Strength Chain Steel Subjected to Fatigue Loading in a Corrosive Environment

[+] Author Affiliations
Tom Lassen, Jan Henriksen, Nina K. Holthe

Agder University College, Grimstad, Norway

Jose L. Arana

Basque Country University, Bilbao, Spain

Luis Canada

Vicinay Cadenas, Bilbao, Spain

Paper No. OMAE2005-67242, pp. 93-101; 9 pages
doi:10.1115/OMAE2005-67242
From:
  • ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering
  • 24th International Conference on Offshore Mechanics and Arctic Engineering: Volume 3
  • Halkidiki, Greece, June 12–17, 2005
  • Conference Sponsors: Ocean, Offshore and Arctic Engineering Division
  • ISBN: 0-7918-4197-9 | eISBN: 0-7918-3759-9
  • Copyright © 2005 by ASME

abstract

The present article presents the fatigue crack growth behavior of new high strength steels designated R4S grade. Eight Compact Tension (CT) specimens with 25 mm thickness were subjected to constant amplitude loading while exposed to seawater without and with cathodic protection. The Cathodic Potential (CP) was set to −890 mV and −1100 mV relative to an Ag/AgCl reference cell. Rates in air are included as a reference. The crack growth parameters were determined from a linear relation between da/dN and δK for a log-log scale. The derived figures are given in the table below. The figures for dry air and cathodic protection are valid for δK between 15 and 30 MPam0.5 . Below this range the slope m of the linear relation will change and further investigations have to be carried out for this region. The figures for free corrosion are valid for δK values from 10 to 30 MPam0.5 . The threshold value for δK is close to 5 MPam0.5 in this case. The measured growth rates were compared with the rates for medium strength carbon manganese steels found in rules and regulation, i.e. BS7910. The present growth rates are well within the scatter band given for these steels in air and free corrosion. The present growth rates found in seawater with cathodic protection are however substantially lower than the rates given in BS7910. When a cathodic potential of −1100 mV was applied, crack closure was observed at medium levels of δK. The explanation is the formation of calcareous deposit in the wake of the crack front that gives significantly reduced growth rates and finally leads to crack closure. This finding is a surprise for a high strength steel. The results are promising and should be investigated further. Finally, a linear elastic fracture mechanics model was established to study the fatigue behavior in a stud-less link. The model was used to construct S-N curves that are consistent with experimental fatigue lives and the design curve given in the DNV rules. The present growth parameters were used in conjuction with a crack-like initial flaw with depth in the range from 0.12 to 0.20 mm. The difference found between the growth rates in dry air and in free corrosion are in accordance with tested fatigue lives for these two environments.

Copyright © 2005 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