Analysis and estimation of yield strength of API X80 linepipe steel pipe by low-cycle fatigue tests

Seok Su Sohn, Seung Youb Han, Sang Yong Shin, Jin Ho Bae, Kisoo Kim, Nack J. Kim, Hyoung Seop Kim, Sunghak Lee

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


In the present study, spiral piping was conducted on API X80 linepipe steel, and the outer and inner wall pipe yield strengths were measured. A low-cycle fatigue test was conducted on a leveled X80 steel sheet to simulate piping and flattening processes, and the strain hardening and Bauschinger effects, induced from different strain histories, were evaluated and combined using Swift's equation and the Bauschinger stress parameter, respectively. By analyzing the stress-strain curves obtained from the low-cycle fatigue test, the yield strengths of the outer and inner walls were estimated to be 592 MPa and 492 MPa, respectively, which are lower by 20-80 MPa than that of the actual pipe used. Possible reasons for measured and estimated yield strength differences could be the simulation determining procedure of the pre-strain and Bauschinger stress parameters, preposition of same strain hardening behavior depending on strain history, and pre-strain differences depending on thickness location in the steel sheet during piping.

Original languageEnglish
Pages (from-to)597-606
Number of pages10
JournalMetals and Materials International
Issue number4
Publication statusPublished - 2012 Aug
Externally publishedYes


  • Alloys
  • Bauschinger effect
  • Cold working
  • Low-cycle fatigue test
  • Workhardening

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry


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