Influence of stress re-distribution on hydrogen-induced fatigue crack propagation

Daisuke SaSaki, Motomichi Koyama, Hiroshi Noguchi

Research output: Contribution to journalArticlepeer-review

Abstract

In order to clarify influence of stress re-distribution effect on hydrogen-induced fatigue crack propagation, we investigated fatigue crack propagation rates and brittle-like fracture ratio. The experiments were conducted in nitrogen and hydrogen gas atmosphere with ferrite-pearlite steels having different pearlite ratio, respectively. The crack propagation rates and the brittle-like fracture ratio decreased as pearlite ratio increased. To explain the changes of crack propagation rates and fracture ratio, we proposed that the stress re-distribution effect causing stress and strain relaxation at a crack tip contributes to suppression of the hydrogen-induced fatigue crack propagation. As a verification, finite element methods were operated with models having different width of the hard phase and different distance between a crack tip and a hard phase in plane stress and strain conditions, respectively. The finite element method analysis showed that stress re-distribution effect was smaller in plane strain condition than that in plane stress condition, indicating that a large hardness difference is crucial in plane stress condition to suppress the hydrogen-induced fatigue crack propagation.

Original languageEnglish
Pages (from-to)46-53
Number of pages8
JournalTetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan
Volume104
Issue number1
DOIs
Publication statusPublished - 2018

Keywords

  • Fatigue
  • Fatigue crack growth
  • Ferrite
  • Hydrogen embrittlement
  • Pearlite
  • Pre-cracked specimen
  • Stress re-distribution

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Metals and Alloys
  • Materials Chemistry

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