Effects of crack size, stress ratio and hydrogen on the near threshold fatigue crack propagation of high strength steel

Kazutoshi Yanagihara, Satoshi Ohyanagi, Masanobu Kubota, Chu Sakae, Yoshiyuki Kondo

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The effects of crack size, stress ratio and absorbed hydrogen on the fatigue crack propagation characteristics of high strength steel were studied near threshold regime. The test material was SCM440H low alloy steel. The material was quenched in vacuum and tempered at low temperature to achieve high strength and to lower the initial content of hydrogen of the material. The effects of crack size and stress ratio on the fatigue crack propagation rate and threshold stress intensity factor were investigated in air at first. These data offered a baseline as a reference. The effect of absorbed hydrogen was examined using a material in which hydrogen was introduced by cathodic charging. It was verified that the absorbed hydrogen in high strength steel affected the high cycle fatigue crack propagation characteristics. The fatigue crack propagation rate near threshold region was accelerated and ΔK th was lowered. The concentration of about 1ppm hydrogen caused 20% reduction of ΔK th. Since absorbed hydrogen has an influence even on high cycle fatigue crack propagation, it should be taken into account in the evaluation of defect of hydrogen utilization machine.

Original languageEnglish
Pages (from-to)1237-1243
Number of pages7
JournalZairyo/Journal of the Society of Materials Science, Japan
Issue number12
Publication statusPublished - Dec 1 2005


All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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