Evaluation of hydrogen embrittlement susceptibility of high strength steel based on local approach

Shusaku Takagi, Satoshi Terasaki, Kaneaki Tsuzaki, Tadanobu Inoue, Fumiyoshi Minami

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6 Citations (Scopus)

Abstract

In order to evaluate the hydrogen embrittlement susceptibility of high strength steel independently of stress concentration factor Kt and specimen size, Local Approach method modified to evaluate the hydrogen content distribution in the specimen was used. In the method it was considered that the size of micro cracks depends on the hydrogen content. The stepwise hydrogen embrittlement tests were carried out to obtain the hydrogen embrittlement susceptibility of the material which was 1400 MPa grade JIS SCM440 (0.40C-0.24Si-0.81Mn-1.03Cr-0.16Mo (mass%)). Stress was applied to the specimen, which is circumferentially notched round-bar type with the stress concentration factor of 4.9, after hydrogen pre-charging and homogenization treatments. The applied stress on the first step was set at 702 MPa and the stress of 14 MPa was increased on and after the second step. The holding time of stress was over 12 h on the first step and over 2 h on and after the second step. The diffusible hydrogen content was measured by thermal desorption analysis immediately after fracture. The distribution of stress and hydrogen content near notch root was calculated by FE-analysis. In the modified Local Approach method the new parameter Σw,cr was introduced including the stress factor and hydrogen content factor. The parameter Σw,cr obtained by the stepwise test obeyed the Weibull distribution as the Weibull stress in the conventional Local Approach. The hydrogen embrittlement susceptibility of any specimens with various stress concentration factors was able to be evaluated uniquely by the Local Approach considering the effect of hydrogen content distribution.

Original languageEnglish
Pages (from-to)125-131
Number of pages7
JournalYosetsu Gakkai Ronbunshu/Quarterly Journal of the Japan Welding Society
Volume22
Issue number1
DOIs
Publication statusPublished - Feb 2004

All Science Journal Classification (ASJC) codes

  • Mechanics of Materials
  • Mechanical Engineering
  • Surfaces, Coatings and Films
  • Metals and Alloys

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