Effects of hydrogen concentration, specimen thickness and loading frequency on the hydrogen enhanced crack propagation of low alloy steel

Y. Kondo, K. Mizobe, M. Kubota

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    Crack propagation of SCM440H low alloy steel under varying load is enhanced by absorbed hydrogen. Substantial acceleration of crack propagation rate up to 1000 times was observed compared with that of uncharged material. The role of factors affecting enhanced acceleration was investigated by changing hydrogen concentration absorbed in metal, specimen thickness and loading frequency. Results are as follows. (1) 0.2 mass ppm diffusible hydrogen in metal was enough to cause enhanced acceleration. The predominant fracture mode showing acceleration was quasi cleavage. (2) In the case of thin specimen thinner than 0.8mm, the tri-axiality of stress is weak, and the enhanced crack propagation did not appear. However, the introduction of side-groove to 0.8mm specimen in order to increase the tri-axiality resulted in enhanced acceleration. (3) Lower loading frequency resulted in higher crack propagation rate in cycle domain. The crack propagation rate in time domain was almost constant irrespective of loading frequency. Enough concentration of hydrogen, tri-axiality and low loading frequency resulted in enhanced acceleration of fatigue crack propagation.

    Original languageEnglish
    Title of host publicationMaterials Structure and Micromechanics of Fracture VI
    PublisherTrans Tech Publications Ltd
    Pages519-522
    Number of pages4
    ISBN (Print)9783037850060
    DOIs
    Publication statusPublished - 2011

    Publication series

    NameKey Engineering Materials
    Volume465
    ISSN (Print)1013-9826
    ISSN (Electronic)1662-9795

    All Science Journal Classification (ASJC) codes

    • General Materials Science
    • Mechanics of Materials
    • Mechanical Engineering

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