Digital Repository, ECF14, Cracow 2002

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On the Most Adequate Round Notched Specimen for Hydrogen Embrittlement Testing

Last modified: 2013-02-10


This paper studies a wide range of axisymmetric notched specimens in orderto choose the most adequate geometry for measuring the hydrogen embrittlementsusceptibility of metallic materials in the form of bar or wire, widely used in civilengineering. Since hydrogen transport by stress-assisted diffusion depends on bothhydrogen concentration and hydrostatic stress distributions, the comparison betweendifferent geometries is performed on the basis of their distributions of hydrostatic stresscalculated by an elastic-plastic finite element code and using the stress-strain lawassociated with a constitutive equation typical of a high-strength steel. The computationsallow an analysis of the depth of the maximum hydrostatic stress point (place towardswhich hydrogen diffuses) and its evolution with time, these two being the key items forhydrogen transport by stress-assisted lattice diffusion. Finally, a discussion is presentedabout the advantages of notched geometries for hydrogen embrittlement testing and aboutthe most adequate specimen considering its radial distribution of hydrostatic stress and itsinfluence on hydrogen transport by diffusion. This will provide bases for furtherexperimental analysis of the interactions between the stress-strain field in the material andhydrogen-assisted corrosion processes.

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