Hydrogen Embrittlement of Steels - Testing and Modelling as a Joint Effort

To study the phenomenon of stress corrosion cracking (SCC) and hydrogen embrittlement (HE) of metallic materials, and in particular of high strength steels, fracture mechanics based techniques are well suited. Experiments using a rising displacement test technique and pre-cracked specimens were employed for experimental characterisation of the susceptibility of these materials to environmentally assisted cracking and to study the mechanisms of failure caused by the uptake of atomic hydrogen from a corrosive environment. This work was complemented by simulating the degradation process caused by HE. The experimental work was partly performed in conjunction with the Technical Committee 10, Environmentally Assisted Cracking, of the European Structural Integrity Society, ESIS, in the context of two European research projects. As a result, a new ISO standard on EAC testing, ISO 7339 Part 9, was established. The work is now focused on the development of suitable modelling approaches to HE. Such models can either be used in addition to experimental testing or, to some extent, can replace traditional SCC testing.