Until recently most work on hydrogen stress cracking has been directed toward evaluation of failure susceptibility and external or environmental variable influencing it rather than to a study of internal or metallurgical variables. Snape1 concluded from a review of the literature that the reported effects of composition and structure on sulfide cracking susceptibility are inconsistent. He further reports results on the effect of microstructural variations consistent with the suggestion that such cracking resistance correlates with notch sensitivity or toughness.2,3
Major variables influencing susceptibility have been identified, but evidence indicates that elusive compositional (impurity) and structural variables also exist which are not evident from standard metallographic examination and chemical analyses. For example, it has been reported variously that susceptibility to brittle fracture as determined by a variety of methods varies considerably, not only from alloy to alloy, but also from heat to heat of the same grade. Capus4...
