Critical Assessment 38: Assessment of the intrinsic susceptibility to hydrogen embrittlement for qualification of steels

Abstract

ABSTRACT Exact simulations of engineering practice are often difficult to accomplish with test methods of materials performance against hydrogen embrittlement (HE). Instead, it is proposed that assessment of the intrinsic susceptibility to HE be adaptable to diverse usage environments and loading modes. This notion is based on recent findings concerning the predominant role of strain-induced vacancies and their involvement in characteristic features of HE such as microstructural effects and dependence on strain rates and temperatures. The function of hydrogen in enhancing the generation of strain-induced vacancies operates throughout the entire process of fracture, and the density of vacancies is detectable using hydrogen as a tracer. A method is proposed here for using as the parameter the difference in the amounts of tracer-hydrogen between specimens given cyclic stressing with and without hydrogen.