Investigation of Hydrogen Diffusion in High Hardness Steels

Abstract

Development of high hardness steels (HHS) for use in armor, shipbuilding, construction and automotive requires investigation into their sensitivity to hydrogen embrittlement. Hydrogen embrittlement, often caused by environmental corrosion, significantly impairs the mechanical properties of steel, producing increased local hardness and increased likelihood of catastrophic brittle failure. Mitigation of embrittlement can employ the introduction of hydrogen traps or phase barriers into the steel. In this work, we employed the Devanathan-Stachurski method to investigate the diffusion of hydrogen atoms through a steel membrane. The effect of strong hydrogen trapping was observed as an apparent change in hydrogen diffusivity from the initial and subsequent diffusion trials. We compared three different high hardness steel samples and used two methods to determine the apparent diffusivity and number of strong and weak hydrogen traps. Metallographic analysis of the samples illustrates the effect of composition on the diffusivity data. Figure 1