Trapping of hydrogen by sulfur-associated defects in steel

Abstract

Reversible and irreversible trapping behaviors of sulfur-associated defects in steel were studied through electrochemical hydrogen permeation experiments and the results were analyzed to obtain the follow-ing information: an apparent diffusion constant of hydrogen influenced by reversible and irreversible trapping by sulfur-associated defects,D *, was shown to be given as a function of sulfur content, S, in wt ppm.byD * = 1.12·10−6(1 + 0.0933S0.548)−1cm2 s−1. Associated parameters of reversible and irreversible trapping, λ/μ and k, were also expressed as a function of sulfur content, S. Both parameters, λ/μ, and k, are shown to increase with S, suggesting an increase of both reversible and irreversible trap sites with increase in sulfur content in steel.