A Combined Numerical–Experimental Approach for the Critical Hydrogen Diffusion Depth in Steel

Abstract

Herein, a numerical solution of Fick's second law in one dimension with experimentally determined diffusion coefficients at different constant loads is combined with slow strain rate tensile tests and subsequent fractography on dual‐phase steel. From the latter, the depth of the hydrogen embrittled region is determined and correlated to concentration profiles determined by the numerical model. The concentration profiles indicate that incorporating stress dependency of the diffusion coefficient results in different concentration profiles compared to using a constant diffusivity. Additionally, these allow to more accurately determine a critical local hydrogen concentration based on the total diffusible hydrogen concentration at saturation.