The effect of hydrogen on crack growth in X70 pipeline steel under static load

• V.E. Ignatenko and A.I. Marshakov

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31-4, Leninsky prospect, 119071 Moscow, Russia

Abstract: The rates of crack growth during stress corrosion cracking under static mechanical load in X70 pipeline steel in environments with different acidity and hydrogen charging ability and at different steel potentials were determined by the potential drop method. In parallel, in the same environments and under the same conditions, the rates of hydrogen permeation into pipeline steel were determined by the Davanathan–Stachurski electrochemical desorption method. It was shown that an increase in the crack growth rate occurs when the hydrogen flux into the steel exceeds the critical value of 13.7±2 µA/cm² for a 0.5 mm thick membrane. The increase in the crack growth rate under supercritical hydrogen flux into steel is associated with the mechanism of hydrogen embrittlement of steel. The effective coefficients of hydrogen diffusion in pipeline steel were calculated from non-stationary relationships of the hydrogen permeation rate versus time. On their basis, the steady-state concentrations of diffusionally mobile hydrogen in pipeline steel under various hydrogen charging conditions were calculated. It was shown that due to the significant difference in the effective hydrogen diffusion coefficients under various experimental conditions and, consequently, the calculated concentrations of hydrogen in pipeline steel, it is more appropriate to use the hydrogen penetration current through the membrane to monitor the likelihood of hydrogen embrittlement of pipelines.

Keywords: pipeline steel X70, stress corrosion cracking, crack growth rates, hydrogen permeation into steel, hydrogen electrochemical desorption

Int. J. Corros. Scale Inhib., 2026, 15, no. 1, 244-262
doi: 10.17675/2305-6894-2026-15-1-12

Download PDF (Total downloads: 28)

Back to this issue content: 2026, Vol. 15, Issue 1 (pp. 1-... (in progress))