Evaluation of the hydrogen embrittlement behaviour by means of the permeation current measure in slow strain rate conditions of a micro-alloyed steel

The measure of the hydrogen permeation current through a metal membrane is a well-consolidated electrochemical technique to evaluate the effect of the environment, the polarization and the type of steel related to hydrogen diffusion. Permeation tests allow to evaluate the stationary flow of hydrogen and the degree of surface coverage. In this work, permeation tests were carried out in a 35 g/L NaCl solution at -1.05 V and -2 V vs. SCE on a pipeline micro-alloyed steel. The permeation current was measured on samples without load, with a constant load applied and in slow strain rate conditions. Afterwards, hydrogen permeation parameters were correlated to the results of Slow Strain Rate Tests (SSRT) in order to improve the knowledge on the hydrogen embrittlement mechanism of this type of steels.