Adaptation of a Slow Strain Rate Test Method for Highly Hydrogen Resistant Austenitic Stainless Steels

Materials with high resistance to hydrogen induced stress cracking for instance the austenitic stainless steels A286 and P750 are difficult to distinguish from one another in standard conventional tests where they are exposed to hydrogen environment. Therefore, more stringent test environments are required. The standardized test method involves a slow strain rate test in which the specimens are exposed to cathodic polarization. Based on this standardized test method, three parameters were varied. These include the current density, the introduction of a recombination poison into the charging solution and the temperature. Additionally, thermal desorption analysis and scanning electron microscopy were employed to improve interpretation of the obtained results. By the introduction of a recombination poison into the solution a significant increase in the stringency of the test was accomplished, irrespective of the kind and quantity of the recombination poison. Moreover, the test duration was reduced considerably. Alterations in current density and temperature had only a minor effect on the test outcome.