The carbon steels L80, P110 (both according to API 5CT) and 42CrMo4 (UNS G41400) as well as the corrosion resistant alloys (CRAs) Super 13Cr, Duplex 2205 and Alloy 28 were tested with regard to hydrogen embrittlement under the conditions prevailing in an underground natural gas reservoir used for microbiological methanation. Constant load tests (CLTs) and immersion tests in rotating autoclaves were performed. After the tests, the hydrogen content of the immersion specimens was measured. Atmospheres with different partial pressures of H₂ gas with and without brine were used. The experiments were carried out for a duration of 30 days at 25 and 80 °C. Specimens were also immersed in an acidified H₂S saturated aqueous brine solution (NACE TM0177 Solution A) and the Hydrogen uptake was measured after 3 hours, 30 hours and 336 hours of loading.
Significant differences between H₂ and H₂S containing media were found in the behavior under constant load as well as hydrogen uptake of the specimens. A comparison of the results indicates that steel grades suitable for sour service are also suitable for service in atmospheres containing up to 100 bar H₂.