A Compendium of Mechanical Testing of Austenitic Stainless Steels in Hydrogen

Archival materials test data on austenitic stainless steels for service in high pressure hydrogen gas has been reviewed. The bulk of the data were from tests conducted prior to 1983 at the Savannah River Laboratory, the predecessor to the Savannah River National Laboratory, for pressures up to 69 MPa (10,000 psi) and at temperatures within the range from 78 to 400 K (−195 to 127 °C). The data showed several prominent effects and correlations with test conditions: • There was a significant reduction in tensile ductility as measured by reduction of area or by the total elongation with hydrogen. Hydrogen effects were observed when the specimens were tested in the hydrogen environment, or the specimens were precharged in high pressure hydrogen and tested in air or helium. • There was a significant reduction in fracture toughness with hydrogen (and sometimes in tearing modulus which is proportional to the slope of the crack resistance curve). • The effects of hydrogen on ductility can be correlated to the nickel content of the iron-chromium-nickel steels. The optimal nickel content to retain the high tensile ductility in these alloys was 10 to at least 20 wt. %. • The effects of hydrogen can be correlated to the grain size. Large grain sizes exhibited a greater loss of ductility compared to small grain sizes. The Savannah River Laboratory test data, especially those not readily available in the open literature, along with the sources of the data, are documented in this paper.