Abstract
Three types of stainless steel-austenitic, ferritic, duplex-were subjected to sustained load crack propagation tests in moist hydrogen gas. Three-stage crack velocity vs stress intensity behavior was observed for the unstable austenite alloy just as for pure hydrogen gas tests. Moisture essentially eliminated this behavior for the ferritic and duplex alloys. The fractographic features of all specimens failed in moist hydrogen are very similar to those for pure hydrogen. There is a continuous transition from brittle to ductile fracture appearance in the range from 25 °C to 100 °C. These results are rationalized on the basis of an inhibition of hydrogen entry into the metal due to H 2 O. © 1988 The Metallurgical Society of AIME.