EVALUATION OF HYDROGEN ENVIRONMENT EMBRITTLEMENT AND FATIGUE PROPERTIES OF STAINLESS STEELS IN HIGH PRESSURE GASEOUS HYDROGEN (INVESTIGATION OF MATERIALS PROPERTIES IN HIGH PRESSURE GASEOUS HYDROGEN-2)
Hydrogen environment embrittlement (HEE) susceptibility in high pressure gaseous hydrogen was investigated on 300 series austenitic stainless steels and A6061-T6 aluminum alloy. Tensile properties of these materials were evaluated by Slow Strain Rate Testing (SSRT) in gaseous hydrogen pressurized up to 90MPa (13053 psig) in the temperature range from -40 to 85 degrees C (-40 to 185 degrees F). HEE susceptibilities of austenitic stainless steels strongly depended upon the chemical compositions and testing temperatures. A6061-T6 aluminum alloy showed no degradation by hydrogen. Fatigue properties in high pressure gaseous hydrogen were evaluated by the external cyclic pressurization test using tubular specimens. The tubular specimen was filled with high pressure hydrogen gas, and the outside of the specimen was cyclically pressurized with water. Type 304 showed a decrease in the fatigue life in hydrogen gas, while as for type 316L and A6061-T6 the difference of the fatigue life between hydrogen and argon environments was small. HEE susceptibility of investigated materials was discussed based on the stability of an austenitic structure.
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