In the 16th WHEC, we introduced our comprehensive research facilities for evaluating materials properties in several hydrogen environments including liquid hydrogen as well as high pressure gaseous hydrogen at up to 45MPa. To respond to strong requirements for mechanical properties data of the materials used in the fuel cell vehicles with 70MPa-class hydrogen fuel tanks as well as the materials used in the hydrogen refueling stations for the above mentioned FC cars, we have added a new one with which mechanical tests can be conducted in hydrogen gas at higher pressure up to 99MPa.
In this presentation, some features of the new facility are introduced and mechanical properties of A6061-T6 and 316L type stainless steel, both of which are now considered to be the standard structural materials for the parts used in high pressure hydrogen gas, are reported.
The new facility has basically the same configuration as that of the previously installed 45MPa-type one and tests can be conducted at temperatures from –45 to 95ºC. However, to stand the higher pressure and to secure the safety, some special devises are effectively placed.
Mechanical tests such as tensile, fatigue and fatigue crack growth tests are mainly conducted in hydrogen gas at 90MPa pressure, which is slightly higher than the 1.25 times of the 70MPa, rated pressure of the 70MPa on-board fuel tanks. These data will be used for formulating the code and standards of storage and transportation equipment used in high pressure hydrogen gas at around 70MPa or more in Japan.