Pressure Cycling Of Type 1 Pressure Vessels with Gaseous Hydrogen

Type 1 steel pressure vessels are commonly used for the transport of pressurized gases, including gaseous hydrogen. In the majority of cases, these cylinders experience relatively few pressure cycles over their lifetime, perhaps in the hundreds. In emerging markets, such as hydrogen-powered industrial trucks, hydrogen fuel systems are expected to experience thousands of cycles over just a few year period. This study investigates the fatigue life of Type 1 steel pressure vessels by subjecting full- scale vessels to pressure cycles with gaseous hydrogen between nominal pressure of 3.5 and 43.8 MPa. In addition, engineered defects were machined on the inside of several pressure vessels for comparison to fatigue crack growth measurements on materials sectioned from these pressure vessels. As-manufactured pressure vessels have sustained >35,000 cycles with failure, while vessels with machined defects leaked before bursting after 8,000 to 15,000 pressure cycles. The measured number of cycles to failure in these pressure vessels is two to three times greater than predicted using conservative methods based on fatigue crack growth rates measured in gaseous hydrogen.