Design and Life Prediction of Cr-Mo Steel Pressure Vessel for Next Generation Fuel-Cell Forklift Truck

The major characteristics of fuel-cell (FC) forklift are eco-friendly product, high-operation efficiency, saving space, and mobile power supply source, compared to an ordinary engine or gasoline forklift; however, for the widespread commercialization, a FC forklift with higher reliability and lower cost should be developed. Mechanical properties of materials are often degraded in hydrogen environment. According to the present Japanese regulation, only VH3 (metal liner and composite) and VH4 (plastic liner and composite) are allowed for the FC forklift from the viewpoint of safety, though these are generally more expensive than VH1 (all metal). This paper presented a design method of a Cr-Mo steel VH1 pressure vessel for a next generation FC forklift in consideration of the detrimental effect of hydrogen.