Hydrogen Compatibility of Centrifugal Compressor Impeller Material in Hydrogen-Blended Natural Gas Environment

Abstract:

The hydrogen compatibility of FV520B steel immersed in different hydrogen-blended natural gas environments was evaluated through slow strain-rate tensile testing, fatigue crack propagation testing, and fracture toughness testing and fracture morphology and microstructural characteristic were analyzed. The results show that as the hydrogen blending ratio and gas pressure increase, both the tensile strength and yield strength of FV520B steel decrease in different degrees, and the elongation after fracture and the reduction of area also decrease, demonstrating hydrogen induced plastic loss phenomenon. With increasing hydrogen content and gas pressure, the crack growth rate-stress intensity factor range curves shift left, leading to earlier crack propagation and faster entry into unstable fracture of the sample. Meanwhile, the fracture toughness K_IC value of FV520B steel decreases, and a tendency towards brittleness is observed in the low magnification fracture morphology of the material. The present study provides an important basis for evaluating the engineering application of centrifugal compressor impeller materials during transport of hydrogen-blended natural gas.