Crack Growth Analysis of High-Pressure Equipment for Hydrogen Storage

Crack growth analysis (CGA) was applied to estimate the cycle life of the high-pressure hydrogen equipment constructed by the practical materials of 4340 (two heats), 4137, 4130X, A286, type 316 (solution-annealed (SA) and cold-worked (CW)), and type 304 (SA and CW) in 45, 85 and 105 MPa hydrogen and air. The wall thickness was calculated following five regulations of the High Pressure Gas Safety Institute of Japan (KHK) designated equipment rule, KHKS 0220, TSG R0002, JB4732, and ASME Sec. VIII, Div. 3. We also applied CGA for four typical model materials to discuss the effect of ultimate tensile strength (UTS), pressure and hydrogen sensitivity on the cycle life of the high-pressure hydrogen equipment. Leak before burst (LBB) was confirmed in all practical materials in hydrogen and air. The minimum K_IC required for LBB of the model material with UTS of even 1500 MPa was 170 MPa·m^0.5 in 105 MPa. Cycle life qualified 10³ cycles for all practical materials in air. In 105 MPa hydrogen, the cycle life by K_IH was much shorter than that in air for two heats of 4340 and 4137 sensitive to hydrogen gas embrittlement (HGE). The cycle life of type 304 (SA) sensitive to HGE was almost above 10⁴ cycles in hydrogen, while the cycle life of type 316 (SA and CW) was not affected by hydrogen and that of A286 in hydrogen was near to that in air. It was discussed that the cycle life increased with decreasing pressure or UTS in hydrogen. This behavior was due to that K_IH increased or fatigue crack growth (FCG) decreased with decreasing pressure or UTS. The cycle life data of the model materials under the conditions of the pressure, UTS, K_IH, FCG and regulations in both hydrogen and air were proposed quantitatively for materials selection for high-pressure hydrogen storage.