Fatigue Crack Growth Rate Study of New X52 Line Pipe Steel in Hydrogen Blended Methane

Abstract

Abstract Hydrogen is an alternative fuel to consider for decarbonization as its combustion does not result in production of greenhouse gases. The transport of hydrogen from production to end use location is a critical part of deployment and blending of hydrogen in the natural gas transmission and distribution pipeline network is a cost effective option. However, the interaction of hydrogen with the pipeline material needs to be evaluated due to risks associated with hydrogen embrittlement. In this study, fatigue properties of a new X52 line pipe material with an HFW seam weld was evaluated to identify the impact of up to 10% hydrogen blending at a pressure of 1800 psi. A fracture mechanics-based approach was used to test the fatigue crack growth rate (FCGR) of microstructures associated with parent pipe, seam weld, seam weld – heat affected zone (HAZ), girth weld and girth weld HAZ. The gas environment was simulated in an autoclave pressurized to 1800 psi (12.4 MPa) total pressure using 1, 5 and 10 mole% hydrogen blends in methane. FCGR was also measured in 100% methane environment to establish a baseline to compare the properties in the selected hydrogen blends. The Paris curves were measured at a constant R ratio of 0.3. Increase of the FCGR above those measured in the 100% methane environment baseline was observed for all the microstructures at all concentrations of hydrogen. The degree of increase in FCGR as well as in the range of stress intensity factor (ΔK) where the increase was observed, varied to some extent between microstructures. Results were also compared to the ASME B31.12 curve for carbon steel in hydrogen, to understand the degree of conservatism associated with the ASME curve for the hydrogen blends.