Abstract:
In order to evaluate the hydrogen embrittlement risk of in-service X60 natural gas pipelines with hydrogen blending (5% vol. H
2, total pressure 6.4 MPa), the basic properties (including chemical composition, microstructure, microhardness, and mechanical properties) of base metal and (circumferential) weld samples from straight pipe sections and bent pipe sections were analyzed. The hydrogen embrittlement susceptibility of several samples in both air and hydrogen-blended environments was investigated using a slow strain rate test (SSRT). The results indicate that the basic properties of the specimens met the requirements of relevant standards. After hydrogen blending in the environment, the specimens still exhibited ductile fracture with low hydrogen embrittlement susceptibility, and their mechanical properties could meet the service requirements for a 5% hydrogen-blended environment.