Session: MF-02-06 Materials for Hydrogen Service-Test Methods 1

Paper Number: 122079

122079 - Study of Crack Initiation and Fracture Toughness Evaluation on Jic Testing of Linepipe Steel in Gaseous Hydrogen Environment 

Hydrogen is one of the promising energy carrier for achieving the carbon neutral society. The pipeline system is positioned as a major infrastructure indispensable for mass transportation of gaseous hydrogen. It is acknowledged that existing natural gas pipeline can be safely used for hydrogen blend up to 10 or 20%. However, it is also known that mechanical properties of steels are largely degraded even under small partial pressure of hydrogen because of hydrogen embrittlement. Material degradation is considered in the hydrogen pipeline code ASME B31.12. In this code, fracture and fatigue properties of linepipe material under hydrogen need to be evaluated and critical assessment is conducted so that fracture of the pipeline can be avoided during its service life. The fracture toughness is required to be obtained by the test based on the Article KD-10 in ASME BPVC VIII-3. However, most of the line pipes have low strength and high toughness, so the evaluation by the above method is not suitable from the viewpoint of specimen size and mechanical constraint. Therefore, evaluation of fracture toughness by elastic-plastic fracture toughness test has become common. On the other hand, current standards for elastic-plastic fracture toughness tests, such as ASTM E1820, are based on the premise of conducting tests under atmospheric conditions, and do not consider ductility reduction and crack initiation mechanism changes caused by hydrogen entering steel under gaseous hydrogen environment. Therefore, it is not clear whether it is appropriate to evaluate the fracture toughness in gaseous hydrogen environment by applying the current test standard. In this study, the effect of hydrogen on the crack initiation in the JIC testing was investigated, and the method which can evaluate the toughness value based on the fracture behavior of the specimen under the hydrogen gas environment was examined.

Presenting Author: Yoshihiro Nishihara JFE Steel Corporation

Presenting Author Biography: 2019- Researcher, JFE Steel Corporation
-2018 M.S., Tokyo University of Science, Chiba, Japan

Specialties：Electrochemistry and Hydrogen embrittlement

Authors:

Yoshihiro Nishihara JFE Steel Corporation
Ryuichi Inoue JFE Steel Corporation
Hiroshi Okano JFE Steel Corporation
Takahiro Sakimoto JFE Steel Corporation