Session: MF-02-09 Pipeline Infrastructure 2

Paper Number: 122557

122557 - Effect of Strength and Microstructure on Hydrogen Compatibility of Linepipe Steels 

When looking at carbon neutrality in the future, the use of hydrogen and its energy is one of many useful methods. The selection of steel materials suitable for transporting hydrogen is a very important issue for the realization of a hydrogen society. However, it is also known that the mechanical properties of steel deteriorate greatly even under small pressures of hydrogen due to hydrogen embrittlement. Material degradation is considered in the hydrogen pipeline code ASME B31.12. This code requires the failure and fatigue properties of piping materials under hydrogen to be evaluated and critical evaluations are made to avoid pipeline failure during its useful life. In this study, we investigated the basic material behavior and mechanical properties of line pipe steel under high pressure hydrogen environment. The fracture toughness test was conducted using bainite steel obtained from actual UOE steel pipes with different strengths as test materials, in hydrogen at 21 MPa according to an unloading method based on ASTM E1820. As a result, the fracture toughness of API Grade X80 steel was inferior to that of API Grade X65 line pipe. In grade X80, the heat affected zone (HAZ) was inferior to the base metal. The fatigue crack growth characteristics of base metal in hydrogen environment was inferior to those in air, but the effect of strength was small in hydrogen environment. The effect of strength on hydrogen embrittlement was discussed based on the change in fracture morphology after the test and the possible hydrogen trapping sites in each structure.

Presenting Author: Hikaru Imayama JFE Steel Corporation

Presenting Author Biography: JFE Steel Corporation
Steel Research laboratory
Researcher

2019- Researcher, JFE Steel Corporation
-2019 M.S., Kyushu University, Fukuoka, Japan

Specialties：Low temperature toughness of steel

Authors:

Hikaru Imayama JFE Steel Corporation
Daichi Izumi JFE Steel Corporation
Junji Shimamura JFE Steel Corporation
Yoshihiro Nishihara JFE Steel Corporation
Hiroshi Okano JFE Steel Corporation