Session: MF-02-05 Materials for Hydrogen Service-High Alloy Materials 2

Paper Number: 121855

121855 - Fatigue Crack Growth Properties of Martensitic Stainless Steels in High Pressure Hydrogen Gas 

In recent years, high-pressure hydrogen gas has been increasingly harnessed to achieve carbon neutrality. Austenitic stainless steels are commonly employed in high-pressure hydrogen gas environments due to their reduced sensitivity to hydrogen embrittlement, even though they have lower strength. While some low-alloy steels are also widely used, they suffer from poor corrosion resistance. In contrast, martensitic stainless steels offer both high strength and superior corrosion resistance. However, a comprehensive understanding of the detailed mechanical properties of these steels in high-pressure hydrogen gas is still lacking. Fatigue crack growth properties are crucial when designing components for use in high-pressure hydrogen gas environments. To evaluate the compatibility of the martensitic stainless steels for hydrogen service, this study conducted fatigue crack growth tests in a 90 MPa hydrogen gas. The materials used were quenched and tempered, resulting in tensile strengths of approximately 800 to 900 MPa. It has been reported that, Cr-Mo steel, specifically JIS-SCM435 and JIS-SNCM439, with a tempered martensitic structure, exhibits a significant fatigue crack acceleration under the influence of hydrogen. However, this acceleration rate becomes independent of the test frequency, even in high-pressure hydrogen gas, when the tensile strength is below 900 MPa. In contrast, the martensitic stainless steels used in this study demonstrated time-dependent crack acceleration, which increased with a decrease in test frequency. In the presentation, we will discuss the mechanism of the hydrogen-induced crack acceleration, with a focus on the microscopic fracture morphology.

Presenting Author: Nobuyuki Takahashi Daido Steel Co., Ltd.

Presenting Author Biography: Researcher, Daido Steel Co., Ltd. (August 2017 - present)
Master of Engineering, Nagoya Institute of Technology (March 2017)
Bachelor of Engineering, Nagoya Institute of Technology (March 2015)

Authors:

Nobuyuki Takahashi Daido Steel Co., Ltd.
Hisao Matsunaga Kyushu University