オーステナイト系ステンレス鋼SUS304のスモールパンチ試験特性に及ぼす高温水素ガス雰囲気の影響

抄録

We developed a small punch (SP) test system enables SP testing in a hydrogen atmosphere at elevated temperatures in order to utilize the SP testing for the remaining-life assessment of mechanical components used in advanced high-temperature hydrogen technologies, such as SOFC and SOEC. Type 304 stainless steel was subjected to the SP and SP creep tests with a small disk-type specimen. A small disk specimen with a diameter of 8 mm and thickness of 0.5 mm was tested in hydrogen and argon gases. The absolute gas pressure and temperature at which the SP test was carried out were 0.12 MPa and 600℃, respectively. The experimental results showed that the 0.2% proof stress and tensile strength in hydrogen and argon gases, which were predicted based on the SP test results, were consistent with those obtained from the tensile tests. The SP creep rupture time tended to be shorter in hydrogen gas than argon gas, and the equivalent fracture strain (rupture ductility) was slightly higher in hydrogen gas. The results obtained in the SP creep test were also qualitatively in agreement with those in the standard uniaxial creep test.