- 著者
- 今出 政明 張 林 飯島 高志 福山 誠司 横川 清志
- 出版者
- 公益社団法人 日本金属学会
- 雑誌
- 日本金属学会誌 (ISSN:00214876)
- 巻号頁・発行日
- vol.73, no.4, pp.245-250, 2009 (Released:2009-04-01)
- 参考文献数
- 22
- 被引用文献数
- 12 11
The internal reversible hydrogen embrittlement (IRHE) of the thermally hydrogen-charged iron-based superalloy of SUH660 and austenitic stainless steels of SUS 304, 316, 316L, 316LN and 310S was investigated in the temperature range from 300K to 80 K. Hydrogen showed a marked effect on the tensile properties of SUH660 and SUS 304, a minimal effect on those of SUS316 and SUS316LN, and no effect on those of SUS 310S and 316L at room temperature. Although the IRHE of SUH660 decreased with decreasing temperature, those of SUS304, 316 and 316LN increased with decreasing temperature, reached a maximum at around 200 K, and decreased rapidly with decreasing temperature down to 80 K. It was observed that hydrogen caused transgranular fracture along the slip plane in the iron-based superalloy and brittle transgranular fracture along the strain-induced martensite lath in the austenitic stainless steels, respectively. It was suggested that IRHE of the SUH660 depended on the diffusion of hydrogen, and that IRHE of the austenitic stainless steels from 300 K to the maximum IRHE temperature depended on the transformation of strain-induced martensite and the behavior below the maximum IRHE temperature depended on the diffusion of hydrogen.
- 著者
- 松岡 三郎 松永 久生 山辺 純一郎 濱田 繁 飯島 高志
- 出版者
- 一般社団法人 日本機械学会
- 雑誌
- 日本機械学会論文集 (ISSN:21879761)
- 巻号頁・発行日
- vol.83, no.854, pp.17-00264-17-00264, 2017 (Released:2017-10-25)
- 参考文献数
- 29
- 被引用文献数
- 19
Considering in design by analysis, four types of tests, slow-strain-rate tensile (SSRT), fatigue life, fatigue crack-growth (FCG), and elasto-plastic fracture toughness (JIC) tests, were conducted with low-alloy steels, JIS-SCM435 and JIS-SNCM439, in 115 MPa hydrogen gas and air at room temperature (RT). In addition to above tests at RT, the SSRT tests were also conducted in 115 MPa hydrogen gas and air at 120 oC and in 106 MPa hydrogen gas and 0.1 MPa nitrogen gas at -45 oC. The low-alloy steels used in this study had tensile strengths (σB) ranging from 824 to 1201 MPa with fine and coarse tempered-martensitic microstructures. In the SSRT and fatigue life tests, the tensile strength and fatigue limit were not degraded in hydrogen gas. The FCG tests revealed that the FCG rate (da/dN) was accelerated in hydrogen gas; however, there existed an upper bound of the FCG acceleration, showing the FCG rate in hydrogen gas was about 30 times larger than that in air, when σB was lower than 900 MPa. The JIC tests demonstrated that the fracture toughness (KIC) in air was 207 MPa·m1/2 at σB = 900 MPa, whereas the hydrogen-induced crack-growth threshold (KI,H) was 57 MPa·m1/2 at σB = 900 MPa. Based on these results, we proposed advanced guidelines on the use and design for SCM435 and SNCM439 on design by analysis in 115 MPa hydrogen gas, which enable to design the storage cylinders used in 70 MPa hydrogen station with lower cost without compromising safety.