Construction of a guiding principle for developing high-strength steels with excellent resistance to hydrogen embrittlement
| Project/Area Number |
19K04099
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 18010:Mechanics of materials and materials-related
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| Research Institution | Fukuoka University |
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Principal Investigator |
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2019: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Keywords | 水素脆化 / 高強度鋼 / 強度特性 / 水素拡散特性 / フラクトグラフィー |
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| Outline of Research at the Start |
高強度鋼の水素脆化挙動は，水素量，試験速度および強度レベルによって顕著に変化する．このため，条件によっては同じ材料においても水素脆化メカニズムが異なる可能性があり，従来の研究のように，限られた条件下による試験では水素脆化の全貌を捕らえることは困難である．そこで，水素量，試験速度，強化法および強度レベルを変化させた高強度鋼の網羅的な強度試験により，複雑な水素脆化メカニズムを解明するとともに，耐水素脆化特性に有効な強化法を示し，水素用材料開発の指導原理を構築する．
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| Outline of Final Research Achievements |
Effect of hydrogen on tensile properties of two precipitation-hardened martensitic stainless steels with different heat-treatment conditions (H900 and H1150) was investigated. H900 was peak-aged and its tensile strength was 1354 MPa, while H1150 was over-aged and its tensile strength was 1013 MPa. The hydrogen-induced ductility loss was more enhanced with higher hydrogen contents. The detailed observations of fracture surfaces and longitudinal cross-sections revealed that in the case of H1150, the HELP mechanism was dominant at lower hydrogen content and the HEDE was activated at higher hydrogen content. On the other hand, it was expected that the HEDE mechanism dominantly contributed to the ductility loss of H900, irrespective of hydrogen content. These imply that even in the same material, it is difficult to explain the mechanism of its hydrogen embrittlement by the sole mechanism.
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| Academic Significance and Societal Importance of the Research Achievements |
水素社会の実現には，水素機器に利用される材料の水素脆化（水素によって材料の強度特性が劣化する現象）を的確に把握し，水素機器の安全性を十分に保証する必要がある．特に，引張強さが１０００ＭＰａ程度を境に材料の水素脆化挙動が顕著に変化するため，この引張強さ付近の水素脆化挙動を注意深く調査することが重要である．本研究では引張強さ１０００ＭＰａ程度の２種類のステンレス鋼の水素脆化挙動を調査した．その結果，水素脆化のメカニズムを１つのメカニズムで説明することは困難であることを示すとともに，水素脆化を起こしやすい強化機構との関連についての知見を得た．これらは今後の材料開発に役立つ有益な結果といえる．
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Report
(4 results)
Research Products
(6 results)
