1997 Fiscal Year Final Research Report Summary
ON STRESS CORROSION CRACKING RATE IN PURE WATER AT HIGH PRESSURE ・・・・FOR SAFETY IN REACTOR COOLING PIPES・・・・
| Project/Area Number |
08650823
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | NIIGATA INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
NUNOMURA Shigetomo NIIT,ENGINEERING,PROFESSOR, 工学部, 教授 (60016764)
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| Co-Investigator(Kenkyū-buntansha) |
TERASHIMA Shojiro NIIT,ENGINEERING,ASSOCIATE, 工学部, 助手 (20278071)
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| Project Period (FY) |
1996 – 1997
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| Keywords | stress corrosion cracking / SCC / Kiscc / crack propagation rate / ring specimen / cooling system / 2024 aluminum alloy |
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| Research Abstract |
Stress corrosion of pipes in the atomic reactor cooling system has attracted special interest recently. It is abvisable to evaluate the safety of structures in the practical conditions based on statistics. However, to guarantee the safety over an half century, it is impossible to simulate the passage of time. Therefore rapid test technique is indispensable.
Kiscc shows the critical stress condition on stress corrosion cracking (SCC), and is to know the resistance of materials to SCC.Kiscc is evaluate as stress intensity factor where no crack grows eternally. In most laboratory corrosion cracking tests, the slow strain rate test technique (SSRT) (Parkins, 1979) is adopted to obtain the data in relative short time. To investigate the relation between true Kiscc and result from these experimental methods, a large quantity of corrosion crack growth data as the function of stress intensity factor (K) is required.
The purpose of this research is to measure the stress corrosion cracking ratc at
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high pressure in low cost by the ring specimen method developed by the author.
The characteristics of ring specimen having a relatively wide constant K region against crack length when being loaded in compression along the crack orientation.
Miniaturization and multi specimen system are possible theoretically if use the ring test pieces. Manufacturing the test facility and the measurement in aluminum alloy were almost finished by 1996 business year. The measurement of crack propagation rate in SUS316 stainless steel in the simulated high pressure container in the 1997. The mechanical systems worked well, but there were some troubles in the crack legth measurement procedure, and the final test could not be started. Setting up as test piece a reduced scale in approximately 1/2, the noise level went over practical use in the potential difference crack length measurement system which successfully worked in 1996 business year. With improvement of the electronics system, introducing the shell pattern technique and AE methods is examined Less
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