2000 Fiscal Year Final Research Report Summary
A Synthetic Study on the New Non-destructive Evaluation by Magnetic Measurements
| Project/Area Number |
10558075
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
Nuclear engineering
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| Research Institution | Faculty of Engineering |
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Principal Investigator |
TAKAHASHI Seiki Iwate Univ. Faculty of Engineering Professor, 工学部, 教授 (50003851)
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| Co-Investigator(Kenkyū-buntansha) |
KOJIMA Fumio Koube Univ. Faculty of Engineering, Professor, 工学部, 教授 (70234763)
MIYA Kenzou Tokyo Univ. Faculty of Engineering, Professor, 工学部, 教授 (30011191)
ECHIGOYA Junichi Iwate Univ. Faculty of Engineering Professor, 工学部, 教授 (00005539)
KASAI Naoko Electrotechnical Laboratory Head Researcher, 主任研究官
YAMADA Kouji Saitama Univ. Faculty of Engineering, Professor, 工学部, 教授 (30008875)
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| Project Period (FY) |
1998 – 2000
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| Keywords | nondestructive evaluation / magnetization curve / lattice defects (dislocations) / SOUID magnetometer / A533B steel / pressure vessel / SUS304 stainless steel / Barkhausen noise |
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| Research Abstract |
The currently employed nondestructive tests for metal fatigue are, useful in the investigation of cracks and fractures in the materials. The cracks are produced by the pile of dislocations, where the dislocation density is maximum locally. Few investigators have conducted nondestructive tests before the appearance of cracks. In the present study, we investigate the nondestructive evaluation of dislocations before the nucleation of cracks takes place.
One of the important and urgent areas for the application of nondestructive tests is the nuclear power station, especially the pressure vessel. The deterioration of the pressure vessel determines the life time of the nuclear reactor. Since most pressure vessels are made of A533B steel, in the present study the structure sensitive properties are investigated in connection with the plastic deformation in A433B steel by the round robin tests. The results show that the hysteresis measurement is the best method as NDE of the pressure vessel mate
… More
rials.
The Iwate University group has found two parameters which are sensitive to dislocations. The magnetic susceptibility is measured in the low-field range just above the coercive field H_C and the relation between X_C and H is obtained : X_C = c/H^3. The parameter, c, is sensitive to dislocation density and its distribution. The parameter, c, is licensed (Japanese No. 3158182). The other parameter is H_C/X_H, Which is sensitive in the early stage of plastic deformation.
SUS stainless steel is used in the nuclear power station and very important from the viewpoint of NDE.The NDE of SUS 304 stainless steel has been studied for 50 years using the Martensitic transformation. But the magnetic method has not been put to practical use of NDE in the stainless steel. The reason of the difficult practical use has been studied and it is made clear ; The Martensitic phase due to metal fatigue or plastic deformation does not exactly correspond to the lattice defects such as the dislocations and twins. We have concluded that a new parameter, which corresponds to the lattice defects directly, should be found and much data between magnetic properties and lattice defectsshould be accumulated. Less
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