| Project/Area Number |
08455336
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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 | 一般 |
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| Research Field |
Material processing/treatments
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| Research Institution | Osaka University |
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Principal Investigator |
KIKUCHI Yasushi Joining and Welding Research Institute Osaka University, Professor, 接合科学研究所・再帰循環システム研究センター, 教授 (90005405)
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| Co-Investigator(Kenkyū-buntansha) |
黒田 敏雄 大阪大学, 接合科学研究所, 助教授 (00107096)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 1997: ¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1996: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | bacterial corrosion / stainless steel / welds / 金属と微生物 / ステンレス鋼溶接部 / 腐食 |
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| Research Abstract |
The failure in the weld joint occurred in as little as, two months from the start-up of the sewage treatment plant. At the beginning of the failure analysis, crevice corrosion was considered as the main reason since the welding defects. But, the estimated corrosion rate of the welds was too fast. Then, metallurgical failure analysis to understand this behavior was carried out. Finally, it was concluded that the localized corroion on the welds was a kind of Microbiologically Influenced Corrosion (MIC).
The first stage of a laboratory scale test using the stainless steel welds and the residual liquid obtainable from the MIC-affected effluent treatment plant was performed.
The test samples were exposed in the liquid and kept in an incubator at constant temperature. Corrosion pits were found on 316L,308N (0.2% mass nitrogen approximately) and 308 weld metal. The colonies of bacteria several mum in size near the corrosion pits were observed and the types of the bacteria was identified. The evaluation test of corrosion ability of the identified bacteria was planned. MIC susceptibility of the stainless steels used was evaluated.
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