| Project/Area Number |
59460180
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
溶接工学
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| Research Institution | Osaka University |
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Principal Investigator |
YOSHIHIKO MUKAI Faculty of Engineering, Osaka University, 工学部, 教授 (20029044)
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| Co-Investigator(Kenkyū-buntansha) |
ARATA NISHIMURA Faculty of Engineering. Osaka University, 工学部, 助手 (60156099)
MSASATO MURATA Faculty of Engineering, Osaka University, 工学部, 助手 (20030059)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥5,100,000 (Direct Cost: ¥5,100,000)
Fiscal Year 1986: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1985: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1984: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Keywords | Corrosion fatigue / Time strength / Pit / HAZ / 金属溶解 |
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| Research Abstract |
Enviromental effects for fatigue strength of mild steel, high strength steel and stainless were studied.The test enviroment was decided to be 3%NaCl aq.sol. for simulating marine water. The results are as follows.
There were snap points in S-N curves of each material and they were found to be scarcely low than fatigue limit in air. Corrosion fatigue life was decreased in lower stress level with stress frequency decrement but the frequency effect was relatively low in higher stress level. This would be caused that the corrosive damage effect became more significant than fatigue one in long fatigue life condition. Notch effect for corrosion fatigue strength revealed at higher stress level as stress concentration effect,but in lower stress level,it was disappear and corrosion fatigue strength was nearly equal to that of in smooth specimen(kt=1). In addition, corrosion fatigue crack was found to initiate mostly from corrosion pit by SEM observation, The morphology of pits were observed to be heterogenious general corrosion type in high strength steel and macro hole type in high Cr steel. In welded joint,HAZ had best corrosion resistance and weled metal was worst. It was guessed that corrosion fatigue strength improved with hardness increasing.
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