| Project/Area Number |
17360058
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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 |
Production engineering/Processing studies
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| Research Institution | Tokyo University of Agriculture and Technology |
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Principal Investigator |
SASAHARA Hiroyuki Tokyo University of Agriculture and Technology, Institute of Symbiotic Science and Technology, Associate professor, 大学院共生科学技術研究院, 助教授 (00205882)
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| Co-Investigator(Kenkyū-buntansha) |
TSUTSUMI Masaomi Tokyo University of Agriculture and Technology, Institute of Symbiotic Science and Technology, Professor, 大学院共生科学技術研究院, 教授 (90108217)
SATO Ryuta Tokyo University of Agriculture and Technology, Institute of Symbiotic Science and Technology, Research Associate, 大学院共生科学技術研究院, 助手 (60376861)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥12,800,000 (Direct Cost: ¥12,800,000)
Fiscal Year 2006: ¥4,300,000 (Direct Cost: ¥4,300,000)
Fiscal Year 2005: ¥8,500,000 (Direct Cost: ¥8,500,000)
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| Keywords | Cutting / Tool / Friction burnishing / Burnishing / Functional surface / Nanocrystalline Structure / Surface enhancement / Surface hardness / 残留応力 / 機械加工 / 疲労寿命 / ショットピーニング / エンドミル / あらさ |
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| Research Abstract |
The objective of this research is to develop a new tool that can generate compressive residual stress and hardened layer within the machined surface concurrently with the milling process. This tool has cutting edges for material removal and the projection pin for burnishing-like process. It was shown that the proposed cutter could generate effective compressive residual stress within the machined surface simultaneously with the milling process. Residual stress level shows -100 to -200MPa on the machined surface, and -300 to -400MPa at 0.05mm beneath the surface. It is almost comparative with that obtained by the shot peening process.
In the friction stir burnishing process, the burnishing pin rubs on the treating surface with high rotating speed over 10,000min^<-1>, then the tool tip stirs within the very thin surface layer with extremely large strain under high strain rate and increase temperature in the process. The effect of large strain is so drastic that some special features can be given on the surface layer.
As a result of applying this method to 0.45% carbon steel, very hard layer over 700HV was formed on the surface. This hard layer couldn't be etched with acid etchant. Thickness of the hardened layer is 200μm in a maximum case. Very high hardness 800HV is hardly realized without martensitic transformation as usual. But the martensitic structure couldn't be observed in the hardened layer made by this method on some cases. These features are thought to be realized through the formation of very fine nanocristalline structure. X-ray diffraction pattern and SEM observation were conducted to confirm the formation of nanocristalline structure.
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