2010 Fiscal Year Final Research Report
Surface Microstructure Control of Cr-Mo Steels by High-Pressure Gas Cooling after Vacuum Carbonitriding
| Project/Area Number |
20569003
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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 |
Material processing/treatments
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| Research Institution | 仙台高等専門学校 (2009-2010)
Miyagi National College of Technology (2008) |
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Principal Investigator |
WATANABE Youichi 仙台高等専門学校, マテリアル環境工学科, 教授 (60515154)
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| Project Period (FY) |
2008 – 2010
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| Keywords | 鉄鋼材料 / 浸炭窒化 / 窒素 / ガス冷却 / ダイヤモンドライクカーボン(DLC) / 面圧疲れ / ピッティング |
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| Research Abstract |
We have investigated surface microstructures of high silicon containing Cr-Mo steel carbonitrided to high nitrogen content and quenched using cooling power-controlled N2 gas. Pitting resistance of the steel DLC(Diamond-like-carbon)-coated by ion plating process after the carbonitriding and quenching have been investigated under the conditions of a high Hertzian pressure(Pmax) of up to 4.5GPa with slipping of-60% and a 95℃oil-lubricating using roller-pitting tester. XRD analysis shows that the surface hardness and softening resistance during tempering are improved by precipitation ofεand/orγ' nitrides from nitrogen-solute martensite at the carbonitrided layer. Pitting lifetime of the steel DLC-coated after the carobonitriding is approximately 6 times longer than that of non-DLC coated one when Pmax is 4.2GPa. This excellent pitting endurance can be explained from both the DLC adhesion and the friction coefficient decreased by approximately 17% due to the DLC coating. Thus, this hybrid treatment will be expected to be able to applied to the several super-high pressure and/or high revolution speed gears for next generation automobiles.
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Research Products
(5 results)
