Kyushu University Academic Staff Educational and Research Activities Database
List of Papers
Kazuyuki Yagi Last modified date:2019.07.08

Associate Professor / Machine Design and Bionic Systems / Department of Mechanical Engineering / Faculty of Engineering

1. Yasuo Matsuzaki, Kazuyuki Yagi, Joichi Sugimura, In Situ Observation of Heat Generation Behaviour on Steel Surface During Scuffing Process, Tribology Letters, 10.1007/s11249-018-1095-x, 66, 4, 2018.12, In the current study, the heat generation behaviour at plastic flow area in the contact area during a scuffing process was observed in situ using a monochrome high-speed camera that detected both visible and near-infrared light. The scuffing test was conducted using a pin-on-disc test rig comprising a rotating sapphire disc and a fixed martensitic steel pin. Engine oil was supplied as a lubricant. The images captured by the high-speed camera clearly showed changes in the contact area and the heat generation behaviour. It was found that the heat generation behaviour could be classified into three stages during scuffing. In the first stage, local heat generation occurred intermittently at local severe contact points, such as the passing of transfer layers on the sapphire disc and the trailing edge of the contact area. In the second stage, heat generation occurred intermittently over larger areas in which heat had been generated until that time. When the entire contact area had previously generated heat, heat generation became continuous throughout the contact area in the third stage. During the third stage, the contact area was increased rapidly, which caused catastrophic failure. These results highlight important questions regarding material phenomena that remain to be investigated..
2. Takashi Izumi, Kazuyuki Yagi, Jun Koyamachi, Koji Saito, Shuzo Sanda, Satoshi Yamaguchi, Hidenori Ikehata, Yasuhiro Yogo, Joichi Sugimura, Surface Deteriorations During Scuffing Process of Steel and Analysis of Their Contribution to Wear Using In Situ Synchrotron X-Ray Diffraction and Optical Observations, Tribology Letters, 10.1007/s11249-018-1062-6, 66, 3, 2018.09, In a previous study, we developed a novel in situ analysis and observation system that allows for simultaneous synchrotron X-ray diffraction (XRD) and optical observations of a frictional surface. This in situ system was used to investigate the scuffing phenomena of SUJ2 bearing steel (AISI 52100); characteristic surface deteriorations occurred during the scuffing process, including plastic flow, heat-spot formation, austenite transformation, and a decrease in the width of the XRD peaks (indicating a decrease of dislocations and strain). These surface deteriorations are not observed during normal wear, hence it is possible that they cause catastrophic wear during the scuffing of steel. In this study, to elucidate the scuffing mechanism of steel, we focused on the following two points: (1) whether the above surface deteriorations are unique to SUJ2 steel or whether they occur in general steels as well, and (2) the extent to which these surface deteriorations contribute to the wear amount. To achieve these objectives, we performed scuffing tests on four types of steel using the previously developed in situ system. In particular, we focused on the first stage of the scuffing process. The present test results suggest that these surface deteriorations also occur in general steels, and that plastic flow and heat-spot formation, which originate from the same phenomenon, are the dominant contributors to the wear amount during the scuffing of steel. Furthermore, the wear amount per unit plastic flow appears to be independent of steel composition..
3. Yasuo Matsuzaki, Kazuyuki Yagi, Joichi Sugimura, In-Situ Fast and Long Observation System for Friction Surfaces during Scuffing of Steel, Wear, 10.1016/j.wear.2017.06.013, 386-387, 165-172, 2017.06, [URL].
4. Kazuyuki Yagi, Joichi Sugimura, Performance of Balancing Wedge Action in Textured Hydrodynamic Pad Bearings, Transactions of the ASME, Journal of Tribology, 10.1115/1.4033128, 139, 1, 011704, 2016.03, [URL].
5. Kazuyuki Yagi, Seiji Kajita, Takashi Izumi, Jun Koyamachi, Mamoru Tohyama, Koji Saito, Joichi Sugimura, Simultaneous Synchrotron X-ray Diffraction, Near-Infrared, and Visible In Situ Observation of Scuffing Process of Steel in Sliding Contact, Tribology Letters, 10.1007/s11249-015-0636-9, 61, 2, 19-1-19-16, 2016.01, [URL].
6. Kazuyuki Yagi, Joichi Sugimura, Balancing Wedge Action in Textured Converging Bearings, Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 10.1177/1350650115596541, 230, 3, 241-256, 2015.07, [URL].
7. Kazuyuki Yagi, Hajime Sato, Joichi Sugimura, On the Magnitude of Load-Carrying Capacity of Textured Surfaces in Hydrodynamic Lubrication, Tribology Online, 10.2474/trol.10.232, 10, 3, 232-245, 2015.06, [URL].
8. Seiji Kajita, Kazuyuki Yagi, Takashi Izumi, Jun Koyamachi, Mamoru Tohyama, Koji Saito, Joichi Sugimura, In Situ X-Ray Diffraction Study of Phase Transformation of Steel in Scuffing Process, Tribology Letters, 10.1007/s11249-014-0443-8, 57, 1, 6-1-6-11, 2015.01, [URL].
9. Haijiang Li, Kazuyuki Yagi, Joichi Sugimura, Seiji Kajita, Takatoshi Shinyoshi, Role of Wear Particles in Scuffing Initiation, Tribology Online, 10.2474/trol.8.285, 8, 5, 285-294, 2013.12, [URL].
10. Kazuyuki Yagi, Joichi Sugimura, Elastohydrodynamic Simulation of Rayleigh Step Bearings in Thin Film Hydrodynamic Lubrication, Tribology International, 10.1016/j.triboint.2013.04.005, 64, August, 204-214, 2013.04, [URL].
11. Kazuyuki Yagi, Joichi Sugimura, Balancing Wedge Action: A Contribution of Textured Surface to Hydrodynamic Pressure Generation, Tribology Letters, 10.1007/s11249-013-0132-z, 50, 3, 349-364, 2013.04, [URL].
12. Kazuyuki Yagi, Joichi Sugimura, Elastic Deformation in Thin Film Hydrodynamic Lubrication, Tribology International, 10.1016/j.triboint.2012.05.025, 59, March, 170-180, 2012.06, [URL].
13. Kazuyuki Yagi, Joichi Sugimura and Philippe Vergne, Rheological Response of Fatty Alcohols in Sliding Elastohydrodynamic Contacts, Tribology International, 10.1016/j.triboint.2011.12.012, 49, May, 58-66, 2011.12, [URL].
14. Kazuyuki Yagi, Yukito Ebisu, Joichi Sugimura, Seiji Kajita, Toshihide Ohmori and Atsushi Suzuki, In Situ Observation of Wear Process Before and During Scuffing in Sliding Contact, Tribology Letters, 10.1007/s11249-011-9817-3, 43, 3, 361-368, 2011.09, [URL].
15. Kazuyuki Yagi, Philippe Vergne and Tsunamitsu Nakahara, In Situ Pressure Measurements in Dimpled Elastohydrodynamic Sliding Contacts by Raman Microspectroscopy, Tribology International, Vol.42, No.5, pp.724-730., 2009.05, [URL].
16. Kazuyuki Yagi, Wataru Takedomi, Hiroyoshi Tanaka and Joichi Sugimura, Improvement of Lubrication Performance by Micro Pit Surfaces, Tribology Online, Vol. 3, No. 5, pp.285-288., 2008.10, [URL].
17. Kazuyuki Yagi & Philippe Vergne, Abnormal Film Shapes in Sliding Elastohydrodynamic Contacts Lubricated by Fatty Alcohols, Proceedings of the Institution of Mechanical Engineers, Part J, 221, 3, pp287-300., 2007.04, [URL].
18. Tsunamitsu Nakahara & Kazuyuki Yagi, Influence of Temperature Distributions in EHL Film on Its Thickness under High Slip Ratio Conditions, Tribology International, 40, pp632-637., 2007.04, [URL].
19. Kazuyuki Yagi, Keiji Kyogoku & Tsunamitsu Nakahara, Measurements of Temperature Distributions around Longitudinally Grooved Rough Surfaces in Sliding Elastohydrodynamic Point Contacts, STLE Tribology Transactions, 49, 4, pp482-489., 2006.10, [URL].
20. Kazuyuki Yagi, Keiji Kyogoku & Tsunamitsu Nakahara, Experimental Investigation of Effects of Slip Ratio on Elastohydrodynamic Lubrication Film Related to Temperature Distribution in Oil Films, Proceedings of the Institution of Mechanical Engineers, Part J, 220, 4, pp353-363., 2006.08, [URL].
21. Kazuyuki Yagi & Philippe Vergne, Film Thickness Changes in EHD Sliding Contacts Lubricated by a Fatty Alcohol, Tribology Online, 1, 1, pp5-8., 2006.08, [URL].
22. Kazuyuki Yagi, Keiji Kyogoku & Tsunamitsu Nakahara, Relationship between Temperature Distribution in EHL Film and Dimple Formation, Transactions of the ASME, Journal of Tribology, 127, 3, pp658-665., 2005.07, [URL].
23. Masahiro Kawaguchi, Kazuyuki Yagi & Takahisa Kato, An Effect of Dewetting of Lubricated Surfaces on Friction and Wear Properties, Journal of Applied Physics, 97, 10, 10P311., 2005.04, [URL].
24. Shigeka Yoshimoto, Yuichi Yoshida & Kazuyuki Yagi, The Seal System in Aerostatic Journal Bearings for High Vacuum Chambers, Transactions of the ASME, Journal of Tribology, 126, 2, pp310-315., 2004.04, [URL].
25. Feng Guo, Pat Lam Wong, Peiran Yang & Kazuyuki Yagi, Film Formation in EHL Point Contacts under ZEV Conditions, STLE Tribology Transactions, 45, 4, pp521-530., 2002.04, [URL].