초음파나노표면개질기술을 이용한 저널베어링 마찰 및 피로특성 연구
Frictional and Fatigue Characteristics of Journal Bearings by Ultrasonic Nanocrystal Surface Modification (UNSM)
0
조회
0
다운로드
1
인용
0
참고문헌
키워드
초록
In this study, we apply an ultrasonic nanocrystal surface modification (UNSM) technique to radial journal bearings (JBs) and disks made of SUJ2 and SCM440, respectively. We investigate frictional properties of untreated and UNSM-treated specimens using a ball-on-disk tester. We construct the Stribeck curve at the boundary, under mixed and full hydrodynamic lubrication conditions for the specimens using friction dataobtained from JB tests. The friction at the boundary lubrication condition and the transition period to mixed lubrication condition on the UNSM-treated specimens is reduced, which improves the service life of JBs. The major effects of this reduction in the three lubrication regimes can be explained in the terms of improved mechanical properties and the presence of micro dimples. Moreover, we estimate the friction and fatigue properties of SCM440 specimens using a ball-on-disk specimen under dry and oil-lubricated conditions. Friction test results reveal that the UNSM-treated specimens show lower friction coefficient than the untreated specimens under both dry and oil-lubricated conditions. We evaluate the fatigue properties of SCM440 specimens by calculating the Hertzian stress with respect to the failure cycles. Fatigue tests results also reveal that the UNSM-treated specimens possess a longer fatigue life than the untreated specimens. The improved properties are effective in increasing the energy efficiency of bearings.
Abstract
In this study, we apply an ultrasonic nanocrystal surface modification (UNSM) technique to radial journal bearings (JBs) and disks made of SUJ2 and SCM440, respectively. We investigate frictional properties of untreated and UNSM-treated specimens using a ball-on-disk tester. We construct the Stribeck curve at the boundary, under mixed and full hydrodynamic lubrication conditions for the specimens using friction dataobtained from JB tests. The friction at the boundary lubrication condition and the transition period to mixed lubrication condition on the UNSM-treated specimens is reduced, which improves the service life of JBs. The major effects of this reduction in the three lubrication regimes can be explained in the terms of improved mechanical properties and the presence of micro dimples. Moreover, we estimate the friction and fatigue properties of SCM440 specimens using a ball-on-disk specimen under dry and oil-lubricated conditions. Friction test results reveal that the UNSM-treated specimens show lower friction coefficient than the untreated specimens under both dry and oil-lubricated conditions. We evaluate the fatigue properties of SCM440 specimens by calculating the Hertzian stress with respect to the failure cycles. Fatigue tests results also reveal that the UNSM-treated specimens possess a longer fatigue life than the untreated specimens. The improved properties are effective in increasing the energy efficiency of bearings.
참고문헌 (6)
- Lee, N. S., "A Study on Wear Characteristics of High strength aluminum alloys by Surface Hardening", Proceeding of the KSME 2007 Joint Symposium, pp.1601~1606 (2007)
- Pyoun, Y. S., "Tribological Characteristics of radial Jounrnal Bearings by Ultrasonic Nanocrystal Surface Modification Technology", International Journal of Modern Physics B, 24(15), pp.3011~3016 (2010)
- G. Nachman, "Shot Peening-Past, Present, and Future", ASTM Stock Number: MNL56 Proc. 7th Int. Conf. on Shot Peening, pp.1~4 (1999)
- Lee, C. S., "Study of inner Micro Cracks on Rolling Contact Fatigue of Bearing Steels Using Ultrasonic Nano-crystal-Line Surface Modification", Key Engineering Materials, 462-463, pp.979~984 (2011)
- Kenneth G. Budinski, "Guide to friction, wear, and Erosion Testing", Identification of Different Types of Wear, (1), pp.1~15 (2007)
- Pyun, Y. S., "Fatigue Characteristics of SAE52100 Steel via Ultrasonic Nanocrystal Surface Modification Technology", Journal of Nanoscience and Nanotechnology, 12, pp.6089~6095 (2012)