Lookup NU author(s): Dr Moorthy Vaidhianathasamy,
Professor Brian Shaw
Full text for this publication is not currently held within this repository. Alternative links are provided below where available.
The effect of surface features on as-ground gears and the influence of BALINIT (R) C and Nb-S coatings on the initiation of micro-pitting damage have been examined in case-carburised and tempered S156 steel helical gears subjected to contact fatigue using back-to-back gear testing. The initiation of micro-pitting damage has been studied using scanning electron and optical microscopy examination. It has been observed that micro-cracks tend to initiate against the sliding direction preferentially from microvalleys on the surface of as-ground gears, particularly when the depth of micro-valley is favourably oriented at an angle against the sliding direction. It has been found that the micro-pitting damage is drastically reduced in both coated gears. In BALINIT (R) C coated gears, the micro-scale surface irregularities are removed by a wear process resulting in a polished surface of the gear flank below the pitch diameter which is attributed to the effect of hard BALINIT (R) C coating. However, there is region of interface between the polished and unpolished regions of gear flank where there is small scale initiation of micro-pitting due to the absence of BALINIT (R) C coating at micro-valleys. In Nb-S coated gears, the coating tends to penetrate and fill-up the micro-valleys on as-ground surface modifying the gear flank surface. Hence, the micro-pits tend to initiate only at some micro-valley sites where the Nb-S coating is locally removed during running. This study shows that, both BALINIT (R) C and Nb-S coated gears show enhanced resistance to micro-pitting damage by removing localised stress concentration at micro-valleys present on as-ground gears. (C) 2012 Elsevier B.V. All rights reserved.
Author(s): Moorthy V; Shaw BA
Publication type: Article
Publication status: Published
Print publication date: 15/01/2013
ISSN (print): 0043-1648
ISSN (electronic): 1873-2577
Publisher: Elsevier Science
Altmetrics provided by Altmetric