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Lookup NU author(s): Christopher Aylott, Professor Brian ShawORCiD
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Bending fatigue tests were conducted on spur gears manufactured from three commercially available carburizing steels; 20MnCr5, Ovako 236Q and Ovako 158Q (20NiMo9-7F). The purpose of the testing was to support the development of gearing for future automotive electric drive units which requires increased power density, efficiency and reliability. 20MnCr5 is currently used in such applications and was therefore selected as the baseline steel. Ovako 236Q is an ultra-clean variant of the baseline steel that was selected to investigate the effect of inclusion content and Ovako 158Q is an ultra-clean steel specifically designed to inhibit the formation of intergranular oxidation during gas carburizing that was selected to determine if increased bending fatigue performance could be achieved without the need for root grinding and/or shot peening. The uplifts in bending fatigue strength that could potentially be achieved using root grinding and/or duplex shot peening were also investigated for each grade of steel.This paper presents the bending fatigue S-N curves established for each steel and surface condition tested along with the results of the accompanying metallography, micro-hardness measurements, residual stress measurements and fractographic analysis. The 2 candidate steels gave a 20 to 29% uplift in mean strength and superior finite life fatigue performance to 20MnCr5 in the carburized condition thus demonstrating that gains could potentially be made without the need for subsequent root grinding or shot peening. Both candidate steels gave improved finite life performance and/or increased mean strength relative to 20MnCr5 in the duplex shot peened and root ground conditions indicating that notable gains could also be made through alternative steel selection. The test work outlined in this paper has therefore shown the ability for alternative steel selection to either achieve increased power density or decrease cost through reduction of manufacturing stages.
Author(s): Aylott C, Moorthy V, Shaw B
Editor(s): American Gear Manufacturers Association
Publication type: Conference Proceedings (inc. Abstract)
Publication status: Published
Conference Name: Fall Technical Meeting
Year of Conference: 2024
Pages: 49-74
Print publication date: 07/10/2024
Online publication date: 07/10/2024
Acceptance date: 17/05/2024
Publisher: American Gear Manufacturers Association
Library holdings: Search Newcastle University Library for this item
ISBN: 9781643531724
