Open Access

ARTICLE

Fatigue Resistance of Thin Hard Coated Spur Gears

by S. Baragetti¹, A. Terranova²

1 Dipartimento di Progettazione e Tecnologie, Università degli Studi di Bergamo, Viale Marconi 5, 24044 Dalmine (BG), Italy, sergio.baragetti@unibg.it
2 Dipartimento di Meccanica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy, angelo.terranova@polimi.it

Structural Durability & Health Monitoring 2005, 1(4), 267-276. https://doi.org/10.3970/sdhm.2005.001.267

Abstract

Aim of this work is to investigate into the possibility of enhancing the fatigue resistance of CrN PVD coated components. In particular PVD coated spur gears were tested and numerical simulation of crack propagation was carried out. The coating layer micro-hardness and the residual stresses characterising the surface film were measured and the obtained results were introduced in a numerical modelling predicting fatigue life procedure of coated gears used in gearboxes for automotive applications. The number of cycles necessary to reach specified crack depths of coated and uncoated samples was numerically determined and represents a powerful tool to predict fatigue life of coated steel gears. Benefits induced by the presence of coating were pointed out. A sensitivity analysis was carried out too: the effects of the residual stress gradient (evaluated by means of X-ray measurements), and of the elastic properties of bulk material and coating on the fatigue crack propagation were evaluated.

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Keywords

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