Rolling contact fatigue crack propagation in nitrided alloyed steels

Marion Le (1, 2, 3) , Fabrice Ville (1) , xavier Kleber (2) , Jean-Yves Buffiere (2) , Jérôme Cavoret (4) , Marie‐christine Sainte‐catherine (5) , Laurence Briancon (3)

1 LaMCoS - Laboratoire de Mécanique des Contacts et des Structures [Villeurbanne]
2 MATEIS - Matériaux, ingénierie et science [Villeurbanne]
3 DCNS Research
4 SMC - Systèmes Mécaniques et Contacts
5 DGA

Experimental investigations were carried out to better understand the rolling contact fatigue mechanisms in nitrided layers of the 33CrMoV12-9 steel grade. Surface-initiated pitting failure mode was reproduced on a twin-disc machine to analyse crack growth and compressive residual stress behaviour within the nitrided layers. Metallographic examinations, 3D observations by means of high-resolution X-ray computed tomography and residual stress analysis were realised on nitrided 33CrMoV12-9 specimens before and after rolling contact fatigue tests. The study revealed that if the initial compressive residual stresses associated with the surface treatment are released during the process of rolling contact fatigue, pre-existing superficial cracks propagate in the nitrided layers along the intergranular carbides. These precipitates induced by the nitriding process therefore act as preferential crack propagation sites.

Mots clés: nitriding; microstructure; gears; rolling element bearings; compressive residual stresses; twin-disc machine; crack mechanisms; Rolling contact fatigue; surface-initiated pitting

Domaines: Mécanique des matériaux [physics.class-ph]

Marion Le, Fabrice Ville, xavier Kleber, Jean-Yves Buffiere, Jérôme Cavoret, et al.. Rolling contact fatigue crack propagation in nitrided alloyed steels. Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2017, 231 (9), pp.1192--1208. ⟨10.1177/1350650117717824⟩. ⟨hal-01669929⟩