Prediction of microgeometrical influences on micropitting fatigue damage on 32CrMoV13 steel

Fabre, Agnès; Evans, Henry Peredur; Barrallier, Laurent; Sharif, Khairi; Desvignes, M.

doi:10.1016/j.triboint.2012.07.018

Cited by 5 publications

(2 citation statements)

References 31 publications

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“…The discs were also surface-finished to obtain smooth surfaces featured by longitudinal roughnesses of Ra ¼ 0.05 mm, so that the surface crack initiation coming from machining asperities are avoided. [16][17][18] The initiation stage duration was fixed at the number of cycles required to generate the first observable surface cracks (that will be called ''micropitting'' in this paper) on the nitrided disc surfaces so as to confirm the presence of RCF defects within the specimens for the rest of the tests.…”

Section: Experimental Methodologies Test Rig and Contact Conditionsmentioning

confidence: 99%

Rolling contact fatigue crack propagation in nitrided alloyed steels

Ville

Kléber

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part J:

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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.

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Section: Experimental Methodologies Test Rig and Contact Conditionsmentioning

confidence: 99%

Rolling contact fatigue crack propagation in nitrided alloyed steels

Ville

Kléber

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…All the specimens were ground to obtain a smooth surface with longitudinal roughness. The superficial stresses induced by roughness 22–24 were then avoided. The porous and brittle compound layer which is known to enhance micropitting 25 was removed.…”

Section: Methodsmentioning

confidence: 99%

Influence of grain boundary cementite induced by gas nitriding on the rolling contact fatigue of alloyed steels for gears

Ville

Kléber

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part J:

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It is well-known that rolling contact fatigue life can be increased by modifying gear surfaces. For instance, gas nitriding is a thermochemical treatment enhancing superficial hardness, and introducing compressive residual stresses but nitriding alloys can lead to the precipitation of cementite at grain boundaries. In this study, experiments were performed on a twin-disc machine to investigate the influence of the microstructure of nitrided layers on rolling contact fatigue failure modes. Nitrided layers with small grains, thin and short grain boundary cementite filaments showed better resistance to surface originated pitting compared with nitrided layers with coarse precipitates, for similar mechanical properties in terms of hardness and residual stresses. Moreover, examinations carried out on cross sections throughout crack networks revealed the influence of these precipitates on the propagation of rolling contact fatigue cracks, which is at the origin of the differences in performance between thin and coarse microstructures.

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