PSI - Issue 75

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia (2025) 000 – 000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 75 (2025) 158–175

Fatigue Design 2025 (FatDes 2025) The influence of shot peening on gear teeth micropitting- complementary analyses Dr.-Ing. D. Jbily a *, Dr.-Ing.Y. Chen, Dr.-Ing. A. Simonneau b

a Cetim, 52 Av. Felix Louat 60304, Senlis, France b Texelis, 72, route du Palais, 87011 Limoges

© 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of Dr Fabien Lefebvre with at least 2 reviewers per paper This work seeks to explore why shot-peened gears, despite exhibiting higher surface compressive residual stresses and reduced surface roughness, deteriorate more quickly. Analyses were carried out, including surface damage assessments using microscopy and interferometric profiles, and damage mechanism analysis through EBSD technique. Results showed micropitting craters of 10 100 μm in size and 1 - 5 μm in depth, with significant crystallinity reduction in worn areas. Tribological tests were also conducted on tribometer according to ASTM G-133 in crossed cylinder/cylinder mode to measure the friction coefficient. These tests allowed the reproduction of micropitting on the non-peened surface of cylinder extracted from gear after 20 000 cycles, while no micropitting was observed on a shot-peened surface even after 340 000 cycles. © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2025 organizers Abstract Micropitting damage, commonly seen in case-hardened gears, gradually deteriorates the contact surface geometry, potentially leading to macropitting and fatigue failure. A previous study (Jbily et al. (2024)) based on gear contact fatigue tests investigated the effect of shot peening on the micropitting and its development to macropitting on case-hardened gears. A specific shot peening is employed to optimize the surface roughness of the flanks. Initial inspection of gear specimens revealed that shot peening resulted in higher surface residual stress and lower surface roughness compared to ground tooth flanks (without shot peening). Experimental results showed that while both specimens exhibited micropitting, it was more pronounced on the shot-peened tooth flanks, with greater tooth profile loss. Howe ver, it was found that shot peening delayed the onset of macropitting, extending the gear’s durability by more than 50%.

* Corresponding author. E-mail address: dalia.jbily@cetim.fr

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of the Fatigue Design 2025 organizers

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under the responsibility of Dr Fabien Lefebvre with at least 2 reviewers per paper 10.1016/j.prostr.2025.11.018