PSI - Issue 75

D. Jbily et al. / Procedia Structural Integrity 75 (2025) 158–175 Author name / Structural Integrity Procedia (2025)

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SP Pinion

SEM image (EBSD map area)

Band contrast map

Fig. 15. Band contrast map of worn areas in different zones of the tooth dedendum (SP).

4.3. Friction Testing Friction tests were conducted using the TE-77 tribometer (Fig. 16) according to the ASTM G-133 standard in a cylinder/cylinder crossed mode. The upper cylinder has a diameter of 8 mm and is made of 100Cr6 treated to 58 HRC. The lower cylinder (Fig. 17) is taken from the cylindrical part of the REF and SP gears made of 18CrNiMo7 6. It should be noted that, in the absence of new gears and due to the impossibility of using an undamaged part of the available teeth, a sample was taken from the cylindrical shoulder on either side of the gear teeth; this shoulder is not ground but is produced by hard turning, with machining grooves that are longitudinal and parallel to each other, which is similar in terms of topography to the ground flanks.