An Experimental Investigation Replicating the Surface Behavior of Ground Steel Gears in Mixed Lubrication Using Twin-Disk Testing Part 2: Micropitting

Tooth surfaces in heavily loaded power-transmission gearing can often suffer from surface fatigue on the surface roughness scale, known as micropitting. In this paper, the influence of three variables (pressure, slide-roll ratio, and entrainment velocity) on micropitting is investigated using a full-factorial experimental program using a twin-disk test rig. The results showed that pressure was most influential on micropitting growth during the latter phases of the test, with slide-roll ratio being a more important factor during micropit initiation. The full-factorial nature of these tests allowed two- and three-factor effects to be investigated, demonstrating that micropitting is a complex phenomenon influenced by a network of interconnected effects.