Roughness Effect in Micropitting and Rolling Contact Fatigue of Silicon Nitride

Abstract

An experimental analysis of the role of surface roughness parameters on micropitting and the succeeding rolling contact fatigue (RCF) of silicon nitride against AISI 52100 steel under lubricated conditions was performed. In accelerated fatigue tests using a four-ball tester, the arithmetic mean, root mean square, and peak-to-valley roughnesses of silicon nitride surfaces varied, while the roughness of the steel surface was unchanged. The correlation between the fatigue life and roughness parameters for silicon nitride was obtained. The peak-to-valley roughness was the roughness parameter that dominantly affected the RCF life of silicon nitride. The micropitting of surfaces leading to fatigue intensified as the roughness was increased. Extensive micropitting was observed on the rolling track beyond the trailing edge of the spall region in the circumferential direction.

An Experimental Study of Surface Damage on Rolling Bearings in Low Lambda Conditions

“…All tests were performed for a total of 10 × 10 6 rotation cycles at a constant load of 1960 N with the maximum Hertz contact pressure of 2.1 GPa. 2.1 Surface roughness Surface roughness is one of the key parameters influencing surface damage in low Λ conditions [24][25][26][27]. Each test bearing consists of a combination of raceways with roughness ranging from 0.02 to 0.06 µm and steel balls with roughness up to 0.60 µm in the mean-square root (RMS) which is expressed as "Rq".…”