A Study on the Influence of Electrical Discharges on the Formation of White Etching Cracks in Oil-Lubricated Rolling Contacts and Their Detection Using Electrostatic Sensing Technique

Abstract

In bearing applications, the presence of stray and parasitic currents in combination with lubricants has been studied for almost a century and has been found to cause fluting and corrugation damages under high current densities. However, recent research has suggested that at low current densities (<1 mA/mm2) under specific operating conditions, electrical discharges can substantially reduce bearing life due to the formation of white etching cracks (WECs). To date, limited studies have investigated the critical operating and electrical conditions for WEC formation and demonstrated effective fault detection techniques. This study uses a novel monitoring technique known as the electrostatic sensing technique to detect, monitor and characterise electrical discharges in an oil-lubricated steel–steel rolling contact on a TE74 twin-roller machine. The findings demonstrate that WECs can be formed under the influence of electrical discharges in less than 50 h, and the electrostatic sensors are effective for the early detection of critical electrical discharges related to WEC-induced failures.

Predicting Wear under Boundary Lubrication: A Decisive Statistical Study

“…WEC came into the interest of industry and research within more than a decade [34]. The failure has been attributed to material degradation processes (see, for example, [35,36] and more) in relation to lubricants and parametrised conditions (see, for example, [37,38] and more). Even though some patterns with respect to the compositions of lubricants are reported (see, for example, [39,40] and more), a clear pattern in relation to the structure of any chemical and stoichiometry is missing.…”

Rolling Contact Fatigue and White Etching Cracks of Bearings

“…These facts enlarged the parameter field of mechanical engineering, inevitably leading to the question of understanding how a molecular and material scale of a few nanometers in size is related to a submicron's and macro scale [4]. White Etching Cracks and their relation to the presence of transient and persistent electricity have stimulated research on how lubricant chemicals are involved, and whether a numerical description is accessible [7,8]. The forecast of the continuous electrification of automotive drives intensifies the search for new predictors for lubricant chemicals.…”

“…WECs are found within a small window at boundary lubrication. Interestingly, it came out that WEC formation is accompanied in junction with the built-up of specie and their continuous self-charging[7].8.A Validated Computational Study of Lubricants under White Etching Crack Conditions Exposed to Electrical Fields: the authors are presenting within this paper a theory based on ab-initio calculations, that certain chemicals are capable of creating molecular clusters. The ability to upload electrical charges has been directly linked within the paper to the formation of White Etching Cracks[8].…”