CHARACTERIZATION OF SPHERICAL DEBRIS FROM ROLLER BEARINGS UNDER BOUNDARY LUBRICATION

ADRIAN URRESTARAZU; W. R. TUCKART; L. QUINZANI

Mar del plata

Workshop; 3º International Workshop of Tribology; 2015

Asociación Argentina de Tribología

The detection of wear particles in a lubricantprovides a powerful diagnostic technique for thefinding of distress in critical mechanisms and thuspreventing catastrophic failure by allowing timelymaintenance [0]. The presence of wear particles in alubricant can be easily revealed by ferrography andconfirmed by electron microscopy, and theircomposition can be determined by X-ray energyanalysis. On machines where there are manyelements with rolling motion and where vibrationand ultrasound techniques do not allow a reliablediagnosis to early failure (such as in low-speedgear-boxes in cement mills), ferrography plays amost important role.In general, the appearance of large numbers ofspherical particles smaller than 10 mm is associatedwith failures in rolling contact elements. Howeverthe physical process that generates these particles isyet not completely understood and leaves somequestions [2,3]. In a previous work, we have foundan appreciable number of metal microspheres withiron-oxygen and iron-chromium-oxygen elementson ferrograms made on oil samples from gear boxin service. The question arised if these particleswere from the bearing raceway that usually fails. Toanalyze this possibility, we began an experimentalexamination of wear debris from bearings undertotally controlled laboratory conditions. The presentwork concentrates on examining the mechanism offormation and the source of generation of themicrospheres and briefly describes the changes atvarious stages in the wear process.The results from the present study, in aggrementwith other works from the literature, show thatspherical particles appear on ferrograms fromrubbing wear process.