True Brinelling of Ball-Bearing Raceways During Ultrasonic Cleaning

From: R.L. Widner, Failures of Rolling-Element Bearings, Failure Analysis and Prevention, Vol 11, ASM Handbook, ASM International, 1986, p 490–513

Abstract: Randomly selected dictating-machine drive mechanisms, which contained small ball bearings, were found to exhibit unacceptable fluctuations in drive output during the early stages of production. It was indicated that the bearing raceways were being true brinelled before or during installation of the bearings. The preinstallation practices and the procedures for installing the bearings were carefully studied. It was revealed that during one preinstallation step, the lubricant applied by the bearing manufacturer was removed and the bearing was relubricated with another type of lubricant prior to which the bearings were ultrasonically cleaned in trichlorethylene to ensure extreme cleanness. Equally spaced indentations resembling true brinelling were revealed by careful examination of the bearing raceways. It was concluded that the ultrasonic energy transmitted to the balls brinelled the raceways enough to cause fluctuations in machine output. Solvent-vapor cleaning was employed as a corrective technique for removing bearing lubricant.

Keywords: Lubricants; Solvents; Vapor degreasing

Material: Bearing steel (Alloy steel, general)

Failure types: Fretting wear; Surface treatment related failures


During the early stages of production, randomly selected dictating-machine drive mechanisms, which contained small ball bearings, were found to exhibit unacceptable fluctuations in drive output. This seemed to indicate that the bearing raceways were being true brinelled before or during installation of the bearings.
Investigation. The preinstallation practices and the procedures for installing the bearings were carefully studied to determine the cause of failure. New control practices were instigated with no net gain in bearing performance.
One preinstallation procedure involved removing the bearing lubricant applied by the bearing manufacturer and relubricating the bearings with another type of lubricant. The bearings were ultrasonically cleaned in trichlorethylene to ensure extreme cleanness. Careful examination of the bearing raceways at a moderate magnification revealed equally spaced indentations resembling true brinelling. Further examination showed that the ultrasonic cleaning technique was improper in that the ultrasonic energy transmitted to the balls brinelled the raceways enough to cause fluctuations in machine output.
Conclusion. The bearing raceways were true brinelled during ultrasonic cleaning.
Corrective Measures. The lubricant was removed from the bearings by solvent-vapor cleaning instead of by ultrasonic cleaning.

Related Information

Fretting Wear Failures, Failure Analysis and Prevention, Vol 11, ASM Handbook, ASM International, 2002, p 922–940