Stage 1: Discoloration

Metal to metal contact will make the bearing temperature too high, resulting in raceway and roller discoloration. In mild cases, this discoloration is due to lubricant contamination of the bearing surface, while in severe cases, metal discoloration due to high temperature. In all cases, early detection can avoid costly repairs.

Stage 2: Scratches and peeling

Check the bearing for traces of cutting metal or metal spalling – these conditions require immediate attention. Scratches and spalling are easy to occur in high load, low speed applications or at sustained high temperatures, and thin or insufficient lubricating film can accelerate the occurrence of problems.

Stage 3: roller overheating

Lubrication film rupture can lead to direct contact between components and local scratches. In tapered roller bearings, this may appear as scratches on the large end of the roller and the guide rim.

The 4stage: the bearing is completely locked

Extreme local heating will produce metal flow in the bearing, changing the original material and geometry of the bearing. This can lead to excessive tilting of rollers, cage damage and complete bearing lock. If catastrophic damage does occur, it is recommended to consult a bearing specialist to determine the root cause of the problem, as factors other than lubrication may be to blame.

Damage caused by insufficient lubrication varies greatly in appearance and impact on bearing performance. In all cases, the grease quantity, type, grade, viscosity, additives and supply system must be correctly designed for the bearing system. Grease should be selected based on historical experience, load, speed, sealing system, service conditions and life expectancy. If these factors are not properly considered, bearing performance and application effect may be lower than expected.

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