Modern ball bearings are designed around a long and useful life. Sadly, despite efforts being made in design many bearings fail prematurely. Today's operators can benefit from extended bearing life simply by ensuring that bearings are being properly installed and more importantly properly lubricated.
Below are examples of common modes of bearing failure and how to resolve the underlying issues.
Overheating symptoms often surface as discoloration on the balls, races, and the cages. Color will change from gold to blue and in extreme cases the bearing races will deform. Bearings subjected to temperatures greater than 400F will anneal and ultimately soften the metal leading to premature failure.
Common causes for overheating include poor lubrication, contamination, and improper installation.
Contamination is the leading cause of bearing failure, and surprisingly, it is the simplest to correct. Supplying bearings with a constant supply of fresh grease will prevent a great deal of unwanted symptoms such as excessive wear and overheating each one contributing to shortened bearing life. Beyond frequent lubrication operators can look to clean the environment that the bearing exists. Seek to remove dirt, dust, and debris and store lubricant in clean storage rooms.
Blue/Brown discoloration of balls and their tracks is a tell tale sign that bearings are not receiving a proper amount of lubrication. Failures are usually caused by restricted lubricant flow or excessive heat that degrade lubricant properties.
Brinelling occurs when loads exceed the elastic limit of the ring material. Brinell marks show as indentations in the raceways which ultimately increase bearing vibration. Severe brinell marks can cause premature fatigue failure. Any static overload or severe impact can cause brinelling. One common example would be an operator using a hammer to install/ remove bearings.
Brinelling can be addressed through training your maintenance group on best installation practices.
Red / Brown areas on balls, raceways, cages, or bands of ball bearings are symptoms of corrosion. This condition results from exposing bearings to corrosive fluids or gasses. This usually leads to increased vibration and ultimately premature failure.
This can corrected by removing corrosive fluids away from bearings and implement integrally sealed bearings whenever possible. Of course, one could always use Stainless Steel.