A guide to material selection for rolling bearings

By offering a wide choice of materials and heat treatments for rolling bearings, performance and operating life can be optimised, even for the most demanding industrial applications, says Dr Steve Lacey, Engineering Manager at Schaeffler UK.

In recent years, there has been a significant increase in the demand for rolling bearings that, even under extreme operating conditions – including lubricant starvation, highly corrosive or high temperature environments – still provide a long operating life and optimum performance.

But selecting a suitable material or heat treatment process for rolling bearings often requires expert advice and guidance, normally from the manufacturer of the bearings. Selection depends on the application itself and the specific environment in which the bearings will operate. This means a number of factors require careful consideration, such as the mechanical, chemical and thermal requirements placed on the bearings, as well as lubrication conditions, particularly if the application requires dry running bearings.

There is a key role here for the type of materials used for the various bearing components (i.e. rings, rolling elements, cage, etc.) and how these interact. Some of these materials are industry-recognised standard steels (in rolling bearing quality), but others may need to be specially developed by the manufacturer or might involve special surface or heat treatment processes to give the material a certain set of characteristics that are deemed critical for a certain application.