Nationwide Bearing Co Ltd

Bearing Materials

The contact surfaces of bearing rings and the rolling elements are often subjected to repeated heavy stress however, they still must maintain high precision and rotational accuracy. In order to achieve this, the rings and rolling elements have to be constructed of a material that has a high hardness that is also resistant to rolling fatigue as well as being very wear resistant and that is able to hold its dimensional stability.

Standard bearings are made of high carbon chromium bearing steel which can be through hardened and they can be case hardened with a carburized outer layer for the rings and rolling elements within standard bearings. The hardness of the rings and rolling elements is generally between HRC58 and HRC65

Cage materials must have the strength to withstand rotational vibrations and shock loads, they also need a low coefficient of friction, be lightweight and also be able to withstand bearing operating temperatures. For small bearings, cold or hot rolled sheet steel are used for the pressed cages however for some applications brass sheets (Brassed cages are quite often used in spherical roller bearings )or stainless steel are also available. For larger bearings structural carbon steel or high tensible cast brass are more commonly used, occasionally spheroidal graphite cast iron or aluminium alloy cages are also used. On top of this plastic cages are not commonplace and offer the benefits of being light in weight, corrosion resistant and have good sliding properties