The durability represents the main criterion, which imposes itself in the definition of the reliability and of the competition of the bearings. The rotation precision and the functional role of the bearings are realized if it is a good dimensional stability and proper mechanical properties during the running. To fulfill these conditions it is necessary to establish the technological parameters of the processes of primary heat treatment, hot or cold plastic deformation, intermediate heat treatment, mechanical processing, final heat treatment and heat treatment below 0oC or in ultrasonic field. The comparative evaluation of different variants of heat treatment – classic or non-conventional (cryogenic or ultrasonic) which are applied on bearing steels from the point of view of durability have revealed significant increases of the values of real and median du-rability for non-conventional heat treated steels.
