Bearing manufacturing technology of today enables relatively small sized bearings to have high duty ratings. Such bearings are highly stressed and more vulnerable to onset of rolling contact fatigue. Since contact fatigue is initiated at hard non-metallic inclusions, modern day bearings call for exceptional levels of cleanliness. Onset of rolling contact fatigue occurs in a statistical mode that depends on the probability of finding a hard phase of adequate size in the zone of maximum Hertzian stress. Therefore, an objective prediction of bearing life is possible only by counting the number of inclusions present per unit volume of steel with the help of ultrasound based assessment and not by the conventional chart based method.

Considerable work has been done to respond to the emerging needs of the bearing industry. The steel plant has been successfully producing both through hardening and case hardening steels satisfying the requirements of some of the leading bearing manufacturers. The present paper discusses the manufacturing process for bearing steel through Basic Oxygen Furnace-Vacuum Arc Degassing route. This paper also brings out the strategy to control oxygen and titanium. Test results obtained from some leading customers and collaborators are presented.