Bearing component

Abstract

The present invention provides a bearing component formed from a steel composition comprising: (a) from 0.5-1.2 wt. % carbon, (b) from 0.15-2 wt. % silicon, (c) from 0.25-2 wt. % manganese, (d) from 0.85-3 wt. % chromium, (e) optionally one or more of the following elements from 0-5 wt. % cobalt, from 0-2 wt. % aluminium, from 0-0.6 wt. % molybdenum, from 0-0.5 wt. % nickel, from 0-0.2 wt. % vanadium, from 0-0.1 wt. % sulphur, from 0-0.1 wt. % phosphorous, and (f) the balance iron, together with unavoidable impurities.

1 . A bearing component formed from a steel composition comprising:
 (a) from 0.5-1.2 wt. % carbon,   (b) from 0.15-2 wt. % silicon,   (c) from 0.25-2 wt. % manganese,   (d) from 0.85-3 wt. % chromium,   (e) optionally one or more of the following elements
 from 0-5 wt. % cobalt, 
 from 0-2 wt. % aluminium, 
 from 0-0.6 wt. % molybdenum, 
 from 0-0.5 wt. % nickel, 
 from 0-0.2 wt. % vanadium, 
 from 0-0.1 wt. % sulphur, 
 from 0-0.1 wt. % phosphorous, and 
   (f) the balance iron, together with unavoidable impurities.   
     
     
         2 . A bearing component as claimed in  claim 1 , comprising from 0.7-1.1 wt. % carbon, more preferably from 0.75 to 1.05 wt. % carbon. 
     
     
         3 . A bearing component as claimed in  claim 1 , comprising from 0.25-2 wt. % silicon, more preferably from 0.25-1 wt. % silicon, still more preferably from 0.5-1 wt. % silicon. 
     
     
         4 . A bearing component as claimed in  claim 1 , comprising from 0.25-1.9 wt. % manganese, more preferably from 0.25-1.8 wt. % manganese, still more preferably from 0.25-1.7 wt. % manganese. 
     
     
         5 . A bearing component as claimed in  claim 1 , comprising from 0.95-1.5 wt. % chromium, more preferably from 0.95-1.4 wt. % chromium, still more preferably 0.95-1.3 wt. % chromium. 
     
     
         6 . A bearing component as claimed in  claim 1 , comprising one or both of:
 from 0.1-5 wt. % cobalt, and/or   from 0.1-2 wt. % aluminium.   
     
     
         7 . A bearing component as claimed in  claim 1 , comprising one or both of:
 from 1-4 wt. % cobalt, and/or   from 0.5-2 wt. % aluminium.   
     
     
         8 . A bearing component as claimed in  claim 1 , comprising one or both of:
 from 1.8-4 wt. % cobalt, and/or   from 1-2 wt. % aluminium.   
     
     
         9 . A bearing component as claimed in  claim 1 , comprising one or both of:
 from 2-4 wt. % cobalt, and/or   from 1.2-2 wt. % aluminium.   
     
     
         10 . A bearing component as claimed in  claim 1 , comprising from 0.05-0.5 wt. % molybdenum. 
     
     
         11 . A bearing component as claimed in  claim 1 , comprising from 0.05-0.2 wt. % vanadium. 
     
     
         12 . A bearing component as claimed in  claim 1 , wherein the microstructure of the steel composition comprises bainite as the predominant phase or essentially the only phase. 
     
     
         13 . A bearing component as claimed in  claim 1 , wherein the microstructure of the steel is essentially carbide-free. 
     
     
         14 . A bearing component as claimed in  claim 1 , wherein the microstructure of the steel comprises plates of bainite of less than 100 nm thickness. 
     
     
         15 . A bearing component as claimed in  claim 14 , wherein the plates of bainite are interspersed with austenite. 
     
     
         16 . A bearing component as claimed in  claim 1  which is at least one of a rolling element, an inner ring, and an outer ring. 
     
     
         17 . A bearing comprising a bearing component as claimed in  claim 1 .