Thin-walled bearing component, produced without material-removing machining

Abstract

A thin-walled stainless bearing component, in particular a rolling bearing component, such as bearing ring, sleeve or bush, produced without material-removing machining by being deep-drawn from a cold-rolled strip with a carbon content of 0.15-0.25% and a chromium alloying content of at least 12%, and having a martensitic microstructure which is enriched with dissolved nitrogen at least at a side edge zone.

1 . A thin-walled stainless bearing component with an edge zone which is produced without material-removing machining by being deep-drawn from a cold-rolled strip, wherein the strip has a carbon content of 0.15-0.25% and a chromium alloying content of at least 12%, and has a martensitic microstructure which is enriched with dissolved nitrogen at least at the edge zone of the component.  
   
   
       2 . The bearing component as claimed in  claim 1 , wherein the nitrogen content at the edge zone is 0.05-1.5%.  
   
   
       3 . The bearing component as claimed in  claim 2 , wherein the nitrogen content at the edge zone is 0.1-0.5%.  
   
   
       4 . The bearing component as claimed in  claim 1 , wherein the nitrogen enriched edge zone is at least 0.05 mm deep.  
   
   
       5 . The bearing component as claimed in  claim 4 , wherein the nitrogen enriched edge zone is at least 0.1 mm deep.  
   
   
       6 . The bearing component as claimed in  claim 4 , wherein the nitrogen enriched edge zone is at least 0.2 mm deep.  
   
   
       7 . The bearing component as claimed in  claim 4 , wherein the edge zone is at most 0.5 mm deep.  
   
   
       8 . The bearing component as claimed in  claim 7 , wherein the edge zone is at most 0.4 mm deep.  
   
   
       9 . The bearing component as claimed in  claim 1 , wherein the cold-rolled strip is nickel-free.  
   
   
       10 . The bearing component as claimed in  claim 1 , wherein the component hardness on the nitrogen-rich component edge zone is at least 58 HRC.  
   
   
       11 . The bearing component as claimed in  claim 1 , wherein the corrosion resistance is at least 96 h in a salt spray test in accordance with ASTM B117.  
   
   
       12 . A process for producing a bearing component with an edge zone the process comprising, 
 providing an austenitic cold-rolled strip with a carbon content of 0.15-0.25% and a chromium alloying content of at least 12%;    initially deep-drawing the component from the strip; then enriching the strip at the edge zone with nitrogen as part of a heat treatment in a nitrogen-rich atmosphere; and    thereafter cooling the component to form a martensitic microstructure in which nitrogen is present in dissolved form.    
   
   
       13 . The process as claimed in  claim 12 , wherein the nitrogen enrichment is carried out at a temperature of 1000-1200° C.  
   
   
       14 . The process as claimed in  claim 13 , wherein a pressure during the nitrogen treatment is 0.1-3 bar.  
   
   
       15 . The process as claimed in  claim 12 , wherein a pressure during the nitrogen treatment is 0.1-3 bar.  
   
   
       16 . The process as claimed in  claim 15 , wherein the cooling is carried out at a cooling rate of ≦50° C./s.  
   
   
       17 . The process as claimed in  claim 12 , wherein the cooling is carried out at a cooling rate of ≦50° C./s.  
   
   
       18 . The process as claimed in  claim 12 , further comprising after the cooling, performing a low-temperature treatment to form further martensite.  
   
   
       19 . The process as claimed in one of  claim 12 , further comprising performing a heat treatment for tempering the microstructure after the cooling.  
   
   
       20 . The process as claimed in  claim 20 , further comprising performing a heat treatment for tempering the microstructure after the low-temperature treatment