Materials

Inner Ring, Outer Ring, and Ball Materials
Ring and Ball materials are subjected to severe stress reversals of approximately 1000 MPa. For applications with so many high pressure compressive stress reversals endured for such prolonged periods, an extremely pure and hard material is required.  Therefore, careful selection of the raw material is necessary. NMB mainly uses high performance carbon chromium steel; or when good corrosion resistance is required, martensitic stainless steel. Our high carbon chromium steel is supplied to the specification JIS G4805/SUJ2, AISI/SAE52100 or equivalent, which is hardened, providing long life and high load capacity.

"DD400" martensitic stainless steel is a proprietary product of NMB which provides good hardness, long life and good load capacity when compared with other equivalents such as SUS440C.  NMB Stainless Steel has better carbide distribution than other equivalents and therefore gives improved noise characteristics similar to high carbon chromium steel. NMB Stainless Steel provides the same corrosion resistance results when tested with SUS440C in accordance with test procedure ASTM-A380.

 


Material Composition
High Carbon Chromium Bearing
Standard Grade Chemical Composition wt%
C Si Mn P S Cr Mo
JISG4805 SUJ2 0.95-
1.10
0.15-
0.35
0.5
MAX
0.025
MAX
0.025
MAX
1.3-
1.6
-
AISI 52100 0.98-
1.10
0.15-
0.35
0.25-
0.45
0.025
MAX
0.025
MAX
1.3-
1.6
-
Stainless Steel
Standard Grade Chemical Compostion wt%
C Si Mn P S Cr Mo
- DD400 0.6-
0.75
1.00
MAX
1.00
MAX
0.03
MAX
0.02
MAX
11.50-
13.50
0.3
MAX
JISG4303 SUS440C 0.95-
1.2
1.00
MAX
1.00
MAX
0.04
MAX
0.03
MAX
16.00-
18.00
*
* It is also possible to add a maximum of 0.75% molybdenum     


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