About Steel Ball Bearings

Inner Ring, Outer Ring, and Ball Bearing Materials

Stainless Steel ball bearings are machined components that include outer ring, inner ring, ball bearings, shielded bearings, snap rings, and more. Stainless Steel ball bearings are used when there is a need for high efficiency, low torque, long bearing life, and a low noise level. Using stainless steel as the material for ball bearings delivers all these advantages. Stainless Steel ball bearings are also used when applications require bearings to provide superior hardness and anti-corrosion or heat-resistance. NMB has a wide variety of ball bearings, so you can be sure you’ll find the exact ball bearing you need with us. Search for ball bearings by metric and inch sizes, flanged or unflanged bearing options, and by open or shielded bearings.

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 for bearings. 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 for our bearings.

"DD400" martensitic stainless steel is a proprietary product of NMB which provides good hardness, long life and good load capacity for steel ball bearings 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.

Ball Bearing Material Composition

High Carbon Chromium Bearings

Spec Symbol Chemical Component (wt%)
C Si Mn P S Cr Mo
JIS G 4805 SUJ 2 0.95~1.10 0.15~0.35 0.50
MAX
0.025
MAX
0.025
MAX
1.30~1.60 -
AISI/SAE E52100 0.98~1.10 0.15~0.35 0.25~0.45 0.025
MAX
0.025
MAX
1.30~1.60 -

Stainless steel

Spec Symbol Chemical Component (wt%)
C Si Mn P S Cr Mo
- DD400 0.60~0.75 1.00
MAX
1.00
MAX
0.03
MAX
0.02
MAX
11.50~13.50 0.30
MAX
JISG4303 SUS440C 0.95~1.2 1.00
MAX
1.00
MAX
0.04
MAX
0.03
MAX
16.00~18.00 *