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 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.
Developed by NMB's parent company, MKJ3 is a high carbon chromium bearing
steel combined with a special heat treating process. This steel has a higher
hardness and a more stable structure than standard chrome bearing steel.
This allows the steel to retain its shape under adverse conditions. It
is for use in hard disk drives and other specialty applications where the
running accuracy performance was crucial. This material will have higher
shock load resistance, higher load carrying capacity, and will resist increased
noise levels with extended use.
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