|
MATERIALS
There
are essentially two choices for the material used in a ball bearing
- chrome steel or stainless steel. Since the material plays a major
part in the performance of a bearing in any given application, it is
very important that the correct material is used. Note that the
specified material applies to the load bearing components only - the
rings and the balls. The retainer and the shields (if used) are
usually made from a different material and are subject to separate
specification
|
| CHROME STEEL
(AISI 52100 OR EQUIVALENT) |
This is the standard material
used for ball bearing applications where load capacity is the main
consideration. The machinability of this steel is excellent, giving
smooth, low noise raceway finishes, together with superior life.
Chrome steel material is recommended in applications where corrosion
is not a factor.
CHEMICAL COMPOSITION (%):
C
CARBON |
Si
SILICON |
Mn
MANGANESE |
P
PHOSPHOROUS |
S
SULPHUR |
Cr
CHROMIUM |
Mo
MOLYBDENUM |
.95 -
1.1 |
.15 - .35 |
Max .5 |
Max .025 |
Max .025 |
1.3 - 1.6 |
- |
Hardness: 60 - 64 Rockwell
'C'
|
| STAINLESS
STEEL |
| 400 series martensitic stainless steel is
the standard material for miniature and instrument ball bearings
where corrosion resistance is more important than load capacity.
There are 3 types of 400 series stainless steel used in the bearings
described in this handbook. These materials have evolved in response
to different manufacturing and application needs. It is important to
note that the actual material used is generally determined by the
manufacturer, and cannot be specified by the user. |
| DR Stainless
steel
This material is used in the manufacture of
most corrosion-resistant bearings. It has been specifically
developed to give excellent lifetime and low noise characteristics,
combined with superior corrosion-resistance.
CHEMICAL COMPOSITION
(%):
C
CARBON |
Si
SILICON |
Mn
MANGANESE |
P
PHOSPHOROUS |
S
SULPHUR |
Cr
CHROMIUM |
Mo
MOLYBDENUM |
.6 - .7 |
Max 1.0 |
Max 1.0 |
Max .03 |
Max .01 |
12 - 13.5 |
Max
.25 |
Hardness: 58
- 60 Rockwell 'C'
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