ASTM F2488-05

Standard Terminology for Rolling Element Bearings

SCOPE
1.1 This terminology covers terms and their definitions relevant to the materials and processes associated with rolling element bearings.

General Information

• Status: Historical
• Publication Date: 30-Jun-2005
• ICS: 01.040.21 - Mechanical systems and components for general use (Vocabularies)
• ICS: 21.100.01 - Bearings in general
• Technical Committee: F34 - Rolling Element Bearings
• Drafting Committee: F34.91 - Editorial and Terminology

Relations

• Referred By: ASTM F2489-06(2022) - Standard Guide for Instrument and Precision Bearing Lubricants—Part 2 Greases
• Effective Date: 01-Jul-2005

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: F2488 − 05
StandardTerminology for
1
Rolling Element Bearings
This standard is issued under the fixed designation F2488; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope ball gage deviation (∆S), n—difference between the lot mean
diameter and the sum of the nominal diameter and the ball
1.1 This terminology covers terms and their definitions
gage.
relevant to the materials and processes associated with rolling
element bearings.
ball grade (G), n—specific combination of dimensional form
and surface roughness tolerances.Aball grade is designated
2. Terminology
by a grade number followed by the letter “C” indicating
silicon nitride ceramic.
2.1 Definitions:
absolute viscosity (η), n—(sometimes called dynamic viscos-
boundary lubrication, n—condition of lubrication in which
ity or just viscosity)—a measure of the tendency of the fluid
the friction between two surfaces in relative motion is
to resist shear.
determined by the roughness of the surfaces and by the
properties of the lubricant other than viscosity.
acid number, n—measure of the quality of a lubricant. High
DISCUSSION—Antiwear and extreme pressure additives reduce the
acid numbers (much higher than the fresh oil) are an
wear of components operating under this regime.
indication of lubricant oxidation/degradation.
DISCUSSION—Oils with high acid numbers should not be used. Acid case depth, n—thickness, measured radially from the surface
number is measured as milligrams of KOH needed to neutralize1gof
of the hardened case to a point at which carbon content or
oil.
hardness becomes the same as the ball core.
additive, n—any chemical compound added to a lubricant to
centipoise, n—unit of dynamic viscosity.
improve or meet special needs necessary for service (formu-
DISCUSSION—The unit in the cgs system is 1 centipoise (cP). The SI
3
lated lubricants). The most important additives are
unit of dynamic viscosity is 1 Pa-s and equivalent to 10 cP.
antioxidants, rust, and corrosion inhibitors, and extreme
centistoke, n—unit of kinematic viscosity.
pressure (EP) and antiwear (AW) additives.
DISCUSSION—The unit in the cgs system is 1 centistoke (cSt). The SI
2 6
unit of kinematic viscosity is 1 m /s and is equivalent to 10 cSt.
antioxidants (oxidation inhibitors), n— chemical compounds
used to improve the oxidation stability and subsequent
compatibility, n—measure of the ability of a lubricant to be
deterioration of lubricants.
mixed with other lubricants or bearing preservatives (fluids
that form films on metal surfaces to prevent corrosion during
average life (L ), n—for a radial roller bearing, the number of
50
storage) to form a uniform mixture without causing any
revolutionsthat50 %ofagroupofbearingswillcompleteor
resultant reaction or precipitation of material. Compatibility
exceed before the first evidence of fatigue develops.
isalsoameasureoftheabilityofalubricantnottocauseany
DISCUSSION—The average life maybe as much as five times the rating
detrimental effect to metal, plastic, or elastomer materials.
life.
DISCUSSION—It is recommended that any preservative material be
ball gage (S), n— prescribed small amount by which the lot
removed from bearings before lubrication.
mean diameter should differ from nominal diameter, this
contamination, n—(1) presence of mostly solid foreign mate-
amount being one of an established series of amounts.
rials like sand, grinding powder, dust, and so forth, in a
DISCUSSION—A ball gage, in combination with the ball grade and
lubricant that might cause an increase in wear, torque, and
nominal ball diameter, should be considered as the most exact ball size
specification to be used by a customer for ordering purposes. noise and result in reduced bearing life; and (2) presence of
fluids like water, solvents, and other oils that might cause
accelerated oxidation, washout, rusting, or crystallization of
the additives and other phenomena that reduce a bearing’s
1
This terminology is under the jurisdiction ofASTM Committee F34 on Rolling
life.
Element Bearings and is the direct responsibility of Subcommittee F34.91 on
Editorial and Terminology.
corrosion, n—gradual destruction of a metal surface as a result
Current edition approved July 1, 2005. Published August 2005. DOI: 10.1520/
F2488-05. of chemical attack caused by polar or acidic agents like
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F2488 − 05
humidity (water), compounds formed by lubricant deterio- interfacial tension, n—wh
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