ASTM F2488-05(2022)

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.  
1.2 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Dec-2021
• 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

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F2488 − 05 (Reapproved 2022)
Standard Terminology 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 (S), n— prescribed small amount by which the lot
mean diameter should differ from nominal diameter, this
1.1 This terminology covers terms and their definitions
amount being one of an established series of amounts.
relevant to the materials and processes associated with rolling
DISCUSSION—A ball gage, in combination with the ball grade and
element bearings.
nominal ball diameter, should be considered as the most exact ball size
1.2 This international standard was developed in accor-
specification to be used by a customer for ordering purposes.
dance with internationally recognized principles on standard-
ball gage deviation (∆S), n—difference between the lot mean
ization established in the Decision on Principles for the
diameter and the sum of the nominal diameter and the ball
Development of International Standards, Guides and Recom-
gage.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
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
ityorjust viscosity)—ameasureofthetendencyofthefluid
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
lated lubricants). The most important additives are
3
unit of dynamic viscosity is 1 Pa-s and equivalent to 10 cP.
antioxidants, rust, and corrosion inhibitors, and extreme
pressure (EP) and antiwear (AW) additives.
centistoke, n—unit of kinematic viscosity.
DISCUSSION—The unit in the cgs system is 1 centistoke (cSt). The SI
antioxidants (oxidation inhibitors), n— chemical compounds
2 6
unit of kinematic viscosity is 1 m /s and is equivalent to 10 cSt.
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
average life (L ), n—for a radial roller bearing, the number of
50
that form films on metal surfaces to prevent corrosion during
revolutionsthat50 %ofagroupofbearingswillcompleteor
storage) to form a uniform mixture without causing any
exceed before the first evidence of fatigue develops.
resultant reaction or precipitation of material. Compatibility
DISCUSSION—The average life maybe as much as five times the rating
isalsoameasureoftheabilityofalubricantnottocauseany
life.
detrimental effect to metal, plastic, or elastomer materials.
DISCUSSION—It is recommended that any preservative material be
removed from bearings before lubrication.
1
This terminology is under the jurisdiction ofASTM Committee F34 on Rolling
Element Bearings and is the direct responsibility of Subcommittee F34.91 on
contamination, n—(1) presence of mostly solid foreign mate-
Editorial and Terminology.
rials like sand, grinding powder, dust, and so forth, in a
Current edition approved Jan. 1, 2022. Published January 2022. Originally
lubricant that might cause an increase in wear, torque, and
approved in 2005. Last previous edition approved in 2013 as F2488 – 05(2013).
DOI: 10.1520/F2488-05R22. noise and result in reduced bearing life; and (2) p
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