ASTM F2661-07(2015)

Standard Test Method for Determining the Tribological Behavior and the Relative Lifetime of a Fluid Lubricant using the Spiral Orbit Tribometer

SIGNIFICANCE AND USE
5.1 Relevance of the Spiral Orbit Tribometer (SOT)—The SOT was designed to evaluate the relative degradation rates of liquid lubricants in a contact environment similar to that in an angular contact bearing operating in the boundary lubrication regime. It functions as a screening device to quickly select the lubricants, evaluate the ability of various components of a lubricant (base oil, thickener, or additive) to lubricate a contact in rolling, pivoting, and sliding conditions simultaneously, and study their chemical decomposition if necessary. The SOT provides a means to study the tribological behavior of oils and greases during operation, while they undergo changes as a function of typical parameters encountered in the lubrication field (temperature, environment, materials used, load applied, and speed). Test conclusion is defined to be when a friction coefficient limit (typically an increase of 0.1 above the steady state value) is surpassed. Normalized lubricant lifetime is then defined as the number of orbits completed divided by the initial amount of lubricant used (in μg). The SOT was initially developed to evaluate lubricants for space applications, but is also relevant for conventional environments. Some results in vacuum are presented (Fig. 1). At this time, no data for tests in ambient conditions have been published (see Fig. 2). The user of this test method should determine to their own satisfaction whether results of this test procedure correlate with field performance or other bench test procedures.  
Bazinet, D.G., Espinosa, M.A., Loewenthal, S.H., Gschwender, L., Jones, W.R., Jr., Predmore, R.E., “Life of Scanner Bearings with Four Space Liquid Lubricants”, Proc. 37th  Aerospace Mech. Symp., Johnson Space Center, May 19-21, 2004
SCOPE
1.1 This test method covers the quantitative determination of the friction coefficient and the lifetime of oils and greases, when tested on a standard specimen under specified conditions of preparation, speed, Hertzian stress, materials, temperature, and atmosphere, by means of the Spiral Orbit Tribometer (SOT). This test method is intended primarily as an evaluation of the lifetimes of fluid lubricants under vacuum and ambient conditions.  
1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Mar-2015
• ICS: 75.100 - Lubricants, industrial oils and related products
• Technical Committee: F34 - Rolling Element Bearings
• Drafting Committee: F34.02 - Tribology

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: F2661 − 07 (Reapproved 2015)
Standard Test Method for
Determining the Tribological Behavior and the Relative
Lifetime of a Fluid Lubricant using the Spiral Orbit
1
Tribometer
This standard is issued under the fixed designation F2661; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method covers the quantitative determination 3.1 Definitions:
of the friction coefficient and the lifetime of oils and greases, 3.1.1 coeffıcient of friction—the dimensionless ratio of the
when tested on a standard specimen under specified conditions friction force between two bodies to the normal force pressing
of preparation, speed, Hertzian stress, materials, temperature, these bodies together.
and atmosphere, by means of the Spiral Orbit Tribometer
3.1.2 fixed plate—stationary, horizontal flat plate, typically
(SOT).This test method is intended primarily as an evaluation
through which a force (the “load”) is applied to the ball.
of the lifetimes of fluid lubricants under vacuum and ambient
3.1.3 friction coeffıcient limit—maximum value that the
conditions.
friction coefficient is permitted to attain.
1.2 This standard may involve hazardous materials,
3.1.4 guide plate—physical element that deflects the ball to
operations, and equipment. This standard does not purport to
its original orbit radius.
address all of the safety concerns, if any, associated with its
3.1.5 lubricant total amount— mass of lubricant deposited
use. It is the responsibility of the user of this standard to
on the entire ball surface at the beginning of the test.
establish appropriate safety and health practices and to
determine the applicability of regulatory limitations prior to 3.1.6 normalized lifetime—number of ball orbits performed
use.
until the friction coefficient limit is reached divided by the
lubricant total amount initially deposited on the ball.
2. Referenced Documents
3.1.7 rotary plate—flat plate rotating at a constant rate
2
2.1 ASTM Standards:
selected for the test.
D1193Specification for Reagent Water
3.1.8 scrub zone—Region of the ball’s orbit in which the
F22Test Method for Hydrophobic Surface Films by the
ball is in contact with the guide plate.
Water-Break Test
3.1.9 spiral orbit—track traced by the ball on the fixed and
F2215Specification for Balls, Bearings, Ferrous and Non-
rotating plates of the Spiral Orbit Tribometer. The track has a
ferrous for Use in Bearings, Valves, and Bearing Appli-
spiral shape.
cations
G115Guide for Measuring and Reporting Friction Coeffi-
4. Summary of Test Method
cients
4.1 Alubricatedballisclampedbetweentwoparallelplates.
2.2 Anti Friction Bearing Manufacturers Association Stan-
3
One of the plates rotates up to 210 rpm, causing the ball to roll
dards
in a near-circular orbit, but is actually an opening spiral. A
ANSI ABMA ISO 3290(AFBMA Standard 10 Balls)
clamping force, the “load”, provides a chosen mean Hertz
stress (typically 1.5 GPa). The system is targeted to operate in
1
This test method is under the jurisdiction ofASTM CommitteeF34 on Rolling
the boundary lubrication regime due to the combination of the
Element Bearings and is the direct responsibility of Subcommittee F34.02 on
Tribology.
high load, the moderate speed, and the small amount of
Current edition approved April 1, 2015. Published July 2015. Originally
lubricant (approximately 50 µg). The ball rolls and pivots in a
approved in 2007. Last previous edition approved in 2007 as F2661–07. DOI:
spiral orbit and is maintained in the orbit by the guide plate.
10.1520/F2661-07R15.
2
The ball slides on the rotating plate when it contacts the guide
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
plate.Themeasuredforceexertedbytheballontheguideplate
Standards volume information, refer to the standard’s Document Summary page on
is used to determine the friction coefficient. The tribometer
the ASTM website.
3 runs until the coefficient of friction rises to values much larger
Available from American Bearing Manufacturers Association (ABMA), 8221
Old Courthouse Road, Suite 207 Vienna, Virginia 22182. than the initial, steady value.At this point the initial charge of
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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F2661 − 07 (2015)
lubricanthasbeendepletedbytribodegradationandthesystem 6.1.1 General description—Fig. 3 shows a schematic draw-
is running virtually unlubricated. The
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F2661 − 07 F2661 − 07 (Reapproved 2015)
Standard Test Method for
Determining the Tribological Behavior and the Relative
Lifetime of a Fluid Lubricant using the Spiral Orbit
1
Tribometer
This standard is issued under the fixed designation F2661; 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
1.1 This test method covers the quantitative determination of the friction coefficient and the lifetime of oils and greases, when
tested on a standard specimen under specified conditions of preparation, speed, Hertzian stress, materials, temperature, and
atmosphere, by means of the Spiral Orbit Tribometer (SOT). This test method is intended primarily as an evaluation of the lifetimes
of fluid lubricants under vacuum and ambient conditions.
1.2 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all
of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate
safety and health practices and to determine the applicability of regulatory limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
D1193 Specification for Reagent Water
F22 Test Method for Hydrophobic Surface Films by the Water-Break Test
F2215 Specification for Balls, Bearings, Ferrous and Nonferrous for Use in Bearings, Valves, and Bearing Applications
G115 Guide for Measuring and Reporting Friction Coefficients
3
2.2 Anti Friction Bearing Manufacturers Association Standards
ANSI ABMA ISO 3290 (AFBMA Standard 10 Balls)
3. Terminology
3.1 Definitions:
3.1.1 coeffıcient of friction—the dimensionless ratio of the friction force between two bodies to the normal force pressing these
bodies together.
3.1.2 fixed plate—stationary, horizontal flat plate, typically through which a force (the “load”) is applied to the ball.
3.1.3 friction coeffıcient limit—maximum value that the friction coefficient is permitted to attain.
3.1.4 guide plate—physical element that deflects the ball to its original orbit radius.
3.1.5 lubricant total amount— mass of lubricant deposited on the entire ball surface at the beginning of the test.
3.1.6 normalized lifetime—number of ball orbits performed until the friction coefficient limit is reached divided by the lubricant
total amount initially deposited on the ball.
3.1.7 rotary plate—flat plate rotating at a constant rate selected for the test.
3.1.8 scrub zone—Region of the ball’s orbit in which the ball is in contact with the guide plate.
3.1.9 spiral orbit—track traced by the ball on the fixed and rotating plates of the Spiral Orbit Tribometer. The track has a spiral
shape.
1
This test method is under the jurisdiction of ASTM CommitteeF34 on Rolling Element Bearings and is the direct responsibility of Subcommittee F34.02 on Tribology.
Current edition approved June 1, 2007April 1, 2015. Published July 2007 July 2015. Originally approved in 2007. Last previous edition approved in 2007 as F2661–07.
DOI: 10.1520/F2661-07.10.1520/F2661-07R15.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
Available from American Bearing Manufacturers Association (ABMA), 8221 Old Courthouse Road, Suite 207 Vienna, Virginia 22182.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
F2661 − 07 (2015)
4. Summary of Test Method
4.1 A lubricated ball is clamped between two parallel plates. One of the plates rotates up to 210 rpm, causing the ball to roll
in a near-circular orbit, but is actually an opening spiral. A clamping force, the “load”, provides a chosen mean Hertz stress
(typically 1.5 GPa). The system is targeted to operate in the boundary lubrication regime due to the combination of the high load,
the moderate speed, and the small amount of lubricant (approximately 50 μg). The ball rolls and pivots in a spiral orbit and is
maintained in the orbit by the guide plate. The ball slides on the rotating plate when it contacts the guide plate. The measured force
exerted by the ball on the guide pla
...