ASTM D3702-94(2014)
(Test Method)Standard Test Method for Wear Rate and Coefficient of Friction of Materials in Self-Lubricated Rubbing Contact Using a Thrust Washer Testing Machine
Standard Test Method for Wear Rate and Coefficient of Friction of Materials in Self-Lubricated Rubbing Contact Using a Thrust Washer Testing Machine
SIGNIFICANCE AND USE
4.1 This test method is used to determine the equilibrium rate of wear and coefficient of friction of materials in rubbing contact under useful operating conditions, that is, combinations of pressure and velocity that fall below the PV (pressure × velocity) limit of the test material. The user of this test method should determine to his own satisfaction whether the results of this test procedure correlate with field performance or other bench test machines. If the test conditions are changed, the wear rates may change and the relative value of one material with respect to another may also change.
4.2 Test conditions may be selected from Table 1.
4.3 The precision of wear measurement is relatively independent of test duration or amount of wear, but the precision of wear rate (calculation) improves with test duration and amount of wear. It is generally believed that useful wear rate precision requires the selection of a test duration sufficient to produce 0.1 mm (0.004 in.) of wear. Test durations will often be in the 50 to 4000-h range.
SCOPE
1.1 This test method covers the determination of wear rate and coefficient of friction for self-lubricated materials in rubbing contact by a testing machine2 that utilizes a thrust washer specimen configuration.
Note 1: This machine may also be used to measure coefficient of friction.
1.2 The values in SI units are to be regarded as the standard. In cases where materials, products, or equipment are available only in inch-pound units, SI values in parentheses are for information only.
1.3 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 determine the applicability of regulatory limitations prior to use.
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Designation: D3702 − 94 (Reapproved 2014)
Standard Test Method for
Wear Rate and Coefficient of Friction of Materials in Self-
Lubricated Rubbing Contact Using a Thrust Washer Testing
1
Machine
This standard is issued under the fixed designation D3702; 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 2.1.3 wear rate—the rate of material removal or dimen-
sional change due to wear per unit of exposure parameter; for
1.1 This test method covers the determination of wear rate
example, quantity of material removed (mass, volume, thick-
and coefficient of friction for self-lubricated materials in
2 ness) in unit distance of sliding or unit time.
rubbing contact by a testing machine that utilizes a thrust
washer specimen configuration. 2.2 Definitions of Terms Specific to This Standard:
2.2.1 torque—reaction of a tendency to turn due to friction
NOTE 1—This machine may also be used to measure coefficient of
forces between specimens traveling in a circular path. It is the
friction.
product of a restraining force and the radius at which it acts to
1.2 ThevaluesinSIunitsaretoberegardedasthestandard.
balance the frictional torque.
In cases where materials, products, or equipment are available
only in inch-pound units, SI values in parentheses are for
3. Summary of Test Method
information only.
3.1 The test machine is operated with a test specimen
1.3 This standard does not purport to address all of the
rotating under load against a stationary steel washer. Each test
safety concerns, if any, associated with its use. It is the
consists of break-in for 40 h followed by a selected test
responsibility of the user of this standard to establish appro-
duration, each at the same selected normal load and speed.
priate safety and health practices and determine the applica-
Load is obtained by application of dead weights to the 10:1
2 2
bility of regulatory limitations prior to use.
lever arm. The contact area is 1.29 cm (0.20 in. ). The mean
rubbing velocity is related to spindle rotational speed:
2. Terminology
1rpm=0.0848m⁄min (0.278ft⁄min).
2.1 Definitions:
3.2 The thickness change of the test specimen and torque
2.1.1 coeffıcient of friction, µ or f—in tribology—thedimen-
during test are measured for each test.
sionlessratioofthefrictionforce(F)betweentwobodiestothe
3.3 Wear rate in centimetres per hour (inches per hour) and
normal force (N) pressing these bodies together.
coefficient of friction is reported.
µ or f 5 F/N (1)
~ !
4. Significance and Use
2.1.1.1 Discussion—A distinction is often made between
static coefficient of friction and kinetic coefficient of friction.
4.1 This test method is used to determine the equilibrium
rate of wear and coefficient of friction of materials in rubbing
2.1.2 wear—damage to a solid surface, generally involving
contactunderusefuloperatingconditions,thatis,combinations
progressive loss of material, due to relative motion between
of pressure and velocity that fall below the PV (pres-
that surface and a contacting substance or substances.
sure×velocity) limit of the test material. The user of this test
method should determine to his own satisfaction whether the
1
resultsofthistestprocedurecorrelatewithfieldperformanceor
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
other bench test machines. If the test conditions are changed,
Subcommittee D02.L0.05 on Solid Lubricants.
the wear rates may change and the relative value of one
CurrenteditionapprovedMay1,2014.PublishedJuly2014.Originallyapproved
material with respect to another may also change.
in 1978. Last previous edition approved in 2009 as D3702–94(2009). DOI:
10.1520/D3702-94R14.
4.2 Test conditions may be selected from Table 1.
2
An example known to the committee at this time is the Falex Multispecimen
Test Machine, available from Falex Corp., 1020 Airpark Drive, Sugar Grove, IL
4.3 The precision of wear measurement is relatively inde-
60554. This manufacturer recommends a maximum test load of 808 lb (367 kg). If
pendentoftestdurationoramountofwear,buttheprecisionof
you are aware of alternative suppliers, please provide this information to ASTM
wear rate (calculation) improves with test duration and amount
International Headquarters. Your comments will receive careful consideration at a
1
meeting of the responsible technical committee, which you may attend. of wear. It is generally believed that useful wear rate precision
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428
...
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: D3702 − 94 (Reapproved 2009) D3702 − 94 (Reapproved 2014)
Standard Test Method for
Wear Rate and Coefficient of Friction of Materials in Self-
Lubricated Rubbing Contact Using a Thrust Washer Testing
1
Machine
This standard is issued under the fixed designation D3702; 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 determination of wear rate and coefficient of friction for self-lubricated materials in rubbing
2
contact by a testing machine that utilizes a thrust washer specimen configuration.
NOTE 1—This machine may also be used to measure coefficient of friction.
1.2 The values in SI units are to be regarded as the standard. In cases where materials, products, or equipment are available only
in inch-pound units, SI values in parentheses are for information only.
1.3 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 determine the applicability of regulatory
limitations prior to use.
2. Terminology
2.1 Definitions:
2.1.1 coeffıcient of friction, μ or f—in tribology—the dimensionless ratio of the friction force (F) between two bodies to the
normal force (N) pressing these bodies together.
μ or f 5 F/N (1)
~ !
1
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.L0.05 on Solid Lubricants.
Current edition approved Oct. 1, 2009May 1, 2014. Published November 2009July 2014. Originally approved in 1978. Last previous edition approved in 20042009 as
D3702–94(2004).D3702 –94 (2009). DOI: 10.1520/D3702-94R09.10.1520/D3702-94R14.
2
An example known to the committee at this time is the Falex Multispecimen Test Machine, available from Falex Corp., 1020 Airpark Drive, Sugar Grove, IL 60554.
This manufacturer recommends a maximum test load of 808 lb (367 kg). If you are aware of alternative suppliers, please provide this information to ASTM International
1
Headquarters. Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend.
2.1.1.1 Discussion—
A distinction is often made between static coefficient of friction and kinetic coefficient of friction.
2.1.2 wear—damage to a solid surface, generally involving progressive loss of material, due to relative motion between that
surface and a contacting substance or substances.
2.1.3 wear rate—the rate of material removal or dimensional change due to wear per unit of exposure parameter; for example,
quantity of material removed (mass, volume, thickness) in unit distance of sliding or unit time.
2.2 Definitions of Terms Specific to This Standard:
2.2.1 torque—reaction of a tendency to turn due to friction forces between specimens traveling in a circular path. It is the
product of a restraining force and the radius at which it acts to balance the frictional torque.
3. Summary of Test Method
3.1 The test machine is operated with a test specimen rotating under load against a stationary steel washer. Each test consists
of break-in for 40 h followed by a selected test duration, each at the same selected normal load and speed. Load is obtained by
2 2
application of dead weights to the 10:1 lever arm. The contact area is 1.29 cm (0.20 in. ). The mean rubbing velocity is related
to spindle rotational speed: 11 rpm = 0.0848 m rpm = 0.0848 ⁄min (0.278 ft m/min (0.278 ft/min).⁄min).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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D3702 − 94 (2014)
3.2 The thickness change of the test specimen and torque during test are measured for each test.
3.3 Wear rate in centimetres per hour (inches per hour) and coefficient of friction is reported.
4. Significance and Use
4.1 This test method is used to determine the equilibrium rate of wear and coefficient of friction of materials in rubbing contact
under useful operating conditions, that is, combinations of pressure and velocity that fall below the PV (pressure × velocity) limit
of the test material. The user of this test method should determin
...
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