Standard Test Method for Fretting Wear Protection by Lubricating Greases

SIGNIFICANCE AND USE
This test method is used to evaluate the property of lubricating greases to protect oscillating bearings from fretting wear. This method, used for specification purposes, differentiates among greases allowing low, medium, and high amounts of fretting wear under the prescribed test conditions. The test has been used to predict the fretting performance of greases in wheel bearings of passenger cars shipped long distances.5 Test results do not necessarily correlate with results from other types of service. It is the responsibility of the user to determine whether test results correlate with other types of service.
SCOPE
1.1 This test method evaluates the fretting wear protection provided by lubricating greases.
1.2 The values stated in SI units are to be regarded as the standard. Other units 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. For specific hazard statements, See 7.2, 7.3, 7.3.1, and 9.2.

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Publication Date
09-Nov-2002
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ASTM D4170-97(2002)e1 - Standard Test Method for Fretting Wear Protection by Lubricating Greases
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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.
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Designation:D4170–97 (Reapproved 2002)
Standard Test Method for
Fretting Wear Protection by Lubricating Greases
This standard is issued under the fixed designation D4170; 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.
´ NOTE—Warning statements were moved from notes into text editorially in March 2003.
1. Scope wear debris is abrasive iron oxide (Fe O ) having the appear-
2 3
ance of rust, which gives rise to the nearly synonymous terms,
1.1 This test method evaluates the fretting wear protection
fretting corrosion and friction oxidation. A related, but some-
provided by lubricating greases.
what different phenomenon often accompanies fretting wear.
1.2 The values stated in SI units are to be regarded as the
False brinelling is localized fretting wear that occurs when the
standard. Other units are for information only.
rolling elements of a bearing vibrate or oscillate with small
1.3 This standard does not purport to address all of the
amplitude while pressed against the bearing race. The mecha-
safety concerns, if any, associated with its use. It is the
nism proceeds in stages: (1) asperities weld, are torn apart, and
responsibility of the user of this standard to establish appro-
form wear debris that is subsequently oxidized; (2) due to the
priate safety and health practices and determine the applica-
small-amplitude motion, the oxidized detritus cannot readily
bility of regulatory limitations prior to use. For specific hazard
escape, and being abrasive, the oxidized wear debris acceler-
statements, See 7.2, 7.3, 7.3.1, and 9.2.
ates the wear. As a result, wear depressions are formed in the
2. Referenced Documents
bearing race. These depressions appear similar to the Brinell
depressions obtained with static overloading. Although false
2.1 ASTM Standards:
brinelling can occur in this test, it is not characterized as such,
Test Methods for Rating Motor, Diesel, andAviation Fuels;
and instead, it is included in the determination of fretting wear.
Motor Fuels (Section I), Reference Materials and Blending
Accessories (Annex 2), Reference Fuels (A2.7.3.3), and
4. Summary of Test Method
Table 32 (Specification for n-Heptane Motor Fuel)
4.1 The tester is operated with two ball thrust bearings,
2.2 Military Standard:
lubricatedwiththetestgrease,oscillatedthroughanarcof0.21
MIL-S-22473D Sealing, Locking and Retaining Com-
rad (12°), at a frequency of 30.0 Hz (1800 cpm), under a load
pounds, Single-Component
of 2450 N (550 lbf), for 22 h at room temperature (Note 1).
3. Terminology
Fretting wear is determined by measuring the mass loss of the
bearing races.
3.1 Definitions:
3.1.1 fretting wear, n—a form of attritive wear caused by
NOTE 1—Arc, frequency, and load are factory-set operating conditions
vibratory or oscillatory motion of limited amplitude character-
and should not be altered. The load spring constant may change over an
ized by the removal of finely-divided particles from the extended time period. Spring calibration should be checked periodically
and, if necessary, a suitable shim should be fabricated to obtain the
rubbing surfaces.
required load (63 %) at the assembled length of the spring.
3.1.1.1 Discussion—Air can cause immediate local oxida-
tion of the wear particles produced by fretting wear. In
5. Significance and Use
addition, environmental moisture or humidity can hydrate the
5.1 This test method is used to evaluate the property of
oxidation product. In the case of ferrous metals, the oxidized
lubricating greases to protect oscillating bearings from fretting
wear. This method, used for specification purposes, differenti-
This test method is under the jurisdiction of ASTM Committee D02 on
ates among greases allowing low, medium, and high amounts
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
of fretting wear under the prescribed test conditions. The test
D02.G0 on Lubricating Grease.
has been used to predict the fretting performance of greases in
Current edition approved Nov. 10, 2002. Published March 2003. Originally
wheel bearings of passenger cars shipped long distances. Test
approved in 1982. Last previous edition approved in 1997 as D4170–97. DOI:
10.1520/D4170-97R02E01.
Annual Book of ASTM Standards, Vol 05.04.
3 5
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Verdura, T. M., “Development of a Standard Test to Evaluate Fretting
Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098. Protection Quality of Lubricating Grease,” NLGI Spokesman, Volume XLVII,
NLGI Lubricating Grease Guide, 3rd edition. Number 5, August, 1983, pp. 157–67.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D4170–97 (2002)
FIG. 1 Fafnir Friction Oxidation Tester and Time Switch
results do not necessarily correlate with results from other
types of service. It is the responsibility of the user to determine
whether test results correlate with other types of service.
6. Apparatus
,
6 7
6.1 Falex Fretting Wear Tester, Model F-1581, as pur-
chased and illustrated in Figs. 1 and 2.
6.2 Spring Guide, conforming to description in Fig. 3,ifnot
supplied with tester.
,
8 7
6.3 Test Bearings, of the ball thrust type having an inside
diameter of 16.00 6 0.025 mm (0.630 6 0.001 in.), an outside
diameter of 35.69 6 0.025 mm (1.405 + 0.001 in.), and
assembled height of 15.75 6 0.25 mm (0.620 6 0.010 in.) and
equipped with nine 7.142-mm (0.2812-in.) diameter balls in a
pressed steel retainer; all surfaces (except retainer) to be
ground. Different surface finishes are provided on commercial
bearings. Bearings with ground surfaces are lustrous; tumbled
bearings appear slightly dulled or grayish. Bearings with
ground races, as specified in 6.3 are required to obtain correct
results. Tumbled bearings with reground races are satisfactory.
Magnification should be used to inspect the races to verify that
they have been ground. Part-number bearings are provided
with ground races. A drawing of the test bearing, giving
complete,detaileddimensionsandspecificationsisavailablein
9 FIG. 2 Chuck and Housing Assembly
D02-1159.
8,10
6.4 Vibration Mount, upon which the tester is placed.
6.5 Time Switch, (optional) shown in Fig. 1 and described in
detail in Fig. 4, or a commercial equivalent.
,
7 11
6.6 Ultrasonic Cleaner.
Falex Fretting Wear Tester, formerly known as the Fafnir Friction Oxidation
Tester, is available from Falex Corp., 1020 Airpark Dr., Sugar Grove, IL 60554.
6.7 Analytical Balance having a capacity of about 100 g
The sole source of supply of the apparatus known to the committee at this time
and with a minimum sensitivity of 0.1 mg.
is listed. If you are aware of alternative suppliers, please provide this information to
ASTMHeadquarters.Yourcommentswillreceivecarefulconsiderationatameeting
1 7. Reagents and Materials
of the responsible technical committee, which you may attend.
Andrews (Part No. 06X65) have been found to be satisfactory. Prepared
7.1 Purity of Reagents—Reagent grade chemicals shall be
bearings (part number F-1581-50 (formerly FL-1081)), that is, with set screw flat
used in all tests. Unless otherwise indicated, it is intended that
(see 8.1), are available from Falex Corp., 1020Airpark Dr., Sugar Grove, IL60554.
Supporting data (the results of the cooperative test program, from which these
values have been derived) have been filed atASTM International Headquarters and
may be obtained by requesting Research Report D02-1159. A Bransonic 2200 cleaner (Branson Ultrasonics Co., Danbury, CT 06813)
Isomode Vibration control Pad No. 3451801 has been found satisfactory and having a capacity of about 3 L ( ⁄4 gal) operating at a frequency of about 55 kHz,
is available from rubber products suppliers. with a power input of about 125 W, has been found satisfactory.
´1
D4170–97 (2002)
8.2 Scribesuitableidentificationmarksontheouterlandsof
bearing races to distinguish races of upper bearing from races
of lower bearing. Identification marks should not be scribed on
back or periphery of the bearing race.
8.3 Fill tank of ultrasonic cleaner with distilled water to a
depth of 30 to 40 mm. Place two bearing sets in a 250-mL
beaker containing about 125-mL of n-heptane. Cover beaker
and place in ultrasonic bath. After cleaning for 10 to 15 min,
transfer bearing parts to second beaker containing 125 mL of
n-heptane (see 7.2). Clean for 8 to 10 min, then repeat
operation for two additional 4 to 5-min washes, using new
n-heptane and clean beakers each time.
8.4 Place bearing parts onto freshly cleaned, glass Petri
FIG. 3 Spring Guide
dishes or aluminum moisture dishes to air dry. Bearings should
be propped against rim of dish to permit air circulation. Clean
all reagents shall conform to the specifications of the Commit-
bearings must not be rotated or air blown. Do not place
tee on Analytical Reagents of the American Chemical Society
bearings on any surface other than freshly cleaned glass or
where such specifications are available. Other grades may be
metal. Do not touch bearings with bare hands; use forceps or
used, provided it is first ascertained that the reagent is of
tongs, or wear surgeon gloves or finger cots.
sufficiently high purity to permit its use without lessening the
8.5 When bearings are dry, place dishes containing bearings
accuracy of the determination.
in a desiccator and let stand for a minimum of 30 min.
7.2 n-Heptane,reagentgradeorASTMMotorFuelGrade3.
8.6 Weigh the upper and lower bearing race pairs separately
(Warning—Flammable. Health hazard.)
to the nearest 0.1 mg. (Each race pair consists of two races.)
7.3 1,1,1-Trichloroethane, reagent grade. (Warning—
9. Procedure
Health hazard.)
7.3.1 A functionally equivalent solvent, may be substituted 9.1 In a dust-free environment, install the test grease in
unused, cleaned, weighed bearings.
throughout this test method wherever 1,1,1-trichloroethane is
9.1.1 Fill the ball tracks of the bearing races with the test
specified. To be functionally equivalent, the solvent must not
grease. Use a suitable spatula to strike the grease level with the
affect test results, clean as effectively as 1.1.1-trichloroethane,
bearing lands. Bearing backs and bearing seats must be kept
have similar volatility characteristics, leave no residue on
evaporation, and contain no water or additives. (Warning—If free of grease and particulate matter. Clean with a lint–free
cloth slightly moistened w
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