ASTM D4693-97(2002)e1
(Test Method)Standard Test Method for Low-Temperature Torque of Grease-Lubricated Wheel Bearings
Standard Test Method for Low-Temperature Torque of Grease-Lubricated Wheel Bearings
SCOPE
1.1 This test method determines the extent to which a test grease retards the rotation of a specially-manufactured, spring-loaded, automotive-type wheel bearing assembly when subjected to low temperatures. Torque values, calculated from restraining-force determinations, are a measure of the viscous resistance of the grease. This test method was developed with greases giving torques of less than 35 N·m at 40°C.
1.2 The values stated in SI units are to be regarded as the standard. The 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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An American National Standard
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Designation: D 4693 – 97 (Reapproved 2002)
Standard Test Method for
Low-Temperature Torque of Grease-Lubricated Wheel
Bearings
This standard is issued under the fixed designation D 4693; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Warning information was moved editorially from notes to section text in September 2002.
1. Scope (EMF) Tables for Standardized Thermocouples
E 563 Practice for Preparation and Use of Freezing Point
1.1 This test method determines the extent to which a test
Reference Baths
grease retards the rotation of a specially-manufactured, spring-
E 585/E 585M Specification for Compacted Mineral-
loaded, automotive-type wheel bearing assembly when sub-
Insulated, Metal-Sheathed, Base-Metal Thermocouple
jected to low temperatures. Torque values, calculated from
Cable
restraining-force determinations, are a measure of the viscous
E 608 Specification for Metal-Sheathed Base-Metal Ther-
resistance of the grease. This test method was developed with
mocouples
greases giving torques of less than 35 N·m at −40°C.
2.2 Military Standard:
1.2 The values stated in SI units are to be regarded as the
MIL-G-10924F Specification for Automotive and Artillery
standard. The values in parentheses are for information only.
2.3 Other Standard:
1.3 This standard does not purport to address all of the
Anti-Friction Bearing Manufacturer Assoc. (AFBMA) Stan-
safety concerns, if any, associated with its use. It is the
dard 19, 1974 (ANSI B. 3.19-1975)
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
3. Terminology
bility of regulatory limitations prior to use.
3.1 Definitions:
2. Referenced Documents 3.1.1 automotive wheel bearing grease, n—a lubricating
grease specifically formulated to lubricate automotive wheel
2.1 ASTM Standards:
bearings at relatively high grease temperatures and bearing
D 217 Test Methods for Cone Penetration of Lubricating
speeds.
Grease
D 3527
D 1403 Test Method for Cone Penetration of Lubricating
3.1.2 lubricant, n—any material interposed between two
Grease Using One-Quarter and One-Half Scale Cone
surfaces that reduces the friction or wear between them.
Equipment
D 4175
D 3527 Test Method for Life Performance of Automotive
3.1.3 lubricating grease, n—a semi-fluid to solid product of
Wheel Bearing Grease
a dispersion of a thickener in a liquid lubricant.
D 4175 Terminology Relating to Petroleum, Petroleum
3.1.3.1 Discussion—The dispersion of the thickener forms a
Products, and Lubricants
4 two-phase system and immobilizes the liquid lubricant by
E 1 Specification for ASTM Thermometers
surface tension and other physical forces. Other ingredients are
E 77 Test Method for Inspection and Verification of Ther-
4 commonly included to impact special properties. D 217
mometers
3.1.4 thickener, n—in lubricating grease, a substance com-
E 220 Test Method for Calibration of Thermocouples by
posed of finely-divided, particles dispersed in a liquid lubricant
Comparison Techniques
to form the product’s structure.
E 230 Specification and Temperature-Electromotive Force
3.1.4.1 Discussion—The solid thickener can be fibers (such
as various metallic soaps) or plates or spheres (such as certain
non-soap thickeners) which are insoluble or, at the most, only
This test method is under the jurisdiction of Committee D02 on Petroleum
very slightly soluble in the liquid lubricant. The general
Products and Lubricants and is the direct responsibility of Subcommittee D02.G0 on
Lubricating Grease.
requirements are that the solid partices be extremely small,
Current edition approved June 10, 1997. Published October 1997. Originally
published as D 4693–87. Last previous edition D 4693–95.
Annual Book of ASTM Standards, Vol 05.01.
3 5
Annual Book of ASTM Standards, Vol 05.02. Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Annual Book of ASTM Standards, Vol 14.03. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D 4693 – 97 (2002)
FIG. 1 Low-Temperature Torque Apparatus
which drive a specially-manufactured spindle-bearings-hub assembly
uniformly dispered, and capable of forming a relatively stable,
equipped with a spring-loading mechanism. For apparatus contained
gel-like structure with the liquid lubricant. D 217
totally within the cold chamber, the drive system should be prepared by
replacing the grease in the motor bearings with a suitable low-temperature
4. Summary of Test Method
grease (<1 N·m torque at −40°C), such as one meeting the requirements of
4.1 A freshly stirred and worked sample of test grease is
Specification MIL-G-10924F or similar, and the lubricant in the gear
packed into the bearings of a specially-manufactured,
reducer should be replaced with a suitable low-temperature (< −50°C pour
automotive-type spindle-bearings-hub assembly. The assembly point) worm-gear lubricant. In addition, if not already so-equipped,
large-diameter (152 mm), narrow-width (13 mm) timing pulleys and a
is heated and then cold soaked at −40°C, unless another test
suitable timing belt should be used.
temperature is specified by the grease specification. The
spindle is rotated at 1 rpm and the torque required to prevent
6.2 Torque Measuring System, consisting of a strain-gage
rotation of the hub is measured at 60 s. load cell with a matching bridge-balance unit, a suitable
strip-chart recorder to record the load-cell output, and a series
5. Significance and Use
of weights (up to 20 kg, at least) suitable for load-cell
5.1 This test method differentiates among greases having
calibration.
distinctly different low-temperature characteristics. This test is
NOTE 2—In order to calculate torque from force measurements, the
used for specification purposes and correlates with its precursor
load cell should be located a known distance from the test-unit centerline;
which has been used to predict the performance of greases in
100 mm is convenient. A convenient way to do this is to centrally drill a
automotive wheel bearings in low-temperature service. It is
1.78-mm diameter hole (No. 50 drill) in the torque arm, 100 mm from the
the responsibility of the user to determine the correlation with spindle centerline; temporarily replace the load cell contact with a second
contact having a 1.59-mm diameter pin (soldered in place) extending
other types of service.
about 5 mm above the contact point; position the load cell to permit
insertion of the pin in the torque-arm hole; secure the position of the load
6. Apparatus
cell by tightening the clamping screws; replace pin contact with original
6.1 Low-Temperature Wheel Bearing Torque Apparatus,
contact before running test.
illustrated in Fig. 1.
6.3 Temperature Measuring System, consisting of Type T
NOTE 1—Several apparatus configurations are available, differing
(preferred) or Type J (acceptable), 3.18-mm diameter metal-
mainly in the drive system. For example, with large cold chambers, a
sheathed, grounded thermocouples meeting Specifications
unitized apparatus (see Fig. 1) can be used totally within the cold chamber.
E 585/E 585M and E 608 and conforming to the special limits
With small cold chambers, the drive system can be mounted externally
of error defined in Table 1 of Specification E 230; a suitable
and only the test unit subjected to low temperature. Regardless of the
potentiometer, satisfying the requirements for Groups B or C as
exact configuration, the essential apparatus consists of a 1/3 hp electric
motor connected to a gear reducer by means of a timing belt and pulleys, described in Test Method E 220; an ASTM 73C precision
6 8
Verdura, T. M., “Performance of Service Station Wheel Bearing Greases in a Mobil SHC 624 (or similar), available from Mobil Oil Corporation, 3225
New Low-Temperature Test,” NLGI Spokesman 35 10-21 (1971). Gallows Rd., Fairfax, VA 22037.
7 9
Available from Koehler Instrument Co., 1595 Sycamore Avenue, Bohemia, A Model 3167-50 load cell and matching electronic circuitry are available from
L.I., NY 11716. Lebow Associates, Inc., 1728 Maplelawn, Troy, MI 48062.
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D 4693 – 97 (2002)
TABLE 1 Torque Test Results at −40°C with NLGI Reference
tions, 1.1.1-trichloroethane or chloroform shall be used unless
System A (Batch 3)
contractual parties agree on the acceptability of the function-
Mean value 3.7 N·m
ally equivalent solvent.
Standard deviation 0.67 N·m
7.4.1.1 To be functionally equivalent, the solvent must not
Confidence limits, 95 %:
affect test results, must clean as effectively as 1.1.1-
Lower 3.2
Upper 4.1
trichloroethane, have similar volatility characteristics, leave no
residue on evaporation, and contain no water or additives.
NOTE 4—This test method (and the precision values) was originally
thermometer meeting Specification E 1, certified (traceable to
developed using chloroform. This was subsequently replaced by 1.1.1-
National Institute of Standards and Technology certification) or
trichloroethane which was declared an ozone depleting substance by the
verified and calibrated according to Test Method E 77; a
U.S. Environmental Protection Agency (EPA). Federal regulations ban the
suitable comparator as described in Test Method E 77; and an
production of this material after December 31, 1995, but existing stocks
ice bath prepared according to Practice E 563.
may continue to be used. Currently there are no EPA restrictions on the use
of chloroform, but the user should be aware of its health hazards, if it is
NOTE 3—Other temperature-measuring instrumentation, such as a pre-
used. No other solvent intended as a substitute for 1.1.1-trichloroethane in
cision platinum resistance thermometer, may be used instead of thermo-
this test method has been cooperatively evaluated. (Warning—If the
couples, providing the limits of error are within those defined in
functionally equivalent solvent is flammable or a health hazard, proper
Specification E 230.
precautions should be taken.)
6.4 Test Bearing—Use LM67010-LM67048 and LM11910-
8. Calibration
LM11949 (AFBMA Standard 19) inboard and outboard ta-
pered roller bearings, respectively.
8.1 Torque Calibration:
6.5 Low-Temperature Test Chamber, equipped with internal
8.1.1 Place the load cell in the cold chamber at −40°C and
fan, and capable of maintaining the spindle at −40 6 0.5°C,
allow it to come to temperature equilibrium. Electrically null
and with sufficient capacity to cool the spindle at the rate
the load cell and recording potentiometer using the adjusting
shown in Fig. 2(A) and Fig. 2(B).
potentiometer of the matching network. Adjust or standardize
6.6 Laboratory Oven, forced air, capable of maintaining 70
the range potentiometer as needed to achieve the desired
6 3°C.
zero-point and full-scale calibration. Select a millivolt range on
6.7 Grease Packer, as described in Test Method D 3527 or
the recording potentiometer, and record pen displacement as a
equivalent.
known force is applied to the load cell. (It may be necessary to
6.8 Ultrasonic Cleaner.
fabricate a platform to attach to the load cell to support the
calibrating weights.) Apply several forces (up to about 200 N
7. Reagents and Materials
or more) in stepwise fashion while recording pen displacement
7.1 Purity of Reagents—Reagent grade chemicals shall be
as a function of applied force. Calibrate the other millivolt
used in all tests. Unless otherwise indicated, it is intended that
ranges in similar fashion until limited by either maximum
all reagents shall conform to the specifications of the Commit-
displacement or maximum load. Remove forces stepwise to
tee on Analytical Reagents of the American Chemical Society
determine possible hysteresis.
where such specifications are available. Other grades may be
8.1.2 Construct a plot of pen displacement as a function of
used, provided it is first ascertained that the reagent is of
force for each millivolt range. Use these plots for the subse-
sufficiently high purity to permit its use without lessening the
quent determination of torque for the test greases. Ordinarily,
accuracy of the determination.
the plots will be linear, and simple conversion factors can be
7.2 Ethylene Glycol, commercial automotive antifreeze.
calculated.
(Warning—Moderately toxic. Can be harmful if inhaled,
8.1.3 This calibration need be done only at the time of initial
swallowed or absorbed through skin. Contact can irritate eyes,
setup and when occasional checks indicate that it is required.
or mucosa.)
The torque measuring system is to be standardized before each
7.3 Chloroform, reagent grade. (Warning—Health hazard.)
test, however.
7.4 1,1,1-Trichloroethane, reagent grade. (Warning—
8.2 Temperature Calibration:
Health hazard.)
8.2.1 In order to obtain precise torque measurements, an
7.4.1 For routine testing, a functionally equivalent solvent
accurate temperature calibration is essential. Meticulous at-
may be substituted throughout this test method wherever
tention to the details described in the several ASTM methods of
1.1.1-trichloroethane is specified. However, in referee situa-
temperature calibration is of paramount importance.
8.2.2 Calibrate the temperature-measuring system, includ-
ing both the potentiometer and the spindle thermocouple, at
Timken or Bower bearings are suitable.
0°C and −40°C by comparing the observed temperature with
A Bransonic 220 (Branson Cleaning Equipment Co., Shelton CN 06484),
having a capacity of about 4 L operating at an output frequency of about 55 kHz, that of the certified thermometer as described in Test Method
with a power input of about 125 W, has been found satisfactory.
E 220. Alternatively, both thermometer and thermocouple can
Reagent Chemicals, American Chemical Society Specifications, American
be calibrated using the freezing point of mercury as described
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
in Test Method E 77. The reference ice bath is to be made in
listed by the American Chemical Society, see Analar Standards for Laboratory
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
accordance with Practice E 563.
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. NOTE 5—A suitable low-temperature liquid bath can be made with a 65
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