ASTM D6425-99
(Test Method)Standard Test Method for Measuring Friction and Wear Properties of Extreme Pressure (EP) Lubricating Oils Using SRV Test Machine
Standard Test Method for Measuring Friction and Wear Properties of Extreme Pressure (EP) Lubricating Oils Using SRV Test Machine
SCOPE
1.1 This test method covers an extreme pressure (EP) lubricating oil's coefficient of friction and its ability to protect against wear when subject to high-frequency, linear oscillation motion. The procedure is identical to that described in DIN 51834.
1.2 This test method can also be used to determine the ability of a non-EP lubricating oil to protect against wear and its coefficient of friction under similar test conditions.
1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
1.4 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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Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: D 6425 – 99
Standard Test Method for
Measuring Friction and Wear Properties of Extreme
Pressure (EP) Lubricating Oils Using SRV Test Machine
This standard is issued under the fixed designation D 6425; 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.
1. Scope 3.1.2 coeffıcient of friction μ or f, n—in tribiology, the
dimensionless ratio of the friction force (F ) between two
f
1.1 This test method covers an extreme pressure (EP)
bodies to the normal force (F ) pressing these bodies together.
n
lubricating oil’s coefficient of friction and its ability to protect
G40
against wear when subjected to high-frequency, linear oscilla-
tion motion. The procedure is identical to that described in DIN μ 5 F / F ! (1)
~
f n
51834.
3.1.3 EP lubricating oil, n—a liquid lubricant containing an
1.2 This test method can also be used to determine the
extreme pressure (EP) additive
ability of a non-EP lubricating oil to protect against wear and
3.1.4 extreme pressure (EP) additive, n—in a lubricant,a
its coefficient of friction under similar test conditions.
substance that minimizes damage to metal surfaces in contact
1.3 The values stated in SI units are to be regarded as the
under high stress rubbing conditions. D 4175
standard. The values given in the parentheses are for informa-
3.1.5 Hertzian contact area, n—the apparent area of contact
tion only.
between two nonconforming solid bodies pressed against each
1.4 This standard does not purport to address all of the
other, as calculated from Hertz’ equations of elastic deforma-
safety concerns, if any, associated with its use. It is the
tion. G40
responsibility of the user of this standard to establish appro-
3.1.6 Hertzian contact pressure, n—the magnitude of the
priate safety and health practices and determine the applica-
pressure at any specified location in a Hertzian contact area, as
bility of regulatory limitations prior to use.
calculated from Hertz’ equations of elastic deformation.
G40
2. Referenced Documents
3.1.7 lubricant, n—any substance interposed between two
2.1 ASTM Standards:
surfaces for the purpose of reducing the friction or wear
D 4175 Terminology Relating to Petroleum, Petroleum
between them. G40
Products, and Lubricants
3.1.8 wear, n—damage to a solid surface, generally involv-
G 40 Terminology Relating to Wear and Erosion
ing progressive loss of material, due to relative motion between
2.2 Other Standards:
that surface and a contacting substance or substances. G40
DIN 17230 Roller Bearing Steels
3.1.9 C.L.A., n—in measuring surface finish, the arithmetic
DIN 51834, Tribiological Test in the Translatory Oscillation
average of the absolute distances of all profile points from the
Apparatus (Part 2: Determination of Friction and Wear
mean line for a given distance.
Data for Lubricating Oils)
3.1.10 Rz, n—in measuring surface finish, the average of all
Ry values (peak to valley heights) in the assessment length.
3. Terminology
3.1.11 Ry, n—in measuring surface finish, the vertical
3.1 Definitions:
distance between the top of the highest peak and the bottom of
3.1.1 break-in, n—in tribiology, an initial transition process
the deepest valley in one sampling length of the roughness
occurring in newly established wearing contacts, often accom-
profile.
panied by transients in coefficient of friction or wear rate, or
3.2 Definitions of Terms Specific to This Standard:
both, that are uncharacteristic of the given tribiological sys-
3.2.1 seizure, n—the stopping of relative motion as the
tem’s long term behavior. (Synonym: run-in, wear-in) G40
result of interfacial friction.
4. Summary of Test Method
This test method is under the jurisdiction of ASTM Committee D-2 on
4.1 This test method is performed on an SRV test machine
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.L0.11 on Tribiological Properties of Industrial Fluid Lubricants.
Current edition approved June 10, 1999. Published August 1999.
2 5
Annual Book of ASTM Standards, Vol 05.02. Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003-0785,
Annual Book of ASTM Standards, Vol 03.02. Sheffield Measurement Division, Warner and Swazey, 1985, p. 21.
4 6
Available from Deutsches Institut für Normunge, Beuth Verlag GmbH, Burg- ASM Handbook, “Friction, Lubrication, and Wear Technology,” Vol 18,
grafenstrasse6, D-10787 Berlin, Germany. October 1992.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 6425
using a test ball oscillated at constant frequency and stroke Friction coefficients are recorded in relation to time by a chart
amplitude and under constant load (F ), against a test disk that recorder, or by data acquisition in a computer.
n
has been moistened with the lubricant specimen. The platform 6.1.1 On the firmly mounted receiving block (1) in the test
to which the test disk is attached is held at a constant chamber (see Fig. 3), there is a piezoelectric device (2) to
temperature. measure the friction force, F , and the friction coefficient, f; the
f
holder for the test disk (3) with a thermostat-controlled
NOTE 1—The frequency of oscillation, stroke length, test temperature,
electrical resistance heating element (4); a resistance thermom-
test load, test duration, and test ball and disk material can be varied from
eter (5); the oscillation drive rods (6); an exchangeable holder
those specified in this test method. The test ball yields Hertzian point
for the test ball (7); and the load rods of the loading device (8).
contact geometry. To obtain line or area contact, test pieces of differing
configurations can be substituted for the test ball.
6.1.2 The design of the receiving block for the test disk
should be such that it has integrated cooling coils, or that
4.2 The friction force, F , is measured by a piezo-electric
f
cooling coils are wound round it, so that temperatures below
device in the test disk assembly. Peak values of coefficient of
ambient are possible. The test disk (9) and the test ball (10) are
friction, f, are determined and recorded as a function of time.
inserted into their respective holders (3, 4) (see Fig. 3).
4.3 After a pre-set test period, the test machine and chart
6.1.3 Disks are generally used as the lower test piece. Balls,
recorder are stopped and the wear scar on the ball is measured.
cylinders, rings, or specialized shapes may be used, with
If a profilometer is available, a trace of the wear scar on the test
appropriate holders, as the upper test piece (see Fig. 4).
disk can also be used to obtain additional wear information.
6.2 Microscope, equipped with a filar eyepiece graduated in
5. Significance and Use 0.01-mm divisions or equipped with a micrometre stage
readable to 0.01 mm. Magnification should be sufficient to
5.1 This test method can be used to determine anti-wear
allow for ease of measurement. One to 103 magnification has
properties and coefficient of friction of EP lubricating oils at
been found acceptable.
selected temperatures and loads specified for use in applica-
6.3 Syringe, suitable for applying 0.03 mL of the lubricating
tions in which high-speed vibrational or start-stop motions are
oil under test.
present for extended periods of time under initial high Hertzian
6.4 Tweezers, straight, round, about 200-mm long, with
point contact pressures. It has found application as a screening
non-marring tips.
test for lubricants used in gear or cam/follower systems. Users
6.5 Torque Wrench, initial torque 0.5 to 5 nm.
of this test method should determine whether results correlate
6.6 Ultrasonic Cleaner.
with field performance or other applications.
7. Reagents and Materials
6. Apparatus
7.1 Test Balls, AISI 52100 Steel, 60 6 2 HRC hardness,
6.1 SRV Test Machine (see Fig. 1), consists of an oscilla-
0.025 6 0.005-μm C.L.A. surface finish, 10-mm diameter.
tion drive, a test chamber (see Fig. 2), and a loading device 7
7.2 Test Disk, AISI 52100 steel, 62 6 1 HRC hardness,
with a servomotor and a load cell. The machine is operated by
0.45 to 0.65-μm Rz lapped surface, 24 6 0.5-mm diameter by
a control device for the oscillating drive, a timer, a load control,
7.86 0.1-mm thick.
a frequency control, a stroke control, a data amplifier to
NOTE 2—Test pieces made to 100 Cr 6 roller bearing steel (see DIN
determine the friction coefficient, and a switch and a controller
17230) are equivalent.
for the heating. An oscilloscope may be used for monitoring.
7.3 n-Heptane, reagent grade.
NOTE 3—Warning: Flammable. Health Hazard.
The sole source of supply known to the committee at this time is Optimol
7.4 Isopropanol, reagent grade.
Instruments Prüftechnik GmbH, Friedenstrasse 10, D 81671 Munich, Germany. If
you are aware of alternative suppliers, please provide this information to ASTM
NOTE 4—Warning: Flammable. Health Hazard.
Headquarters. Your comments will receive careful consideration at a meeting of the
7.5 Toluene, reagent grade.
responsible technical committee, which you may attend.
FIG. 1 SRV Test Machine
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
D 6425
FIG. 2 Test Chamber
1. Receiving Block 6. Oscillation Drive Rod
2. Piezoelectric Measuring Device 7. Test Ball Holder
3. Test Disk Holder 8. Load Rod
4. Electrical Resistance Heater 9. Test Disk
5. Resistance Thermometer 10. Test Ball
FIG. 3 Test Chamber Elements
NOTE 5—Warning: Flammable. Health Hazard.
7.6 Cleaning Solvent, a mixture of equal volumes of
n-hep
...
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