ASTM D2981-94(1998)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.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.
An American National Standard
Designation: D 2981 – 94 (Reapproved 1998)
Standard Test Method for
Wear Life of Solid Film Lubricants in Oscillating Motion
This standard is issued under the fixed designation D 2981; 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 tion under conditions of macroscopic relative motion between
two bodies.
1.1 This test method covers the evaluation of wear life of a
3.1.4 wear—damage to a solid surface, generally involving
bonded solid film lubricant under oscillating motion by means
progressive loss of material, due to relative motion between
of a block-on-ring friction and wear testing machine.
that surface and a contacting substance or substances.
1.2 The values stated in either inch-pound units or SI
(metric) units are to be regarded separately as standard. Within
4. Summary of Test Method
the text the SI units are shown in brackets. The values stated in
4.1 The test machine is operated using a coated steel testing
each system are not exact equivalents, therefore each system
ring oscillating against a steel test block. The oscillating speed
must be used independently of the other. Combining values of
is 87.5 6 1 cpm at a 90° arc. The specimens are worn-in for 1
the two systems may result in nonconformance with the
min at 13.6 kg (30 lb) normal load obtained by application of
specification.
0.454 kg (1 lb) of dead weight to the 0:1 ratio lever system.
1.3 This standard does not purport to address all of the
Wear-in is followed by application of a normal load of 283 kg
safety concerns, if any, associated with its use. It is the
(630 lb) obtained by application of 9.53 kg (21 lb) of dead
responsibility of the user of this standard to establish appro-
weight to the 30:1 ratio lever system for the duration of the test.
priate safety and health practices and determine the applica-
4.2 One measurement is made:
bility of regulatory limitations prior to use.
4.2.1 wear life—the number of cycles required for the
2. Referenced Documents frictional force to rise to a predetermined value.
2.1 ASTM Standards:
5. Significance and Use
D 2714 Test Method for Calibration and Operation of the
3 5.1 This test method is used for determining the wear life
Falex Block-on-Ring Friction and Wear Test Machine
properties of bonded solid lubricants in oscillating motion
3. Terminology under the prescribed test conditions. This test method differ-
entiates between bonded solid lubricants with respect to their
3.1 Definitions:
wear life. If the test conditions are changed, relative wear life
3.1.1 coeffıcient of friction, μ or f—in tribology, the dimen-
may change and relative ratings of the bonded solid film
sionless ratio of the friction force (F) between two bodies to the
lubricants may be different.
normal force (N) pressing these two bodies together.
μ or f 5 ~F/N! (1)
6. Apparatus
3.1.1.1 Discussion—A distinction is often made between
6.1 Block-on-Ring Test Machine, equipped with oscillating
static coeffıcient of friction and kinetic coeffıcient of friction.
drive, load cell transducer and recorder described in detail in
3.1.2 friction force—the resisting force tangential to the
Annex A1 and illustrated in Fig. 1.
interface between two bodies when, under the action of an
6.2 Test Ring, SAE 4620 Steel, having a Rockwell hardness
external force, one body moves or tends to move relative to the
of HRC 58-63. Each ring had a ground face of 8.163 mm 6
other.
0.127 mm (0.3216 0.005 in.), a diameter of 34.9885 6
3.1.3 kinetic coeffıcient of friction—the coefficient of fric-
0.0254, −0.1270 mm (1.3775 6 0.001, −0.005 in.) and an
eccentricity between the inner and outer surface of 60.038 mm
(0.0015 in.). The surface finish of the outside diameter of each
ring prior to lubricant coating application should be from 500
This test method is under the jurisdiction of ASTM Committee D-2 on
to 750 nm (20 to 30 μin.) rms.
Petroleum Products and Lubricants, and is the direct responsibility of Subcommittee
2 5
6.3 Test Block, SAE 01 Steel with test surface of 0.635 6
D02.0L on Industrial Lubricants.
Current edition approved Feb. 15, 1994. Published April 1994. Originally
0.021, −0.000 mm (0.250 6 0.0005, −0.0000 in.) wide and
published as D 2981 – 71. Last previous edition D 2981 – 88e .
The Block-on-Ring Test machine is available from Falex Corp., 1020 Airpark
Dr., Sugar Grove, IL 60554. Available from Falex Corp., 1020 Airpark Dr., Sugar Grove, IL 60554.
3 5
Annual Book of ASTM Standards, Vol 05.01. SAE 01 is also known as Starrett 406 or Marshall Oilcrat.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, 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 2981
machine. Standard drive machines will operate only at 87.5
cpm; for variable drive units the 87.5 cpm speed is set before
specimens are mounted. Run the machine for 1 min to
accomplish initial wear-in of the coated specimen and then stop
the machine. Gently lower 27.3 kg (60 lb) of additional weight
onto the bale rod, bringing the total to 28.3 kg (63 lb) or 283
kg (630 lb) normal load on the specimen. Start the machine
again and run until failure occurs due to excessive friction, as
described above. Record friction during the break-in cycle and
also record the number of revolutions to failure.
10. Calculation
FIG. 1 Falex Block-on-Ring Test Machine with Recorder
10.1 Calculate the coefficient of friction from the friction
force values as follows:
1.575 6 0.005 mm (0.620 6 0.0002 in.) long and having a
f 5 F/W (2)
Rockwell hardness of HRC 58-63. Each block should have the
test surface ground to a finish of 100 to 200 nm (4 to 8 μin.) where:
f = coefficient of friction,
rms and be perfectly square with all outside edges.
F = friction force, kg (lb), and
7. Reagents
W = normal load, kg (lb).
7.1 Solvents, safe, nonfilming, nonchlorinated.
11. Report
8. Preparation of Apparatus
11.1 The report shall include the following:
8.1 Before each test, thoroughly clean the test block, the
11.1.1 Report the friction force in both directions at 50, 100,
shaft, specimen holder, lock nut, lock washer, and the tapered
and 1000 cycles. Record the number of revolutions to failure,
and threaded sections of the test shaft, using the solvents
(point after wear-in at which a coefficient of friction of 0.1 is
described in 6.1.
reached).
8.2 Using clean, lint-free cotton gloves, mount the test block
11.1.2 Indicate where failure occurred, whether in the in-
in the block holder and position both securely in the cylindrical
side, middle or outside of the wear track of the test ring.
slot of the specimen holder. Holding the test block in place,
mount the test ring over the test shaft and press into position
12.
...