ASTM D2783-88(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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.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.
Designation: D 2783 – 88 (Reapproved 1998) An American National Standard
Standard Test Method for
Measurement of Extreme-Pressure Properties of Lubricating
Fluids (Four-Ball Method)
This standard is issued under the fixed designation D 2783; 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 index is the average of the sum of the corrected loads
determined for the ten applied loads immediately preceding the
1.1 This test method covers the determination of the load-
weld pair.
carrying properties of lubricating fluids. The following two
3.1.2 weld point—under the conditions of this test, the
determinations are made:
lowest applied load in kilograms at which the rotating ball
1.1.1 Load-wear index (formerly Mean-Hertz load) and
welds to the three stationary balls, indicating the extreme-
1.1.2 Weld point by means of the four-ball extreme-pressure
pressure level of the lubricants-force (or newtons) has been
(EP) tester.
exceeded.
1.2 This standard does not purport to address all of the
3.1.2.1 Discussion— Some lubricants do not allow true
safety concerns, if any, associated with its use. It is the
welding, and extreme scoring of the three stationary balls
responsibility of the user of this standard to establish appro-
results. In such cases, the applied load which produces a
priate safety and health practices and determine the applica-
maximum scar diameter of 4 mm is reported as the weld point.
bility of regulatory limitations prior to use.
3.1.3 corrected load—the load in kilograms-force (or new-
1.3 The values stated in either inch-pound units or SI
tons) for each run obtained by multiplying the applied load by
(metric) units are to be regarded separately as standard. Within
the ratio of the Hertz scar diameter to the measured scar
the text the inch-pound units are shown in brackets. The values
diameter at that load.
stated in each system are not exact equivalents, therefore each
3.1.4 Hertz scar diameter—the average diameter, in milli-
system must be used independently of the other. Combining
metres, of an indentation caused by the deformation of the balls
values of the two systems may result in nonconformance with
under static load (prior to test). It may be calculated from the
the specification.
equation
2. Referenced Documents
22 1/3
D 5 8.73 3 10 ~P! (1)
h
2.1 ASTM Standards:
where:
D 484 Specification for Hydrocarbon Drycleaning Sol-
D 5 Hertz diameter of the contact area, and,
vents h
P 5 the static applied load.
2.2 ANSI Standard:
3.1.5 compensation scar diameter—the average diameter, in
B 3.12 Metal Balls
millimetres, of the wear scar on the stationary balls caused by
3. Terminology
the rotating ball under an applied load in the presence of a
lubricant, but without causing either seizure or welding.
3.1 Definitions:
3.1.5.1 Discussion—The wear scar obtained shall be within
3.1.1 load-wear index (or the load-carrying property of a
5 % of the values noted in Table 1, Column 3.
lubricant)—an index of the ability of a lubricant to minimize
3.1.6 Hertz line—a line of plot on logarithmic paper, as
wear at applied loads. Under the conditions of this test, specific
shown in Fig. 1, where the coordinates are scar diameter in
loadings in kilograms-force (or newtons) having intervals of
millimetres and applied load in kilograms-force (or newtons),
approximately 0.1 logarithmic units, are applied to the three
obtained under static conditions.
stationary balls for ten runs prior to welding. The load-wear
3.1.7 compensation line—a line of plot on logarithmic
paper, as shown in Fig. 1, where the coordinates are scar
This test method is under the jurisdiction of ASTM Committee D-2 on
diameter in millimetres and applied load in kilograms-force (or
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
newtons), obtained under dynamic conditions.
D02.Lon Industrial Lubricants.
Current edition approved Oct. 31, 1988. Published December 1988. Originally 3.1.7.1 Discussion—Coordinates for the compensation line
e1
published as D 2783 – 69 T. Last previous edition D 2783 – 82 .
are found in Table 1, Columns 1 and 3.
This method was prepared under the joint sponsorship of the American Society
3.1.7.2 Discussion—Some lubricants give coordinates
of Lubrication Engineers. Accepted by ASLE January 1969.
Discontinued; see 1984 Annual Book of ASTM Standards, Vol 05.01. which are above the compensation line. Known examples of
Available from American National Standards Institute, 11 W. 42nd St., 13th
such fluids are methyl phenyl silicone, chlorinated methyl
Floor, New York, NY 10036.
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 2783
TABLE 1 Suggested Form for Recording Test Results
rotating against three steel balls held stationary in the form of
Column 1 Column 2 Column 3 Column 5 a cradle. Test lubricant covers the lower three balls. The
Column4
Applied Average Scar Compensation Corrected
rotating speed is 1760 6 40 rpm. The machine and test
LD
A h
Load, kg Diameter, Scar Diameter, Load,
Factor
A lubricant are brought to 18.33 to 35.0°C (65 to 95°F) and then
(L) mm (X) mm kg (LD /X)
h
a series of tests of 10-s duration are made at increasing loads
6 0.95
until welding occurs. Ten tests are made below the welding
8 1.40
10 0.21 1.88
point. If ten loads have not been run when welding occurs and
13 0.23 2.67
the scars at loads below seizure are within 5 % of the
16 0.25 3.52
compensation line (AB Fig. 1) no further runs are necessary.
20 0.27 4.74
24 0.28 6.05
The total can be brought to ten by assuming that loads below
32 0.31 8.87
the last nonseizure load will produce wear scars equal to the
40 0.33 11.96
“compensation scar diameter.” Values of these “assumed” scars
50 0.36 16.10
63 0.39 21.86
are given in Table 1. For clarification of “last nonseizure load”
80 0.42 30.08
and “weld point” see Fig. 1.
100 0.46 40.5
126 0.50 55.2
5. Significance and Use
160 0.54 75.8
200 0.59 102.2
5.1 This test method, used for specification purposes, dif-
250 137.5
ferentiates between lubricating fluids having low, medium, and
315 187.1
400 258
high level of extreme-pressure properties. The user of this
500 347
method should determine to his own satisfaction whether
620 462
800 649 results of this test procedure correlate with field performance or
A
other bench test machines.
To convert from kilograms-force to newtons, multiply by 9.806.
6. Apparatus
6.1 Four-Ball Extreme-Pressure Tester, illustrated in Fig. 2
and Fig. 3 .
NOTE 1—It is important to distinguish between the four-ball EP tester
and the four-ball wear tester. The four-ball EP tester is designed for testing
under more severe conditions and lacks the sensitivity necessary for the
four-ball wear test.
6.2 Microscope, equipped with a calibrated measuring scale
and readable to an accuracy of 0.01 mm.
6.3 Timer, graduated in tenths of a second.
NOTE 2—Optional equipment with four-ball apparatus consists of a
friction-measuring device electrically driven and conveniently graduated
ABE—Compensation line.
in 10-s markings.
B—Point of last nonseizure load.
BC—Region of incipient seizure.
7. Materials
CD—Region of immediate seizure.
D—Weld point.
7.1 Stoddard Solvent, in accordance with Specification
FIG. 1 Schematic Plot of Scar Diameter Versus Applied Load
D 484.
phenyl silicone, silphenylene, phenyl ether, and some mixtures
NOTE 3—Warning: Flammable. Harmful if inhaled. See A1.1.)
of petroleum oil and chlorinated paraffins.
7.2 Heptane
3.1.8 last nonseizure load—the last load at which the
measured scar diameter is not more than 5 % above the
NOTE 4—Warning: Flammable. Harmful if inhaled. See A1.2.)
compensation line at the load. See Fig. 1.
7.3 Test Balls —Test balls shall be chrome alloy steel, made
3.1.9 incipient seizure or initial seizure region—that region
from AISI standard steel No. E-52100, with diameter of 12.7
at which, with an applied load, there is a momentary break-
mm (0.5 in.), Grade 25 EP (Extra Polish). Such balls are
down of the lubricating film. This breakdown is noted by a
described in ANSI Specifications B 3.12, for Metal Balls. The
sudden increase in the measured scar diameter and a momen-
Extra-Polish finish is not described in that specification. The
tary deflection of the indicating pen of the optional friction-
measuring device. See Fig. 1.
3.1.10 immediate seizure region—that region of the scar-
Further details applicable to this method may be found in: Sayles, F. S., et al.,
load curve characterized by seizure or welding at the startup or
“The Four-Ball E. P. Tester, An ASTM Method of Test,” National Lubricating
Grease Institute, NLGIA, Vol 32, No. 5, August 1968, pp. 162–167.
by large wear scars. Initial deflection of indicating pen on the
Satisfactory sources of supply for this instrument are Falex Corp., 1020 Airpark
optional friction-measuring device is larger than with nonsei-
Dr., Sugar Grove, IL 60554–9585 and Stanhope-Seta Ltd., Park Close, Egham,
zure loads. See Fig. 1.
Englefield Green, Surrey, England TW20 OXD.
Steel balls meeting this description were used in developing the precision of the
4. Summary of Test Method
test. They are available from the manufacturer of the test machine. All balls used in
4.1 The tester is operated with one steel ball under load one test should be taken from one carton (of 500 balls) as received from the supplier.
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 2783
FIG. 2 Sectional View of Four-Ball Tester
FIG. 3 Four-Ball EP Test Machine
Rockwell C hardness shall be 64 to 66, a closer limit than is (Warning—See Note 8 and A1.2.)
found in the ANSI requirement.
NOTE 5—Do not use solvents such as carbon tetrachloride or other
solvents that may inherently possess load-carrying properties which may
8. Preparation of Apparatus
affect the results.
8.1 Thoroughly clean four new test balls, test-lubricant cup,
and chuck assemblies by first washing with Stoddard solvent 8.2 Lower the crosshead by raising the lever arm. Lock the
(Note 9) (Warning—See Note 7 and A1.1.) and then heptane. lever arm in the raised position by means of a locking
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 2783
NOTE 10—It is recommended that prior to selection of Option A or B,
arrangement for that purpose.
the operator examines visually the test balls to ascertain no gross
discrepancy in the wear scars formed on the test balls; if discrepancy is
9. Procedure
noted, then wear scar measurements on all three test balls must be made.
9.1 Place the three test balls in the test-lubricant cup. Place
9.9 Record (Table 1, Column 2) for the 784 N (80-kg) load
the lock ring over the test balls and screw down the nut
the average scar diameter by any one of the three techniques
securely (Note 6). Pour the lubricating fluid to be tested over
described in 9.8. Compare this average scar diameter with the
the three test balls until they are covered.
compensation scar diameter (Table 1, Column 3).
NOTE 6—Subsequent independent investigations reported in 1971 by
9.10 Make additional runs at consecutively higher test loads
several laboratories indicate that optimum test repeatability is obtained
(Table 1, Column 1), recording the measured scar diameter(s)
when the force on the lock-down nut is maintained within the range 68 6
7 h· m (50 6 5 ft·lb), applied and measured by means of a torque wrench. (Note 11) and discarding test balls, until welding occurs (Note
Significantly lower weld points were obtained when the force applied was
12). Make a check run at this point. If welding does not occur
approximately 136 N·m (100 ft·lb).
on the check run, repeat the test at the next higher load until
welding is verified.
9.2 Bring the lubricant and cup to 18 to 35°C (65 to 95°F).
9.3 Press one ball into the ball chuck (Note 7) and mount the
NOTE 11—Measuring the scar diameter(s) of test balls in the incipient
chuck into the chuck-holder.
and immediate seizure region is sometimes difficult due to the flow of
metal obliterating the full contact area formed by the rotating ball. In such
NOTE 7—Examine the chuck and top ball after each run. If the ball
cases the metal flow can generally be removed or peeled off with a suitable
shows signs of movement in the chuck, even though welding of the
instrument. See Fig. 4 and Fig. 5. If the scar periphery is obscure or not
four-balls did not occur, the chuck should be replaced. When welding
well defined an estimate of the scar diameter is made. See Fig. 6 and Fig.
occurs slippage between ball and chuck nearly always occurs. If the chuck
7.
has metal from the top ball adhering to it, the metal must be removed or
NOTE 12—Shut off the motor immediately to prevent damage to the
the chuck replaced.
tester. Excessive seizure between the ball and ball chuck may result if
9.4 Install the test-lubricant cup assembly on the test appa-
caution is not observed. Welding may be detected by any or all of the
ratus in contact with the fourth ball. Place the spacer between
following: (1) If friction-measuring device is used, a sharp transverse
cup and thrust bearing. movement of the indicating pen, (2) increased noise level of motor, (3)
smoking from test-oil cup, (4) a sudden drop in the lever arm.
9.5 Place the weight tray and sufficient weights on the
horizontal arm in the correct notch for a base test load of 784
9.11 If the measured scar diameter for the 784 N (80-kg)
N (80 kg). Release the lever arm and gently apply (Note 8) the
load is more than 5 % from the compensation scar diameter,
test load to the balls, making certain the cup assembly and
make the next run at the next lower load (Table 1, Column 1).
spacer are centered. If the optional friction-measuring device is
Continue this procedure until the last nonseizure load is
used, connect the calibrated arm on the test-lubricant cup to the
determined.
indicator spring by means of the clip and wire.
NOTE 13—When the optional friction-measuring device is used, the last
NOTE 8—Shock-loading should be avoided as it may deform the balls
...