ASTM D2783-03(2009)
(Test Method)Standard Test Method for Measurement of Extreme-Pressure Properties of Lubricating Fluids (Four-Ball Method)
Standard Test Method for Measurement of Extreme-Pressure Properties of Lubricating Fluids (Four-Ball Method)
SIGNIFICANCE AND USE
This test method, used for specification purposes, differentiates between lubricating fluids having low, medium, and high level of extreme-pressure properties. The user of this method should determine to his own satisfaction whether results of this test procedure correlate with field performance or other bench test machines.
SCOPE
1.1 This test method covers the determination of the load-carrying properties of lubricating fluids. The following two determinations are made:
1.1.1 Load-wear index (formerly Mean-Hertz load).
1.1.2 Weld point by means of the four-ball extreme-pressure (EP) tester.
1.2 For the determination of the load-carrying properties of lubricating greases, see Test Method D 2596.
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.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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Designation: D2783 − 03(Reapproved 2009)
Standard Test Method for
Measurement of Extreme-Pressure Properties of Lubricating
Fluids (Four-Ball Method)
This standard is issued under the fixed designation D2783; 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.
1. Scope diameter in millimetres and applied load in kilograms-force (or
newtons), obtained under dynamic conditions.
1.1 This test method covers the determination of the load-
3.1.1.1 Discussion—Coordinates for the compensation line
carrying properties of lubricating fluids. The following two
are found in Table 1, Columns 1 and 3.
determinations are made:
3.1.1.2 Discussion—Some lubricants give coordinates
1.1.1 Load-wear index (formerly Mean-Hertz load).
1.1.2 Weldpointbymeansofthefour-ballextreme-pressure which are above the compensation line. Known examples of
such fluids are methyl phenyl silicone, chlorinated methyl
(EP) tester.
phenyl silicone, silphenylene, phenyl ether, and some mixtures
1.2 For the determination of the load-carrying properties of
of petroleum oil and chlorinated paraffins.
lubricating greases, see Test Method D2596.
3.1.2 compensation scar diameter—the average diameter, in
1.3 This standard does not purport to address all of the
millimetres, of the wear scar on the stationary balls caused by
safety concerns, if any, associated with its use. It is the
the rotating ball under an applied load in the presence of a
responsibility of the user of this standard to establish appro-
lubricant, but without causing either seizure or welding.
priate safety and health practices and determine the applica-
3.1.2.1 Discussion—The wear scar obtained shall be within
bility of regulatory limitations prior to use.
5 % of the values noted in Table 1, Column 3.
1.4 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information
3.1.3 corrected load—the load in kilograms-force (or new-
only.
tons) for each run obtained by multiplying the applied load by
the ratio of the Hertz scar diameter to the measured scar
2. Referenced Documents
diameter at that load.
2.1 ASTM Standards:
3.1.4 Hertz line—a line of plot on logarithmic paper, as
D2596 Test Method for Measurement of Extreme-Pressure
shown in Fig. 1, where the coordinates are scar diameter in
Properties of Lubricating Grease (Four-Ball Method)
millimetres and applied load in kilograms-force (or newtons),
2.2 ANSI Standard:
obtained under static conditions.
B 3.12 Metal Balls
3.1.5 Hertz scar diameter—the average diameter, in
3. Terminology
millimetres, of an indentation caused by the deformation of the
balls under static load (prior to test). It may be calculated from
3.1 Definitions:
the equation
3.1.1 compensation line—a line of plot on logarithmic
paper, as shown in Fig. 1, where the coordinates are scar 22 1/3
D 5 8.73 310 P (1)
~ !
h
where:
This test method is under the jurisdiction of ASTM Committee D02 on
D = Hertz diameter of the contact area, and
h
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
P = the static applied load.
D02.L0.11 on Tribiological Properties of Industrial Fluids and Lubricates.
Current edition approved April 15, 2009. Published July 2009. Originally
3.1.6 immediate seizure region—that region of the scar-load
approved in 1969. Last previous edition approved in 2003 as D2783 – 03.
curve characterized by seizure or welding at the startup or by
This method was prepared under the joint sponsorship of the American Society
of Lubrication Engineers. Accepted by ASLE January 1969. DOI: 10.1520/D2783-
large wear scars. Initial deflection of indicating pen on the
03R09.
optional friction-measuring device is larger than with nonsei-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
zure loads. See Fig. 1.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
3.1.7 incipient seizure or initial seizure region—that region
the ASTM website.
at which, with an applied load, there is a momentary break-
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. down of the lubricating film. This breakdown is noted by a
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D2783 − 03 (2009)
3.1.10 weld point—under the conditions of this test, the
lowest applied load in kilograms at which the rotating ball
welds to the three stationary balls, indicating the extreme-
pressure level of the lubricants-force (or newtons) has been
exceeded.
3.1.10.1 Discussion—Some lubricants do not allow true
welding, and extreme scoring of the three stationary balls
results. In such cases, the applied load which produces a
maximum scar diameter of 4 mm is reported as the weld point.
4. Summary of Test Method
4.1 The tester is operated with one steel ball under load
ABE—Compensation line.
rotating against three steel balls held stationary in the form of
B—Point of last nonseizure load.
BC—Region of incipient seizure.
a cradle. Test lubricant covers the lower three balls. The
CD—Region of immediate seizure.
rotating speed is 1760 6 40 rpm. The machine and test
D—Weld point.
lubricant are brought to 18 to 35°C (65 to 95°F) and then a
FIG. 1 Schematic Plot of Scar Diameter Versus Applied Load
series of tests of 10-s duration are made at increasing loads
until welding occurs. Ten tests are made below the welding
TABLE 1 Suggested Form for Recording Test Results
point. If ten loads have not been run when welding occurs and
Column 2 Column 3 Column 5
Column 1
the scars at loads below seizure are within 5 % of the
Column4
Applied Average Scar Compensation Corrected
LD
h
A compensation line (AB Fig. 1) no further runs are necessary.
Diameter, Scar Diameter, Load,
Load, kg
Factor
A
(L)
mm (X) mm kg (LD /X) The total can be brought to ten by assuming that loads below
h
6 0.95
the last nonseizure load will produce wear scars equal to the
8 1.40
“compensationscardiameter.”Valuesofthese“assumed”scars
10 0.21 1.88
are given in Table 1. For clarification of “last nonseizure load”
13 0.23 2.67
16 0.25 3.52
and “weld point” see Fig. 1.
20 0.27 4.74
24 0.28 6.05
5. Significance and Use
32 0.31 8.87
40 0.33 11.96
5.1 This test method, used for specification purposes, dif-
50 0.36 16.10
ferentiates between lubricating fluids having low, medium, and
63 0.39 21.86
80 0.42 30.08
high level of extreme-pressure properties. The user of this
100 0.46 40.5
method should determine to his own satisfaction whether
126 0.50 55.2
160 0.54 75.8 resultsofthistestprocedurecorrelatewithfieldperformanceor
200 0.59 102.2
other bench test machines.
250 137.5
315 187.1
400 258 6. Apparatus
500 347
6.1 Four-Ball Extreme-Pressure Tester, illustrated in Figs.
620 462
800 649
2 and 3.
A
To convert from kilograms-force to newtons, multiply by 9.806.
NOTE 1—It is important to distinguish between the four-ball EP tester
andthefour-ballweartester.Thefour-ballEPtesterisdesignedfortesting
under more severe conditions and lacks the sensitivity necessary for the
four-ball wear test.
sudden increase in the measured scar diameter and a momen- 6.2 Microscope, equipped with a calibrated measuring scale
and readable to an accuracy of 0.01 mm.
tary deflection of the indicating pen of the optional friction-
measuring device. See Fig. 1.
6.3 Timer, graduated in tenths of a second.
3.1.8 last nonseizure load—the last load at which the
NOTE 2—Optional equipment with four-ball apparatus consists of a
measured scar diameter is not more than 5 % above the
friction-measuring device electrically driven and conveniently graduated
compensation line at the load. See Fig. 1.
in 10-s markings.
3.1.9 load-wear index (or the load-carrying property of a
7. Materials
lubricant)—an index of the ability of a lubricant to minimize
wearatappliedloads.Undertheconditionsofthistest,specific
loadings in kilograms-force (or newtons) having intervals of
approximately 0.1 logarithmic units, are applied to the three
Further details applicable to this method may be found in: Sayles, F. S., et al.,
“The Four-Ball E. P. Tester, An ASTM Method of Test,” National Lubricating
stationary balls for ten runs prior to welding. The load-wear
Grease Institute, NLGIA, Vol 32, No. 5, August 1968, pp. 162–167.
index is the average of the sum of the corrected loads
SatisfactorysourcesofsupplyforthisinstrumentareFalexCorp.,1020Airpark
determinedforthetenappliedloadsimmediatelyprecedingthe
Dr., Sugar Grove, IL 60554–9585 and Stanhope-Seta Ltd., Park Close, Egham,
weld pair. Englefield Green, Surrey, England TW20 OXD.
D2783 − 03 (2009)
FIG. 2 Sectional View of Four-Ball Tester
FIG. 3 Four-Ball EP Test Machine
machine parts. Reagent Grade Stoddard solvent is an example of a solvent
7.1 Cleaning Solvent, safe, non-film forming, nonchlori-
that has been found suitable.
nated. (Warning— Flammable. Harmful if inhaled. See A1.1.)
NOTE 3—Certain petroleum distillates, formerly used as solvents, have
been eliminated due to possible toxic effects. Each user should select a
solvent that can meet applicable safety requirements and thoroughly clean
D2783 − 03 (2009)
NOTE 7—Shock-loading should be avoided as it may deform the balls
7.2 Rinse Solvent, same as in 7.1, but with higher volatility.
permanently.
ASTM n-Heptane is an example of one such rinse solvent that
has been found suitable. (Warning—Flammable. Harmful if
9.6 Start the motor and run for 10 6 0.2 s.
inhaled. See A1.2.)
NOTE 8—The time for the apparatus to “coast” to a stop is not
7.3 Test Balls —Test balls shall be chrome alloy steel, made considered.
from AISI standard steel No. E-52100, with diameter of 12.7
9.7 Remove the test-lubricant cup assembly; remove the
mm (0.5 in.), Grade 25 EP (Extra Polish). Such balls are
chuck and discard the ball.
described in B3.12, for Metal Balls. The Extra-Polish finish is
9.8 Measure the scar diameter of test balls as follows:
not described in that specification. The Rockwell C hardness
9.8.1 Option A—Remove the test balls. Clean the balls with
shall be 64 to 66, a closer limit than is found in the ANSI
cleaning solvent (see 7.1) and then rinse solvent (see 7.2).
requirement.
Wipe dry with a soft cloth. Place the individual balls on a
suitable holder and by means of a microscope, measure to the
8. Preparation of Apparatus
nearest 0.01 mm the scar diameters both parallel (horizontal)
8.1 Thoroughly clean four new test balls, test-lubricant cup,
and normal (vertical) to the striations in the scar surface of one
and chuck assemblies by first washing with cleaning solvent
of the three test balls (Note 9).
(see 7.1) and then rinse solvent (see 7.2).
9.8.2 Option B—Leave the balls clamped in the cup. Pour
NOTE 4—Do not use solvents such as carbon tetrachloride or other
out the lubricating fluid. Wash the ball surfaces with cleaning
solvents that may inherently possess load-carrying properties which may
solvent (see 7.1) and then the rinse solvent (see 7.2). Using a
affect the results.
microscope,measuretothenearest0.01mmthescardiameters
8.2 Lower the crosshead by raising the lever arm. Lock the
both parallel (horizontal) and normal (vertical) to the striations
lever arm in the raised position by means of a locking
in the scar surface of one of the three test balls (Note 9).
arrangement for that purpose.
9.8.3 Measurements by microscope of the scar diameters on
all three balls, rather than one ball as outlined in Options A or
9. Procedure
B, may be made if the operator so desires.
9.1 Place the three test balls in the test-lubricant cup. Place
NOTE9—ItisrecommendedthatpriortoselectionofOptionAorB,the
the lock ring over the test balls and screw down the nut
operator examines visually the test balls to ascertain no gross discrepancy
securely (Note 5). Pour the lubricating fluid to be tested over
in the wear scars formed on the test balls; if discrepancy is noted, then
the three test balls until they are covered. wear scar measurements on all three test balls must be made.
9.9 Record (Table 1, Column 2) for the 784 N (80-kg) load
NOTE 5—Subsequent independent investigations reported in 1971 by
several laboratories indicate that optimum test repeatability is obtained the average scar diameter by any one of the three techniques
when the force on the lock-down nut is maintained within the range 68 6
described in 9.8. Compare this average scar diameter with the
7η·m(50 65ft·lb),applied,andmeasuredbymeansofatorquewrench.
compensation scar diameter (Table 1, Column 3).
Significantly lower weld points were obtained when the force applied was
approximately 136 N·m (100 ft·lb).
9.10 Make additional runs at consecutively higher test loads
(Table 1, Column 1), recording the measured scar diameter(s)
9.2 Bring the lubricant and cup to 18 to 35°C (65 to 95°F).
(Note 10) and discarding test balls, until welding occurs (Note
9.3 Pressoneballintotheballchuck(Note6)andmountthe
11). Make a check run at this point. If welding does not occur
chuck into the chuck-holder.
on the check run, repeat the test at the next higher load until
NOTE 6—Examine the chuck and top ball after each run. If the ball
welding is verified.
shows signs of movement in the chuck, even though welding of the
NOTE 10—Measuring the scar diameter(s) of test balls in the incipient
four-balls did not occur, the chuck should be replaced. When welding
and immediate seizure region is sometimes difficult due to the flow of
occursslippagebetweenballandchucknearlyalwaysoccurs.Ifthechuck
metal obliterating the full contact area formed by the rotating ball. In such
has metal from the top ball adhering to it, the metal must be removed or
casesthemetalflowcangenerallyberemovedorpeeledoffwithasuitable
the chuck replaced.
instrument. See Figs. 4 and 5. If the scar periphery is obscure or not well
9.4 Install the test-lubricant cup assembly on the test appa-
defined an estimate of the scar diameter is made. See Figs. 6 and 7.
ratus in contact with the fourth ball. Place the spacer between
NOTE 11—Shut off the motor immediately to prevent damage to the
cup and thrust bearing. tester. Excessive seizure between the ball and ball chuck may result if
caution is not observed. Welding may be detected by any or all of the
9.5 Place the weight tray and sufficient weights on the
following: (1) If friction-measuring devic
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
An American National Standard Designation: D 2783 – 03 (Reapproved 2009)
Designation:D2783–88(Reapproved1998)
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the determination of the load-carrying properties of lubricating fluids. The following two
determinations are made:
1.1.1Load-wear index (formerly Mean-Hertz load) and
1.1.1 Load-wear index (formerly Mean-Hertz load).
1.1.2 Weld point by means of the four-ball extreme-pressure (EP) tester.
1.2
1.2 For the determination of the load-carrying properties of lubricating greases, see Test Method D 2596.
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.
1.3The values stated in either inch-pound units or SI (metric) units are to be regarded separately as standard. Within the text the
inch-pound units are shown in brackets. The values stated in each system are not exact equivalents, therefore each system must
be used independently of the other. Combining values of the two systems may result in nonconformance with the specification.
1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
2. Referenced Documents
2.1 ASTM Standards:
D484Specification for Hydrocarbon Drycleaning Solvents 2596 Test Method for Measurement of Extreme-Pressure Properties
of Lubricating Grease (Four-Ball Method)
2.2 ANSI Standard:
B 3.12 Metal Balls
3. Terminology
3.1 Definitions:
3.1.1 load-wear index (or the load-carrying property of a lubricant)—an index of the ability of a lubricant to minimize wear at
appliedloads.Undertheconditionsofthistest,specificloadingsinkilograms-force(ornewtons)havingintervalsofapproximately
0.1 logarithmic units, are applied to the three stationary balls for ten runs prior to welding. The load-wear index is the average of
the sum of the corrected loads determined for the ten applied loads immediately preceding the weld pair. compensation line—a
line of plot on logarithmic paper, as shown in Fig. 1, where the coordinates are scar diameter in millimetres and applied load in
kilograms-force (or newtons), obtained under dynamic conditions.
3.1.1.1 Discussion—Coordinates for the compensation line are found in Table 1, Columns 1 and 3.
3.1.1.2 Discussion—Some lubricants give coordinates which are above the compensation line. Known examples of such fluids
are methyl phenyl silicone, chlorinated methyl phenyl silicone, silphenylene, phenyl ether, and some mixtures of petroleum oil and
chlorinated paraffins.
This test method is under the jurisdiction of ASTM Committee D-2 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.L on
Industrial Lubricants.
´1
Current edition approved Oct. 31, 1988. Published December 1988. Originally published as D2783–69T. Last previous edition D2783–82 .
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products and Lubricants and is the direct responsibility of Subcommittee D02.L0.11
on Tribiological Properties of Industrial Fluids and Lubricates.
Current edition approved April 15, 2009. Published July 2009. Originally approved in 1969. Last previous edition approved in 2003 as D 2783 – 03.
This method was prepared under the joint sponsorship of the American Society of Lubrication Engineers. Accepted by ASLE January 1969.
Discontinued; see 1984 Annual Book of ASTM Standards, Vol 05.01.
For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American National Standards Institute, 11 Institute (ANSI), 25 W. 42nd43rd St., 13th4th Floor, New York, NY 10036.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D2783–03 (2009)
ABE—Compensation line.
B—Point of last nonseizure load.
BC—Region of incipient seizure.
CD—Region of immediate seizure.
D—Weld point.
FIG. 1 Schematic Plot of Scar Diameter Versus Applied Load
TABLE 1 Suggested Form for Recording Test Results
Column 1 Column 2 Column 3 Column 5
Column4
Applied Average Scar Compensation Corrected
LD
A h
Load, kg Diameter, Scar Diameter, Load,
Factor
A
(L) mm (X) mm kg (LD /X)
h
6 0.95
8 1.40
10 0.21 1.88
13 0.23 2.67
16 0.25 3.52
20 0.27 4.74
24 0.28 6.05
32 0.31 8.87
40 0.33 11.96
50 0.36 16.10
63 0.39 21.86
80 0.42 30.08
100 0.46 40.5
126 0.50 55.2
160 0.54 75.8
200 0.59 102.2
250 137.5
315 187.1
400 258
500 347
620 462
800 649
A
To convert from kilograms-force to newtons, multiply by 9.806.
3.1.2 weld point—under the conditions of this test, the lowest applied load in kilograms at which the rotating ball welds to the
three stationary balls, indicating the extreme-pressure level of the lubricants-force (or newtons) has been exceeded. compensation
scar diameter—the average diameter, in millimetres, of the wear scar on the stationary balls caused by the rotating ball under an
applied load in the presence of a lubricant, but without causing either seizure or welding.
3.1.2.1 Discussion— Some lubricants do not allow true welding, and extreme scoring of the three stationary balls results. In
such cases, the applied load which produces a maximum scar diameter of 4 mm is reported as the weld point. —The wear scar
obtained shall be within 5 % of the values noted in Table 1, Column 3.
3.1.3 corrected load—the load in kilograms-force (or newtons) for each run obtained by multiplying the applied load by the
ratio of the Hertz scar diameter to the measured scar diameter at that load.
3.1.4 Hertz line—a line of plot on logarithmic paper, as shown in Fig. 1, where the coordinates are scar diameter in millimetres
and applied load in kilograms-force (or newtons), obtained under static conditions.
3.1.5 Hertz scar diameter—the average diameter, in millimetres, of an indentation caused by the deformation of the balls under
static load (prior to test). It may be calculated from the equation
22 1/3
D 5 8.73 3 10 ~P! (1)
h
where:
D = Hertz diameter of the contact area, and, and
h
D2783–03 (2009)
P = the static applied load.
3.1.5compensation scar diameter—the average diameter, in millimetres, of the wear scar on the stationary balls caused by the
rotating ball under an applied load in the presence of a lubricant, but without causing either seizure or welding.
3.1.5.1Discussion—The wear scar obtained shall be within 5% of the values noted in Table 1, Column 3.
3.1.6 Hertz line—a line of plot on logarithmic paper, as shown in immediate seizure region—that region of the scar-load curve
characterized by seizure or welding at the startup or by large wear scars. Initial deflection of indicating pen on the optional
friction-measuring device is larger than with nonseizure loads. See Fig. 1, where the coordinates are scar diameter in millimetres
and applied load in kilograms-force (or newtons), obtained under static conditions. .
3.1.7 compensation line—a line of plot on logarithmic paper, as shown in incipient seizure or initial seizure region—that region
at which, with an applied load, there is a momentary breakdown of the lubricating film. This breakdown is noted by a sudden
increase in the measured scar diameter and a momentary deflection of the indicating pen of the optional friction-measuring device.
SeeFig.1,wherethecoordinatesarescardiameterinmillimetresandappliedloadinkilograms-force(ornewtons),obtainedunder
dynamic conditions.
3.1.7.1Discussion—Coordinates for the compensation line are found in Table 1, Columns 1 and 3.
3.1.7.2Discussion—Some lubricants give coordinates which are above the compensation line. Known examples of such fluids
are methyl phenyl silicone, chlorinated methyl phenyl silicone, silphenylene, phenyl ether, and some mixtures of petroleum oil and
chlorinated paraffins. .
3.1.8 last nonseizure load—the last load at which the measured scar diameter is not more than 5 % above the compensation line
at the load. See Fig. 1.
3.1.9 incipient seizure or initial seizure region—that region at which, with an applied load, there is a momentary breakdown
of the lubricating film. This breakdown is noted by a sudden increase in the measured scar diameter and a momentary deflection
of the indicating pen of the optional friction-measuring device. See Fig. 1. load-wear index (or the load-carrying property of a
lubricant)—an index of the ability of a lubricant to minimize wear at applied loads. Under the conditions of this test, specific
loadingsinkilograms-force(ornewtons)havingintervalsofapproximately0.1logarithmicunits,areappliedtothethreestationary
balls for ten runs prior to welding. The load-wear index is the average of the sum of the corrected loads determined for the ten
applied loads immediately preceding the weld pair.
3.1.10 immediateseizureregion—thatregionofthescar-loadcurvecharacterizedbyseizureorweldingatthestartuporbylarge
wear scars. Initial deflection of indicating pen on the optional friction-measuring device is larger than with nonseizure loads. See
Fig. 1. weld point—under the conditions of this test, the lowest applied load in kilograms at which the rotating ball welds to the
three stationary balls, indicating the extreme-pressure level of the lubricants-force (or newtons) has been exceeded.
3.1.10.1 Discussion—Some lubricants do not allow true welding, and extreme scoring of the three stationary balls results. In
such cases, the applied load which produces a maximum scar diameter of 4 mm is reported as the weld point.
4. Summary of Test Method
4.1 The tester is operated with one steel ball under load rotating against three steel balls held stationary in the form of a cradle.
Test lubricant covers the lower three balls. The rotating speed is 1760 6 40 rpm. The machine and test lubricant are brought to
18.3318 to 35.0°C35°C (65 to 95°F) and then a series of tests of 10-s duration are made at increasing loads until welding occurs.
Ten tests are made below the welding point. If ten loads have not been run when welding occurs and the scars at loads below
seizure are within 5 % of the compensation line (AB Fig. 1) no further runs are necessary. The total can be brought to ten by
assuming that loads below the last nonseizure load will produce wear scars equal to the “compensation scar diameter.” Values of
these “assumed” scars are given in Table 1. For clarification of “last nonseizure load” and “weld point” see Fig. 1.
5. Significance and Use
5.1 This test method, used for specification purposes, differentiates between lubricating fluids having low, medium, and high
level of extreme-pressure properties. The user of this method should determine to his own satisfaction whether results of this test
procedure correlate with field performance or other bench test machines.
6. Apparatus
6.1 Four-Ball Extreme-Pressure Tester, illustrated in Fig. 2Figs. 2 and and Fig. 33.
NOTE 1—It is important to distinguish between the four-ball EPtester and the four-ball wear tester.The four-ball EPtester 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.
Further details applicable to this method may be found in: Sayles, F. S., et al., “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.
SatisfactorysourcesofsupplyforthisinstrumentareFalexCorp.,1020AirparkDr.,SugarGrove,IL60554–9585andStanhope-SetaLtd.,ParkClose,Egham,Englefield
Green, Surrey, England TW20 OXD.
D2783–03 (2009)
FIG. 2 Sectional View of Four-Ball Tester
FIG. 3 Four-Ball EP Test Machine
NOTE 2—Optional equipment with four-ball apparatus consists of a friction-measuring device electrically driven and conveniently graduated in 10-s
markings.
7. Materials
7.1Stoddard Solvent, in accordance with Specification D484.
NOTE3—Warning:
7.1 Cleaning Solvent, safe, non-film forming, nonchlorinated. (Warning— Flammable. Harmful if inhaled. See A1.1.)
D2783–03 (2009)
7.2Heptane
NOTE4—Warning: 3—Certain petroleum distillates, formerly used as solvents, have been eliminated due to possible toxic effects. Each user should
select a solvent that can meet applicable safety requirements and thoroughly clean machine parts. Reagent Grade Stoddard solvent is an example of a
solvent that has been found suitable.
7.2 Rinse Solvent, same as in 7.1, but with higher volatility.ASTM n-Heptane is an example of one such rinse solvent that has
been found suitable. (Warning—Flammable. Harmful if inhaled. See A1.2.)
7.3 Test Balls —Test balls shall be chrome alloy steel, made fromAISI standard steel No. E-52100, with diameter of 12.7 mm
(0.5 in.), Grade 25 EP (Extra Polish). Such balls are described in ANSI Specifications B 3.12, for Metal Balls. The Extra-Polish
finish is not described in that specification. The Rockwell C hardness shall be 64 to 66, a closer limit than is found in the ANSI
requirement.
8. Preparation of Apparatus
8.1Thoroughly clean four new test balls, test-lubricant cup, and chuck assemblies by first washing with Stoddard solvent (Note
9) (Warning—See Note 7 and A1.1.) and then heptane. (Warning—See Note 8 and A1.2.)
8.1 Thoroughly clean four new test balls, test-lubricant cup, and chuck assemblies by first washing with cleaning solvent (see
7.1) and then rinse solvent (see 7.2).
NOTE5—Do 4—Do not use solvents such as carbon tetrachloride or other solvents that may inherently possess load-carrying properties which may
affect th
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