Standard Test Method for Determining Extreme Pressure Properties of Lubricating Greases Using A High-Frequency, Linear-Oscillation (SRV) Test Machine

SIGNIFICANCE AND USE
This laboratory test method can be used to quickly determine extreme pressure properties of lubricating greases at selected temperatures specified for use in applications where high-speed vibrational or start-stop motions are present with high Hertzian point contact. This test method has found wide application in qualifying lubricating greases used in constant velocity joints of front-wheel-drive automobiles. Users of this test method should determine whether results correlate with field performance or other applications.
SCOPE
1.1 This test method covers a procedure for determining extreme pressure properties of lubricating greases under high-frequency linear-oscillation motion using the SRV test machine. This test method can also be used for evaluating extreme pressure properties of lubricating fluid.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
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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ASTM D5706-05(2011)e1 - Standard Test Method for Determining Extreme Pressure Properties of Lubricating Greases Using A High-Frequency, Linear-Oscillation (SRV) Test Machine
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
´1
Designation:D5706–05 (Reapproved 2011)
Standard Test Method for
Determining Extreme Pressure Properties of Lubricating
Greases Using a High-Frequency, Linear-Oscillation (SRV)
Test Machine
This standard is issued under the fixed designation D5706; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
´ NOTE—Updated 7.6 and Fig. 1, and added Note 3 editorially in July 2011.
1. Scope 2.2 Other Standards:
DIN EN ISO 683-17 Heat-treated Steels, alloy steels and
1.1 This test method covers a procedure for determining
free-cuttingsteels–Part17:Ballandrollerbearingsteels
extreme pressure properties of lubricating greases under high-
DIN EN ISO 13565-2:1998 Geometrical Product Specifica-
frequency linear-oscillation motion using the SRV test ma-
tions (GPS) – Surface texture: Profile method; Surfaces
chine.Thistestmethodcanalsobeusedforevaluatingextreme
having stratified functional properties – Part 2: Height
pressure properties of lubricating fluid.
characterizationusinglinearmaterialratiocurve(replaces
1.2 The values stated in SI units are to be regarded as
DIN 4776:1990: Measurement of surface roughness; pa-
standard. No other units of measurement are included in this
rametersR ,R ,R ,M ,M forthedescriptionofthe
K PK VK r1 r2
standard.
material portion)
1.3 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
3. Terminology
responsibility of the user of this standard to establish appro-
3.1 Definitions:
priate safety and health practices and determine the applica-
3.1.1 break-in, n—in tribology, an initial transition process
bility of regulatory limitations prior to use.
occurring in newly established wearing contacts, often accom-
2. Referenced Documents panied by transients in coefficient of friction or wear rate, or
both, which are uncharacteristic of the given tribological
2.1 ASTM Standards:
system’s long-term behavior. G40
A295/A295M Specification for High-Carbon Anti-Friction
3.1.2 coeffıcient of friction, µ or f, n—in tribology, the
Bearing Steel
dimensionless ratio of the friction force (F) between two
D217 Test Methods for Cone Penetration of Lubricating
bodies to the normal force (N) pressing these bodies together.
Grease
G40
D4175 Terminology Relating to Petroleum, Petroleum
3.1.3 Hertzian contact area, n—theapparentareaofcontact
Products, and Lubricants
between two nonconforming solid bodies pressed against each
D6425 Test Method for Measuring Friction andWear Prop-
other, as calculated from Hertz’s equations of elastic deforma-
erties of Extreme Pressure (EP) Lubricating Oils Using
tion. G40
SRV Test Machine
3.1.4 Hertzian contact pressure, n—the magnitude of the
E45 TestMethodsforDeterminingtheInclusionContentof
pressure at any specified location in a Hertzian contact area, as
Steel
calculated from Hertz’s equations of elastic deformation.
G40 Terminology Relating to Wear and Erosion
G40
3.1.5 lubricant, n—any material interposed between two
This test method is under the jurisdiction of ASTM Committee D02 on
surfaces that reduces the friction or wear, or both, between
PetroleumProductsandLubricantsandisthedirectresponsibilityofSubcommittee
them. D4175
D02.G0.04 on Functional Tests - Tribology.
3.1.6 lubricating grease, n—asemi-fluidtosolidproductof
Current edition approved July 1, 2011. Published August 2011. Originally
approved in 1995. Last previous edition approved in 2005 as D5706–05. DOI:
a dispersion of a thickener in a liquid lubricant. D217
10.1520/D5706-05R11E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
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 AvailablefromDeutschesInstitutfurNormunge.V.(DIN),Burggrafenstrasse6,
the ASTM website. 10787 Berlin, Germany, http://www.din.de.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
´1
D5706–05 (2011)
FIG. 1 SRV Test Machine, Model III (left), Model 4 (right)
3.1.6.1 Discussion—Thedispersionofthethickenerformsa 3.2.2.1 Discussion—Inthistestmethod,seizureisindicated
two-phase system and immobilizes the liquid lubricant by
by a sharp rise in the coefficient of friction, over steady state,
surfacetensionandotherphysicalforces.Otheringredientsare of greater than 0.2 for over 20 s. In severe cases, a stoppage in
commonly included to impart special properties.
the motor will occur.
3.1.7 thickener, n—in lubricating grease, a substance com-
3.2.3 SRV, n—Schwingung, Reibung, Verschleiss (Ger-
posed of finely divided solid particles dispersed in a liquid
man); oscillating, friction, wear (English translation).
lubricant to form the grease structure. D217
3.1.7.1 Discussion—The thickener can be fibers (such as
4. Summary of Test Method
various metallic soaps) or plates or spheres (such as certain
4.1 This test method is performed on an SRV test machine
non-soapthickeners)whichareinsolubleor,atmost,onlyvery
using a steel test ball oscillating against a stationary steel test
slightly soluble in the liquid lubricant. The general require-
disk with lubricant between them. Test load is increased in
mentsarethatthesolidparticlesbeextremelysmall,uniformly
100-N increments until seizure occurs. The load, immediately
dispersed, and capable of forming a relatively stable, gel-like
prior to the load at which seizure occurs, is measured and
structure with the liquid lubricant.
reported.
3.1.8 Ra (C.L.A.), n—in measuring surface finish, the arith-
metic average of the absolute distances of all profile points
NOTE 1—Test frequency, stroke length, temperature, and ball and disk
from the mean line for a given distance.
material can be varied to simulate field conditions. The test ball yields
point-contact geometry. To obtain line or area contact, test pieces of
3.1.8.1 Discussion—C.L.A. means center line average, and
differing configurations can be substituted for the test balls.
it is a synonym for Ra.
3.1.9 Rpk, n—reduced peak height according to DIN EN
5. Significance and Use
ISO13565-2:1998.Rpkisthemeanheightofthepeaksticking
out above the core profile section. 5.1 This laboratory test method can be used to quickly
3.1.10 Rvk, n—reduced valley height according to DIN EN determineextremepressurepropertiesoflubricatinggreasesat
selected temperatures specified for use in applications where
ISO 13565-2:1998. Rvk is the mean depth of the valley
reaching into the material below the core profile section. high-speed vibrational or start-stop motions are present with
high Hertzian point contact. This test method has found wide
3.1.11 Ry, n—in measuring surface finish, the vertical
application in qualifying lubricating greases used in constant
distance between the top of the highest peak and the bottom of
velocity joints of front-wheel-drive automobiles. Users of this
the deepest valley in one sampling length.
test method should determine whether results correlate with
3.1.12 Rz (DIN), n—in measuring surface finish, the aver-
field performance or other applications.
age of all Ry values (peak to valley heights) in the assessment
length.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 extreme pressure, adj—in lubrication—characterized
Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003-0785,
by metal surfaces in contact under high-stress rubbing condi- Sheffield Measurement Division, Warner and Swasey, 1985, p. 21.
Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003-0785,
tions.
Sheffield Measurement Division, Warner and Swasey, 1985, p. 25.
3.2.2 seizure, n—localized fusion of metal between the
Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003-0785,
rubbing surfaces of the test pieces. Sheffield Measurement Division, Warner and Swasey, 1985, pp. 31, 29.
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D5706–05 (2011)
7.5 Toluene, reagent grade. (Warning—Flammable. Health
hazard)
7.6 Cleaning Solvent, the test disks have to be cleaned by a
liquid solvent (non-chlorinated, non-film forming).
NOTE 3—It is recommended to use a mixture of equal volumes of
n-heptane, isopropanol, and toluene, all as reagent grades. (Warning—
Flammable. Health hazard.)
8. Preparation of Apparatus
8.1 Turnonthetestmachineandchartrecorderandallowto
warm up for 15 min prior to running tests.
8.2 Select the friction data to be presented in the crest peak
value position in accordance with the manufacturer’s direc-
tions.
NOTE 4—In most cases, this is accomplished by positioning the sliding
switchonelectroniccardNO.291.35.20E(frontsideofelectronicsbehind
the front panel) and the sliding switch located on the back panel of the
control unit.
1. Oscillation drive rod 6. Electrical resistance heater
2. Test ball holder 7. Resistance thermometer
8.3 Turn the amplitude knob to ZERO.
3. Load rod 8. Test disk holder
8.4 Switch the stroke adjustment to AUTO position.
4. Test ball 9. Piezoelectric measuring device
8.5 Set the frequency to 50 Hz.
5. Test disk 10. Receiving block
8.6 Set the desired span and calibrate the chart recorder in
FIG. 2 Test Chamber Elements
accordance with the manufacturer’s instructions. Select the
desired chart speed.
6. Apparatus
6.1 SRV Test Machine, illustrated in Fig. 1 and Fig. 2.
9. Procedure
9.1 Clean the test ball and disk by wiping the surfaces with
7. Reagents and Materials
laboratory tissue soaked with the cleaning solvent. Repeat
7.1 Test Balls, 52100 steel, Rockwell hardness number of
wipinguntilnodarkresidueappearsonthetissue.Immersethe
60 6 2 on Rockwell C scale (HRC), 0.025 6 0.005-µm Ra
test ball and disk in a beaker of the cleaning solvent under
surface finish, 10-mm diameter.
ultrasonic vibration for 10 min. Dry the test ball and disk with
7.2 Lower Test Disk, vacuum arc remelted (VAR) AISI
a clean tissue to ensure no streaking occurs on the surface.
52100 steel with an inclusion rating using Method D, TypeA,
9.2 Procedures A and B:
as severity level number of 0.5 according toTest Methods E45
9.2.1 Procedure A—Place a small amount (approximately
and Specification A295/A295M or an inclusion sum value
0.1to0.2g,thesizeofapea)oflubricatinggreasetobetested
K1# 10 according to DIN EN ISO 683-17 and spherodized
on the cleaned test disk in an area such that overlapping with
annealed to obtain globular carbide, Rockwell hardness num-
previous wear scars will not occur.
ber of 60 6 2 on Rockwell C scale (HRC), the surfaces of the
9.2.2 Procedure B—Place the grease caliper with 1 mm in
disk being lapped and free of lapping raw materials. The
height on the cleaned disc. Fill the opening of the grease
topography of the disk will be determined by four values,
caliper with grease. Remove any excess grease by means of a
24-mm diameter by 7.85 mm thick:
spatula.Removethegreasecaliperbyliftingitupwards.Fasten
0.5 µm < Rz (DIN) < 0.650 µm
the disc in the specimen holder.
0.035 µm < Ra (C.L.A.) < 0.050 µm
9.3 Place the cleaned test ball on the top and in the middle
0.020 µm < Rpk < 0.035 µm
ofthelubricatinggreasespecimensothatthelubricatinggrease
0.050 µm < Rvk < 0.075 µm
makes a circular symmetric pad between the test ball and disk.
NOTE 2—The DIN 17230-1980 was replaced by DIN EN ISO 683-17. 9.4 Ensure the machine is unloaded (indicated by a load
reading of−13 or−14 N) and carefully place disk containing
7.3 n-Heptane, reagent grade. (Warning—Flammable.
the lubricating grease specimen and test ball on the test area
Health hazard.)
platform.
7.4 Isopropanol, reagent grade. (Warning—Flammable.
9.5 Tighten both the ball and disk clamps until resistance to
Health hazard.)
tightening just begins. Then load unit to 100 N and tighten the
ball and disk clamps to a torque of 2.5 N·m. Reduce the load
to 50 N for break-in.
The sole source of supply of the apparatus known to the committee at this time
is Optimol Instruments Prüftechnik GmbH, Westendstrasse 125, D-80339, Munich
9.6 Turn on the heater control and set to the desired
Germany, http://www.optimol-instruments.de. If you are aware of alternative
temperature.
suppliers, please provide this information to ASTM International Headquarters.
9.7 Set the load charge amplifier to the setting that corre-
Your comments will receive careful consideration at a meeting of the responsible
technical committee, which you may attend. sponds to the 400-N load.
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D5706–05 (2011)
9.8 Change the load charge amplifier at each load in requesting Research Report RR:D02-1410 or read in Dick-
accordance with the manufacturer’s instructions when the ey’s publication. The stroke was 1.0 mm for Procedure A.
coefficient of friction at each test load is to be studied. 11.2 The following criteria should be used for judging the
9.9 When the temperature has stabilized, turn on the chart acceptability of results (95% probability) for lubricating
recorder and depress the drive start toggle switch until the greases which have load carrying capacities of 1200 N or less
timerbeginstocountandthenadjustthestrokeamplitudeknob intheSRVapparatususingProcedureAwith1.0mmofstroke.
to 1.00 mm for Procedure A and to 1.5 mm for Procedure B. 11.2.1 Repeatability—The difference between successive
9.10 When the digital timer reaches 30 s, increase the load results obtained by the same operator with the same apparatus
to100Nusingtheslowrampspeedrateandmaintainthisload under constant operating conditions on identical test material
for 2 min for ProcedureAand 15 min for Procedure B.The 2– would, in the long run, in the normal and correct operation of
or 15–min interval includes the loading ramp sequence. In- thetestmethodexceedthefollowingvaluesonlyinonecasein
creasetheloadby100Nevery2minusingtheslowrampuntil twenty.
a load of 1200 N is reached, or the load limit of the test
Fortestsrunat50°C:0.7X
apparatus is attained, or failure occurs. Failure is indicated by
Fortestsrunat80°C:0.6 ~X 1122!
a rise in coefficient of friction of greater than 0.2 over steady
state for over 20 s or a stoppage in the oscillating of the test
where:
machine (see Test Method D6425).
X = the average of two results, N.
11.2.2 Reproducibility—The difference between two single
NOTE 5—Because a 30-s break-in at 50 N is used, the load increase
and independent results obtained by different operators work-
times will occur on the half minute of even minutes.
NOTE 6—TheSRVtestmachinesavailableafter1992haveamaximum ingindifferentlaboratoriesonidenticaltestmaterialswou
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