ASTM D7421-08
(Test Method)Standard Test Method for Determining Extreme Pressure Properties of Lubricating Oils Using High-Frequency, Linear-Oscillation (SRV) Test Machine
Standard Test Method for Determining Extreme Pressure Properties of Lubricating Oils Using 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 oils at selected temperatures specified for use in applications where not only high-speed vibrational or start-stop motions are present with high Hertzian point contact. This test method has found wide application in qualifying lubricating oils used in constant velocity joints of front-wheel-drive automobiles, gear-hydraulic circuit, rear axles, gears and engine components. 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 oils for hydraulics, gears and engines under high-frequency linear-oscillation motion using the SRV test machine.
Note 1—This test method was developed and the international round robin tests were jointly performed with the DIN 51834 working group. This procedure is based on the 2005 revision of Test Method D 5706 for greases and differs regarding the stroke length and the cleaning solvent.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
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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Standards Content (Sample)
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Designation:D7421–08
Standard Test Method for
Determining Extreme Pressure Properties of Lubricating
Oils Using High-Frequency, Linear-Oscillation (SRV) Test
Machine
This standard is issued under the fixed designation D7421; 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 E45 Test Methods for Determining the Inclusion Content of
Steel
1.1 This test method covers a procedure for determining
G40 Terminology Relating to Wear and Erosion
extreme pressure properties of lubricating oils for hydraulics,
2.2 DIN Standards:
gears and engines under high-frequency linear-oscillation mo-
DIN 51631:1999 Mineral spirits; special boiling point spir-
tion using the SRV test machine.
its; requirements
NOTE 1—This test method was developed and the international round
DIN EN ISO 683-17 Heat-treated Steels, alloy steels and
robin tests were jointly performed with the DIN 51834 working group.
free-cutting steels – Part 17 : Ball and roller bearing steels
This procedure is based on the 2005 revision of Test Method D5706 for
(Replaces DIN 17230-1980)
greases and differs regarding the stroke length and the cleaning solvent.
DIN EN ISO 13565-2:1998 Geometrical Product Specifica-
1.2 The values stated in SI units are to be regarded as
tions (GPS) – Surface texture: Profile method; Surfaces
standard. No other units of measurement are included in this
having stratified functional properties – Part 2: Height
standard.
characterization using linear material ratio curve [Re-
1.3 This standard does not purport to address all of the
placement of DIN 4776:1990: Measurement of surface
safety concerns, if any, associated with its use. It is the
roughness; parameters R ,R ,R ,M ,M for the
K PK VK r1 r2
responsibility of the user of this standard to establish appro-
description of the material portion]
priate safety and health practices and determine the applica-
2.3 ISO Standards:
bility of regulatory limitations prior to use.
ISO 1250:1972 Mineral solvents for paints, white spirits
and related hydrocarbon solvents
2. Referenced Documents
2.1 ASTM Standards:
3. Terminology
A295/A295M Specification for High-Carbon Anti-Friction
3.1 Definitions:
Bearing Steel
3.1.1 break-in, n—in tribology, an initial transition process
D235 Specification for Mineral Spirits (Petroleum Spirits)
occurring in newly established wearing contacts, often accom-
(Hydrocarbon Dry Cleaning Solvent)
panied by transients in coefficient of friction or wear rate, or
D4175 Terminology Relating to Petroleum, Petroleum
both, which are uncharacteristic of the given tribological
Products, and Lubricants
system’s long-term behavior. G40
D5706 Test Method for Determining Extreme Pressure
3.1.2 coeffıcient of friction, µorf, n—in tribology, the
Properties of Lubricating Greases Using a High-
dimensionless ratio of the friction force (F) between two
Frequency, Linear-Oscillation (SRV) Test Machine
bodies to the normal force (N) pressing these bodies together.
D6425 Test Method for Measuring Friction and Wear Prop-
G40
erties of Extreme Pressure (EP) Lubricating Oils Using
3.1.3 Hertzian contact area, n—apparent area of contact
SRV Test Machine
between two nonconforming solid bodies pressed against each
other, as calculated from Hertz’s equations of elastic deforma-
tion published in 1881. G40
3.1.4 Hertzian contact pressure, n—magnitude of the pres-
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
sure at any specified location in a Hertzian contact area, as
D02.L0 on Industrial Lubricants.
Current edition approved Feb. 1, 2008. Published March 2008. DOI: 10.1520/
D7421-08.
2 3
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Available from Beuth Verlag GmbH (DIN, Deutsches Institut fur Normung
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM e.V.), Burggrafenstrasse 6, 10787, Berlin, Germany, http://www.en.din.de.
Standards volume information, refer to the standard’s Document Summary page on Available from International Organization for Standardization (ISO), 1 rue de
the ASTM website. Varembé, Case postale 56, CH-1211, Geneva 20, Switzerland, http://www.iso.ch.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7421–08
calculated from Hertz’s equations of elastic deformation. The
Hertzian contact pressure can also be calculated and reported
as maximum value P in the centre of the contact or as
max
P as average over the total contact area. G40
average
3.1.5 lubricant, n—any material interposed between two
surfaces that reduces the friction or wear, or both between
them. D4175
3.1.6 Ra (C.L.A.), n—in measuring surface finish, the arith-
metic average of the absolute distances of all profile points
from the mean line for a given distance. Amstutz
3.1.6.1 Discussion—C.L.A. means center line average, and
it is the synonym to Ra.
3.1.7 Rpk, n—Reduced peak height according to DIN EN
ISO13565-2:1998.Rpkisthemeanheightofthepeaksticking
out above the core profile section.
3.1.8 Rvk,, n—Reduced valley height according to DIN EN
ISO 13565-2:1998. Rvk is the mean depth of the valley
FIG. 1 SRV Test Machine (Model III)
reaching into the material below the core profile section.
3.1.9 Ry, n—in measuring surface finish, the vertical dis-
In SRV IV models, the test described here is run horizontally and without
tancebetweenthetopofthehighestpeakandthebottomofthe
inclination. SRV I and II models can also perform this test, but they are
deepest valley in one sampling length. Amstutz
limited with regard to maximum load and stroke. As modern and high
3.1.10 Rz (DIN), n—in measuring surface finish, the aver-
performance oils may exceed an O.K.-load of 1200 N, seizure may not be
age of all Ry values (peak to valley heights) in the assessment
reached. Optimol Instruments supplies an upgrade kit to allow for SRV I
5 6
length. Amstutz and SRV II models to be operated at 1600 N, if needed.
3.2 Definitions of Terms Specific to This Standard:
5. Significance and Use
3.2.1 extreme pressure, adj—in lubrication, characterized
5.1 This laboratory test method can be used to quickly
by metal surfaces in contact under high-stress rubbing condi-
determine extreme pressure properties of lubricating oils at
tions. It is not limited to metallic materials.
selected temperatures specified for use in applications where
3.2.2 seizure, n—localized fusion of metal or other materi-
not only high-speed vibrational or start-stop motions are
als between the rubbing surfaces of the test pieces.
present with high Hertzian point contact. This test method has
3.2.2.1 Discussion—In this test method, seizure is indicated
found wide application in qualifying lubricating oils used in
by a sharp rise in the coefficient of friction, over steady state,
constantvelocityjointsoffront-wheel-driveautomobiles,gear-
of >0.2 for over 20 s. In severe cases, a stoppage in the motor
hydraulic circuit, rear axles, gears and engine components.
will occur. (These criteria were believed to be right, because
Users of this test method should determine whether results
this test method is related to liquid lubricants.)
correlate with field performance or other applications.
3.2.3 SRV, n—Schwingung, Reibung, Verschleiß (Ger-
man); oscillating, friction, wear (English translation).
6. Apparatus
4. Summary of Test Method
illustrated in Figs. 1-3.
6.1 SRV Test Machine,
4.1 This test method is performed on an SRV test machine 6.2 Test Balls, 52100 steel, 60 6 2 Rc hardness, 0.025 6
0.005-µm Ra surface finish, 10-mm diameter.
using a steel test ball oscillating against a stationary steel test
disk with lubricant between them. Test load is increased in 6.3 Lower Test Disk, vacuum arc remelted (VAR) AISI
52100 steel with a inclusion rating using Method D, Type A,
100-N increments until seizure occurs. The load, immediately
prior to the load at which seizure occurs, is measured and and a severity level number of 0.5 according to Specification
A295/A295M or Test Methods E45 or an inclusion sum value
reported as O.K.-load, which can be converted in Hertzian
contact pressures. K1 # 10 in accordance with DIN EN ISO 683-17 and
spherodized annealed to obtain globular carbide, 60 62Rc
NOTE 2—Test frequency, stroke length, temperature, and ball and disk
hardness, with the surfaces of the disk being lapped and free of
material can be varied to simulate field conditions. The test ball yields
lapping raw materials. The topography of the disk will be
point-contact geometry. To obtain line or area contact, test pieces of
determined by four values, 24-mm diameter by 7.85 mm thick:
differing configurations can be substituted for the test balls.
NOTE 3—With regard to the test chamber and the operating conditions,
SRV models III and IV are identical. However, the SRV IV allows to
incline the axis of movement. Both models are fully computer controlled.
The sole source of supply of the apparatus known to the committee at this time
is Optimol Instruments GmbH,Westendstr. 125, D-80339 Munich, Germany. If you
are aware of alternative suppliers, please provide this information to ASTM
Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003-0785, International Headquarters. Your comments will receive careful consideration at a
Sheffield Measurement Division, Warner and Swasey, 1985. meeting of the responsible technical committee, which you may attend.
D7421–08
8.3 Turn the amplitude knob to ZERO.
8.4 Switch the stroke adjustment to AUTO position.
8.5 Set the frequency to 50 Hz.
8.6 Set the desired span and calibrate the chart recorder in
accordance with the manufacturer’s instructions. Select the
desired chart speed.
8.7 Turnontheheatercontrol,andpreheatthediskholderto
the desired temperature. 50°C, 80°C, and 120°C are recom-
mended (see Table 1). When the temperature has stabilized,
turn on the chart recorder and depress the drive start toggle
switchuntilthetimerbeginstocountandthenadjustthestroke
amplitude knob to 2.00 mm.
8.8 Set the load charge amplifier to setting that corresponds
to the 400-N load.
8.9 Change the load charge amplifier at each load in
accordance with the manufacturer’s instructions whe
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