ASTM D7594-24e1

Standard Test Method for Determining Fretting Wear Resistance of Lubricating Greases Under High Hertzian Contact Pressures Using a High-Frequency, Linear-Oscillation (SRV) Test Machine

SIGNIFICANCE AND USE
5.1 This test method can be used to determine anti-wear properties and coefficient of friction of greases in order to prevent “fretting” wear under linear oscillation with associated low strokes and high Hertzian contact pressures at selected temperatures and loads specified for use in applications in which induced, high-speed vibrational motions are present for extended periods of time. It has found application as a screening test for grease lubricants used in ball and roller bearings, roller or ball screw (spindle) drives or side shaft systems (Tripode or Rzeppa type) for example, so-called constant velocity (CV) joints. 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 the lubricating action of greases in order to prevent “fretting” wear under linear oscillation with associated low strokes and high Hertzian contact pressures under high-frequency linear-oscillation motion using the SRV test machine. By performing additional, nonmandatory extreme-pressure tests in accordance with Test Method D5706, the test grease should be shown to be able to withstand a Hertzian contact pressure of at least 2200 MPa without adhesive failure.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 14-Jan-2024
• ICS: 75.100 - Lubricants, industrial oils and related products
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.G0.04 - Functional Tests - Tribology

Relations

• Replaces: ASTM D7594-24 - Standard Test Method for Determining Fretting Wear Resistance of Lubricating Greases Under High Hertzian Contact Pressures Using a High-Frequency, Linear-Oscillation (SRV) Test Machine
• Effective Date: 15-Jan-2024
• Referred By: ASTM D8324-21 - Standard Guide for Selection of Environmentally Acceptable Lubricants for the U.S. Environmental Protection Agency (EPA) Vessel General Permit
• Effective Date: 15-Jan-2024

Overview

ASTM D7594-24e1 is the internationally recognized standard test method for determining the fretting wear resistance of lubricating greases under high Hertzian contact pressures using a high-frequency, linear-oscillation (SRV) test machine. Developed by ASTM, this method provides a systematic procedure to evaluate the anti-wear properties and coefficient of friction of greases in applications where high-frequency vibrational motions and substantial contact pressures are present, such as in ball and roller bearings, spindle drives, and constant velocity joints. Reliable assessment of lubricating greases ensures optimal performance and longevity of machinery subjected to fretting wear.

Key Topics

• Fretting Wear Resistance: The method assesses a lubricant’s ability to minimize wear in oscillating conditions with low stroke lengths and significant contact pressure.
• High-Frequency Linear Oscillation: Utilization of an SRV test machine replicates real-world operating conditions, allowing for controlled and repeatable laboratory testing.
• Coefficient of Friction: Measurement and reporting of changes in friction between contacting surfaces throughout the test duration provide essential insight into lubricant performance.
• Anti-Wear Performance: The test identifies greases that effectively prevent micro-motions from causing damaging fretting wear.
• Test Parameters: Typical test variables include load, frequency (e.g., 50 Hz), amplitude (e.g., 0.30 mm), and temperature (common test points: 50°C, 80°C, 120°C).
• Result Reporting: Outcomes include average wear scar diameter, wear volume (when measurable), coefficient of friction values, and observation of seizure events.

Applications

ASTM D7594-24e1 is widely applied in several key industrial sectors:

• Bearings: Evaluation of lubricating greases for use in ball and roller bearings exposed to vibrational loads.
• Automotive Components: Screening of greases for CV joints, side shaft systems, and spindle drives to extend service life and minimize maintenance.
• Manufacturing Equipment: Used in the selection and quality control of greases for high-speed or precision machinery components exposed to oscillating stresses.
• R&D and Quality Assurance: Provides manufacturers with data to optimize grease formulations and ensure conformity to performance expectations before field deployment.
• Failure Analysis: Used to investigate wear mechanisms and diagnose lubricant-related wear failures in mechanical systems.

Related Standards

Several standards complement or are referenced within ASTM D7594-24e1:

• ASTM D5706 - Test Method for Determining Extreme Pressure Properties of Lubricating Greases Using a High-Frequency, Linear-Oscillation (SRV) Test Machine
• ASTM D6425 - Test Method for Measuring Friction and Wear Properties of Extreme Pressure (EP) Lubricating Oils Using SRV Test Machine
• ASTM D7755 - Practice for Determining the Wear Volume on Standard Test Pieces Used by High-Frequency, Linear-Oscillation (SRV) Test Machine
• ASTM D217 - Test Methods for Cone Penetration of Lubricating Grease
• DIN 51834-3 - Testing of Lubricants-Tribological Test in Translatory Oscillation Apparatus-Part 3: Determination of Tribological Behaviour of Materials in Cooperation with Lubricants
• DIN EN ISO 13565-2 - Geometrical Product Specifications (GPS)-Surface Texture

Practical Value

Applying ASTM D7594-24e1 allows grease suppliers, bearing manufacturers, and end users to:

• Confidently compare grease products for critical equipment subjected to vibration and high contact stress.
• Optimize maintenance schedules by selecting greases proven to extend component life.
• Reduce operational downtime and costs associated with component failure due to inadequate lubrication.
• Support regulatory compliance and documentation in international trade, thanks to adherence to World Trade Organization principles.

ASTM D7594-24e1 serves as a cornerstone for quality assurance and product development in specialized lubrication scenarios, helping ensure machinery reliability and performance in demanding operational environments.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
´1
Designation: D7594 − 24
Standard Test Method for
Determining Fretting Wear Resistance of Lubricating
Greases Under High Hertzian Contact Pressures Using a
High-Frequency, Linear-Oscillation (SRV) Test Machine
This standard is issued under the fixed designation D7594; 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.
ε NOTE—Editorially corrected precision statement in April 2024.
1. Scope* D217 Test Methods for Cone Penetration of Lubricating
Grease
1.1 This test method covers a procedure for determining the
D235 Specification for Mineral Spirits (Petroleum Spirits)
lubricating action of greases in order to prevent “fretting” wear
(Hydrocarbon Dry Cleaning Solvent)
under linear oscillation with associated low strokes and high
D4175 Terminology Relating to Petroleum Products, Liquid
Hertzian contact pressures under high-frequency linear-
Fuels, and Lubricants
oscillation motion using the SRV test machine. By performing
D5706 Test Method for Determining Extreme Pressure
additional, nonmandatory extreme-pressure tests in accordance
Properties of Lubricating Greases Using a High-
with Test Method D5706, the test grease should be shown to be
Frequency, Linear-Oscillation (SRV) Test Machine
able to withstand a Hertzian contact pressure of at least
D6425 Test Method for Measuring Friction and Wear Prop-
2200 MPa without adhesive failure.
erties of Extreme Pressure (EP) Lubricating Oils Using
1.2 The values stated in SI units are to be regarded as
SRV Test Machine
standard. No other units of measurement are included in this
D7421 Test Method for Determining Extreme Pressure
standard.
Properties of Lubricating Oils Using High-Frequency,
1.3 This standard does not purport to address all of the
Linear-Oscillation (SRV) Test Machine
safety concerns, if any, associated with its use. It is the D7755 Practice for Determining the Wear Volume on Stan-
responsibility of the user of this standard to establish appro-
dard Test Pieces Used by High-Frequency, Linear-
priate safety, health, and environmental practices and deter- Oscillation (SRV) Test Machine
mine the applicability of regulatory limitations prior to use. E45 Test Methods for Determining the Inclusion Content of
1.4 This international standard was developed in accor-
Steel
dance with internationally recognized principles on standard- G40 Terminology Relating to Wear and Erosion
ization established in the Decision on Principles for the
2.2 Other Standards:
Development of International Standards, Guides and Recom-
DIN 51834-3:2008-12 Testing of Lubricants—Tribological
mendations issued by the World Trade Organization Technical
Test in Translatory Oscillation Apparatus—Part 3: Deter-
Barriers to Trade (TBT) Committee.
mination of Tribological Behaviour of Materials in Coop-
eration with Lubricants
2. Referenced Documents
DIN 51631:1999 Special-Boiling-Point Spirits—
2.1 ASTM Standards:
Requirements and Testing
A295/A295M Specification for High-Carbon Anti-Friction
DIN EN ISO 683-17 Heat-Treated Steels, Alloy Steels and
Bearing Steel
Free-Cutting Steels—Part 17: Ball and Roller Bearing
Steels [Replaces DIN 17230-1980]
DIN EN ISO 13565-2:1998 Geometrical Product Specifica-
This test method is under the jurisdiction of ASTM Committee D02 on
tions (GPS)—Surface Texture: Profile Method—Surfaces
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Having Stratified Functional Properties—Part 2: Height
Subcommittee D02.G0.04 on Functional Tests - Tribology.
Current edition approved Jan. 15, 2024. Published February 2024. Originally
Characterization Using the Linear Material Ratio Curve
approved in 2010. Last previous edition approved in 2019 as D7594 – 19.
DOI:10.1520/D7594-24E01.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Available from Available from Beuth Verlag GmbH (DIN–DIN Deutsches
Standards volume information, refer to the standard’s Document Summary page on Institut fur Normung e.V.), Burggrafenstrasse 6, 10787, Berlin, Germany, http://
the ASTM website. www.en.din.de.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D7594 − 24
[Replaces DIN 4776-1990] slightly soluble in the liquid lubricant. The general require-
ments are that the solid particles be extremely small, uniformly
3. Terminology
dispersed, and capable of forming a relatively stable, gel-like
structure with the liquid lubricant.
3.1 Definitions:
3.1.1 break-in, n—in tribology, an initial transition process
3.2 Definitions of Terms Specific to This Standard:
occurring in newly established wearing contacts, often accom-
3.2.1 extreme pressure, adj—in lubrication, characterized
panied by transients in coefficient of friction or wear rate, or
by metal surface in contact under high-stress rubbing condi-
both, that are uncharacteristic of the given tribological system’s
tions.
long-term behavior. G40
3.2.2 fretting wear, n—wear arising as a result of fretting.
3.1.2 coeffıcient of friction, μ or ƒ, n—in tribology, the
Small amplitude oscillatory motion, usually tangential, be-
dimensionless ratio of the friction force (F) between two
tween two solid surfaces in contact.
bodies to the normal force (N) pressing these bodies together.
3.2.3 seizure, n—localized fusion of metal between the
G40
rubbing surfaces of the test pieces. D5706
3.1.3 Hertzian contact area, n—apparent area of contact
3.2.3.1 Discussion—In this test method, seizure is indicated
between two nonconforming solid bodies pressed against each
by a sharp rise in the coefficient of friction, over steady state,
other, as calculated from Hertz’s equations of elastic
of greater than 0.2 for over 20 s, or a coefficient of friction
deformation. G40
>0.35 or by any examples shown in Test Method D5706 and
3.1.4 Hertzian contact pressure, n—magnitude of the pres-
D7421). If any of these conditions occur, the test is not valid.
sure at any specified location in a Hertzian contact area, as (These criteria were believed to be right, because this standard
calculated from Hertz’s equations of elastic deformation. The
is related to greases.) The evidence of adhesive wear mor-
Hertzian contact pressure can also be calculated and reported phologies should be controlled by micro-optical examination
as maximum value P in the centre of the contact or as
of the wear scar and track. In severe cases, a stoppage in the
max
P as average over the total contact area. D7421 motor will occur.
average
3.1.5 lubricant, n—any material interposed between two
3.3 Abbreviations:
surfaces that reduces the friction or wear between them. D217
3.3.1 SRV, n—Schwingung, Reibung, Verschleiß (German);
oscillating, friction, wear (English translation).
3.1.6 lubricating grease, n—a semi-fluid to solid product of
a dispersion of a thickener in a liquid lubricant. D217
3.1.6.1 Discussion—The dispersion of the thickener forms a 4. Summary of Test Method
two-phase system and immobilizes the liquid lubricant by
4.1 This test method is performed on an SRV test machine
surface tension and other physical forces. Other ingredients are
using a steel test ball oscillating under constant frequency,
commonly included to impart special properties.
short stroke amplitude and under constant load (F ), against a
n
3.1.7 Ra (C.L.A.), n—in measuring surface finish, the arith-
stationary steel test disk with a grease lubricant between them
metic average of the absolute distances of all profile points
in order to determine the coefficient of friction and wear scar
from the mean line for a given distance.
diameter.
3.1.7.1 Discussion—C.L.A. means center line average, and
4.2 For the nonmandatory extreme pressure test (see Ap-
it is a synonym to Ra. Amstutz
pendix X1), the test load is increased in 100 N increments until
3.1.8 Rpk, n—reduced peak height according to DIN EN
seizure occurs (see Test Method D5706). The load, immedi-
ISO 13565-2:1998. Rpk is the mean height of the peak sticking
ately prior to the load at which seizure occurs, is measured and
out above the core profile section.
reported.
3.1.9 Rvk, n—reduced valley height according to DIN EN
NOTE 1—Test frequency, stroke length, temperature, and ball and disk
ISO 13565-2:1998. Rvk is the mean depth of the valley
material can be varied to simulate field conditions. The test ball yields
reaching into the material below the core profile section. point-contact geometry. To obtain line or area contact, test pieces of
differing configurations can be substituted for the test balls.
3.1.10 Rz (DIN), n—in measuring surface finish, the average
4.3 The friction force, F , is measured by a piezo-electric
of all Ry values (peak to valley heights) in the assessment
f
device in the test disk assembly. Peak values of coefficient of
length. Amstutz
friction, f, are determined and recorded as a function of time for
3.1.11 thickener, n—in lubricating grease, a substance com-
SRV I and II models. SRV III and IV models can display the
posed of finely divided particles dispersed in a liquid lubricant
hysteresis (friction force or coefficient of friction over stroke
to form the product’s structure. D217
length) and save test data electronically.
3.1.11.1 Discussion—The thickener can be fibers (such as
various metallic soaps) or plates or spheres (such as certain
4.4 After a preset test period, the test machine and chart
non-soap thickeners) which are insoluble or, at most, only very
recorder stopped and the wear scar on the ball is measured. If
a profilometer is available, a trace of the wear track on the test
disk and the wear scar of the ball (See DIN 51834-3 and
Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003–0785,
Appendix X1) can also be used to obtain additional wear
Sheffield Measurement Division, Warner and Swasey, 1985, p. 21.
information (wear volume in mm and wear rate of disk and
Amstutz, Hu, “Surface Texture: The Parameters,” Bulletin MI-TP-003–0785,
Sheffield Measurement Division, Warner and Swasey, 1985, p. 29, 31. ball in mm /Nm).
´1
D7594 − 24
FIG. 1 SRV Test Machine (Model III)
1. Oscillation Drive Rod 6. Electrical Resistance Heater
2. Test Ball Holder 7. Resistance Thermometer
3. Load Rod 8. Test Disk Holder
5. Significance and Use
4. Test Ball 9. Piezoelectric Measuring Device
5.1 This test method can be used to determine anti-wear
5. Test Disk 10. Receiving Block
properties and coefficient of friction of greases in order to
FIG. 2 Test Chamber Elements of SRV III
prevent “fretting” wear under linear oscillation with associated
low strokes and high Hertzian contact pressures at selected
temperatures and loads specified for use in applications in
which induced, high-speed vibrational motions are present for
extended periods of time. It has found application as a
screening test for grease lubricants used in ball and roller
bearings, roller or ball screw (spindle) drives or side shaft
systems (Tripode or Rzeppa type) for example, so-called
constant velocity (CV) joints. Users of this test method should
determine whether results correlate with field performance or
other applications.
6. Apparatus
6.1 SRV Test Machine , illustrated in Figs. 1-4.
7. Reagents and Materials
7.1 Test Balls , 52100 steel, 60 HRC 6 2 HRC, 0.025 μm 6
0.005 μm Ra surface finish, 10 mm diameter.
7.2 Lower Test Disk , Vacuum arc remelted (VAR) AISI
52100 steel with an inclusion rating using Method D, Type A,
as severity level number of 0.5 in accordance with Test
Methods E45 and Specification A295/A295M or an inclusion
sum value K1 ≤ 10 in accordance with DIN EN ISO 683-17
FIG. 3 SRV Test Machine (Model IV)
and spherodized annealed to obtain globular carbide, 60 HRC
6 2 HRC, the surfaces of the disk being lapped and free of
lapping raw materials. The topography of the disk will be
0.020 μm < Rpk < 0.035 μm
determined by four values, 24 mm 6 0.5 mm diameter by
0.050 μm < Rvk < 0.075 μm
7.85 mm 6 0.1 mm thick:
7.3 Cleaning Solvent—The test disks have to be cleaned by
0.500 μm < Rz (DIN) < 0.650 μm
a liquid solvent (non-chlorinated, non-film forming). It is
0.035 μm < Ra (C.L.A.) < 0.050 μm
recommended to use special boiling point spirit type 2-A in
accordance with DIN 51631:1999 (published in English).
The sole source of supply of the apparatus known to the committee at this time
(Warning—Flammable. Health hazard.).
is Optimol Instruments GmbH, Flößergasse 3, D-81369 Munich, Germany. If you
NOTE 2—In the case of unavailability, please refer to Specification
are aware of alternative suppliers, please provide this information to ASTM
International Headquarters. Your comments will receive careful consideration at a D235 regarding Type I, Class C (with less than 2 % by volume of
meeting of the responsible technical committee, which you may attend. aromatics), mineral spirits.
´1
D7594 − 24
8.8.1 Start conditions (thermostatic stabilization):
Temperature: for example, 50 °C ± 1 K, 80 °C ± 1 K or 120 °C ± 1 K
Test load: 50 N ± 1 N
Start delay: 300 s (is displayed by all versions of the SRV software).
8.8.2 Cut-off criteria for friction, if occurs:
Coefficient of friction, f (cut-off value for permanent increase of level):
0.3 during t > 20 s
Coefficient of friction, f (cut-off value for one-off increase of level): 0.35
8.8.3 Test parameters:
Frequency: 50 Hz
Stroke: 0.30 mm
Temperature: for example, 50 °C, 80 °C or 120 °C
Pre-load: 50 N for 30 s
Test load: running-in under 50 N for 30 s, then constant load of 100 N
Test duration 240.5 min
8.8.4 Sample rates for result-relevant measurement chan-
nels:
Coefficient of friction, f: #32 ms
Stroke: #2 s
Test load: #2 s
Frequency: #2 s
Temperature: #2 s.
NOTE 6—For SRV V models, it is recommended to do one sampling per
period (that is, 20 ms) for coefficient of friction and stroke.
FIG. 4 Test Chamber Elements of SRV Models IV and V
9. Procedure
9.1 Installation of the Test Pieces and Lubricating Oil
Specimen in the Test Chamber:
8. Preparation of Apparatus
9.1.1 Using solvent-resistant gloves, clean the test ball, ball
Preparation of SRV I and II Models
holder, and disk by wiping the surfaces with laboratory tissue
soaked with the cleaning solvent (single boiling point spirit
8.1 Turn on the test machine and chart recorder and allow to
type 2-A in accordance with DIN 51631:1999. (Warning—
warm up for 15 min prior to running tests.
This mixture is flammable and a health hazard.) Repeat wiping
8.2 Select the friction data to be presented in the crest peak
until no dark residue appears on the tissue. Immerse the test
value position in accordance with the manufacturer’s direc-
ball and disk in a beaker of the cleaning solvent under
tions.
ultrasonic vibration for 10 min. Dry the test ball and disk with
NOTE 3—In most cases, this is accomplished by positioning the sliding
a clean tissue to ensure no streaking occurs on the surface.
switch on electronic card NO. 291.35.20E (front side of electronics behind
the front panel) and the sliding switch located back on the panel o
...