ASTM D2266-23

Standard Test Method for Wear Preventive Characteristics of Lubricating Grease (Four-Ball Method)

SIGNIFICANCE AND USE
5.1 The four-ball wear-test method can be used to determine the relative wear-preventing properties of greases under the test conditions and if the test conditions are changed the relative ratings may be different. No correlation has been established between the four-ball wear test and field service. The test method cannot be used to differentiate between Extreme Pressure (EP) and Non-Extreme Pressure (Non-EP) Greases.4
SCOPE
1.1 This test method covers the determination of the wear preventive characteristics of greases in sliding steel-on-steel applications. It is not intended to predict wear characteristics with metal combinations other than steel-on-steel or to evaluate the extreme pressure characteristics of the grease.  
1.2 The values stated in SI units are to be regarded as the standard except where the test apparatus or consumable parts are only available in other units. In such cases, these will be regarded as standard. The values given in parentheses are for information only.  
1.3 This standard does not purport to address all of the safety problems, 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: 30-Jun-2023
• 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

• Refers: ASTM D6300-24 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Mar-2024
• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D6300-23a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Dec-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D6300-19a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Dec-2019
• Refers: ASTM D6300-16 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Apr-2016
• Refers: ASTM D4172-94(2016) - Standard Test Method for Wear Preventive Characteristics of Lubricating Fluid (Four-Ball Method)
• Effective Date: 01-Jan-2016
• Refers: ASTM D6300-15 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2015
• Refers: ASTM D6300-14a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2014
• Refers: ASTM D6300-14ae1 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Jun-2014
• Refers: ASTM D6300-14 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-May-2014
• Refers: ASTM D6300-13a - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 01-Dec-2013
• Refers: ASTM D6300-13 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 15-Jul-2013
• Refers: ASTM D4172-94(2010) - Standard Test Method for Wear Preventive Characteristics of Lubricating Fluid (Four-Ball Method)
• Effective Date: 01-May-2010
• Refers: ASTM D6300-08 - Standard Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products and Lubricants
• Effective Date: 15-Dec-2008

Overview

ASTM D2266-23, titled "Standard Test Method for Wear Preventive Characteristics of Lubricating Grease (Four-Ball Method)", is a globally recognized standard published by ASTM International. This test method is designed to determine the wear preventive properties of lubricating greases in steel-on-steel sliding applications, using the Four-Ball Method. While not intended to predict field performance or evaluate extreme pressure (EP) properties, ASTM D2266-23 plays a crucial role in quality control, product development, and comparative analysis of grease formulations within laboratory environments.

Key Topics

• Purpose: Evaluates the relative ability of lubricating grease to prevent wear in steel-on-steel contact under controlled conditions.
• Test Method: Utilizes a four-ball apparatus where three stationary steel balls are clamped together and covered with the test grease; a fourth rotating steel ball is pressed against them under constant load, speed, and temperature. The average wear scar diameter on the stationary balls determines performance.
• Conditions: Standard test parameters are strictly defined for temperature, load, speed, and duration to ensure repeatability and comparability.
• Limitations: Results are specific to the test conditions and do not predict actual field performance, nor do they differentiate between EP and non-EP greases.

Applications

Industrial Lubricant Evaluation

• Quality Control: ASTM D2266-23 is widely used by lubricant manufacturers for batch quality assurance, ensuring grease meets wear protection specifications before shipment.
• Product Development: R&D laboratories employ the four-ball wear test method to compare new grease formulations and optimize additive packages for enhanced wear resistance.
• Benchmarking: The method allows reliable comparison between products from different suppliers or different product lines within the same organization.

Equipment and Component Reliability

• Steel-On-Steel Applications: The standard is relevant wherever steel components operate under sliding conditions, such as gears, bearings, or other dynamically loaded assemblies.
• Regulatory and Defense Sectors: Recognized and used by governmental agencies, including the U.S. Department of Defense, to replace older federal test standards for lubricating greases.

Laboratory Standardization

• Reproducibility: By standardizing test procedures and equipment, ASTM D2266-23 ensures consistent data for precision studies and inter-laboratory comparison.

Related Standards

• ASTM D4172: Standard Test Method for Wear Preventive Characteristics of Lubricating Fluid (Four-Ball Method) - similar methodology applied to lubricating oils rather than greases.
• ASTM D4175: Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants - defines relevant technical terms.
• ASTM D6300: Practice for Determination of Precision and Bias Data for Use in Test Methods - guides on evaluating precision and bias in petroleum product testing.
• ANSI B3.12: Specifies standards for metal balls used in the Four-Ball apparatus.

Practical Value

Implementing ASTM D2266-23 in lubricant testing programs enables:

• Objective measurement and comparison of grease wear preventive properties.
• Data-driven product improvements and informed material selection for industrial maintenance.
• Compliance with supplier, customer, or regulatory requirements for grease performance documentation.

By using the systematic approach provided in ASTM D2266-23, industries can ensure consistent lubrication quality and enhance the reliability of machinery operating in steel-on-steel contact scenarios.

Keywords: ASTM D2266-23, four-ball method, lubricating grease, wear preventive characteristics, grease testing, steel-on-steel, lubricant quality standards, industrial lubrication, ASTM standards.

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.
Designation: D2266 − 23
Standard Test Method for
Wear Preventive Characteristics of Lubricating Grease
(Four-Ball Method)
This standard is issued under the fixed designation D2266; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* D6300 Practice for Determination of Precision and Bias
Data for Use in Test Methods for Petroleum Products,
1.1 This test method covers the determination of the wear
Liquid Fuels, and Lubricants
preventive characteristics of greases in sliding steel-on-steel
applications. It is not intended to predict wear characteristics 2.2 ANSI Standard:
with metal combinations other than steel-on-steel or to evaluate B3.12 for Metal Balls
the extreme pressure characteristics of the grease.
3. Terminology
1.2 The values stated in SI units are to be regarded as the
standard except where the test apparatus or consumable parts
3.1 Definitions:
are only available in other units. In such cases, these will be
3.1.1 For definitions of terms used in this test method, refer
regarded as standard. The values given in parentheses are for
to Terminology D4175.
information only.
3.2 There are no terms in this test method that require new
or other than dictionary definitions.
1.3 This standard does not purport to address all of the
safety problems, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 4. Summary of Test Method
priate safety, health, and environmental practices and deter-
4.1 Three ⁄2 in. (12.7 mm) diameter steel balls are clamped
mine the applicability of regulatory limitations prior to use.
together and covered with the lubricant to be evaluated. A
1.4 This international standard was developed in accor-
fourth ⁄2 in. diameter steel ball, referred to as the top ball, is
dance with internationally recognized principles on standard-
pressed with a force of 40 kgf (392 N) into the cavity formed
ization established in the Decision on Principles for the
by the three clamped balls for three-point contact. The tem-
Development of International Standards, Guides and Recom-
perature of the lubricating grease specimen is regulated at
mendations issued by the World Trade Organization Technical
75 °C (167 °F) and then the top ball is rotated at 1200 r ⁄min for
Barriers to Trade (TBT) Committee.
60 min. Lubricants are compared by using the average size of
the scar diameters worn on the three lower clamped balls.
2. Referenced Documents
NOTE 1—Because of differences in the construction of the various
2.1 ASTM Standards:
machines on which the four-ball test can be made, the manufacturer’s
D4172 Test Method for Wear Preventive Characteristics of
instructions should be consulted for proper machine setup and operation.
Lubricating Fluid (Four-Ball Method)
NOTE 2—Although the test can be run under other test parameters, the
D4175 Terminology Relating to Petroleum Products, Liquid
precision noted in Section 11 can vary when testing with other than test
parameters listed in Section 8.
Fuels, and Lubricants
5. Significance and Use
This test method is under the jurisdiction of ASTM Committee D02 on
5.1 The four-ball wear-test method can be used to determine
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
the relative wear-preventing properties of greases under the test
Subcommittee D02.G0.04 on Functional Tests - Tribology.
Current edition approved July 1, 2023. Published August 2023. Originally
conditions and if the test conditions are changed the relative
approved in 1964. Last previous edition approved in 2015 as D2266 – 01 (2015).
ratings may be different. No correlation has been established
DOI: 10.1520/D2266-23.
between the four-ball wear test and field service. The test
This test method has been adopted for use by government agencies to replace
Method 6514 of Federal Test Method Standard No. 791b.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
*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
D2266 − 23
method cannot be used to differentiate between Extreme
Pressure (EP) and Non-Extreme Pressure (Non-EP) Greases.
6. Apparatus
6.1 Four-Ball Wear-Tester and Accessories—See Fig. 1 and
Fig. 2.
NOTE 3—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 heavier loads and more severe conditions; it lacks the
sensitivity necessary for performing four-ball wear test.
6.2 Microscope, capable of measuring the diameters of the
scars produced on the three stationary balls to an accuracy of
0.01 mm. It is more efficient to measure the scars without
removing the three balls from the holder.
FIG. 2 Falex Corporation (Roxanna) Four-Ball Test Arrangement
7. Reagents and Materials
7.1 Test Balls , chrome alloy steel, made from AISI standard
steel No. E-52100, with diameter of 0.5 in. (12.7 mm), Grade
25 EP (Extra Polish). Such balls are described in B3.12, for
Metal Balls. The Extra-Polish finish is not described in that
specification. The Rockwell C hardness shall be 64 to 66, a
Further details on this test method may be found in the article by Stalling, L.,
closer limit than is found in the ANSI requirement.
NLGI Spokesman, Vol 31, No. 11, February 1988, pp. 396–401. This article has been
submitted as a research report, but it does not follow research report guidelines
NOTE 4—Steel balls meeting this description were used in developing
because the work was conducted before research report guidelines were instituted.
the precision of the test.
The sole source of supply of the Four-Ball Wear Test Machine known to the
7.2 Cleaning Fluids for preparing balls and apparatus for
committee at this time is Falex Corp., 1020 Airpark Drive, Sugar Grove, IL 60554.
the test should be those capable of removing metal preservative
If you are aware of alternative suppliers, please provide this information to ASTM
coating from the balls, eliminating carryover effects from one
International Headquarters. Your comments will receive careful consideration at a
meeting of the responsible technical committee, which you may attend.
test to the next. The cleaning fluid selected should be non-film-
This company can also furnish a microscope with a special base to measure the
forming and not contribute to the wear or antiwear properties
wear scars without removing the balls from the test-oil cup. Discontinued models of
of the test lubricant. (for example, chlorinated solvents should
the Four-Ball Wear Test Machine made by Precision Scientific Co. and Roxanna
not be used.)
Machine Works are also satisfactory.
The sole source of supply of the microscope known to the committee at this
time is Falex Corp., 1020 Airpark Drive, Sugar Grove, IL 60554. If you are aware
8. Test Conditions
of alternative suppliers, please provide this information to ASTM International
Headquarters. Your comments will receive careful consideration at a meeting of the
8.1 The test shall be conducted under the following condi-
responsible technical committee, which you may attend.
tions:
Falex Corp. Microscope F-1519-31 measures directly to 0.1 mm and by
Temperature 75 °C ± 2 °C (167 °F ± 4 °F)
interpolation to 0.01 mm. A higher resolution version, F-1519-31A, measures to
Speed 1200 r ⁄min ± 60 r ⁄min
0.001 mm.
Duration 60 min ± 1 min
Steel balls meeting this description were used in developing the precision of the
Load 40 kgf ± 0.2 kgf (392 N ±
test. They are available from the manufacturer of the test machine and some ball
2 N)
manufacturers. Some opera
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM 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.
Designation: D2266 − 01 (Reapproved 2015) D2266 − 23
Standard Test Method for
Wear Preventive Characteristics of Lubricating Grease
(Four-Ball Method)
This standard is issued under the fixed designation D2266; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope Scope*
1.1 This test method covers the determination of the wear preventive characteristics of greases in sliding steel-on-steel
applications. It is not intended to predict wear characteristics with metal combinations other than steel-on-steel or to evaluate the
extreme pressure characteristics of the grease.
1.2 The values stated in SI units are to be regarded as the standard except where the test apparatus or consumable parts are only
available in other units. In such cases, these will be regarded as standard. The values given in parentheses are for information only.
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and healthsafety, 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.
2. Referenced Documents
2.1 ASTM Standards:
D4172 Test Method for Wear Preventive Characteristics of Lubricating Fluid (Four-Ball Method)
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D6300 Practice for Determination of Precision and Bias Data for Use in Test Methods for Petroleum Products, Liquid Fuels, and
Lubricants
2.2 ANSI Standard:
B3.12 for Metal Balls
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology D4175.
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
D02.G0.04 on Functional Tests - Tribology.
Current edition approved April 1, 2015July 1, 2023. Published June 2015August 2023. Originally approved in 1964. Last previous edition approved in 20082015 as
D2266 – 01 (2008).(2015). DOI: 10.1520/D2266-23.
This test method has been adopted for use by government agencies to replace Method 6514 of Federal Test Method Standard No. 791b. DOI: 10.1520/D2266-01R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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 (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
*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
D2266 − 23
3.2 There are no terms in this test method that require new or other than dictionary definitions.
4. Summary of Test Method
1 1
4.1 Three ⁄2 in. (12.7 mm) diameter steel balls are clamped together and covered with the lubricant to be evaluated. A fourth ⁄2 in.
diameter steel ball, referred to as the top ball, is pressed with a force of 40 kgf (392 N) into the cavity formed by the three clamped
balls for three-point contact. The temperature of the lubricating grease specimen is regulated at 75 °C (167 °F) and then the top
ball is rotated at 1200 r ⁄min for 60 min. Lubricants are compared by using the average size of the scar diameters worn on the three
lower clamped balls.
NOTE 1—Because of differences in the construction of the various machines on which the four-ball test can be made, the manufacturer’s instructions
should be consulted for proper machine setup and operation.
NOTE 2—Although the test can be run under other test parameters, the precision noted in Section 11 can vary when testing with other than test parameters
listed in Section 8.
5. Significance and Use
5.1 The four-ball wear-test method can be used to determine the relative wear-preventing properties of greases under the test
conditions and if the test conditions are changed the relative ratings may be different. No correlation has been established between
the four-ball wear test and field service. The test method cannot be used to differentiate between Extreme Pressure (EP) and
Non-Extreme Pressure (Non-EP) Greases.
6. Apparatus
6.1 Four-Ball Wear-Tester and Accessories—See Fig. 1 and Fig. 2.
NOTE 3—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 heavier loads and more severe conditions; it lacks the sensitivity necessary for performing four-ball wear test.
FIG. 1 Precision Scientific Company Four-Ball Test Arrangement
Further details on this test method may be found in the article by Stalling, L., NLGI Spokesman, Vol 31, No. 11, February 1988, pp. 396–401. This article has been
submitted as a research report, but it does not follow research report guidelines because the work was conducted before research report guidelines were instituted.
The sole source of supply of the Four-Ball Wear Test Machine known to the committee at this time is Falex Corp., 1020 Airpark Drive, Sugar Grove, IL 60554. If you
are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of
the responsible technical committee, which you may attend.
This company can also furnish a microscope with a special base to measure the wear scars without removing the balls from the test-oil cup. Discontinued models of the
Four-Ball Wear Test Machine made by Precision Scientific Co. and Roxanna Machine Works are also satisfactory.
D2266 − 23
FIG. 2 Falex Corporation (Roxanna) Four-Ball Test Arrangement
6.2 Microscope, capable of measuring the diameters of the scars produced on the three stationary balls to an accuracy of 0.01 mm.
It is more efficient to measure the scars without removing the three balls from the holder.
7. Reagents and Materials
7.1 Test Balls , chrome alloy steel, made from AISI standard steel No. E-52100, with diameter of 0.5 in. (12.7 mm), Grade 25 EP
(Extra Polish). Such balls are described in B3.12, 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.
NOTE 4—Steel balls meeting this description were used in developing the precision of the test.
7.2 Cleaning Fluids for preparing balls and apparatus for the test should be those capable of removing metal preservative coating
from the balls, eliminating carryover effects from one test to the next. The cleaning fluid selected should be non-film-forming and
not contribute to the wear or antiwear properties of the test lubricant. (for example, chlorinated solvents should not be used.)
8. Test Conditions
8.1 The test shall be conducted under the following conditions:
Temperature 75 °C ± 2 °C (167 °F ± 4 °F)
Speed 1200 r ⁄min ± 60 r ⁄min
Duration 60 min ± 1 min
Load 40 kgf ± 0.2 kgf (392 N ±
2 N)
NOTE 5—Although the test can be run under other conditions, the precision limits described in Section 11 apply only to tests conducted under the
conditions described in Section 8.
9. Preparation of Apparatus
9.1 Set up the drive of the test machine to obtain a spindle speed of 1200 r ⁄min 6 60 r ⁄min.
9.2 Set the temperature controller to maintain a test temperature of 75 °C 6 2 °C (167 °F 6 4 °F).
The sole source of supply of the microscope known to the committee at this time is Falex Corp., 1020 Airpark D
...