ASTM G181-21

Standard Test Method for Conducting Friction Tests of Piston Ring and Cylinder Liner Materials Under Lubricated Conditions

SIGNIFICANCE AND USE
5.1 The efficiency and fuel economy of spark ignition and diesel engines is affected in part by the friction between moving parts. Although no reliable, in situ friction measurements exist for fired internal combustion engines, it has been estimated that at least half of the friction losses in such engines are due to those at the ring and liner interface. This test method involves the use of a reciprocating sliding arrangement to simulate the type of oscillating contact that occurs between a piston ring and its mating cylinder bore surface near the top-dead-center position in the cylinder where most severe surface contact conditions occur. There are many types of engines and engine operating environments; therefore, to allow the user the flexibility to tailor this test to conditions representative of various engines, this standard test method allows flexibility in selecting test loads, speeds, lubricants, and durations of testing. Variables that can be adjusted in this procedure include: normal force, speed of oscillation, stroke length, duration of testing, temperature of testing, method of specimen surface preparation, and the materials and lubricants to be evaluated. Guidance is provided here on the set-up of the test, the manner of specimen fixturing and alignment, the selection of a lubricant to simulate conditioned oil characteristics (for a diesel engine), and the means to run-in the ring specimens to minimize variability in test results.  
5.2 Engine oil spends the majority of its operating lifetime in a state that is representative of use-conditioned oil. That is, fresh oil is changed by exposure to the heat, chemical environment, and confinement in lubricated contact. It ages, changing viscosity, atomic weight, solids content, acidity, and chemistry. Conducting piston ring and cylinder liner material evaluations in fresh, non-conditioned oil is therefore unrealistic for material screening. But additive-depleted, used oil can result in high wear and corros...
SCOPE
1.1 This test method covers procedures for conducting laboratory bench-scale friction tests of materials, coatings, and surface treatments intended for use in piston rings and cylinder liners in diesel or spark-ignition engines. The goal of this procedure is to provide a means for preliminary, cost-effective screening or evaluation of candidate ring and liner materials. A reciprocating sliding arrangement is used to simulate the contact that occurs between a piston ring and its mating liner near the top-dead-center position in the cylinder where liquid lubrication is least effective, and most wear is known to occur. Special attention is paid to specimen alignment, running-in, and lubricant condition.  
1.2 This test method does not purport to simulate all aspects of a fired engine’s operating environment, but is intended to serve as a means for preliminary screening for assessing the frictional characteristics of candidate piston ring and liner material combinations in the presence of fluids that behave as use-conditioned engine oils. Therefore, it is beyond the scope of this test method to describe how one might establish correlations between the described test results and the frictional characteristics of rings and cylinder bore materials for specific engine designs or operating conditions.  
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.4 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.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International ...

General Information

• Status: Published
• Publication Date: 31-Oct-2021
• ICS: 27.020 - Internal combustion engines
• Technical Committee: G02 - Wear and Erosion
• Drafting Committee: G02.50 - Friction

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:G181 −21
Standard Test Method for
Conducting Friction Tests of Piston Ring and Cylinder Liner
1
Materials Under Lubricated Conditions
This standard is issued under the fixed designation G181; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers procedures for conducting
laboratory bench-scale friction tests of materials, coatings, and
2. Referenced Documents
surface treatments intended for use in piston rings and cylinder
2
2.1 ASTM Standards:
liners in diesel or spark-ignition engines. The goal of this
D6838 Test Method for Cummins M11 High Soot Test
procedure is to provide a means for preliminary, cost-effective
3
(Withdrawn 2019)
screening or evaluation of candidate ring and liner materials.A
E177 Practice for Use of the Terms Precision and Bias in
reciprocating sliding arrangement is used to simulate the
ASTM Test Methods
contact that occurs between a piston ring and its mating liner
E691 Practice for Conducting an Interlaboratory Study to
near the top-dead-center position in the cylinder where liquid
Determine the Precision of a Test Method
lubrication is least effective, and most wear is known to occur.
G40 Terminology Relating to Wear and Erosion
Special attention is paid to specimen alignment, running-in,
and lubricant condition.
3. Terminology
1.2 This test method does not purport to simulate all aspects
3.1 For definitions, see Terminology G40.
of a fired engine’s operating environment, but is intended to
3.2 Definitions of Terms Specific to This Standard:
serve as a means for preliminary screening for assessing the
frictional characteristics of candidate piston ring and liner 3.2.1 conditioned oil—a lubricating oil whose viscosity,
material combinations in the presence of fluids that behave as composition, and other function-related characteristics have
use-conditioned engine oils. Therefore, it is beyond the scope been altered by use in an operating engine, such that the oil’s
of this test method to describe how one might establish effects on friction and wear reflect those characteristic of the
correlationsbetweenthedescribedtestresultsandthefrictional long-term, steady-state engine operation.
characteristics of rings and cylinder bore materials for specific
3.2.2 conformal contact—in friction and wear testing, any
engine designs or operating conditions.
macro-geometric specimen configuration in which the curva-
ture of one contact surface matches that of the countersurface.
1.3 The values stated in SI units are to be regarded as
3.2.2.1 Discussion—Examples of conformal contact include
standard. No other units of measurement are included in this
a flat surface sliding on a flat surface and a ball rotating in a
standard.
socket that conforms to the shape of the ball.Apair of surfaces
1.4 This standard does not purport to address all of the
may begin a wear or friction test in a non-conformal contact
safety concerns, if any, associated with its use. It is the
configuration, but develop a conformal contact as a result of
responsibility of the user of this standard to establish appro-
wear.
priate safety, health, and environmental practices and deter-
3.2.3 lubrication regime—in liquid-lubricated sliding
mine the applicability of regulatory limitations prior to use.
contact, a certain range of friction coefficients that results from
1.5 This international standard was developed in accor-
a combination of contact geometry, lubricant viscosity
dance with internationally recognized principles on standard-
characteristics, surface roughness, normal pressure, and the
ization established in the Decision on Principles for the
relative speed of the bearing surfaces.
Development of International Standards, Guides and Recom-
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1
This test method is under the jurisdiction of ASTM Committee G02 on Wear contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
and Erosion and is the direct responsibility of Subcommittee G02.50 on Friction. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Nov. 1, 2021. Published November 2021. Originally the ASTM website.
3
approved in 2004. Last previous edition approved in 2017 as G181 – 11 (2017). The last approved version of this historical stan
...

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: G181 − 11 (Reapproved 2017) G181 − 21
Standard Test Method for
Conducting Friction Tests of Piston Ring and Cylinder Liner
1
Materials Under Lubricated Conditions
This standard is issued under the fixed designation G181; 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 procedures for conducting laboratory bench-scale friction tests of materials, coatings, and surface
treatments intended for use in piston rings and cylinder liners in diesel or spark-ignition engines. The goal of this procedure is to
provide a means for preliminary, cost-effective screening or evaluation of candidate ring and liner materials. A reciprocating sliding
arrangement is used to simulate the contact that occurs between a piston ring and its mating liner near the top-dead-center position
in the cylinder where liquid lubrication is least effective, and most wear is known to occur. Special attention is paid to specimen
alignment, running-in, and lubricant condition.
1.2 This test method does not purport to simulate all aspects of a fired engine’s operating environment, but is intended to serve
as a means for preliminary screening for assessing the frictional characteristics of candidate piston ring and liner material
combinations in the presence of fluids that behave as use-conditioned engine oils. Therefore, it is beyond the scope of this test
method to describe how one might establish correlations between the described test results and the frictional characteristics of rings
and cylinder bore materials for specific engine designs or operating conditions.
1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.4 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 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
2.1 ASTM Standards:
3
D6838 Test Method for Cummins M11 High Soot Test (Withdrawn 2019)
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
G40 Terminology Relating to Wear and Erosion
1
This test method is under the jurisdiction of ASTM Committee G02 on Wear and Erosion and is the direct responsibility of Subcommittee G02.50 on Friction.
Current edition approved June 1, 2017Nov. 1, 2021. Published June 2017November 2021. Originally approved in 2004. Last previous edition approved in 20112017 as
G181 – 11.G181 – 11 (2017). DOI: 10.1520/G0181-11R17.10.1520/G0181-21.
2
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’sstandard’s Document Summary page on the ASTM website.
3
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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G181 − 21
3. Terminology
3.1 For definitions, see Terminology G40.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 conditioned oil—a lubricating oil whose viscosity, composition, and other function-related characteristics have been altered
by use in an operating engine, such that the oil’s effects on friction and wear reflect those characteristic of the long-term,
steady-state engine operation.
3.2.2 conformal contact—in friction and wear testing, any macro-geometric specimen configuration in which the curvature of one
contact surface matches that of the countersurface.
3.2.2.1 Discussion—
Examples of conformal contact include a flat surface sliding on a flat surface and a ball rotating in
...