ASTM B939-21

Standard Test Method for Radial Crushing Strength, <emph type="bdit">K</emph>, of Powder Metallurgy (PM) Bearings and Structural Materials

SIGNIFICANCE AND USE
5.1 The radial crushing strength test is a destructive procedure used to determine a material strength characteristic of PM bearings and hollow cylindrical test specimens. These data can be used to grade, classify, and evaluate the materials.  
5.2 The PM bearing Specifications B438 and B439 require the use of this test method as an acceptance test for the strength of oil-impregnated sintered bearings.  
5.3 This test method may be used by powder producers and parts manufacturers as a lot acceptance test for metal powders and lubricated powder mixtures intended for the production of porous parts.  
5.4 Companies in the PM industry use this test as a manufacturing control test because it is appropriate for production practices.  
5.5 Radial crushing strength is a property of the PM material but is not a design value. However, experience has shown that the radial crushing strength of a material is approximately twice the ultimate tensile strength.
SCOPE
1.1 This test method covers the equipment and laboratory procedure for the determination of the radial crushing strength of materials using either a plain powder metallurgy (PM) bearing or a thin-walled hollow cylindrical test specimen. This is a destructive test that produces quantitative results.  
1.2 Limitations:  
1.2.1 The principle of this procedure is based on the material being tested having minimal ductility. The permanent deflection of the cylinder during the test should not exceed 10 % of the outside diameter.  
1.2.2 The radial crushing strength test results should be used only as a guide if the test specimen has a wall thickness that is greater than one-third of the outside diameter. These test results should then only be used for comparison with data from the test specimens of like materials and similar dimensions.  
1.3 Units—With the exception of the values for density and the mass used to determine density, for which the use of the gram per cubic centimetre (g/cm3) and gram (g) units are the industry standard, the values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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 Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-Mar-2021
• ICS: 77.160 - Powder metallurgy
• Technical Committee: B09 - Metal Powders and Metal Powder Products
• Drafting Committee: B09.04 - Bearings

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: B939 − 21
Standard Test Method for
Radial Crushing Strength,K, of Powder Metallurgy (PM)
1
Bearings and Structural Materials
This standard is issued under the fixed designation B939; 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.
1. Scope* 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This test method covers the equipment and laboratory
procedure for the determination of the radial crushing strength B243Terminology of Powder Metallurgy
B438Specification for Bronze-Base Powder Metallurgy
of materials using either a plain powder metallurgy (PM)
bearing or a thin-walled hollow cylindrical test specimen.This (PM) Bearings (Oil-Impregnated)
B439Specification for Iron-Base Powder Metallurgy (PM)
is a destructive test that produces quantitative results.
Bearings (Oil-Impregnated)
1.2 Limitations:
B925Practices for Production and Preparation of Powder
1.2.1 The principle of this procedure is based on the
Metallurgy (PM) Test Specimens
material being tested having minimal ductility. The permanent
E456Terminology Relating to Quality and Statistics
deflection of the cylinder during the test should not exceed
E691Practice for Conducting an Interlaboratory Study to
10% of the outside diameter.
Determine the Precision of a Test Method
1.2.2 Theradialcrushingstrengthtestresultsshouldbeused
3
2.2 MPIF Standard:
only as a guide if the test specimen has a wall thickness that is
MPIF Standard 55Determination of Radial Crush Strength
greaterthanone-thirdoftheoutsidediameter.Thesetestresults
(K) of Powder Metallurgy (PM) Test Specimens
shouldthenonlybeusedforcomparisonwithdatafromthetest
specimens of like materials and similar dimensions.
3. Terminology
1.3 Units—With the exception of the values for density and
3.1 Definitions—Definitions of powder metallurgy (PM)
the mass used to determine density, for which the use of the
terms can be found in Terminology B243. Additional descrip-
3
gram per cubic centimetre (g/cm ) and gram (g) units are the
tive information is available under “General Information on
industry standard, the values stated in inch-pound units are to
PM” on the ASTM B09 web page.
be regarded as standard. The values given in parentheses are
mathematical conversions to SI units that are provided for
4. Summary of Test Method
information only and are not considered standard.
4.1 Radial crushing strength is determined by subjecting a
1.4 This standard does not purport to address all of the
plain sleeve bearing or a thin-walled cylindrical test specimen
safety concerns, if any, associated with its use. It is the
to a controlled compressive force applied perpendicular to its
responsibility of the user of this standard to establish appro-
central axis under uniformly increasing load until fracture
priate safety, health, and environmental practices and deter-
occurs.
mine the applicability of regulatory limitations prior to use.
4.2 The term “radial crushing strength,” as used in this test
1.5 This international standard was developed in accor-
method is the stress at fracture calculated from the breaking
dance with internationally recognized principles on standard-
load and the dimensions of the test specimen.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
5. Significance and Use
mendations issued by the World Trade Organization Technical
5.1 The radial crushing strength test is a destructive proce-
Barriers to Trade (TBT) Committee.
dureusedtodetermineamaterialstrengthcharacteristicofPM
1 2
This test method is under the jurisdiction of ASTM Committee B09 on Metal For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Powders and Metal Powder Products and is the direct responsibility of Subcom- contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
mittee B09.04 on Bearings. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved April 1, 2021. Published April 2021. Originally the ASTM website.
3
approved in 2005. Last previous edition approved in 2015 as B939–15. DOI: Available from Metal Powder Industries Federation (MPIF), 105 College Rd.
10.1520/B0939-21. East, Princeton, NJ 08540, http://www.mpif.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
1

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...

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: B939 − 15 B939 − 21
Standard Test Method for
Radial Crushing Strength, K, of Powder Metallurgy (PM)
1
Bearings and Structural Materials
This standard is issued under the fixed designation B939; 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 the equipment and laboratory procedure for the determination of the radial crushing strength of
materials using either a plain powder metallurgy (PM) bearing or a thin-walled hollow cylindrical test specimen. This is a
destructive test that produces quantitative results.
1.2 Limitations:
1.2.1 The principle of this procedure is based on the material being tested having minimal ductility. The permanent deflection of
the cylinder during the test should not exceed 10 % of the outside diameter.
1.2.2 The radial crushing strength test results should be used only as a guide if the test specimen has a wall thickness that is greater
than one-third of the outside diameter. These test results should then only be used for comparison with data from the test specimens
of like materials and similar dimensions.
1.3 Units—With the exception of the values for density and the mass used to determine density, for which the use of the gram per
3
cubic centimetre (g/cm ) and gram (g) units are the industry standard, the values stated in inch-pound units are to be regarded as
standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are
not considered 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:
B243 Terminology of Powder Metallurgy
B438 Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)
1
This test method is under the jurisdiction of ASTM Committee B09 on Metal Powders and Metal Powder Products and is the direct responsibility of Subcommittee B09.04
on Bearings.
Current edition approved April 1, 2015April 1, 2021. Published April 2015April 2021. Originally approved in 2005. Last previous edition approved in 20092015 as
B939 – 09.B939 – 15. DOI: 10.1520/B0939-15.10.1520/B0939-21.
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’s Document Summary page on the ASTM website.
*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

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B939 − 21
B439 Specification for Iron-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)
B925 Practices for Production and Preparation of Powder Metallurgy (PM) Test Specimens
E456 Terminology Relating to Quality and Statistics
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3
2.2 MPIF Standard:
MPIF Standard 55 Determination of Radial Crush Strength (K) of Powder Metallurgy (PM) Test Specimens
3. Terminology
3.1 Definitions—Definitions of powder metallurgy (PM) terms can be found in Terminology B243. Additional descriptive
information is available in the related material section of Vol 02.05 of the under “General Information on PM” on the Annual Book
of ASTM Standards.ASTM B09 web page.
4. Summary of Test Method
4.1 Radial crushing strength is determined by subjecting a plain sleeve bearing or a thin-walled cylindrical test specimen to a
controlled compressive force applied perpendicular to its central axis under uniformly increasing load until fracture occurs.
4.2 The term “radial crushing strength,” as used in this test met
...