ASTM B438-21

Standard Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)

ABSTRACT
This specification covers sintered bronze, oil-impregnated bearings made primarily from elemental copper, tin, lead, and graphite powders. This specification covers the following variables: Grades (available in three bronze base compositions identifiable by different graphite contents and one leaded bronze grade) and Type (Grades 1 and 2 are available in four types described by specific density ranges. Grade 3 is available in two types and Grade 4 is available in one type). Sintered bronze bearings shall be made by molding or briquetting metal powder mixtures to the proper density. The material shall conform to the required chemical composition for copper, tin, graphite, iron, lead, zinc, nickel, and antimony. The density of bearings supplied impregnated with lubricant shall be within the prescribed limits. Oil content of bearings shall not be less than the prescribed value for each grade and type of material. The material of different grades and types shall conform to the prescribed radial crushing strength requirements. An acceptance specification for the minimum bearing breaking load may be established for any specific standard oil-impregnated bearing. Chemical analysis shall be made for each representative sample of chips, which may be obtained by milling, drilling, filing, or crushing a bearing with clean dry tools without lubrication.
SCOPE
1.1 This specification covers porous metallic sleeve, flange, thrust, and spherical bronze-base bearings that are produced from mixed metal powders utilizing powder metallurgy (PM) technology and then impregnated with oil to supply operating lubrication.  
1.2 Included are the specifications for the chemical, physical, and mechanical requirements of those bronze-base PM materials that have been developed and standardized specifically for use in the manufacture of these self-lubricating bearings.  
1.3 This specification is applicable to the purchase of bronze-base bearings (oil-impregnated) that were formerly covered by military specifications and are intended for government or military applications. Those additional government requirements that only apply to military bearings are listed in the Supplementary Requirements section of this specification.  
1.4 This specification accompanies Specification B439 that covers the requirements for Iron-Base Powder Metallurgy (PM) Bearings, (Oil-Impregnated).  
1.5 Typical applications for bronze-base bearings are listed in Appendix X1.  
1.6 Bearing dimensional tolerance data are shown in Appendix X2, while engineering information regarding installation and operating parameters of PM bearings is included in Appendix X3. Additional useful information on self-lubricating bearings can be found in MPIF Standard 35, ISO 5755 and the technical literature.2  
1.7 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 is 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.  
1.8 The following safety hazards caveat pertains only to the test methods described in this specification. 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.  
1.9 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: 21.100.01 - Bearings in general
• 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:B438 −21
Standard Specification for
Bronze-Base Powder Metallurgy (PM) Bearings (Oil-
1
Impregnated)
This standard is issued under the fixed designation B438; 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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* regarded as standard. The values given in parentheses are
mathematical conversions to SI units that are provided for
1.1 This specification covers porous metallic sleeve, flange,
information only and are not considered standard.
thrust, and spherical bronze-base bearings that are produced
1.8 The following safety hazards caveat pertains only to the
from mixed metal powders utilizing powder metallurgy (PM)
test methods described in this specification. This standard does
technology and then impregnated with oil to supply operating
not purport to address all of the safety concerns, if any,
lubrication.
associated with its use. It is the responsibility of the user of this
1.2 Included are the specifications for the chemical,
standard to establish appropriate safety, health, and environ-
physical, and mechanical requirements of those bronze-base
mental practices and determine the applicability of regulatory
PM materials that have been developed and standardized
limitations prior to use.
specifically for use in the manufacture of these self-lubricating
1.9 This international standard was developed in accor-
bearings.
dance with internationally recognized principles on standard-
1.3 This specification is applicable to the purchase of
ization established in the Decision on Principles for the
bronze-base bearings (oil-impregnated) that were formerly
Development of International Standards, Guides and Recom-
coveredbymilitaryspecificationsandareintendedforgovern-
mendations issued by the World Trade Organization Technical
ment or military applications. Those additional government
Barriers to Trade (TBT) Committee.
requirements that only apply to military bearings are listed in
the Supplementary Requirements section of this specification. 2. Referenced Documents
3
1.4 This specification accompanies Specification B439 that
2.1 ASTM Standards:
covers the requirements for Iron-Base Powder Metallurgy
B243Terminology of Powder Metallurgy
(PM) Bearings, (Oil-Impregnated).
B439Specification for Iron-Base Powder Metallurgy (PM)
Bearings (Oil-Impregnated)
1.5 Typical applications for bronze-base bearings are listed
B939Test Method for Radial Crushing Strength, K,of
in Appendix X1.
Powder Metallurgy (PM) Bearings and Structural Materi-
1.6 Bearing dimensional tolerance data are shown in Ap-
als
pendix X2, while engineering information regarding installa-
B946Test Method for Surface Finish of Powder Metallurgy
tion and operating parameters of PM bearings is included in
(PM) Products
Appendix X3. Additional useful information on self-
B962Test Methods for Density of Compacted or Sintered
lubricating bearings can be found in MPIF Standard 35, ISO
Powder Metallurgy (PM) Products Using Archimedes’
2
5755 and the technical literature.
Principle
1.7 With the exception of the values for density and the B963 Test Methods for Oil Content, Oil-Impregnation
mass used to determine density, for which the use of the gram Efficiency, and Surface-Connected Porosity of Sintered
3
per cubic centimetre (g/cm ) and gram (g) units is the industry Powder Metallurgy (PM) Products Using Archimedes’
standard, the values stated in inch-pound units are to be Principle
E9Test Methods of Compression Testing of Metallic Mate-
rials at Room Temperature
1
This specification is under the jurisdiction ofASTM Committee B09 on Metal
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.04 on Bearings.
3
Current edition approved April 1, 2021. Published May 2021. Originally For referenced ASTM standards, visit the ASTM website, www.astm.org, or
approved in 1966. Last previous edition approved in 2017 as B438– 17. DOI: contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
10.1520/B0438-21. Standards volume information, refer to the standard’s Document Summary page on
2
Machine Design Magazine, Vol 54, #14, June 17, 1982, pp. 130-142. 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

--------------------
...

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: B438 − 17 B438 − 21
Standard Specification for
Bronze-Base Powder Metallurgy (PM) Bearings (Oil-
1
Impregnated)
This standard is issued under the fixed designation B438; 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*
1.1 This specification covers porous metallic sleeve, flange, thrust, and spherical bronze-base bearings that are produced from
mixed metal powders utilizing powder metallurgy (PM) technology and then impregnated with oil to supply operating lubrication.
1.2 Included are the specifications for the chemical, physical, and mechanical requirements of those bronze-base PM materials that
have been developed and standardized specifically for use in the manufacture of these self-lubricating bearings.
1.3 This specification is applicable to the purchase of bronze-base bearings (oil-impregnated) that were formerly covered by
military specifications and are intended for government or military applications. Those additional government requirements that
only apply to military bearings are listed in the Supplementary Requirements section of this specification.
1.4 This specification accompanies Specification B439 that covers the requirements for Iron-Base Powder Metallurgy (PM)
Bearings, (Oil-Impregnated).
1.5 Typical applications for bronze-base bearings are listed in Appendix X1.
1.6 Bearing dimensional tolerance data are shown in Appendix X2, while engineering information regarding installation and
operating parameters of PM bearings is included in Appendix X3. Additional useful information on self-lubricating bearings can
2
be found in MPIF Standard 35, ISO 5755 and the technical literature.
1.7 With the exception of density values for which the g/cmthe values for density and the mass used to determine density, for
3
which the use of the gram per cubic centimetre (g/cm unit ) and gram (g) units is 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.
1.8 The following safety hazards caveat pertains only to the test methods described in this specification. 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
This specification 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, 2017April 1, 2021. Published April 2017May 2021. Originally approved in 1966. Last previous edition approved in 20132017 as B438 –
13.17. DOI: 10.1520/B0438-17.10.1520/B0438-21.
2
Machine Design Magazine, Vol 54, #14, June 17, 1982, pp. 130-142.
*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

---------------------- Page: 1 ----------------------
B438 − 21
1.9 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
3
2.1 ASTM Standards:
B243 Terminology of Powder Metallurgy
B439 Specification for Iron-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)
B939 Test Method for Radial Crushing Strength, K, of Powder Metallurgy (PM) Bearings and Structural Materials
B946 Test Method for Surface Finish of Powder Metallurgy (PM) Products
B962 Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle
B963 Test Methods for Oil Content, Oil-Impregnation Efficiency, and Surface-Connected Porosity of Sintered Powder
Metallurgy (PM) Products Using Archimedes’ Principle
E9 Test Methods of Compression Testing of Metallic
...