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 selflubricating bearings can be found in MPIF Standard 35, ISO 5755 and the technical literature.2
1.7 With the exception of density values for which the g/cm3 unit 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 and health 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.
ASTM B438-17 Referenced Document
ASTM B243 Standard Terminology of Powder Metallurgy*, 2023-05-01 Update
ASTM B439 Standard Specification for Iron-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)*, 2021-04-01 Update
ASTM B939 Standard Test Method for Radial Crushing Strength, *, 2024-04-21 Update
ASTM B946 Standard Test Methods for Surface Roughness of Powder Metallurgy (PM) Products*, 2023-02-01 Update
ASTM B962 Standard Test Methods for Density of Compacted or Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle*, 2023-09-01 Update
ASTM B963 Standard Test Methods for Oil Content, Oil-Impregnation Efficiency, and Surface-Connected Porosity of Sintered Powder Metallurgy (PM) Products Using Archimedes’ Principle*, 2024-02-01 Update
ASTM E1019 Standard Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel and in Iron, Nickel, and Cobalt Alloys*, 2024-04-21 Update
ASTM E29 Standard Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications
ASTM E9 Standard Test Methods of Compression Testing of Metallic Materials at Room Temperature
ISO 2795 Plain bearings — Sintered bushes — Dimensions and tolerances*, 2020-06-02 Update
ISO 5755 Sintered metal material — Specifications*, 2022-10-03 Update
ASTM B438-17 history
2021ASTM B438-21 Standard Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)
2017ASTM B438-17 Standard Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)
2013ASTM B438-13 Standard Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)
2008ASTM B438-08 Standard Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)
2005ASTM B438/B438M-05 Specification for Bronze Powder Metallurgy (P/M) Bearing (Oil-Impregnated)
2004ASTM B438/B438M-04 Standard Specification for Sintered Bronze Bearings (Oil-Impregnated)
2000ASTM B438/B438M-00a Standard Specification for Sintered Bronze Bearings (Oil-Impregnated)
2000ASTM B438/B438M-00 Standard Specification for Sintered Bronze Bearings (Oil-Impregnated)
2000ASTM B438/B438M-95ae1 Standard Specification for Sintered Bronze Bearings (Oil-Impregnated)