ASTM B438 - 13

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

    Active Standard ASTM B438 | Developed by Subcommittee: B09.04

    Book of Standards Volume: 02.05

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    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.

    This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.

    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 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.

    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    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 Interconnected Porosity of Sintered Powder Metallurgy (PM) Products Using Archimedes Principle

    B966 Test Method for Permeability of Powder Metallurgy (PM) Bearings Using Nitrogen Gas

    B970 Test Method for Cleanliness of Powder Metallurgy (PM) Bearings and Structural Parts

    E9 Test Methods of Compression Testing of Metallic Materials at Room Temperature

    E29 Practice for Using Significant Digits in Test Data to Determine Conformance with Specifications

    E1019 Test Methods for Determination of Carbon, Sulfur, Nitrogen, and Oxygen in Steel, Iron, Nickel, and Cobalt Alloys by Various Combustion and Fusion Techniques

    MPIF Standard

    MPIF Standard 35 Materials Standards for PM Self-Lubricating Bearings Available from Metal Powder Industries Federation (MPIF), 105 College Rd. East, Princeton, NJ 08540-6692,

    ISO Standard

    ISO 2795 Plain Bearings Made from Sintered Material--Dimensions and Tolerances

    ISO 5755 Sintered Metal Materials - Specifications

    Government Standards

    MIL-B-5687 Bearings, Sleeve, Washers, Thrust, Sintered, Metal Powder, Oil-Impregnated, General Specification For

    MIL-PRF-17331 Lubrication Oil, Steam Turbine and Gear, Moderate Service

    MIL-PRF-6085 Lubricating Oil: Instrument, Aircraft, Low Volatility Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, Electronic copies of military specifications may be obtained from

    MS17795 Bearing, Sleeve, Plain, Sintered Bronze, Oil-Impregnated

    MS17796 Bearing, Sleeve, Flanged, Sintered Bronze, Oil-Impregnated

    MS21783 Bearing, Washer, Thrust, Sintered Bronze, Oil-Impregnated

    QPL-17331 Lubricating Oil, Steam Turbine and Gear, Moderate Service

    QPL-6085 Lubricating Oil Instrument, Aircraft, Low Volatility

    ICS Code

    ICS Number Code 21.100.01 (Bearings in general)

    UNSPSC Code

    UNSPSC Code 31171500(Bearings)

    Referencing This Standard
    Link Here
    Link to Active (This link will always route to the current Active version of the standard.)

    DOI: 10.1520/B0438

    Citation Format

    ASTM B438-13, Standard Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated), ASTM International, West Conshohocken, PA, 2013,

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