ASTM B439-21

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: B439 − 18 B439 − 21
Standard Specification for
Iron-Base Powder Metallurgy (PM) Bearings (Oil-
Impregnated)
This standard is issued under the fixed designation B439; 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 the requirements for porous iron-base metallic sleeve, flange, thrust, and spherical bearings that are
produced from metal powders utilizing powder metallurgy (PM) technology and then impregnated with oil to supply operating
lubrication.
1.2 Listed are the chemical, physical, and mechanical specifications for those standardized ferrous PM materials that have been
developed specifically for the manufacture of self-lubricating bearings.
1.3 This standardspecification is a companion to Specification B438 that covers the requirements for porous oil-impregnated
bronze-base bearings.
1.4 Typical applications for self-lubricating iron-base PM bearings are discussed in Appendix X1.
1.5 Commercial 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 (Bearings), ISO 5755, and the technical literature.
1.6 Units—With the exception of the values for density and the mass used to determine density, for which the use of the g/cmgram
per cubic centimetre (g/cm unit ) and gram (g) units is the long-standing practice of the PM industry, 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 to be regarded as standardstandard.
1.7 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.
1.8 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.
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, 2018April 1, 2021. Published May 2018May 2021. Replaces portions of B612 and B782. Originally approved in 1966 to replace portions
of B202. Last previous edition approved in 20122018 as B439 – 12.B439 – 18. DOI: 10.1520/B0439-18.10.1520/B0439-21.
Machine Design Magazine, Vol 54, No. 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
B439 − 21
2. Referenced Documents
2.1 ASTM Standards:
B243 Terminology of Powder Metallurgy
B438 Specification for Bronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)
B939 Test Method for Radial Crushing Strength, K, of Powder Metallurgy (PM) Bearings and Structural Materials
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 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 Inert Gas Fusion Techniques
2.2 MPIF Standard:
MPIF Standard 35 Materials Standards for PM Self-Lubricating Bearings
2.3 ISO Standards:
ISO 2795 Plain bearings from sintered metal—Dimensions and tolerances
ISO 5755 Sintered Metal Materials – Specifications,Specifications
3. Terminology
3.1 Definitions—The definitions of the terms used in this specification are found in Terminology B243. Additional descriptive
information is available in the Related Materials section of Volume 02.05 of the under “General Information on PM” on the Annual
Book of ASTM Standards.ASTM B09 web page.
4. Classification
4.1 The following list of standardized iron-base oil-impregnated PM bearing material compositions classified by composition are
included in this specification. Their complete chemical, physical, and mechanical requirements can be found in the specification
tables. Typical applications are discussed in Annex A1.
4.2 The three-part alphanumeric PM Material Designation Code, developed by the PM industry, is used to identify these materials.
A complete explanation of this classification system is presented in Annex A1.
4.2.1 Iron and Iron-Carbon Bearing Materials, (Prefix F)
4.2.1.1 Iron Materials
F-0000-K15
F-0000-K23
4.2.1.2 Iron-Carbon Materials
F-0005-K20
F-0005-K28
F-0008-K20
F-0008-K32
4.2.2 Iron-Copper Bearing Materials (Prefix FC)
4.2.2.1 Low-Copper Materials
FC-0200-K20
FC-0200-K34
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Metal Powder Industries Federations, Federation (MPIF), 105 College RoadRd. East, Princeton, NJ 08540, http://www.info@mpif.org. http://
www.mpif.org.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.International Organization for
Standardization (ISO), ISO Central Secretariat, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva, Switzerland, https://www.iso.org.
B439 − 21
4.2.2.2 Medium-Copper Materials
FC-1000-K20
FC-1000-K30
FC-1000-K40
4.2.2.3 High-Copper Materials
FC-2000-K25
FC-2000-K30
FC-2000-K40
4.2.3 Iron-Copper-Carbon Bearing Materials (Prefix FC)
4.2.3.1 Low-Copper-Carbon Materials.
FC-0205-K20
FC-0205-K35
FC-0208-K25
FC-0208-K40
4.2.3.2 Medium-Copper-Carbon Materials.
FC-0508-K35
FC-0508-K46
4.2.3.3 High-Copper-Carbon Materials.
FC-2008-K44
FC-2008-K46
4.2.4 Iron-Graphite Bearing Materials (Prefix FG)
FG-0303-K10
FG-0303-K12
FG-0308-K16
FG-0308-K22
4.2.5 Iron-Bronze-Graphite (Diluted Bronze) Bearing Materials (Prefix FCTG)
FCTG-3604-K16
FCTG-3604-K22
4.2.6 Diffusion Alloyed Iron-Bronze Bearing Materials (Prefix FDCT)
FDCT-1802-K22
FDCT-1802-K31
FDCT-1802-K39
5. Ordering Information
5.1 Purchase orders or contracts for iron-base oil-impregnated PM bearings covered by this purchasing specification shall include
the following information:
5.1.1 A copy of the bearing print showing dimensions and tolerances (Section 10),
5.1.2 Reference to this ASTM specification, including date of issue,
5.1.3 Identification of bearing material by the PM Material Designation Code (Section 4),
5.1.4 Request for certification and test report documents, if required (Section 16),
5.1.5 Type and grade of special lubricating oil, if required (6.2.3), and
5.1.6 Instructions for special packaging, if required (Section 17).
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6. Materials and Manufacture
6.1 Porous Metallic Bearing:
6.1.1 Porous iron-base bearings shall be processed from a mixture of elemental, prealloyed, or diffusion-alloyed metal powders
with or without the additions of copper, tin, bronze, or graphite powder that together meet the specified chemical composition of
the material.
6.1.2 The powder mixture shall be compacted to produce a green bearing of the required dimensions, shape, and density
6.1.3 The green bearings shall then be sintered in a furnace having a protective atmosphere for a time and temperature cycle that
will produce the required sintered ferrous-base PM material.
6.1.4 After sintering, the iron-base bearings are normally sized to achieve the density, dimensional characteristics, concentricity,
and surface finish required of the finished metallic bearing.
6.2 Oil for Operating Lubrication:
6.2.1 The surface-connected porosity in the bearings shall be filled to the required volume with lubricating oil, either by an
extended soaking in the hot oil or preferably by a vacuum impregnation operation.
6.2.2 A medium viscosity petroleum oil is the lubricant used for most bearing applications, but extreme operating conditions such
as elevated temperatures, intermittent rotation, extremely low speeds, or heavy loads may require a synthetic lubricant or an oil
with a different viscosity.
6.2.3 Unless otherwise specified by the purchaser, a high-grade turbine oil with antifoaming additives and containing corrosion
-6 -6 2
and oxidation inhibitors, having a kinematic viscosity of 280 to 500 SSU [(60 × 10 to 110 × 10 m /s), (60 to 110 cSt)] at 100 °F
(38 °C) is normally used as the general purpose lubricating oil.
7. Chemical Composition
7.1 Chemical Composition Specifications—Each iron-base PM bearing material shall conform to the chemical composition
requirements prescribed in Table 1 when determined on a clean test sample obtained from oil-free bearings.
7.2 Limits on Nonspecified Elements—By agreement between the purchaser and the producer, limits may be established and
chemical analyses required for elements or compounds not specified in Table 1.
8. Physical Properties
8.1 Oil Content—For each bearing material, the oil content of the as-received bearing shall not be less than the minimum
percentage listed in Table 2.
8.2 Impregnation Effıciency—A minimum of 90 % of the surface-connected porosity in the as-received bearings shall be
impregnated with lubricating oil.
8.3 Impregnated Density—The density of the sample bearings, when fully impregnated with lubricating oil, shall meet the
requirements specified in Table 2 for each bearing material.
9. Mechanical Properties
9.1 Radial Crushing Strength—The radial crushing strength of the oil-impregnated bearing material determined on a plain sleeve
bearing or a test specimen prepared from a flange or spherical bearing shall meet the minimum and maximum (if required) strength
values listed in Table 2.
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TABLE 1 Compositional Specifications for Iron-Base PM Bearing Materials
Material Designation
Chemical Composition Requirements
Code
Total Combined Graphitic
Iron Copper Tin All Others
Carbon Carbon Carbon
mass % mass % mass % mass %
A B
mass % mass % mass %
Iron and Iron-Carbon
F-0000-K15 bal. 0 to 0.3 0 to 1.5 0 to 2.0
F-0000-K23 bal. 0 to 0.3 0 to 1.5 0 to 2.0
F-0005-K20 bal. 0.3 to 0.6 0 to 1.5 0 to 2.0
F-0005-K28 bal. 0.3 to 0.6 0 to 1.5 0 to 2.0
F-0008-K20 bal. 0.6 to 0.9 0 to 1.5 0 to 2.0
F-0008-K32 bal. 0.6 to 0.9 0 to 1.5 0 to 2.0
Iron-Copper
FC-0200-K20 bal. 0 to 0.3 1.5 to 3.9 0 to 2.0
FC-0200-K34 bal. 0 to 0.3 1.5 to 3.9 0 to 2.0
FC-1000-K20 bal. 0 to 0.3 9.0 to 11.0 0 to 2.0
FC-1000-K30 bal. 0 to 0.3 9.0 to 11.0 0 to 2.0
FC-1000-K40 bal. 0 to 0.3 9.0 to 11.0 0 to 2.0
FC-2000-K25 bal. 0 to 0.3 18.0 to 22.0 0 to 2.0
FC-2000-K30 bal. 0 to 0.3 18.0 to 22.0 0 to 2.0
FC-2000-K40 bal. 0 to 0.3 18.0 to 22.0 0 to 2.0
Iron-Copper-Carbon
FC-0205-K20 bal. 0.3 to 0.6 1.5 to 3.9 0 to 2.0
FC-0205-K35 bal. 0.3 to 0.6 1.5 to 3.9 0 to 2.0
FC-0208-K25 bal. 0.6 to 0.9 1.5 to 3.9 0 to 2.0
FC-0208-K40 bal. 0.6 to 0.9 1.5 to 3.9 0 to 2.0
FC-0508-K35 bal. 0.6 to 0.9 4.0 to 6.0 0 to 2.0
FC-0508-K46 bal. 0.6 to 0.9 4.0 to 6.0 0 to 2.0
FC-2008-K44 bal. 0.6 to 0.9 18.0 to 22.0 0 to 2.0
FC-2008-K46 bal. 0.6 to 0.9 18.0 to 22.0 0 to 2.0
Iron-Graphite
FG-0303-K10 bal. 0 to 0.5 2.0 to 3.0 0 to 2.0
FG-0303-K12 bal. 0 to 0.5 2.0 to 3.0 0 to 2.0
FG-0308-K16 bal. 0.5 to 1.0 1.5 to 2.5 0 to 2.0
FG-0308-K22 bal. 0.5 to 1.0 1.5 to 2.5 0 to 2.0
Iron-Bronze (Diluted Bronze)
C
FCTG-3604-K16 bal. 0.5 to 1.3 0.5 max 34.0 to 38.0 3.5 to 4.5 0 to 2.0
C
FCTG-3604-K22 bal. 0.5 to 1.3 0.5 max 34.0 to 38.0 3.5 to 4.5 0 to 2.0
Diffusion Alloyed Iron-Bronze
D
FDCT-1802-K22 bal. 0 to 0.1 17.0 to 19.0 1.5 to 2.5 0 to 1.0
D
FDCT-1802-K31 bal. 0 to 0.1 17.0 to 19.0 1.5 to 2.5 0 to 1.0
D
FDCT-1802-K39 bal. 0 to 0.1 17.0 to 19.0 1.5 to 2.5 0 to 1.0
A
The The combined carbon value listed is based on the mass percent of the iron content, not the mass percent of the alloy.
B
Graphitic Graphitic Carbon is also known as Free Graphite.
C
These These compositions usually contain 0.5 to 1.3 % graphite.
D
These These compositions have no added graphite
10. Dimensions, Mass, and Permissible Variations
10.1 This specification is applicable to iron-base PM sleeve and flange bearings having a 3 to 1 maximum length to inside diameter
ratio and a 20 to 1 maximum length to wall thickness ratio.
10.2 Standard sleeve, flange, thrust, and spherical PM bearings covered by this specification are illustrated by Figs. 1-4. Most PM
bearings are small and weigh less than one-quarter pound (~100 g) but they can be produced in sizes that will accommodate shafts
up to approximately 8 in. (200 mm) in diameter.
10.3 Permissible variations in dimensions shall be within the limits specified on the bearing drawing accompanying the order or
shall be within the limits specified in the purchase order or contract.
10.4 Recommended commercial tolerances for iron-base PM bearings are referenced throughout the tables in Appendix X2.
10.5 Chamfers of 30 to 45° are generally used on PM bearings to break the corners.
B439 − 21
TABLE 2 Physical and Mechanical Property Specifications for Iron-Base PM Bearing Materials
Material Designation
A
Physical Requirements Mechanical Requirements
Code
Oil Content Impregnated Radical Crushing Strength,
vol % Density (K)
3 3
g/cm 10 psi MPa
min max min max
Iron and Iron-Carbon
F-0000-K15 21 5.6 to 6.0 12 100
F-0000-K23 17 6.0 to 6.4 23 160
F-0005-K20 21 5.6 to 6.0 20 140
F-0005-K28 17 6.0 to 6.4 28 190
F-0008-K20 21 5.6 to 6.0 20 140
F-0008-K32 17 6.0 to 6.4 32 220
Iron-Copper
FC-0200-K20 22 5.6 to 6.0 20 140
FC-0200-K34 17 6.0 to 6.4 34 230
FC-1000-K20 22 5.6 to 6.0 20 140
FC-1000-K30 19 5.8 to 6.2 30 210
FC-1000-K40 17 6.0 to 6.4 40 280
FC-2000-K25 22 5.6 to 6.0 25 170
FC-2000-K30 19 5.8 to 6.2 30 210
FC-2000-K40 17 6.0 to 6.4 40 280
Iron-Copper-Carbon
FC-0205-K20 22 5.6 to 6.0 20 140
FC-0205-K35 17 6.0 to 6.4 35 240
FC-0208-K25 22 5.6 to 6.0 25 170
FC-0208-K40 17 6.0 to 6.4 40 280
FC-0508-K35 22 5.6 to 6.0 35 240
FC-0508-K46 17 6.0 to 6.4 46 320
FC-2008-K44 22 5.6 to 6.0 44 300
FC-2008-K46 17 6.0 to 6.4 46 320
Iron-Graphite
FG-0303-K10 18 5.6 to 6.0 10 25 70 170
FG-0303-K12 12 6.0 to 6.4 12 35 80 240
FG-0308-K16 18 5.6 to 6.0 16 45 110 310
FG-0308-K22 12 6.0 to 6.4 22 55 150 380
Iron-Bronze (Diluted Bronze)
FCTG-3604-K16 22 5.6 to 6.0 16 36 110 250
FCTG-3604-K22 17 6.0 to 6.4 22 50 150 340
Diffusion Alloyed Iron-Bronze
FDCT-1802-K22 24 5.6 to 6.0 22 150
FDCT-1802-K31 19 6.0 to 6.4 31 215
FDCT-1802-K39 13 6.4 to 6.8 39 270
A
These These requirements are based on bearings in the finished, oil-impregnated condition.
FIG. 1 Standard Sleeve Bearing
11. Workmanship, Finish, and Appearance
11.1 The bearings should have a matte surface, and not show oxidation. The surfaces of sized bearings should have a smooth bright
finish.
11.2 When cut or fractured, the exposed surface shall exhibit a uniform appearance.
11.3 If metallographic examination is performed to determine degree of sintering, it should be done at 200 to 400× magnification.
The iron materials should show a predominantly ferritic or pearlitic phase with uniformly dispersed graphitic carbon (if present).
High copper content Iron-Copper materials should show evidence of melted copper as a copper rich skeletal network around a
B439 − 21
FIG. 2 Standard Flange Bearing
FIG. 3 Standard Thrust Bearing
FIG. 4 Standard Spherical Bearing
ferrous interior structure. Diluted Bronze material should show a bronze phase with no visible free tin, dispersed throughout an
iron matrix. The structure should not show an excessive number of original particle boundaries.
11.4 To verify the presence of oil in the bearing, the as-received bearing may be heated to approximately 300 °F (150 °C) for
approximately 5 min. If oil is present, the surfaces will show beads of oil being exuded from the open porosity.
11.5 When bearings are ordered as being “dry-to-the-touch” to allow automated handling by the purchaser, the excess surface oil
is normally removed by a centrifugal tumbling operation. It is important that the Oil Content test (13.3.1) be performed after the
surface drying treatment to make certain that the required volume of lubricating oil is present.
12. Sampling
12.1 Lot—Unless otherwise specified, a lot shall be defined as “a specific quantity of bearings manufactured under traceable,
controlled conditions as agreed to between the producer and purchaser” (see Terminology B243).
12.2 Sampling Plan—The number of sample bearings agreed to between the producer and the purchaser to be used for dimensional
inspection (13.1), chemical analysis (13.2), physical tests (13.3), and mechanical tests (13.4) shall be taken randomly from
locations throughout the lot.
13. Test Methods
13.1 Dimensional Measurements:
13.1.1 Using suitable measuring equipment, the inside diameter of the bearings shall be measured to the nearest 0.0001 in. (0.0025
mm). The other bearing dimensions only require instrumentation capable of measuring to the tolerances specified on the bearing
drawing.
B439 − 21
13.2 Chemical Analysis:
13.2.1 Oil Extraction—Bearings and test samples must be dry and free of oil before performing chemical tests. The preferred
method of oil removal is by use of the Soxhlet Apparatus specified in Test Method B963. However, upon agreement between
purchaser and producer, a low-temperature furnace treatment [1000 to 1200 °F (540 to 650 °C)] with a flowing nitrogen or other
inert gas atmosphere may be used to volatilize any oil or lubricant that may be present.
13.2.2 Test Sample—An oil-free test sample of chips shall then be obtained by milling, drilling, filing, or crushing the bearings
using clean dry tools without lubrication.
13.2.3 Metallic Elements—The chemical analysis for specified metallic elements shall then be performed in accordance with the
test methods prescribed in Volume 03.05 of the Annual Book of ASTM Standards or by another approved method agreed upon
between the producer and the purchaser.
13.2.4 Carbon Analysis—Carbon analysis is a set of procedures for determining the total carbon, the graphitic carbon, and the
combined carbon in iron-base PM bearings. Total carbon is the sum of graphitic carbon and the total combined carbon.
13.2.4.1 Total Carbon—Determine the total carbon in accordance with Test Method E1019 with the exception that a sample size
as small as 0.25 g may be used upon agreement between purchaser and producer.
13.2.4.2 Combined Carbon (Preferred Method)—The combined carbon content in the iron portion is most easily determined by
a metallographic estimate. The etched cross section of the iron matrix is viewed at 200 to 400× magnification and the combined
carbon in the iron is estimated from the relative amounts of ferrite and pearlite in the structure. 100 % pearlite is equal to
approximately 0.8 % combined carbon in the iron portion. The total combined carbon in the composition is then determined by
multiplying the estimated combined carbon in the iron by the percentage of iron in the material.
13.2.4.3 Graphitic Carbon (Preferred Method)—Subtract the calculated total combined carbon from the total carbon as
determined by Test Method E1019 (13.2.4.1) to obtain the graphitic carbon in the bearing.
13.2.4.4 Graphitic Carbon (Alternative Method)—This wet chemical analytical procedure may be used to determine graphitic
carbon content but it is time-consuming and has been found to lack precision. Weigh and transfer a 0.25 g sample of chips to a
400 mL beaker. Add 25 mL of distilled water, then carefully add 25 mL of concentrated nitric acid and gently boil until all the
iron is in solution. At this point, add five to ten drops of 48 mass % hydrofluoric acid to ensure complete solubility of all carbides,
silicates, and other compounds. Filter the solution through a porous combustion crucible, wash with hot water until free of acid,
then rinse with ethyl alcohol. Dry at 212 °F (100 °C) for 1 h. After drying, add approximately 1 g of carbon-free iron chips and
1 g of copper chips (or another approved accelerator) and follow Test Method E1019 for determining the total carbon.
13.2.4.5 Combined Carbon (Alternative Method)—If the graphitic carbon has been determined by wet chemical analysis
(13.2.4.4)), then the amount of total combined carbon is obtained by subtracting the amount of the graphitic carbon from the total
carbon obtained in accordance with Test Method E1019 (13.2.4.1). Divide this total combined carbon value by the percentage of
iron in the composition to determine the amount of combined carbon in the iron portion.
13.3 Physical Properties:
13.3.1 Oil Content—The oil content of the as-received bearing shall be determined following the procedure for Oil Content By
Volume As Received in Test Method B963.
13.3.2 Impregnation Effıciency—The efficiency of the oil-impregnation process in volume percent units shall be calculated as the
ratio of the Oil Content by Volume as received to the Surface-Connected Porosity using the procedures and formulas in Test Method
B963.
13.3.3 Impregnated Density—The impregnated density in g/cm units, measured after they have been fully impregnated, shall be
determined following the procedure for Impregnated Density in Test Method B962.
13.4 Mechanical Properties:
B439 − 21
13.4.1 Radial Crushing Strength—Radial crushing strength in psi (MPa) is the mechanical property by which the strength of
oil-impregnated PM bearing material is characterized and evaluated. It is determined by breaking plain thin-walled bearings or
hollow cylindrical test specimens under diametrical loading, following the procedures described in Test Method B939, and
calculating the radial crushing strength according to the material strength formula contained therein.
13.4.1.1 Plain sleeve bearings and thrust bearings are tested in the as-received oil-impregnated condition. For acceptance, the
radial crushing strength, determined on the test bearings, shall not be less than the minimum nor more than the maximum (if
applicable) strength specification values listed in Table 2 for the bearing material.
13.4.1.2 Flanged oil-impregnated bearings shall be tested by cutting off the flange and crushing the body as a plain sleeve bearing.
For acceptance, the radial crushing strength so determined shall meet the minimum and maximum (if applicable) material strength
requirements prescribed in Table 2. The testing procedure and material strength requirements of the flange shall be a matter of
agreement between producer and purchaser.
13.4.1.3 To evaluate spherical, or bearings of other configuration, a number of sample bearings from the lot shall first be machined
to a right circular cylinder, measured, and then crushed to determine the radial crushing strength of the oil-impregnated bearing
material. This value shall not be less than the minimum nor more than the maximum (if applicable) radial crushing strength
specified in Table 2 for the material in the sample bearings.
13.4.2 Bearing Breaking Load—If agreed to by the producer and the purchaser, an acceptance specification for the minimum
(maximum) bearing breaking load, P , (P ) in lbf (N), may be established for any specific standard oil-impregnated bearing.
min max
This simplifies acceptance testing because the decision is now based solely upon reading the output of the testing machine without
a need for further calculations. This acceptance procedure can be very useful when evaluating multiple or repeat shipments of the
same bearing.
13.4.2.1 The following formula is used to calculate the breaking load, P, for a hollow cylinder or bearing test specimen.
K 3L 3t
P , P 5 (1)
~ !
min max
D 2 t
where:
P , (P ) = minimum (maximum) bearing breaking load, lbf (N),
min max
K = minimum (maximum) radial crushing strength, psi (MPa),
L = length of bearing, in. (mm),
t = wall thickness, [t = (D – d)/2], in. (mm),
D = outside diameter, in. (mm), and
d = inside diameter, in. (mm).
13.4.2.2 The minimum (maximum) breaking load, P (P ) required for acceptance of any specific plain sleeve or thrust
min max
bearing is calculated using the minimum (maximum) radial crushing strength value specified for that specific bearing material from
Table 1 and the actual D, d and L dimensions of the as-received bearing
NOTE 1—Using the allowable print dimensions that minimize (maximize) the volume of the bearing for the calculations will result in a breaking load
specification(s) that will be applicable to any lot of that specific bearing.
13.4.2.3 The minimum (maximum) acceptable breaking load for a specific flanged bearing shall be calculated by first cutting off
the flange and measuring the outside diameter, D, the inside diameter, d and the length, L of the body. Then, using the minimum
(maximum) radial crushing strength for the oil-impregnated bearing material in Table 1 for K in the breaking load formula and the
measured dimensions of the body, a P , (P ) value may be calculated. This will be the minimum (maximum) bearing breaking
min max
load required for the body of that specific flanged bearing. The test procedure and breaking load requirements for the flange shall
be a matter of agreement between purchaser and producer.
13.4.2.4 For acceptance testing of whole spherical bearings, a minimum (maximum) bearing breaking load specification, P ,
min
(P ) may be established on a specific whole spherical oil-impregnated bearing. First, the radial crushing strength, K , is
max a
determined on that specific spherical bearing machined to a plain cylinder as in 13.4.1.3. Second, whole spherical bearings from
the same lot are crushed, keeping their axes horizontal, to determine the breaking load, P , of the whole bearing. Then, using the
a
correlation formula, the specifications for the breaking load of that whole spherical bearing are calculated as follows:
B439 − 21
K 3P
a
P , ~P ! 5 (2)
min max
K
a
where:
P , (P ) = specification for the minimum (maximum) bearing breaking load of a specific whole spherical bearing, lbf (N),
min max
K = radial crushing strength of the machined test spherical bearings according to 13.4.1.3, psi (MPa),
a
K = minimum (maximum) radial crushing strength for the bearing material, (from Table 1), psi (MPa), and
P = breaking load of whole test spherical bearings, lbf (N).
a
13.5 Conformance:
13.5.1 Dimensional Measurements—For purposes of determining conformance with the dimensional specifications, the tolerance
limits specified on the bearing print are considered absolute limits as defined in Practice E29.
13.5.2 Chemical, Physical, Mechanical Test Results—For purposes of determining conformance with these specifications, an
observed value or calculated value shall be rounded “to the nearest unit” in the last right-hand digit used in expressing the
specification limit, in accordance with the rounding-off method of Practice E29.
13.5.3 Measurement Uncertainty—The precision and bias of the test result values shall be considered by the producer and
purchaser when determining conformance.
14. Inspection
14.1 The producer shall have the primary responsibility to conduct the necessary measurements and tests to ensure that the
bearings meet the requirements of the purchase order and this specification before they are shipped to the customer.
14.2 Upon notification to the purchaser by the producer, all or a portion of the required conformance tests may be contracted to
a qualified third party.
14.3 Upon receipt of the shipment, the purchaser may conduct whatever quality control inspections that he feels are necessary to
confirm compliance to the purchasing requirements.
15. Rejection and Rehearing
15.1 Rejection based on tests made in accordance with this specification shall be reported in writing to the producer within 30 days
of receipt of the shipment. The rejected bearings, however, shall not be returned without written authorization from the producer.
15.2 In case of dissatisfaction with the test results, either the purchaser or producer may make a claim for rehearing.
16. Certification and Test Report
16.1 The purchaser may require in the purchase order or contract that the producer shall supply a Certificate of Compliance stating
that the bearings were produced and tested in accordance with this specification and met all requirements.
16.2 In addition, when required by the purchase order or contract, the producer shall furnish a Test Report that lists the numerical
results obtained from the chemical, physical, and mechanical tests performed on the sample bearings.
16.3 Either the Certificate of Compliance or the Test Report ma
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