1、Designation: B 438 08Standard Specification forBronze-Base Powder Metallurgy (PM) Bearings (Oil-Impregnated)1This standard is issued under the fixed designation B 438; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las
2、t revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers porous metallic sleeve, flange,thrust and spherical bronze-base bearings that are producedfrom
3、 mixed metal powders utilizing powder metallurgy (PM)technology and then impregnated with oil to supply operatinglubrication.1.2 Included are the specifications for the chemical, physi-cal and mechanical requirements of those bronze-base PMmaterials that have been developed and standardized specifi-
4、cally for use in the manufacture of these self-lubricatingbearings.1.3 This specification is applicable to the purchase ofbronze-base bearings (oil-impregnated) that were formerlycovered by military specifications and are intended for govern-ment or military applications. Those additional government
5、requirements that only apply to military bearings are listed inthe Supplementary Requirements section of this specification.1.4 This specification acccompanies Specification B 439that covers the requirements for Iron-Base Powder Metallurgy(PM) Bearings, (Oil-Impregnated).1.5 Typical applications for
6、 bronze-base bearings are listedin Appendix X1.1.6 Bearing dimensional tolerance data are shown in Ap-pendix X2, while engineering information regarding installa-tion and operating parameters of PM bearings is included inAppendix X3. Additional useful information on self-lubricating bearings can be
7、found in MPIF Standard 35 and thetechnical literature.21.7 With the exception of density values for which theg/cm3unit is the industry standard, the values stated ininch-pound units are to be regarded as standard. The SIequivalents of inch-pound units, shown in parenthesis, havebeen converted in acc
8、ordance with IEEE/ASTM SI 10, may beapproximate and are only for information.1.8 The following safety hazards caveat pertains only to thetest methods described in this specification. This standard doesnot purport to address all of the safety concerns, if any,associated with its use. It is the respon
9、sibility of the user of thisstandard to establish appropriate safety and health practicesand determine the applicability of regulatory limitations priorto use.2. Referenced Documents2.1 ASTM Standards:3B 243 Terminology of Powder MetallurgyB 328 Test Method for Density, Oil Content, and Intercon-nec
10、ted Porosity of Sintered Metal Structural Parts andOil-Impregnated BearingsB 439 Specification for Iron-Base Powder Metallurgy (PM)Bearings (Oil-Impregnated)B 939 Test Method for Radial Crushing Strength, K,ofPowder Metallurgy (P/M) Bearings and Structural Materi-alsB 946 Test Method for Surface Fin
11、ish of Powder Metal-lurgy (P/M) ProductsE9 Test Methods of Compression Testing of Metallic Ma-terials at Room TemperatureE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 1019 Test Methods for Determination of Carbon, Sulfur,Nitrogen, and Oxygen in S
12、teel and in Iron, Nickel, andCobalt Alloys2.2 MPIF Standard:MPIF Standard 35 Materials Standards for PM Self-Lubricating Bearings42.3 IEEE/ASTM Standard:SI 10 American National Standard for Use of the Interna-tional System of Units (SI): The Modernized MetricSystem31This specification is under the j
13、urisdiction of ASTM Committee B09 on MetalPowders and Metal Powder Products and is the direct responsibility of Subcom-mittee B09.04 on Bearings.Current edition approved June 1, 2008. Published July 2008. Originally approvedin 1966. Last previous edition approved in 2005 as B 438/B 438M 05.2Machine
14、Design Magazine, Vol 54, #14, June 17, 1982, pp. 130-142.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.4Ava
15、ilable from MPIF, 105 College Road East, Princeton, NJ 08540, telephone(609) 452-7700.1*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.2.4 ISO Standard:ISO 2795 Plain B
16、earings Made from Sintered MetalDimensions and Tolerances52.5 Government Standards:MIL-PRF-6085 Lubricating Oil: Instrument, Aircraft, LowVolatility6QPL-6085 Lubricating Oil: Instrument, Aircraft, Low Vola-tility6MIL-PRF-17331 Lubrication Oil, Steam Turbine and Gear,Moderate Service6QPL-17331 Lubric
17、ating Oil, Steam Turbine and Gear, Mod-erate Service6MIL-B-5687 Bearings, Sleeve, Washers, Thrust, Sintered,Metal Powder, Oil-Impregnated, General SpecificationFor6MS17795 Bearing, Sleeve, Plain, Sintered Bronze, Oil-Impregnated6MS17796 Bearing, Sleeve, Flanged, Sintered Bronze, Oil-Impregnated6MS21
18、783 Bearing, Washer, Thrust, Sintered Bronze, Oil-Impregnated63. Terminology3.1 DefinitionsThe definitions of the terms used in thisspecification are found in Terminology B 243. Additionaldescriptive information is available in the Related Materialssection of Volume 02.05 of the Annual Book of ASTMS
19、tandards.4. Classification4.1 This specification uses the established three-part alpha-numeric PM Material Designation Code to identify the non-ferrous materials used for self-lubricating PM bearings. Thecomplete explanation of this classification system is presentedin Annex A1.4.2 The following sta
20、ndard oil-impregnated bronze-basebearing material compositions are contained in this specifica-tion:4.2.1 Prefix CTBronze:CT-1000-K19Bronze with 24 % oilCT-1000-K26Bronze with 19 % oilCT-1000-K37Bronze with 12 % oilCT-1000-K40Bronze with9%oil4.2.2 Prefix CTGBronze-Graphite:CTG-1001-K17Bronze, 1 % gr
21、aphite with 22 % oilCTG-1001-K23Bronze, 1 % graphite with 17 % oilCTG-1001-K30Bronze, 1 % graphite with9%oilCTG-1001-K34Bronze, 1 % graphite with7%oil4.2.3 Prefix CTGBronze-High Graphite:CTG-1004-K10Bronze, 4 % graphite with 11 % oilCTG-1004-K15Bronze, 4 % graphite with a trace or up to8%oil4.2.4 Pr
22、efix CTG-MODBronze-Lead-Graphite (MilitaryGrade):CTG-1001-K23-MODBronze, 3 % lead, 1 % graphite with 17 % oil4.2.5 Prefix CFTGBronze-Iron-Graphite (DilutedBronze):CFTG-3806-K14Bronze, 40 % iron, 0.75 % graphite with 22 % oilCFTG-3806-K22Bronze, 40 % iron, 0.75 % graphite with 17 % oil5. Ordering Inf
23、ormation5.1 Purchase orders or contracts for bronze-base, oil-impregnated bearings covered by this purchasing specificationshall include the following information:5.1.1 A copy of the bearing print showing dimensions andtolerances (Section 10),5.1.2 Reference to this ASTM Standard, including date ofi
24、ssue,5.1.3 Identification of bearing material by the PM MaterialDesignation Code (section 4.2),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(section 6.2 or S2.2),5.1.6 Instructions for Special Packaging
25、, if required (Sec-tion 17).5.2 Those additional government requirements necessary onorders for military bearings are prescribed in the Supplemen-tary Requirements section.6. Materials and Manufacture6.1 Porous Metallic Bearing:6.1.1 Sintered bronze-base bearings shall be produced byfirst compacting
26、 pre-alloyed bronze or elemental copper and tinpowders and any other additives appropriate for the composi-tion to the proper density and bearing configuration.6.1.2 The green bearings shall then be sintered in a protec-tive atmosphere furnace for a time and temperature relationshipthat will produce
27、 the required sintered bronze-base PM mate-rial.6.1.3 After sintering, the bronze-base bearings are normallysized to achieve the density, dimensional characteristics, con-centricity and surface finish required of the metallic bearing.6.2 Oil for Operating Lubrication:6.2.1 The interconnected or open
28、 porosity in the bearingsshall be filled to the required volume with lubricating oil, eitherby an extended soaking in the hot oil or preferably by a vacuumimpregnation operation.6.2.2 Amedium viscosity petroleum oil is normally used formost bearing applications, but extreme operating conditionssuch
29、as elevated temperatures, intermittent rotation, extremelylow speeds or heavy loads may require a synthetic lubricant oran oil with a different viscosity.6.2.3 Unless otherwise specified by the purchaser, a high-grade turbine oil with antifoaming additives and containingcorrosion and oxidation inhib
30、itors, having a kinematic viscos-ity of 280 to 500 SSU (60 3 10-6to 110 3 10-6m2/s), (60 to110 cSt) at 100F (38C) is normally used as a generalpurpose lubricating oil.7. Chemical Composition7.1 Chemical Composition SpecificationsEach bronze-base PM bearing material shall conform to the chemical5ISO
31、standards are available from the American National Standards Institute(ANSI), 16 West 42nd Street, New York, NY 10036, (212) 642-4900.6Available from Standardization Documents Order Desk, Bldg 4, Sec. D, 700Robbins Ave, Philadelphia, PA 19111-5094. Electronic copies of military specifi-cations may b
32、e obtained from http:/assist.daps.dla.mil/.B438082requirements prescribed in Table 1 when determined on a cleantest sample from oil-free bearings.7.2 Limits on Nonspecified ElementsBy agreement be-tween the purchaser and the supplier, limits may be establishedand chemical analyses required for eleme
33、nts or compounds notspecified in Table 1.8. Physical Properties8.1 Oil ContentFor each bearing material, the oil contentof the as-received bearing shall not be less than the minimumpercentage listed in Table 1.8.2 Impregnation EffciencyA minimum of 90 % of theinterconnected porosity in the as-receiv
34、ed bearings shall beimpregnated with lubricating oil.8.3 Impregnated DensityThe density of the sample bear-ings, when fully impregnated with lubricating oil, shall meetthe requirements prescribed in Table 1 for each bearingmaterial.9. Mechanical Properties9.1 Radial Crushing StrengthThe radial crush
35、ing strengthof the oil-impregnated bearing material determined on a plainsleeve bearing or a test specimen prepared from a flange orspherical bearing shall meet the minimum and maximum (ifrequired) strength values listed in Table 1.10. Dimensions, Mass, and Permissible Variations10.1 This standard i
36、s applicable to bronze-base PM sleeveand flange bearings havinga4to1maximum length to insidediameter ratio and a 24 to 1 maximum length to wall thicknessratio.10.2 Sleeve, flange, thrust and spherical PM bearings cov-ered by this specification are illustrated by Figs. 1-4. Most PMbearings are small
37、and weigh less than one-quarter pound(100 g) but they can be produced in sizes that will accom-modate shafts up to approximately 8 in. (200 mm) in diameter.TABLE 1 Specifications for Bronze-Base Materials used in PM BearingsMaterial Designation CodeChemical Requirements Physical Requirements Mechani
38、cal RequirementsCoppermass %Tinmass %Leadmass %GraphiticCarbonmass %Ironmass %AllOthersmass %Radial CrushingStrength, KImpregnated Densityg/cm3Content Oilvol %103psi (MPa)BronzeCT-1000-K19 bal 9.5-10.5 0.3 max 1.0 max 1.0 max 6.0-6.4 24 minA19 min (130 min)CT-1000-K26 bal 9.5-10.5 0.3 max 1.0 max 1.
39、0 max 6.4-6.8 19 min 26 min (180 min)CT-1000-K37 bal 9.5-10.5 0.3 max 1.0 max 1.0 max 6.8-7.2 12 min 37 min (260 min)CT-1000-K40 bal 9.5-10.5 0.3 max 1.0 max 1.0 max 7.2-7.6 9 min 40 min (280 min)Bronze-GraphiteCTG-1001-K17 bal 9.5-10.5 0.5-1.8 1.0 max 1.0 max 6.0-6.4 22 minB17 min (120 min)CTG-1001
40、-K23 bal 9.5-10.5 0.5-1.8 1.0 max 1.0 max 6.4-6.8 17 min 23 min (160 min)CTG-1001-K30 bal 9.5-10.5 0.5-1.8 1.0 max 1.0 max 6.8.7.2 9 min 30 min (210 min)CTG-1001-K34 bal 9.5-10.5 0.5-1.8 1.0 max 1.0 max 7.2-7.6 7 min 34 min (230 min)Bronze-High GraphiteCTG-1004-K10 bal 9.2-10.2 2.5-5.0 1.0 max 1.0 m
41、ax 5.8-6.2 11 min 10 min (70 min)CTG-1004-K15 bal 9.2-10.2 2.5-5.0 1.0 max 1.0 max 6.2-6.6C15 min (100 min)Bronze-Lead-Graphite (Military Grade)CTG-1001-K23-MODDbal 9.5-10.5 2.0-4.0 0.5-1.75 1.0 max 0.5 max 6.4-6.8 17 min 23 min (160 min)Bronze-Iron-Graphite (Diluted Bronze)CFTG-3806-K14 bal 5.5-6.5
42、 E36.0-40.0F2.0 max 5.6-6.0 22 min 14-35 (100-240)CFTG-3806-K22 bal 5.5-6.5 E36.0-40.0F2.0 max 6.0-6.4 17 min 22-50 (150-340)AFor an oil content of 27 % min, density range shall be 5.8-6.2 g/cm3and radial crushing strength shall be 15 000 psi (100 MPa) minimum.BFor an oil content of 25 % min, densit
43、y range shall be 5.8-6.2 g/cm3and radial crushing strength shall be 13 000 psi (90 MPa) minimum.CAt maximum graphite (5 %) and density (6.6 g/cm3), this material will contain only a trace of oil. At3%graphite and 6.2-6.6 g/cm3density, it shall contain 8 vol% (min.)of oil.DAdditional chemical require
44、ments are: Zinc0.75 % max, Nickel0.35 % max, Antimony0.25 % max.EGraphitic carbon content is typically 0.5-1.3 %; total carbon shall be 0.5-1.3 %.FThe iron portion may contain 0.5 % max metallurgically combined carbon.FIG. 1 Standard Sleeve BearingB43808310.3 Permissible variations in dimensions sha
45、ll be withinthe tolerance limits shown on the bearing print accompanyingthe order or shall be within the limits specified in the purchaseorder or contract. Dimensional tolerances of bearings formilitary or government applications shall meet the require-ments specified in the Supplementary Requiremen
46、ts section.10.4 Recommended commercial tolerances for bronze-basePM bearings are referenced throughout the tables in AppendixX2.10.5 Chamfers of 30-45 are generally used on PM bearingsto break the corners.11. Workmanship, Finish and Appearance11.1 The bearings should have a matte surface and not sho
47、woxidation. The surfaces of sized bearings should have asmooth, bright finish.11.2 When cut or fractured, the exposed surface of thebearings should exhibit a uniform visual appearance.11.3 If metallographic examination is performed to deter-mine degree of sintering, it should be done at 200-4003magn
48、ification. In 90Cu-10Sn bronze bearings, the microstruc-ture should be alpha bronze with no silver-gray tin-rich coppercompounds and with a minimum of reddish copper-rich areas.The structure should have a very minimum number of originalparticle boundaries. Diluted Bronze material should show abronze
49、 phase with no visible free tin, dispersed throughout aniron matrix.11.4 To verify that oil is present, heat the bearing to about300F (150C) for 5 minutes. If oil is present, the bearingsurfaces exhibit beads of oil being exuded from the pores.11.5 When bearings are ordered as being “dry-to-the-touch”to allow automated handling by the purchaser, the excesssurface oil is normally removed by a centrifugal operation. It isimportant that the Oil Content test (13.3.2) be performed afterthe surface drying treatment to make certa
