Designation:B438/B438M–04
Standard Specification for
形容走路的成语Sintered Bronze Bearings(Oil-Impregnated)1
This standard is issued under thefixed designation B438/B438M;the number immediately following the designation indicates the year of original adoption or,in the ca of revision,the year of last revision.A number in parenthes indicates the year of last reapproval.
A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.
This standard has been approved for u by agencies of the Department of Defen.
1.Scope
1.1This specification covers sintered bronze,oil-impregnated bearings made primarily from elemental copper, tin,and graphite powders.The manufacturer may,at his discretion,u prealloyed bronze powder in the blend.
1.2This specification covers the following variables:
1.2.1Grades—Available in four bronze ba composition grades identifiable by different graphite contents.
1.2.2Type—Grades1and2are available in four types described by specific density ranges.
1.3Bearings ordered to this specification will normally be sized after sintering and will be impregnated with a lubricating oil unless otherwi specified by print.
1.4The values stated in either inch-pound or SI units are to be regarded parately as standard.Within the text,the SI units are shown in brackets.The values stated in each system are not exact equivalents;therefore,each system shall be ud inde-pendently of the other.Combining values from the two systems may result in nonconformance with the specification.
2.Referenced Documents
2.1ASTM Standards:2
B328Test Method for Density,Oil Content,and Intercon-nected Porosity of Sintered Metal Structural Parts and Oil-Impregnated Bearings
E9Test Methods of Compression Testing of Metallic Ma-terials at Room Temperature
2.2Government Standards:
MIL-PRF-6085Lubricating Oil:Instrument,Aircraft,Low V olatility3
MIL-PRF-17331Lubrication Oil:Steam Turbine and Gear, Moderate Service3
交际舞FED-STD-151Metals Test Method3
3.Ordering Information
3.1Orders for parts under this specification shall include the following information:
3.1.1Dimensions and tolerances(Section9),
3.1.2Grade and type,
3.1.3Density specification(Table1and Table2),and
3.1.4Oil type.
4.Materials and Manufacture
4.1Sintered bronze bearings shall be made by molding or briquetting metal powder mixtures to the proper density.The green bearing shall be sintered at a time–temperature relation-ship to produce a microstructure that is esntially alpha bronze and contains no tin-rich phas visible at3003.Sintered bronze bearings are normally sized after sintering to maintain the dimensional characteristics required of the bearing.After sizing and inspection,they are impregnated with a lubricating oil unless otherwi specified.
5.Chemical Composition
5.1The material shall conform to the requirements as to the chemical composition prescribed in Table3.
6.Physical Properties
6.1Density—The density of bearings supplied impregnated with lubricant shall be within the limits prescribed in Table1 and Table2,when determined in accordance with Test Method B328.
6.2Oil Content—Oil content of bearings shall not be less than shown in Table4for each grade and type when deter-mined in accordance with Test Method B328.
程训钊
7.Mechanical Properties
7.1The manufacturer and purchar shall agree on a repre-ntative number of specimens for tests.
7.2Radial Crushing Force—Radial crushing force shall be determined by compressing the test specimen between twoflat steel surfaces at a“no load”speed not greater than0.2in./min [5.0mm/min],the direction of the load being normal to the longitudinal axis of the specimen.The point at which the load
1This specification is under the jurisdiction of ASTM Committee B09on Metal
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B09.04on Bearings.
Current edition approved April1,2004.Published May2004.Originally
approved in1966.Last previous edition approved in2000as B438–00a.
2For referenced ASTM standards,visit the ASTM website,www.astm,or
contact ASTM Customer Service at rvice@astm.For Annual Book of ASTM
Standards volume information,refer to the standard’s Document Summary page on
the ASTM website.
3Available from Standardization Documents Order Desk,Bldg.4Section D,700
Robbins Ave.,Philadelphia,PA19111–5094,Attn:NPODS.
1
Copyright©ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.
drops as a result of the first crack shall be considered the crushing strength.This test shall be applied to plain cylindrical bearings.Flanged bearings shall be tested by cutting off the flange and compressing the two ctions parately.Each ction shall meet the minimum strength requirements pre-scribed in Table 5.
7.2.1Radial crushing force shall not be less than the value calculated as follows:
爱国主义歌曲P 5KLT 2/~D 2T !
(1)
where:
P =radial crushing force,pounds [N],
D =outside diameter of bearing,inches [mm],T =wall thickness of bearing,inches [mm],
K =strength constant as shown in Table 5for grade and
type specified,psi [MPa],and L =length of bearing,inches [mm].
7.2.2Concerning spherical bearings,sample parts from a lot will be machined to a straight wall and radially crushed to calculate the K value.Sample parts from the same lot will be radially crushed as is (whole part).By correlation,the mini-mum radial crush value will be established on the whole bearing and so specified as the minimum radial crush value for the part.
8.Chemical Analysis
8.1If required by purcha agreement,one sample for chemical analysis shall be taken from each lot.A reprentative sample of chips may be obtained by milling,drilling,filing,or crushing a bearing with clean dry tools without lubrication.To obtain oil-free chips,the parts lected for test shall have the oil extracted in accordance with Test Method B 328if neces-sary.
8.2The chemical analysis shall be made in accordance with the methods prescribed in V ol 03.05of the Annual Book of ASTM Standards or by any other method agreed upon between the manufacturer and the purchar.
9.Dimensions and Tolerances
9.1Permissible variations in dimensions shall be within the limits specified on the drawings describing the bearings ac-companying the order or shall be within the limits specified on the order.
10.Workmanship,Finish,and Appearance
10.1Bearings shall be uniform in composition,clean,and conform to applicable drawings.
剁手图片11.Sampling
11.1Lot —Unless otherwi specified,a lot shall consist of parts of the same form and dimensions made from powders of the same composition,formed and sintered under the same conditions,and submitted for inspection at one time.12.Inspection
12.1Unless otherwi specified,inspection of parts sup-plied on contract shall be made by the purchar at the destination.
13.Rejection许姬
13.1Parts that fail to conform to the requirements of this specification may be rejected.Rejection should be reported to the producer or supplier promptly and in writing.
14.Certification
14.1When specified in the purcha order or contract,a producer’s certification shall be furnished to the purchar that the parts were manufactured,sampled,tested,and inspected in accordance with this specification and have been found to meet
TABLE 1Density Requirements (Oil Impregnated)
Type
Density,g/cm 3
Grades 1and 21 5.8–6.2A Grades 1,2,and 42 6.4–6.8Grades 1and 23 6.8–7.2Grades
1and 24
7.2–7.6
A
Maximum density limit of 6.2g/cm 3has been established on Type 1to ensure meeting an oil content of 27%minimum.Satisfactory bearings can also be produced between Type 1and Type 2.The bearings have slightly higher strength constants and slightly lower oil content.
TABLE 2Density Requirements (Oil Impregnated)
Type Density,g/cm 3
Grade 3
1 5.8–6.22
6.2–6.6
TABLE 3Chemical Requirements (Composition,%)
Element Grade 1Grade 2Grade 3Grade 4Copper 87.2–90.585.7–90.082.8–88.380.9–88.0Tin
9.5–10.59.5–10.59.2–10.29.5–10.5Graphite 0–0.30.5–1.8 2.5–5.00.50–1.75Iron,max
1.0 1.0 1.0 1.0Total other elements by difference,max 1.0
1.0
1.0
0.5Lead
2.0–4.0Zinc,max 0.75Nickel,max 0.35Antimony,max
0.25
N OTE —Grade 4to be ud for special government needs.
TABLE 4Oil Content (Oil Content,Volume %,Min)
Type Grade 1Grade 2Grade 3Grade 41272511A ...B 173129 (4)
9
7
...
...
A At 3%graphite,Type 1will contain 14%min oil content.
B
At 3%graphite,Type 2will contain 8%min oil content.At 5%graphite,Type 2will contain only a minimal amount of oil.
TABLE 5Strength Constant K (Strength Constants,Min),A psi
[MPa]
Type Grade 1Grade 2Grade 3Grade 4115000[105]13000[90]10000[70]...[...]226000[180]23000[160]15000[105]
23000[160]
337000[255]30000[205]...[...]...[...]4
40000
歌曲大全100首[275]
34000[235]
...[...]
...[...]
A
For the K value specification to be valid,wall thickness must be less than one third of the outside
diameter.
the requirements.When specified in the purcha order or contract,a report of the test results shall be furnished.
14.2The purcha order must specify whether or not the certification includes chemistry.
14.3Upon request of the purchar in the contract or order, the certification of an independent third party indicating conformance to the requirements of this specification may be considered.
15.Supplementary Requirements
15.1For some materials,supplementary requirements may be specified.Usually the apply only when specified by the purchar in the inquiry,contract,or order.The supplemen-tary requirements shall appear parately.
15.2Special Government Requirements—Requirements that are special to government needs are listed in15.2.1 through15.2.9.
15.2.1Materials shall conform to Table3,Grade4.Con-tractor shall furnish a percent composition analysis on an oil-free basis for each lot showing the percentage for each element as specified in Table3.Bearing shall conform to this specification and supporting military specification as appli-cable.
15.2.2High-grade nongumming petroleum lubricants,such as MIL-PRF-6085,MIL-PRF-17331(Military Symbol 2190–TEP),or as specified on referenced military standard specification sheets shall be ud to impregnate the bearings.
15.2.3When specified,afirst-article inspection shall be performed on bearings.Four samples shall be made available forfirst-article inspection and tested for chemical require-ments,density,porosity,radial
crushing strength,oil excretion, and dimensional characteristics as specified herein,Test Method B328,FED-STD-151,or in an otherwi specified document.Any defect or failure shall be cau for rejection of the lot.Waivers for minor defects may be addresd to the contracting officer.
15.2.4When procured from a contractor versus the actual manufacturer,a certificate of quality conformance(COQC) supplied by the manufacturer of the bearing may be furnished in lieu of actual performance of such testing by the contractor, provided lot identity has been maintained and can be demon-strated to the Government.The certificate shall include the name of the contractor,contractor number,name of manufac-turer,NSN,item identification,name of the component or material,lot number,lot size,dimensions,date of testing,test method,individual test results,and specification requirements.
15.2.5When specified in the contract or purcha order, packaging and marking shall be completed in accordance with the provisions of the contract.
15.2.6Oil excretion of the bearing shall be verified by placing the bearing in the chamber of a preheated oven.Oven temperature shall be nominally300°F[149°C].Exposure shall be5min.During the period,beads shall exude uniformly from the bearing surface.Lack of appreciable sweating of the
lubricant on the bearing surface will be cau for rejection. Lubricant content may be verified using Test Method B328.
15.2.7Unless otherwi specified,the contractor is respon-sible for testing.The contractor may u their own or any other suitable facility for the performance of testing and inspection, unless an exception is stated.The Government rerves the right to perform an inspection t forth herein to assure supplies and sources conform to the prescribed requirements.
15.2.8Records of examination and tests performed by or for the contractor shall be maintained and made available to the Government by the contractor for a period of three years after delivery of the products and associate material.
15.2.9All requirements shall be as specified herein.Refer-ence military standard specification sheets shall take prece-dence unless otherwi specified in the contract or purcha order.
16.Related Specifications
16.1MPIF Standards:
16.1.1MPIF Standard35-Material Standard35for P/M Self Lubricating Bearings.
16.2ISO Standards:
16.2.12795–Plain Bearings Made From Sintered Material—Dimensions and Tolerances.
16.2.25755–Sintered Metal Material Specifications.
17.Keywords
17.1density;K strength constant;oil content;oil-impregnated bearings;porosity
APPENDIXES
(Nonmandatory Information)
X1.EXPLANATORY INFORMATION
X1.1Design Information
X1.1.1In calculating permissible loads,the operating con-ditions,housing conditions,and construction should be con-sidered.The maximum static bearing load should not exceed 8500psi[60MPa]of projected bearing area(length times inside diameter of bearing)for this material.Thisfigure is 75%of t
he value for the compression deformation limit[yield strength,permanent t of0.001in.[0.025mm]for specimens 11⁄8in.[30mm]in diameter and1in.[25mm]in length]as determined in accordance with Test Methods E
9.
X1.2Permissible Loads
X1.2.1Permissible loads for various operating conditions are given in Table X1.1.
X1.3Dimensional Tolerances
X1.3.1Commercial dimensional tolerances are included in Table X1.2.Clor tolerances can be held with special tooling or processing,or both.
X1.3.2The commercial tolerances listed in Table X1.2are intended for bearings with a 4to 1maximum length to inside diameter ratio and a 24to 1maximum length to wall thickness ratio.
X1.3.3Fig.X1.1,Fig.X1.2,and Fig.X1.3illustrate stan-dard sleeve,standard flange bearings,and standard thrust bearings,respectively.Their dimensions are referenced throughout the tolerance tables.Standard chamfer tolerances are also listed in Table X1.2.
X1.4Press Fits
X1.4.1Plain cylindrical journal bearings are commonly installed by press fitting the bearing into a housing with an inrtion arbor.For housings rigid enough to withstand the press fit without appreciable distortion and for bearings with wall thickness approximately one eighth of the bearing outside diameter,the press fits shown in Table X1.3are recommended.X1.5Running Clearance
X1.5.1Proper running clearance for sintered bearings de-pends to a great extent on the particular application.Therefore,only minimum recommended clearances are listed in Table X1.4.The maximu
m running clearances will automatically be held within good design practice for average conditions.It is assumed that ground steel shafting having a recommended finish of 4to 16root mean square (rms)will be ud and all bearings will be oil impregnated.
X1.6Flange and Thrust Bearing Specifications
X1.6.1Diameter and thickness specifications for flange and thrust washers are shown in Table X1.5.
TABLE X1.1Permissible Loads
Shaft Velocity,ft/min [m/s]
Permissible Loads,psi [MPa]
Grades 1,2,3,and 4Type I
Type II
Type III
Type IV
Slow and intermittent 3200[22]4000[28]4000[28]4000[28]25[0.125]2000[14]2000[14]2000[14]2000[14]50to 100[0.25–0.50],incl 500[3.4]550[3.9]550[3.9]550[3.9]Over 100to 150[0.50–0.75],incl
325[2.2]365[2.5]365[2.5]365[2.5]Over 150to 200[0.75–1.00],incl
250[1.7]280[1.9]280[1.9]280[1.9]Over 200[1.00]
A A A A
A
For shaft velocities over 200ft/min [1.00m/s],the permissible loads may be calculated as follows:
P 550000/V @1.75/V ](1)where:
P =safe load,psi [MPa]of projected area,and V =shaft velocity,ft/min [m/s].
N OTE 1—With a shaft velocity of less than 50ft/min [0.25m/s]and a permissible load greater than 1000psi [0.15MPa],an extreme pressure lubricant should be ud.
N OTE 2—With good heat dissipation and heat removal techniques,higher PV ratings can be obtained.
TABLE X1.2Commercial Dimensional Tolerances
Inside Diameter,d ,and Outside Diameter,D ,in.[mm]Total Diameter Tolerances,in.[mm]Over Through ...1[25]0.001[0.025]1[25] 1.5[40]0.0015[0.04]1.5[40]2[50]0.002[0.05]2[50] 2.5[65]0.0025[0.064]2.5[65]
3[75]
0.003[0.076]
Length Tolerances,L ,in.[mm]
Over
1.5[40]0.005[0.13]1.5[40]3[75]0.010[0.25]3[75]
4.5[115]0.015[0.38]Outside Diameter,D ,
in.[mm]Length,L ,in.[mm]Concentricity,
6in.[mm]Over Through Over Through ...1[25]0[0]0[25]0.003[0.08]...1[25]1[25] 1.5[40]0.004[0.1]...1[25] 1.5[40]2[50]0.004[0.1]...1[25]2[50] 2.5[65]0.005[0.13]...1[25] 2.5[65]3[75]0.
005[0.13]1[25]2[50]0[0]1[25]0.004[0.1]1[25]2[50]1[25] 1.5[40]0.005[0.13]1[25]2[50] 1.5[40]2[50]0.005[0.13]1[25]2[50]2[50] 2.5[65]0.006[0.15]1[25]2[50] 2.5[65]3[75]0.006[0.15]2[50]3[75]0[0]1[25]0.005[0.13]2[50]3[75]1[25] 1.5[40]0.006[0.15]2[50]3[75] 1.5[40]2[50]0.006[0.15]2[50]3[75]2[50] 2.5[65]0.007[0.18]2
[50]
3[75]
2.5[65]
世界无烟日手抄报3[75]
0.007
[0.18]
Chamfer Tolerances
Wall Thickness (D-d )1⁄2
Chamfer,C.max,in.[mm]
in.Over Through ...0.040[1]0.008[0.2]0.040[1]0.080[2]0.012[0.3]0.080[2]0.120[3]0.016[0.4]0.120[3]0.160[4]0.025[0.6]0.160[4]0.200
[5]
0.030[0.8]0.200
[5]...
0.030
[0.8]
Angularity Tolerance,6
45°
5°
(from the
face)
FIG.X1.1Standard Sleeve
Bearing
X1.7Lubricating Oil-Impregnant
X1.7.1It was found that the high-grade turbine oil contain-ing rust and oxidation inhibitors and antifoam additives is the most desirable type of oil to be ud.The viscosity should be specified by the ur in accordance with the
application.
FIG.X1.2Standard Flange
Bearing
FIG.X1.3Standard Thrust Bearing
TABLE X1.3Recommended Press Fits
Outside Diameter of Bearing,in.[mm]
Press Fit
Over Through min,in.[mm]max,in.[mm]0.000[0.000]0.760[20]0.001[0.025]0.003[0.08]0.760[20] 1.510[40]0.0015[0.04]0.004[0.10]1.510[40] 2.510[63]0.002[0.05]0.005[0.13]2.510[63] 3.010[75]
0.002[0.05]0.006[0.15]3.010
[75]
...
0.002[0.05]
0.007
[0.18]
TABLE X1.4Running Clearances
Shaft Size,in.[mm]Clearance,min,in.[mm]
Over
Through 0.000[0.000]0.250[6]0.0003[0.008]0.250[6]0.760[20]0.0005[0.013]0.760[20] 1.510[40]0.0010[0.025]1.510[40] 2.510[60]0.0015[0.040]2.510[60]
...[...]
0.0020
[0.050]
