1、SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions.QUESTIONS REGARDING THIS DOCUMENT: (724) 772-8512 FAX: (724) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1973 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001STANDARDSubmitted for recognition as an American National StandardJ471dR
4、EV.JUN66Issued 1939-01Revised 1973-06Superceding J471d AUG73SINTERED POWDER METAL PARTS: FERROUS1. ScopePowder metal (P/M) parts are manufactured by pressing metal powders to the required shape in aprecision die and sintering to produce metallurgical bonds between the particles, thus generating thea
5、ppropriate mechanical properties. The shape and mechanical properties of the part may be subsequentlymodified by repressing or by conventional methods such. as machining and/or heat treating.While powder metallurgy embraces a number of fields wherein metal powders may be used as raw materials,this s
6、tandard is concerned primarily with information relating to mechanical components and bearingsproduced from iron-base materials.2. ReferencesThere are no referenced publications specified herein.3. BearingsPowder metal bearings are classified broadly in two groups: ferrous and nonferrous. While much
7、of the basic information is common to both types, this standard is concerned only with the former. Informationrelating to copper- and aluminum-base materials is under development.3.1 Chemical CompositionThe chemical composition shall be determined on an oil-free basis and shallconform to the limits
8、set out in Table 1. The analysis shall be performed in accordance with ASTM procedure,or any other approved method agreed upon by the manufacturer and the purchaser.Subject to agreement between purchaser and manufacturer metallographic estimates of combined carbonvalues may be used.In cases of disag
9、reement in respect of composition, samples shall be submitted to independent umpireanalysis.3.2 Physical and Mechanical PropertiesA most important characteristic of oil impregnated sintered bearingsis their property of self-lubrication resulting from the internal oil reservoir created by the interco
10、nnected porestructure. The quantity of oil available is thus directly proportional to the pore volume of the bearing. Themechanical strength of bearings of the same composition produced under similar manufacturing conditions isinversely proportional to the pore volume. Although a tensile bar pressed
11、 and sintered under the sameconditions as the bearing is sometimes used to evaluate materials, the generally accepted test is a radialcrush test in which the load required to break the bearing is related to its physical dimensions via a constant,K, specified for each material.SAE J471d Revised JUN66
12、-2-3.2.1 DENSITYThe density of the bearing, fully impregnated with lubricant (see Appendix B), shall conform to thelimits set out in Table 1. If in one bearing the variation of density from any one section to any other is lessthan 0.3 g/CM3, the density of the bearing as a whole shall fall within th
13、e limits prescribed in Table 1. If thispoint-to-point variation exceeds 0.3 g/CM3, the manufacturer and purchaser shall agree upon a criticalsection of the part in which the density requirements of the specification must be fulfilled.3.2.2 OIL CONTENTThe oil content of the bearing shall not be less
14、than that specified in Table 1. (See AppendixB.)3.2.3 RADIAL CRUSHING STRENGTHRadial crushing strength (see Appendix A) shall not be less than the valuecalculated as follows:(Eq. 1)where:P = radial crushing load, lb (N)D = outside diameter of bearing, in. (nini)T = wall thickness of bearing, in. (mm
15、)L = length of bearing, in. (mm)K = strength constant shown in Table I3.2.4 PERMISSIBLE LOADSIn calculating permissible loads, the operating conditions, housing conditions, andconstruction should be considered. Permissible bearing loads for various operating conditions are shown inTable 2. These are
16、 intended only as a general guide.Certain conditions will increase the permissible loads, such as additional lubrication, pressure lubrication,hardening of the shaft, loads of short duration.Certain conditions will tend to reduce the load-carrying capacity of bearings regardless of type or make:cont
17、inued start-stop operation, oscillating and reciprocating motion, extremely high or low temperatures;excessively close or loose bearing clearances; deflection or misalignment of shaft; dust, grit, corrosivefumes, or poor shaft finish.3.3 Dimensional Characteristics3.3.1 TOLERANCESDimensional toleran
18、ces allowed shall conform to the limits prescribed in Tables 3 and 4,unless otherwise agreed between supplier and purchaser.TABLE 1PROPERTIES OF FERROUS P/M BEARINGSSAENo.Density,g/cm3Chemical Composition, %CuChemical Composition, %CChemical Composition, %OthersChemical Composition, %FeMinimum Oil C
19、ontent by Volume, %Strength ConstantpsiStrength Constant MPa850 5.7-6.1 0.25 max 2.0 max Bal 18 25,000 172851 5.7-6.1 0.25-0.60 2.0 max Bal 18 30,000 207862 5.8-6.2 7-11 0.30 max 2.0 max Bal 18 40,000 276863 5.8-6.2 18-22 0.30 max 2.0 max Bal 18 40,000 276P KLT2DT-=SAE J471d Revised JUN66-3-For shaf
20、t velocities in excess of 200 ft/min (61 m/min), the permissible load may be calculated as follows: P = 50,000/Vwhere:P = safe load per square inch of projected area, psiV = shaft velocity, ft/minP = 105/Vor:P = safe load per square metre of projected area, MPaV = shaft velocity, m/minTABLE 2PERMISS
21、IBLE BEARING LOADSShaft Velocityft/minShaft Velocitym/minPermissible LoadsSAE 850/851psiPermissible LoadsSAE 850/851MPaPermissible LoadsSAE 862/863psiPermissible LoadsSAE 862/863MPaStatic (0) 0 7500 52 15,000 103Slow and intermittent (25) 7.6 3600 25 8,000 5550-100 15.2-30.4 1800 12 3,000 21100-150
22、30.4-45.7 450 3.1 700 4.8150-200 45.7-61 300 2.1 400 2.8Over 200 61 225 1.6 300 2.1SAE J471d Revised JUN66-4-TABLE 3COMMERCIAL DIMENSIONAL TOLERANCESNote: This table is intended for bearings with a 3:1 maximum length to inside diameter ratio and a 20:1 maximum length to wall thickness ratio. Bearing
23、s having a greater ratio than these are not covered by the table.Inside Diameter and Outside Diameter inInside Diameter and Outside DiametermmTotal Diameter Tolerance(1)Inside Diameterin1. Total tolerance on the inside diameter and outside diameter is a minus tolerance only.Total Diameter Tolerance(
24、1)Inside DiametermmTotal Diameter Tolerance(1)Outside DiameterinTotal Diameter Tolerance(1) Outside Diameter mmUp to 0.760 Up to 19.31 0.001 0.025 0.001 0.0250.761 to 1.510 19.32 to 38.36 0.0015 0.025 0.0015 0.041.511 to 2.510 38.37 to 63.76 0.002 0.05 0.002 0.052.511 to 3.010 63.77 to 76.46 0.003 0
25、.08 0.002 0.053.011 to 4.010 76.47 to 101.86 0.004 0.10 0.004 0.104.011 to 5.010 101.87 to 127.26 0.005 0.13 0.005 0.135.011 to 6.010 127.27 to 152.65 0.006 0.15 0.006 0.15LengthinLengthmmTotal Length Tolernace(1)in1. Total tolerance is split into plus and minus.Total Length Tolerance(1)mmUp to 1.49
26、5 Up to 37.97 0.010 0.251.496 to 1.990 37.98 to 50.54 0.015 0.381.991 to 2.990 50.55 to 75.96 0.020 0.512.991 to 4.985 75.97 to 126.61 0.030 0.76Outside DiameterinOutside Diameter mmWall Thickness, maxinWall Thickness, maxmmConcentricity Tolerance(1)in1. Total indicator reading.Concentricity Toleran
27、ce(1)mmUp to 1.510 Up to 38.36 Up to 0.355 9.02 0.003 0.081.511 to 2.010 38.37 to 51.06 Up to 0.505 12.83 0.004 0.102.011 to 4.010 51.07 to 101.86 Up to 1.010 25.65 0.005 0.134.011 to 5.010 101.87 to 127.26 Up to 1.510 38.35 0.006 0.155.011 to 6.010 127.27 to 152.65 Up to 2.010 51.05 0.007 0.18SAE J
28、471d Revised JUN66-5-3.3.2 RECOMMENDED PRESS FITSPlain cylindrical journal bearings are commonly installed by press fitting thebearing into a housing using an insertion arbor. For housings rigid enough to withstand the press fit withoutappreciable distortion and for bearings with wall thickness appr
29、oximately one-eighth of the bearing outsidediameter, the press fits shown in Table 5 are recommended.TABLE 4FLANGE AND THRUST BEARINGS DIAMETER AND THICKNESS TOLERANCES(1)Flange Bearings, Flange Diameter Tolerances1. Standard and special tolerances are specified for diameters, thickness, and paralle
30、lism. Special tolerances should not be specified unless required since they require additional or secondary operations and, therefore, are costlier.Diameter RangeinDiameter RangemmStandardinStandardmmSpecialinSpecialmm0 to 1-1/2 0 to 38 0.005 0.13 0.0025 0.06Over 1-1/2 to 3 39 to 76 0.010 0.25 0.005
31、 0.13Over 3 to 6 77 to 152 0.025 0.64 0.010 0.25Flange Bearings, Flange Thickness TolerancesDiameter RangeinDiameter RangemmStandardinStandardmmSpecialinSpecialmm0 to 1-1/2 0 to 38 0.005 0.13 0.025 0.06Over 1-1/2 to 3 39 to 76 0.010 0.25 0.007 0.18Over 3 to 6 77 to 152 0.015 0.38 0.010 0.25Thrust Be
32、arings (1/4 in (6.35 mm) Thickness, max), Thickness Tolerances, All Diameters(1)1. Outiside diameter tolerances same as for flange bearings.StandardinStandardmmSpecialinSpecialmm0.005 0.13 0.0025 0.06Parallelism on Faces, maxDiameter RangeinDiameter RangemmStandardinStandardmmSpecialinSpecialmm0 to
33、1-1/2 0 to 38 0.005 0.13 0.003 0.03Over 1-1/2 to 3 39 to 76 0.007 0.18 0.005 0.13Over 3 to 6 77 to 152 0.010 0.25 0.007 0.18SAE J471d Revised JUN66-6-3.3.3 RUNNING CLEARANCES Proper running clearances for sintered bearings depend to a great extent upon theparticular application. Therefore, only mini
34、mum recommended clearances are listed in Table 6. It is assumedthat ground steel shafting will be used and that all bearings will be oil impregnated.4. Mechanical Components4.1 General InformationThis section of the standard relates to mechanical or structural components such ascams, gears, levers,
35、shock absorber parts, transmission parts, etc., which are produced by powder metallurgymethods. Many of these parts are used in the “as-sintered“ or “as-sized“ condition; however, in a large numberof applications, additional processing of the parts is required. Additional processes include machining
36、, heattreatment, sealing, or surface treatments, These notes are intended to provide a general guide on theapplication and use of some of these processes.4.1.1 HEAT TREATMENTP/M parts are porous and thus provide more surface area in any metal/gas reactionsproceeding during heat treatment. In any giv
37、en set of heat treating circumstances, the depth of carburizationor decarburization will increase with decreasing density. Provided that the proper care is taken to maintainthe appropriate carbon potential, carbonbearing iron-base P/M parts can be heat treated by conventionalquenchhardening methods.
38、 It should be noted that the porous material will, on cooling, absorb some of thequench medium, perhaps resulting in some minor problems during tempering or further treatment.The absorption of fluids by the porous materials usually precludes the use of liquid salt bath treatments.TABLE 5RECOMMENDED
39、PRESS FITSOutsideDiameterBearinginOutsideDiameterBearingmmPress FitMininPress FitMinmmPress FitMaxinPress FitMaxmmUp to 0.760 Up to 19.31 0.001 0.025 0.003 0.030.761 to 1.510 19.32 to 38.36 0.0015 0.04 0.004 0.101.511 to 2.510 38.37 to 63.76 0.002 0.05 0.005 0.132.511 to 3.010 63.77 to 76.45 0.002 0
40、.05 0.006 0.15Over 3.010 Over 76.45 0.002 0.05 0.007 0.18TABLE 6RUNNING CLEARANCESShaft SizeinShaft SizemmTotalClearance,mininTotalClearance,minmmUp to 0.760 Up to 19.31 0.0005 0.010.761 to 1.510 19.32 to 38.36 0.001 0.0251.511 to 2.510 38.37 to 63.76 0.0015 0.04Over 2,510 Over 63.76 0.002 0.05SAE J
41、471d Revised JUN66-7-4.1.2 STEAM TREATMENTThis process consists of heating ferrous parts to 1000-1100 F (540-600 C) andsubjecting them to superheated steam under pressure. A layer of black iron oxide is formed on all externaland internal (interconnected porosity) surfaces. This oxide layer improves
42、wear resistance, surface hardness,compressive strength and, under some conditions, corrosion resistance. The presence of oxide within thepores tends to close these channels, reducing the volume of interconnected porosity and providing ameasure of pressure tightness. Steam treatment usually results i
43、n a decrease in impact resistance. It shouldalso be noted that oxidation can lead to the generation of internal stresses with a general degradation ofmechanical properties.4.1.3 PLATINGP/M parts can be electroplated by conventional techniques providing certain precautions are takento prevent the abs
44、orption of the plating solution into the porous body. Trapped electrolyte will eventuallyexude, causing corrosion and flaking of the plate. The degree of surface preparation required is governed bythe part density. Infiltrated parts and parts with a density in excess of 7.0 g/CM3 can be plated by pr
45、oceduresnormally employed for wrought materials. At lower densities the parts must be scaled by resin impregnation ifthe plating is to be deposited from a liquid electrolyte. Certain types of mechanical plating can be applied toporous materials without difficulty.4.1.4 INFILTRATIONInfiltration is a
46、process in which the residual interconnected porosity in an iron-base P/M partis filled with a metal of lower melting point. The infiltrant, normally copper or a copper-base alloy, is placed incontact with the part and the two are heated above the melting point of the infiltrant. In the liquid state
47、 theinfiltrant is drawn into the interconnected porosity of the part by capillary action. The major disadvantage ofthe process is that it may result in some loss of dimensional accuracy.The process has the following advantages:a. Improved mechanical properties. Higher tensile strength and hardness v
48、alues, together with improvedimpact and fatigue resistance, are obtained as a result of infiltrating the part.b. Elimination of porosity. The sealing effect resulting from the filling of interconnected porosity eliminatesproblems associated with electrolyte entrapment in plating or gas permeation in
49、 heat treatment.Infiltrated parts can usually be used in most applications requiring pressure tightness.4.1.5 IMPREGNATIONImpregnat ion is the process of filling the pores of a part with oil or a plastic resin. Oil is usedprimarily for self-lubricating parts or bearings; plastic resins may be useda. To effect pressure tightness.b. To seal porosity as a pretreatment prior to plating.c. To provide an uninterrupted surface for machining. Impregnation improves tool life and surface finish.
