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: (412) 772-8512 FAX: (412) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (412) 776-4970 FAX: (412) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1991 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001INFORMATIONREPORTAn American National StandardJ459REV.OCT91Issued 1947-0
4、2Revised 1991-10Superseding J459c(R) BEARING AND BUSHING ALLOYSForewordThis Document has not changed other than to put it into the new SAE Technical Standards BoardFormat.1. ScopeThe bearing performance of steel backed half bearings, bushings, and washers is dependent on theproperties and thickness
5、of the lining alloy, the strength and dimensional stability of the steel backing (usuallySAE 1010) and the strength of the bond between the lining alloy and the backing. This SAE InformationReport is primarily concerned with the properties of the lining alloys used in automotive applications, inpart
6、icular, the crankshaft bearings of the internal combustion engine.2. ReferencesThere are no referenced publications specified herein.3. Factors Affecting the Choice of Crankshaft Bearing AlloyThe choice of alloy for the main andconnecting rod bearings of an engine depends on the conditions in the hy
7、drodynamic film separating thebearing surface from the crankshaft. If the dynamic load applied to the bearing through the oil film is high,fatigue strength of the bearing alloy will be the prime consideration. If the thickness of the oil film is low or attimes incomplete, compatibility, or the abili
8、ty to withstand occasional rubbing contact with the crankshaft, willbecome the most important property; the related property of dirt embeddability becomes particularly importantif strict attention to cleanliness is not observed during engine assembly or maintenance. Cavitation of the oilfilm, which
9、may arise from rapid movement of the journal across the bearing clearance or from other causes,requires that the bearing alloy be resistant to erosion by the collapsing vapor bubbles. Both fatigue strengthand cavitation erosion resistance are broadly related to alloy hardness; generally, the harder
10、the alloy thestronger and more cavitation erosion resistant it will be. Dirt embeddability and compatibility, on the otherhand, are inversely related to alloy hardness; generally, the softer the alloy the better will these surfaceproperties be.The correct choice of alloy for a particular engine is t
11、hat which offers the optimum compromise among theseopposing requirements.Corrosion and wear resistance are other important properties of engine bearing alloys. Corrosion resistanceis necessary if engine temperatures are high and there is a danger of oil degradation and the appearance ofan acidic com
12、ponent. Wear resistance is required if the crankshaft surface roughness is comparable to the oilfilm thickness. The choice of crankshaft finishing procedure has become particularly critical with the adoptionof nodular iron crankshafts.Characteristics and applications of typical bearing and bushing a
13、lloys are outlined in Table 1.SAE J459 Revised OCT91-2-4. Tin- and Lead-Based BabbittsThe bearing alloys with the longest history are the tin and lead-basedbabbitts. These soft materials have excellent compatibility and dirt embeddability, but fall short of the fatiguestrength requirements of presen
14、t day automotive engines. There are, however, many bushing applications,and the alloys are still used in the crankshaft bearings of some slow speed marine diesel engines. Corrosionresistance is generally good, although the tin-based alloy can suffer from tin oxide corrosion in watercontaminated oils
15、, and the lead-based alloys are subject to corrosion in acidic oils. A version of lead-basedbabbitt in which the alloy is infiltrated into a steel backed porous copper-based matrix was widely used formany years as a crankshaft bearing, but is nowadays mainly found in camshaft bushings.5. Copper-Lead
16、 AlloysThe copper-lead alloys are stronger than the babbitts, and are used in manyautomotive and heavy-duty engines.The metallurgical structure of the copper-lead crankshaft bearing alloys consists of a fine distribution ofinterconnected lead islands in a copper-tin matrix. The higher the tin conten
17、t, the stronger the matrix, and thehigher the fatigue strength of the bearing. The metallurgical processes consist of lining steel strip continuouslyeither by casting the alloy directly onto the steel, or by first atomizing the alloy and subsequently sintering thepowder to the steel backing. Some la
18、rge bearings are produced by centrifugal or gravity casting onto apreformed steel backing.The lead content of most of the copper-lead crankshaft bearing alloys in current use is in the range of 14 to27%. Alloys with lead contents of 40% or more have fallen into disuse, largely because of the introdu
19、ction oflead free fuel, and a tendency for engine oils to become more corrosive in service. The lead phase of copper-lead alloys is subject to corrosion by oils which have become acidic during high temperature engine operation.Almost all copper-lead crankshaft bearings are protected against corrosio
20、n by a thin overlay of lead-basedalloy electrodeposited on the bearing surface. Lead-tin (PbSn10), lead-tin-copper (PbSn10Cu2), and lead-indium (PbIn7) are the three most common alloys. Lead-tin-indium overlays have been adopted in certainJapanese engines. The function of the tin or indium is to mak
21、e the overlay resistant to corrosive attack by theengine oil as well as to increase fatigue and wear resistance. In the case of the tin-containing overlays, a thinnickel barrier is commonly incorporated between the overlay and the copper-lead to minimize the loss of tinwhich would otherwise occur th
22、rough tin diffusion into the copper-lead at engine operating temperature.The overlay also performs an important function by providing the bearing with a degree of conformabilitytheability to conform to misalignment or imperfect crankshaft geometry. It also has good compatibility and dirtembeddabilit
23、y and allows the harder tin-containing copper-leads to be used with reduced risk of seizure. Theoverlay has a much lower fatigue strength than the underlying copper-lead, and thickness is usually keptbetween 0.02 and 0.03 mm to minimize fatigue damage.6. Aluminum AlloysThe aluminum engine bearing fa
24、mily covers a wide range of alloys which are used bothwith and without overlay. Reticular tin-aluminum (AlSn20Cu1) is widely used in Europe as an automotivecrankshaft bearing alloy. It is not usually overlay plated, but is sometimes given a thin tin flash for improvedrunning-in. The alloy offers a g
25、ood combination of strength and surface properties, but has insufficient fatiguestrength for heavy-duty diesel applications. A softer version containing 40% tin is used in some slow speedmarine diesel engines. Recently lower tin versions of aluminum-tin with 2 to 4% silicon for improved wearresistan
26、ce against nodular iron crankshafts have been adopted in Europe and Japan. In the USA theequivalent alloys commonly used unplated in passenger car engines are two versions of aluminum-lead. Bothalloys have 4 to 10% lead, and 4% silicon. A minor tin addition prevents corrosion of the lead phase.Of th
27、e overlay plated aluminum alloys the most popular is aluminum-silicon-cadmium AlSi4Cd1, widely used inthe USA in automotive applications. An aluminum-cadmium alloy AlCd3Mn1Cu1Ni1 is found in heavy-dutydiesel applications. The high silicon alloy AlSi11Cu1 and an aluminum-zinc alloy AlZn5Si2CuPb are a
28、lsointended for heavy-duty applications.SAE J459 Revised OCT91-3-The overlays used on aluminum are lead-tin and lead-tin-copper with a thin interlayer of nickel or copperincorporated for electrochemical process reasons rather than as a diffusion barrier.The aluminum alloys as a class have excellent
29、corrosion resistance, but may prove more prone to cavitationerosion than the equivalent copper-lead alloy.The aluminum alloys are bonded to steel by either hot or cold roll bonding. All are continuously cast and rolledto bonding thickness, except for one of the aluminum-lead alloys which is produced
30、 as strip by a powdermetallurgy process and subsequently roll bonded.7. Bushings and WashersAutomotive automatic transmissions use a number of steel backed bushings andthrust washers, lined with one or another of the copper or aluminum-based alloys described in Sections 5 and6. The piston pin or sma
31、ll end bushing of both automotive and heavy-duty engines carries heavy dynamicloads and is generally lined with a low lead, high tin copper alloy CuPb10Sn10. The hardness of the alloy andthe poor lubrication conditions require that the pin surface be hard and have a fine surface finish. Bushingswrap
32、ped from wrought bronze strip CuSn4Pb4Zn3 are occasionally used in this application and, together withbronze thrust washers, in some transmission applications.Bronze bushings machined from continuously cast rod and tube are no longer used in engine or transmissionapplications, but may be found in ag
33、ricultural and earthmoving equipment.TABLE 1BEARING AND BUSHING ALLOYS: SUMMARY OF CHARACTERISTICS AND APPLICATIONSSAE No.ISODesignation Characteristics ApplicationsA. Tin- and Lead-Based Alloys:12 SnSb8Cu4 Excellent compatibility, conformability and dirt embeddability; good corrosion resistance and
34、 cavitation erosion resistance; poor fatigue strength and temperature capability.Marine diesel crankshaft bearings, steam turbine journal and thrust bearings, electric motor bushings.13 PbSb10Sn6 Excellent conformability and dirt embeddability; good compatibility, fair corrosion resistance; poor cav
35、itation erosion resistance, fatigue strength and temperature capability. SAE 14 and 15 have higher load carrying ability than SAE 13.Camshaft, transmission, and steering pump bushings.14 PbSb15Sn1015 PbSb15As16 Similar to SAE 13 to 15 but with improved fatigue strength.Camshaft bushings, some less h
36、eavily loaded crankshaft bearings.B. Copper-Based Alloys:48 CuPb30 Good fatigue strength and cavitation erosion resistance, increasing with increasing tin content. Overlay plating is required for corrosion resistance, compatibility and conformability in crankshaft bearing applications.Main and conne
37、cting rod bearings, with overlay; transmission and hydraulic pump bushings.49 CuPb24Sn794 (1) CuPb24Sn47921 CuPb10Sn10 Very good fatigue strength, load carrying capacity and wear resistance; fair corrosion resistance; poor compatibility and conformability.Piston pin (small end), rocker arm and steer
38、ing knuckle bushings; wear plates.7931 SAE J459 Revised OCT91-4-8. Notes8.1 Marginal IndiciaThe (R) is for the convenience of the user in locating areas where technical revisions havebeen made to the previous issue of the report. If the symbol is next to the report title, it indicates a completerevi
39、sion of the report.PREPARED BY THE SAE BEARINGS AND BUSHINGS COMMITTEE485 Fair fatigue strength; fair compatibility and conformability; fair embeddability; fair corrosion resistance.Camshaft bushings and other applications requiring higher fatigue strength than tin- or lead-based alloys.C. Aluminum-
40、Based Alloys:786 AlSn40 Good conformability, dirt embeddability, compatibility and corrosion resistance, poor fatigue strength and cavitation erosion resistance but stronger than babbitt at engine operating temperature.Cross head bearings in marine diesel engines, generally with lead-tin overlay.783
41、 AlSn20Cu Good compatibility, dirt embeddability and corrosion resistance; fair fatigue and cavitation erosion resistance.Crankshaft bearings in passenger car engines. Does not require an overlay, although SAE 783 is often tin flashed.787 788 SAE 787 and 788 have better fatigue strength and better w
42、ear resistance against nodular iron crankshafts than SAE 783.770 AlSn6Cu Good corrosion resistance; fair to good compatibility, conformability, dirt embeddability, fatigue strength, and cavitation erosion resistance.Crankshaft bearings in passenger car and heavy-duty engines, with overlay. Camshaft
43、and transmission bushings, crankshaft thrust washers.780 781 AlSi4Cd782 AlCd3CuNi784 AlSi11Cu Good corrosion resistance, fatigue strength, and cavitation erosion resistance; fair compatibility; poor conformability and dirt embeddability.Crankshaft bearings for heavy-duty engines, with overlay.785 Al
44、Zn5Si2CuPb1. These copper-lead alloy designations have been consolidated to reflect alloy chemistry regardless of method of manufacture.SAE 792 has been combined with SAE 797.SAE 793 has been combined with SAE 798.SAE 794 has been combined with SAE 799.TABLE 1BEARING AND BUSHING ALLOYS: SUMMARY OF C
45、HARACTERISTICS AND APPLICATIONS SAE No.ISODesignation Characteristics ApplicationsSAE J459 Revised OCT91RationaleNot applicable.Relationship of SAE Standard to ISO StandardNot applicable.ApplicationThe bearing performance of steel backed half bearings, bushings, and washers is dependent onthe proper
46、ties and thickness of the lining alloy, the strength and dimensional stability of the steel backing(usually SAE 1010) and the strength of the bond between the lining alloy and the backing. The SAEInformation Report is primarily concerned with the properties of the lining alloys used in automotiveapplications, in particular, the crankshaft bearings of the internal combustion engine.Reference SectionThere are no referenced publications specified herein.Developed by the SAE Bearings and Bushings Committee
