EP0306495B1 - Procede de production d'un materiau antifriction composite et materiau antifriction ainsi produit - Google Patents

Procede de production d'un materiau antifriction composite et materiau antifriction ainsi produit Download PDF

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Publication number
EP0306495B1
EP0306495B1 EP87903629A EP87903629A EP0306495B1 EP 0306495 B1 EP0306495 B1 EP 0306495B1 EP 87903629 A EP87903629 A EP 87903629A EP 87903629 A EP87903629 A EP 87903629A EP 0306495 B1 EP0306495 B1 EP 0306495B1
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EP
European Patent Office
Prior art keywords
lead
percent
copper
lining
strip
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP87903629A
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German (de)
English (en)
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EP0306495A1 (fr
Inventor
Robert G. Alexander
George C. Pratt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Federal Mogul LLC
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Federal Mogul LLC
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Publication of EP0306495A1 publication Critical patent/EP0306495A1/fr
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C9/00—Alloys based on copper
    • C22C9/08—Alloys based on copper with lead as the next major constituent
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
    • B22F7/02—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite layers
    • B22F7/04—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite layers with one or more layers not made from powder, e.g. made from solid metal

Definitions

  • the present invention broadly relates to composite bearing materials which are comprised of a hard metal backing strip, such as steel, having a bearing lining composed of leaded bronze tenaciously bonded to at least one face surface thereof.
  • Such composite bearing materials are eminently suitable and in widespread use for the fabrication of various bearing components for use in internal combustion engines, vehicle suspensions, transmission assemblies or the like.
  • the tin content necessary to provide resistance to corrosion by acidic engine oils is around 3 percent. If there is no nickel barrier the tin content will fall to this value more quickly than when a nickel barrier is present, and the loss of tin is restricted to the formation of nickel tin compound only.
  • breaks in the nickel barrier can occur.
  • the breaks are found above the lead phase and result in a path being made available for diffusion of the tin atoms through the nickel barrier into the copper lead. Because the tin atoms are trapped in the copper lead as the copper tin compound, lead is forced out of the copper lead, carrying the broken nickel barrier with it.
  • the breaks widen, permitting more tin diffusion and the broken section of the nickel barrier may end up half way through the thickness of the overplate.
  • the likelihood of a nickel barrier break occurring is a function of the size of the lead phase underneath it. The coarser the lead the less the support for the barrier and the more likely a break is to occur.
  • the present invention provides for an improved process and an improved composite bearing material produced thereby employing powder metallurgical techniques whereby a satisfactory tenacious bond is obtained between the bearing lining and the steel backing strip employing sintering conditions including time and temperature which inhibit the formation of large-sized lead particles thereby achieving a unique leaded-bronze lining characterized by an extremely fine-sized lead distribution dispersed uniformly throughout the bearing lining matrix.
  • the compacted composite strip is reheated to a temperature of about 1450°F (788°C) to 1600°F (871°C) for an additional period of time to further enhance the physical properties of the lining and to further enhance the bond between the lining and the backing strip.
  • the resintered composite strip is cooled to a temperature below about 800°F (426°C), typically 300°F (149°C) to 450°F (232°C), in a protective atmosphere and, preferably, is again subjected to a warm compaction, typically at a temperature of about 300°F (149°C) to about 450°F (232°C) such as by roll compaction to further enhance the properties of the composite strip and to improve the sizing characteristics thereof.
  • the resultant composite strip can subsequently be employed for fabrication of various bearing components and the outer face of the lining can be machined to final dimensions. It is further contemplated that the machined outer face of the bearing lining can be subjected to an overplate of a suitable bearing metal or metal alloy such as a lead-tin or lead-tin-copper bearing alloy containing up to about 90 percent by weight lead.
  • a suitable bearing metal or metal alloy such as a lead-tin or lead-tin-copper bearing alloy containing up to about 90 percent by weight lead.
  • the bearing lining of the composite bearing material is characterized as having a bearing lining nominally containing about 8 percent to about 35 percent by weight lead, about 0.5 to 10 percent by weight tin with the balance consisting essentially of copper.
  • the bearing lining matrix is further characterized by the fact that the lead constituent thereof is substantially uniformly distributed throughout the lining matrix in the form of fine-sized particles of an average particle size typically less than about 8 microns and there being no lead islands larger than about 44 microns.
  • the composite bearing material in accordance with a preferred practice of the present invention is basically comprised of a steel backing and metal powder lining sintered thereon.
  • the steel backing is typically a low-alloy steel such as SAE Type 1010 or 1020 generally having a thickness of from about 0.040 inch (0.102 cm) up to about 0.250 inch (0.635 cm), typically 0.125 inch (0.317 cm) for most automotive engine connecting rod bearing.
  • the metal powder employed in forming the bearing lining by powder metallurgical techniques comprises a copper-lead-tin prealloyed powder which may generally contain from about 8 percent to about 35 percent lead, up to 10 percent tin with the balance consisting essentially of copper.
  • the use of the powder in a prealloyed form is important to achieve the unique distribution of the lead constituent in the final bearing lining. While it is preferred to employ prealloyed powders wherein each particle thereof is of the same composition as that of the final bearing lining desired, it is contemplated that prealloyed powders of alternative compositions can be mixed together to provide a resultant mixture corresponding to that of the final bearing lining.
  • SAE Grade 797 nominally composed of 80 percent copper, 10 percent lead, 10 percent tin
  • SAE Grade 798 nominally containing 88 percent copper, 8 percent lead and 4 percent tin
  • SAE Grade 799 nominally containing 73.5 percent copper, 23 percent lead and 3.5 percent tin
  • SAE Grade 49 nominally containing 75.5 percent copper, 24 percent lead and 0.5 percent tin
  • SAE Grade 480 nominally composed of 64.5 percent copper, 35 percent lead and 0.5 percent tin.
  • the metallurgical structure of the copper lead lining comprises two distinct phases, namely an interconnected network of lead islands and a copper-rich matrix, the tin being in solution in the copper.
  • the shape of the prealloyed powder particles is not critical although particles of a generally spherical configuration are preferred.
  • the particle size of the prealloyed powder should be less than about 100 mesh (147 microns) with particle sizes ranging to as small as about 1 micron.
  • the prealloyed metal powder contains particles distributed over the permissible size range with 50 percent thereof being less than 325 mesh (44 microns) whereby optimum loose powder packing density is achieved.
  • the loose powder density as applied to the metal plated backing strip generally ranges from about 50 percent to about 60 percent of 100 percent theoretical density.
  • the quantity of powder applied will vary depending upon the specific type of bearing component to be fabricated from the composite bearing material and generally will range from about 0.020 inch (0.050 cm) to about 0.070 inch (0.178 cm) whereby upon subsequent sintering and compaction, the final lining will range in thickness from about 0.010 inch (0.025 cm) to about 0.050 inch (0.127 cm).
  • the steel backing strip which is usually supplied in the form of a coil is subjected to appropriate cleaning such as vapor degreasing, alkaline, or acidic cleaning, wire brushing, and pickling as may be required to remove surfaces and soils and any rust and/or scale on the face surfaces thereof.
  • the cleaned steel backing strip is thereafter advanced in a substantially horizontal position beneath a suitable feed hopper containing the prealloyed leaded-bronze powder which is applied in the form of a substantially uniform layer as controlled by a doctor knife or the like.
  • the strip with the superimposed powder layer thereon is thereafter sintered in a series of two furnaces, each of which is provided with a nonoxidizing atmosphere.
  • the nonoxidizing atmosphere preferably comprises a reducing atmosphere derived from the incomplete combustion of natural gas nominally containing about 12 percent hydrogen, 10 percent carbon monoxide and 5 percent carbon dioxide with the balance consisting essentially of nitrogen.
  • a reducing atmosphere provides the further advantage of reducing any oxides present on the surfaces of the powder particles and to prevent any further oxidation thereof at the elevated sintering temperatures encountered in the sintering furnace.
  • the first furnace is primarily a single induction coil. Induction sintering enables a bond to be established without a long duration heat-up time above 650°C, the temperature at which the lead particles begin to grow.
  • induction sintering electric currents are induced in the steel backing which heat the steel backing directly and the copper-lead powder by conduction and radiation from the steel. The currents may flow in the plane of the steel strip, or around the periphery of the strip or a combination of both depending on the geometry of the induction coil. It is possible that some heat is also produced directly in the powder layer.
  • Induction heating of steel is particularly efficient up to about 730°C, the temperature at which steel ceases to be ferromagnetic.
  • the preferred two furnace sintering process combines induction heating to 730°C with conventional sintering from 730°C to 800/850°C.
  • Such a "hybrid" system offers useful savings in the cost of equipment and in running costs. It has been determined that the fast heat-up rates obtained in the induction part of the hybrid process permit metallurgical structures to be obtained which show little or no loss of the fine lead benefits obtained from a system which consists of induction sintering alone.
  • the second furnace is heated to a temperature ranging from about 1450°F (788°C) up to about 1600°F (871°C).
  • the specific temperature employed in the second sintering furnace will vary somewhat depending upon the particular composition of the prealloyed powder and is adjusted to produce sufficient liquid phase comprised predominantly of lead which effects a wetting of the powder particles and a filling of the interstices present in the powder layer in addition to a wetting of the surface of the steel strip to promote the formation of a tenacious bond.
  • the sintering temperature is controlled at about 1500°F (815°C) for a period of about 3 to about 5 minutes at the sintering temperature.
  • the time at sintering temperature in the second furnace of the first sinter may be reduced to no more than about 2 minutes and preferably less.
  • the total time at sintering temperature in both furnaces will be about 2 minutes. Since lead growth is directly dependent upon the time the alloy is held at or near sintering temperature, the lead size of the alloy as produced by the present invention is significantly finer than that produced by conventional sintering techniques.
  • the second sintering furnace of the first sinter can be eliminated and the entire sintering step effected in the induction coil.
  • induction heating steel beyond 730°C is not efficient. Even so, the total time spent by the composite bearing strip above 650°C would be significantly decreased and preferably just under 1 minute. Lead growth will therefore be at a minimum, and quite probably less than that shown in Table 1 below.
  • the composite strip exits from the sintering furnace and enters a suitable cooling section provided with a nonoxidizing protective atmosphere in which it is cooled to a temperature below about 300°F (149°C) whereafter the strip is compacted to substantially 100 percent of theoretical density to reduce any residual voids in the powder layer.
  • the compaction can conveniently be achieved by passing the strip through a pair of compaction rolls.
  • the composite strip is again reheated in a furnace provided with a nonoxidizing, preferably, reducing atmosphere to a temperature within the same range as the first sintering temperature and preferably about 1500°F (815°C) for a total residence period of about 10 minutes including a preheating period to provide a sintering time at a temperature of about 3 to about 5 minutes to effect a further enhancement of the bond between the bearing lining and the steel backing strip and a further improvement in the physical characteristics of the bearing lining.
  • a nonoxidizing, preferably, reducing atmosphere to a temperature within the same range as the first sintering temperature and preferably about 1500°F (815°C) for a total residence period of about 10 minutes including a preheating period to provide a sintering time at a temperature of about 3 to about 5 minutes to effect a further enhancement of the bond between the bearing lining and the steel backing strip and a further improvement in the physical characteristics of the bearing lining.
  • the steel strip is cooled in a protective atmosphere, preferably by passing the strip through a molten lead bath at a temperature of about 800°F (427°C) which effects a further filling of any residual pores present in the bearing lining.
  • a further final compaction preferably a warm roll compaction step to provide for still further improvements in the properties of the composite strip and to effect a sizing and improved uniformity of the bearing lining thereon.
  • the resultant composite strip can thereafter readily be coiled and transferred to further fabricating operations to fabricate bearing components such as shell-type bearings, bushings, thrust washers, and the like.
  • the face of the bearing lining is usually subjected to a further final finishing operation to provide a precision bearing component.
  • the machined bearing surface can be provided with an overplate of a suitable soft metal bearing lining of any of the types well known in the art.
  • the machined bearing face is electroplated to provide a nickel barrier layer on the lining surface of a thickness typically between 0.0001 and 0.005 mm (0.00004 and 0.0002 inches).
  • a suitable overplate is applied at a thickness of about 0.0005 (0.127 mm) to about 0.0015 inch (0.381 mm).
  • a preferred overlay composition is PbSn10Cu2, and an overlay thickness is about 0.025 mm.
  • Generally suitable is any bearing alloy containing about 2 to about 4 percent copper, about 8 to about 12 percent tin, and the balance consisting essentially of lead.
  • the bearing lining is characterized by the lead constituent thereof being present in the form of extremely fine-sized particles substantially uniformly distributed throughout the lining matrix from the bearing face inwardly to the backing strip.
  • the lead particles are further characterized as being of an average particle size typically less than about 8 microns (distributed at a particle count of at least about 1550 particles per square millimeter) and there being no lead particles larger than 44 microns and less than about 0.4 percent of the lead particles being larger than 36 microns.
  • the extremely fine size of the lead particles and their substantially uniform distribution throughout the lining matrix renders such linings eminently suitable for heavy duty-type bearing applications due to the improved physical properties of such bearing linings in comparison to conventional prior art bearing linings of similar alloy composition in which the lead particles are of substantially greater size and/or of nonuniform distribution.
  • the fine-sized particles are achieved primarily in accordance with the specific conditions employed in the induction sintering process which substantially inhibits an agglomeration of the lead constituent into undesirable larger particles in accordance with prior art practices.
  • SAE type 1010 steel in coil form 0.075 inch (.190 cm) thick was cleaned by conventional procedures.
  • a prealloyed, minus 100 mesh, leaded-bronze powder containing about 14 percent by weight lead, about 3.5 percent tin and the balance copper was applied to one face of the steel coil to a thickness of about 0.047 inch (.119 cm).
  • the powder layer and coil strip was passed through an induction solenoid coil fed from a 650 KHZ generator and the electric current induced in the steel so as to flow around the periphery of the strip.
  • the strip was heated to about 730°C and, upon reaching such temperature, was cooled down and a test strip measuring 6 inches (15.24 cm) by 2 inches (5.08 cm) was taken from the coil strip and transferred to a conventional electric fired sintering furnace, as described herein, and heated to a temperature in excess of 650°C for a period of about 5.1 minutes.
  • the effective total residence time in both furnaces was about 5.2 minutes, and total time at sintering temperature of about 800°C was about 2 minutes.
  • the strip was cooled to room temperature (70°F) (21°C) and densified by passing through a roll compactor to compact the powder layer to about 0.023 inch (.058 cm).
  • the compacted composite test strip was reheated in a conventional sintering furnace to a temperature of about 1490°F (810°C) for an additional period of about 10 minutes including a preheating to temperature and final sinter at temperature of about 3 to about 5 minutes whereafter it was removed and cooled to room temperature.
  • a section of the composite strip was evaluated for bond strength of the lining to the backing strip and was found by test to be about 10,400 psi (497,952 NT/meter 2 ) bond-shear strength.
  • a microscopic inspection of the cross-section of the lining revealed an extremely fine-sized and uniform distribution of the lead particles from the surface to the steel interface as shown in Table 1 below. Total lead particles equalled at least about 1550 per square mm and the average lead particle size was between 4 and 8 microns. Table 1 shows the lead size distribution obtained.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Composite Materials (AREA)
  • Manufacturing & Machinery (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Sliding-Contact Bearings (AREA)

Abstract

Le procédé de production d'un matériau antifriction composite comprenant une matrice de métal en poudre préalliée frittée de plomb-bronze à renfort en acier comprend une première étape de frittage qui consiste à chauffer par induction la poudre préalliée et le renfort en acier jusqu'à environ 150°C puis une seconde étape de frittage pendant laquelle la poudre préalliée et le renfort en acier sont portés à environ 850°C dans un second four de frittage. Ce procédé permet de produire un matériau antifriction composite dans lequel les particules de plomb ont une taille moyenne inférieure à environ 8 microns et dans lequel aucun îlot de plomb n'est supérieur à environ 44 microns.

Claims (4)

1. Alliage de cuivre-plomb-étain formé à partir d'une matière métallique en poudre frittée au moins en partie par chauffage par induction, la teneur en plomb étant comprise entre 8 et 35% en poids et la teneur en étain étant comprise entre 0,5 et 10,0% en poids, et le solde, en dehors des impuretés, étant uniquement du cuivre, la microstructure de l'alliage consistant en îlots de plomb interconnectés dans une matrice riche en cuivre, la dimension moyenne des îlots de plomb étant inférieure à 8 pm et 1 % au maximum des îlots de plomb ayant une dimension supérieure à 40 pm.
2. Matériau antifriction composite comprenant une bande support en acier à au moins une face de laquelle est solidement lié un revêtement antifriction de bronze au plomb, ledit revêtement antifriction étant sensiblement totalement dense et contenant de 8% environ à 35% environ de plomb, jusqu'à 10% d'étain environ et le solde étant uniquement du cuivre, en dehors des impuretés, ledit revêtement antifriction étant en outre caractérisé en ce que son constituant plomb est sensiblement uniformément réparti dans toute la matrice de revêtement sous la forme de fines particules de plomb avec un compte de particules d'au moins 1550 particules environ par mm2, et ayant une dimension moyenne inférieure à 8 pm environ, et dans lequel pas plus de 0,4% environ desdites particules de plomb sont plus grosses que 36 um, ledit revêtement étant formé à partir d'une matière métallique en poudre frittée au moins en partie par chauffage par induction.
3. Matériau antifriction composite suivant la revendication 2, comportant une couche intermédiaire de nickel liée audit revêtement antifriction et comportant une couche de recouvrement en alliage à base de plomb liée à ladite couche intermédiaire, l'épaisseur de la couche intermédiaire étant de 0,001 à 0,005 mm et l'épaisseur de la couche de recouvrement étant de 0,01 à 0,05 mm.
4. Procédé de fabrication d'une bande support en acier comportant un revêtement d'alliage de cuivre-plomb-étain, dans lequel on étale une poudre d'alliage de cuivre-plomb-étain sur une bande en acier, on élève la température de la bande dans un enroulement d'induction jusqu'à une température dépassant 700°C, la température étant ensuite élevée par d'autres moyens à 800-850°C environ pour agglomérer les particules de poudre les unes aux autres et à l'acier, le temps total passé par la bande entre 650°C et 850°C étant inférieur à deux minutes, toute l'opération de chauffage étant effectuée en atmosphère réductrice, et la couche frittée étant ensuite compactée entre des cylindres et refrittée.
EP87903629A 1986-05-28 1987-05-18 Procede de production d'un materiau antifriction composite et materiau antifriction ainsi produit Expired - Lifetime EP0306495B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US86823686A 1986-05-28 1986-05-28
US868236 1986-05-28

Publications (2)

Publication Number Publication Date
EP0306495A1 EP0306495A1 (fr) 1989-03-15
EP0306495B1 true EP0306495B1 (fr) 1991-01-23

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EP87903629A Expired - Lifetime EP0306495B1 (fr) 1986-05-28 1987-05-18 Procede de production d'un materiau antifriction composite et materiau antifriction ainsi produit

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EP (1) EP0306495B1 (fr)
JP (1) JPH01503150A (fr)
KR (1) KR880701295A (fr)
BR (1) BR8707706A (fr)
ES (1) ES2005604A6 (fr)
WO (1) WO1987007308A2 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0726125B2 (ja) * 1990-03-29 1995-03-22 大同メタル工業株式会社 すべり軸受用バイメタルの製造方法
AT402436B (de) * 1995-07-12 1997-05-26 Miba Gleitlager Ag Gleitschicht auf kupferbasis
JP2002060870A (ja) * 2000-08-24 2002-02-28 Taiho Kogyo Co Ltd 微細鉛組織を有するＣｕ−Ｐｂ系銅合金及び内燃機関用すべり軸受

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1086052B (de) * 1957-05-08 1960-07-28 Sintermetal S R L Verfahren zur Herstellung von Verbundmetallstreifen fuer Lagerzwecke od. ae. Verwendungsmoeglichkeiten
FR1370097A (fr) * 1963-07-09 1964-08-21 Mueszentermelo V Paliers bimétalliques en bronze étain-plomb et procédé de fabrication desdits paliers
US4002472A (en) * 1975-05-01 1977-01-11 Federal-Mogul Corporation Process for making composite bearing material
DE2747545A1 (de) * 1977-10-22 1979-05-03 Glyco Metall Werke Gleitlagerlegierung, insbesondere zur verwendung als gleitschicht, auf kupfer-blei-zinn-basis zur herstellung von mehrschichtgleitlagern
JPS5511724A (en) * 1978-07-04 1980-01-26 Arai Pump Mfg Cutter
AU576797B2 (en) * 1983-11-28 1988-09-08 Federal Mogul Corporation Composite bearing material made by powder metalurgy

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Publication number Publication date
WO1987007308A3 (fr) 1988-01-28
BR8707706A (pt) 1989-08-15
EP0306495A1 (fr) 1989-03-15
KR880701295A (ko) 1988-07-26
JPH01503150A (ja) 1989-10-26
ES2005604A6 (es) 1989-03-16
WO1987007308A2 (fr) 1987-12-03

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