DE1775322A1 - Plain bearings with finely divided aluminum as the basic material and process and for its production - Google Patents

Description

Transcript / goe July 23, 1968

Dr.Do/Gw.

Clevite Corporation, Cleveland, Ohio, U.S.A.

Plain bearings with finely divided aluminum as the basic material and process for its production.

The invention relates to a bearing with aluminum as the base metal , which is produced by powder metallurgical processes and in particular a bearing that has a surface layer having premelted aluminum particles.

There are already known plain bearings with aluminum as the basic material, which are manufactured by powder metallurgical processes and the bearing metals commonly used as layering material, such as lead, Contains tin, cadmium, etc. There have been considerable difficulties in the manufacture and use of such bearings result. The problems are essentially based on the difficulty in making the bearings sufficiently robust and to provide security against seizure. The lack of these properties causes the Grain boundaries of the various particles and a tear of the particles of the bearing material from the bearing surface. In The particles of the bearing material are the usual bearings with aluminum as the basic material, which are manufactured using powder metallurgy

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embedded between the aluminum particles and therefore the Distribution of the bearing material fairly rough. In the preparation of of bearing metals of the aluminum-lead-tin type by rolling result, especially when finely dispersed of the material, difficulties in the further processing of such a bearing due to the interaction of the bearing material with the contact surfaces of the pressure rollers, which results in a considerable proportion of the pressed strip gets stuck on the print rollers.

It has been found that the difficulties observed in the known bearings and processes for their manufacture by a bearing layer can be avoided in which the particles of the surface layer mainly consist of powder, the is made of previously fused material, and in the storage material within the particles a fine, has uniform distribution, in contrast to an only uniform distribution of the particles of the bearing material between the aluminum parts in the usual aluminum-based bearings so that an intercalation of the storage material between the aluminum particles is avoided and a free distribution of the bearing material achieved in each aluminum particle will.

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About the difficulties normally encountered when compacting and to avoid coating by rolling a bearing strip consisting of finely divided bearing material, becomes a later removable layer, consisting mainly of aluminum particles and stock material is used · This layer is used after the manufacture of the strip or stock removed again.

It is also well known that when using aluminum-based material containing bearing metal additives, significant amounts are involved Connection problems arise when this material is rolled onto a steel beam, which is common happens in order to achieve the strength required for the bearing »The layer made of a material obtained from a melt Aluminum-based powder made according to the invention is co-pounded with a layer of powder on an aluminum basis or rolled on from pure aluminum. This latter layer is due to the lack of Bearing material metallurgically compatible with the steel girder and can therefore be connected directly to the steel girder. Furthermore, the mixing of the particles creates the base layer a transition zone of considerable depth with that of the premelted layer and therefore promotes the formation of a solid one Connection between the layers.

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The term used "embedding or intercalation of the bearing material between the aluminum ^{particles 11} is defined as the state in the compressed aggregate in which the bearing metal is completely surrounded by aluminum. The boundaries of the individual original particles, ie the bearing metal and the aluminum, are in the final Product distinguishable and undamaged.

It is therefore the main object of the invention to provide a bearing strip and to provide a bearing of aluminum-based powder particles which avoid the above-described and normally encountered difficulties with the known articles, and in which the bearing layer is composed of aluminum-based particles, the bearing metal in finely divided form contain.

Another aim of the invention is to use powder metallurgy to produce a low-friction sliding bearing or a bearing strip create, which have a high fatigue resistance and security against plague eating.

An essential object of the invention is a low-friction slide bearing aluminum base, consisting of a steel backing and a layer of compressed Teilohen

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jAtfWi. ; o gas

usually pure aluminum bonded to the support layer is, exists. The surface or bearing layer is composed of compressed, premelted powder particles made of aluminum base. Each premelted particle contains as an integral part and in itself evenly distributed a bearing metal, usually made of lead, tin, cadmium, etc., so that a layer is obtained, in which the aluminum-based particles are against each other ™ are bounded without particles of the bearing metal in between are embedded *

Furthermore, the invention relates to a method for producing a bearing strip, three separate layers being compacted simultaneously by rollers, which consist of particles on an aluminum basis, and in which a removable layer contains a powder mixture, which mainly consists of aluminum and bearing metal additives such as lead and cadmium , consists. The A intermediate layer is predominantly composed of pre-melted powders, each particle of which is composed of aluminum and a remainder of bearing metals such as lead, tin and cadmium. The base layer of the above three layers consists either of pure aluminum or of a mixture containing more than 55% aluminum with a · »material that is suitable for joining with steel» The three interconnected layers are sintered and then applied

rolled on a steel beam, whereupon the removable layer is removed. - / «.

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BATH ORIGINAL

The invention also relates to a method for producing Bearing strip for vehicle warehouses in which one process step involves heating a mixture of metals, predominantly Aluminum and a remainder of lead, tin, cadmium or others Contains bearing metals. This mixture is heated until it melts and then sprayed to avoid a rapid drop in temperature and to achieve a solidification of the now premelted particles Layers of aluminum-based particles compacted by rolling. A removable surface layer of this triple layer consists of a mixture of mainly aluminum particles and additives of lead, tin and cadmium. A base layer of this Triple layer is composed of either- essentially pure aluminum or at least 55% aluminum with a remainder made of non-bearing metal. The layer of the premelted powder is located between the surface layer and the Base layer · The triple layer is' sintered and the base layer is rolled onto a steel girder and the surface layer is removed from it

For a better understanding of the invention and its details, reference is made to the following description in conjunction with the attached Reference drawing.

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BAD ORfQ] NAL

In the drawing is:

Fig. 1 is a schematic representation of a continuously ar-, production line for the production of bearing strips and bearings according to the invention;

2 shows a schematic representation of a particle with aluminum as the base metal according to the invention; M.

Fig. 3 is a schematic illustration showing how the storage material is surrounded by aluminum after embedding;

Fig. 4 is a perspective view of a common and typical bearing construction, and

Figure 5 is a typical cross-section of the finished bearing. -

The drawing, FIG. 1, shows a crucible 10 for premelting of particles 12 based on aluminum. The raw material 12 is added either in the form of bars or small pieces and can be a mixture of elemental components, a mixture of pure and alloyed material or a mixture of Be alloys. The raw material 12 is used to make the individual components to melt, placed in the crucible 19, heated and in it for a few minutes at a temperature of

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about 980 to 1040 ° C stirred vigorously until the melt has passed into a uniform liquid phase. A melting process of this type is described in more detail in U.S. Patent No. 1,959,029. The crucible 10 is provided with an outflow opening 14, from which the molten mass is ejected under pressure in a continuous stream. Room temperature water or air impinges on the stream of molten mass 16 to break up the stream and the molten mass to be sprayed and at the same time to convert the resulting particles into the solid state. The water is by means of a nozzle 18 so directed against the molten mass that the resulting fine droplets or particles fall into a container 20 and are collected there. Suitable reversals, not shown, are made for the drainage of the water. It can alternatively, instead of water or air, another gas can be used for breaking up the molten stream 16.

Each of the resulting powder particles 22 is predominantly made of aluminum and bearing metal as detailed in the table below; the bearing metal is distributed uniformly through and through in each aluminum-based particle, as shown schematically in FIG. this can be contrasted with a conventional storage structure, which is created by pressing together powder mixtures of aluminum and bearing metal receives, and in which the bearing metal in

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the final product only intercalated between the aluminum particles is, even if a complete merger of the aggregate has been achieved; such a structure is shown in FIG shown. In contrast, the premelted components with aluminum as the base material according to the invention have within of the individual particles have a fine, uniform distribution of the bearing metal, see FIG. 2, while the structure according to FIG the technology used up to now only a uniform distribution of the particles of the bearing metal between the aluminum particles has, see. Fig. 3

Each and every particle of the aluminum-based premelted material is stretched in the rolling direction. However, since the bearing metal is finely and evenly distributed in each particle, it is only slightly elongated. A typical premelted aluminum-based powder particle of the final structure is, in a preferred embodiment, about 100µ long and about 40µ wide and thick. The average distance between the particles of the bearing metal is approximately 5 / ^u

The premelted particles 22 are then collected, dried and processed into a storage strip by being brought into the middle opening of a funnel-shaped container 24, on the left-hand side of which (in the drawing) powder-

BADORfGINAL 109822/0569

Particles 26 are based on aluminum, which serve to form a base or connecting layer, and on the right Side of layer 22 is filled with a mixture 28 of particles of bearing metal and particles based on aluminum, which serve to form a removable layer the purpose of which is to facilitate rolling and compacting of the aluminum particles 22. The particles 26 of the base layer consist of a material that is free of bearing metal to prevent the Prevent pre-melted material 22 on the pressure rollers and to obtain a surface suitable for the connection. Materials 26 and 28 are made of aluminum selected so as to prevent sticking during rolling, as noted above, and a similar or equal coefficient of friction with the rollers 30 is obtained so that an essentially equal powder feed is achieved between the rollers.

The bearing layer 22 is composed solely of premelted particles for almost all bearing applications. However, for some special applications, for example to reduce surface sensitivity, it is possible to use the premelted particles together with particles in elemental form. Pre-melted particles can be obtained in the solid state by transferring a different material things-containing melt. The proportion of bearing metal of the latter

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should not exceed 50% by weight of the total bearing layer. `` Furthermore, the particles 22 of the bearing layer should not contain more than 20% by weight of additives (as listed in the table), based on the total weight of the material, and the additives, together with the bearing material, should not exceed 5%.

In the preferred embodiment, the aluminum powder m particles 26 of substantially pure aluminum. However, also particles with at least 55 wt -% of aluminum are used, the balance being made of a different material than the bearing metal.. The particles 26 can be either elemental or in an alloyed form.

The particles 28 of the removable layer are of the preferred type Embodiment mainly made of aluminum and the rest consists of a mixture of additives and bearing metal either in elemental or in alloyed form. '

The following table shows the composition of the three layers in detail.

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composition
in 6% by weight

base layer Min. reason Si Cu Mn additions Ni Fe Zn Cr Zr Ti Bearing metal - 0 Pb Cd Bi Sb (26) Max. material 0 0 0 Mg 0 0 0 0 0 0 Sn 25th - - _ Warehousing Min. AL 13th 7th 1.5 0 3 2 8th 1 1 1 _ 0 _ _ - - (22) * Max. 55 0 0 0 6th 0 0 0 0 0 0 50 0 0 0 0 removable Min. 100 13th 7th 1.5 0 3 2 8th 1 1 1 25 25 25th 25th (V, layer
(28) Max. 55 0 0 0 6th 0 0 0 0 0 0 0 0 0 0 OO 95 13th 7th 1.5 0 3 2 8th 1 1 1 50 50 50 50 50 6th 98 —Ο

* The bearing layer 22 must contain at least 5 % bearing metal.

The powder particles 22, 26 and 28 are then passed through the pressure rollers 30 out and tightly pressed together. The resulting triple layer is sintered in two stages in the sintering furnace 32. The first holding time in the furnace 32 is about two hours at about 200 ° C. and is determined to remove the gas from the mixture can escape so that no bubbles are formed. The temperature in the sintering furnace is then set for the sintering of the triple layer 32 increased to 310 to 59O ° C. The exact temperature and time will vary depending on the interior desired Structure. For example, sintering was done at about 3 ^ 0 C during half an hour found satisfactory.

The sintered strip is then passed through rollers Jk and a steel backing is rolled face to face onto the base layer. Depending on the end use of the storage material, the structure obtained is optionally subsequently tempered in a tempering furnace 38 at a temperature of approximately 30 ° to 400 ° C. for approximately 30 minutes.

The strip composed of the powder particles 28, 22 and 26 and the carrier layer is cut or punched out and formed into a bearing of the usual shape according to known methods for bearing manufacture, as shown in FIG. K.

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The bearing structure resulting from the procedure described above is shown in Fig. 5 in section. Every layer on Aluminum base is characterized by the number that denotes the particles that make up each of these layers is.

A In order to expose the bearing layer 22, the bearing B, cf. Fig. 4, according to conventional methods to the appropriate. Dimensions drilled until the layer 28 is completely removed. This Operation can possibly be carried out before the bearing strip is punched out.

While the most economical and preferred type, the invention however, it is also possible to change the composition of the base layer, e.g. by Storage of bearing metal, which is normally not suitable for making the connection with the steel support layer is. In this case, in accordance with normal practice, the backing layer must be provided with an interlayer connecting layer, such as a thin layer of nickel, to ensure the adhesion of the multilayer on aluminum base to ensure on the carrier layer »

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The following are typical examples of the composition of each of the aluminum-based layers according to the invention specified. -

Base layer 26:

1. 100 % aluminum (commercial grade)

2. 9k% aluminum and 6 % silicon

3. 0.8 96 silicon, k, k% copper, 0.8 96 manganese, 0 _t k% magnesium, the remainder aluminum.

Bearing layer 22:

1. 8.5 96 lead, 1.5 96 tin, Λ% silicon,

1 96 copper, the remainder aluminum

2. 17 96 lead, 3 96 tin, 1 96 copper, the remainder aluminum

3. 20 96 tin, 1 96 copper, the remainder aluminum. Removable Layer 28:

1. 20 96 tin, 1 96 copper, the remainder aluminum

2. 20% lead, the remainder aluminum

3. 17 96 lead, 3 96 tin, the remainder aluminum.

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Claims (1)

Patent claims » 1. Plain bearing or material for its production, consisting of a steel layer serving as a carrier and a layer connected to the steel layer and consisting essentially of finely divided aluminum and bearing metal, characterized in that it consists of a base layer W sintered onto the steel layer (36) (26) pure of finely divided aluminum or of a predominantly made of aluminum alloy, and from a sintered on the base layer bearing layer of particles of aluminum or aluminum alloys, in which at least 5 wt -.% of a bearing metal with up to 25% lead, up to 25 % tin, up to 25 % cadmium, up to 25 % bismuth and up to 25 % antimony are embedded. 2. plain bearing or material according to claim 1, characterized ^ characterized in that the base layer consists of about 94 % aluminum and about 6 % silicon. 3. plain bearing or material according to claim 1, characterized in that the base layer consists of about 93.6% aluminum, about 0.8 % silicon, about 4.4 % copper, about 0.8 % manganese and about 0.4 % magnesium consists. 109822/0569 k, plain bearing or material according to claim!., characterized in that the base layer consists of 0 to 13 % silicon, 0 to 7 % copper, 0 to 1.5 % manganese, 0 to 6% magnesium, 0 to 3 % nickel, 0 up to 2 % iron, 0 to 8 % zinc, 0 to 1 % chromium, 0 to 1 % zircon, 0 to 1 % titanium, the remainder aluminum. 5. plain bearing or material according to one of claims 1 to 4l ·, characterized in that the base layer is directly connected to the steel layer. 6. plain bearing or material according to any one of claims 1 to 5, characterized in that each particle of the bearing layer consists of 55 to 95% aluminum. 7. plain bearing or material according to any one of claims 1 to 6, characterized in that the Particles of the bearing layer embedded bearing metal does not make up more than 20% of the total weight of the material 8. plain bearing or material according to one of claims 1 to, characterized in that the weight of the aluminum and the bearing metal in the bearing layer makes up at least 60% of the total weight of the material 1C3822 / 0B69 9 »Plain bearing or material according to one of claims 1 to 8, characterized in that the bearing layer consists of about 8.5 % lead, about 1.5 % tin, about k% silicon, about 1 % copper, the remainder aluminum. ^ 10. plain bearing or material according to one of claims 1 to 8, characterized in that the bearing layer consists of about 17% lead, about 3 % tin, about 1 % copper, the remainder aluminum. 11. Plain bearing or material according to one of claims 1 to 8, characterized in that the bearing layer consists of about 20% tin, about 1 % copper, the remainder aluminum. "12. Plain bearing or material according to one of claims 1 to 8, characterized in that the bearing layer of 0 to 13 % silicon, 0 to 7 % copper, 0 to 1.5 % manganese, 0 to 6 % magnesium, 0 to 3 % Nickel, 0 to 2 % iron, 0 to 8 % zinc, 0 to 1 % chromium, 0 to 1 % zirconium, 0 to 1 % titanium, the remainder aluminum. 109822/0569 13. Material for producing a plain bearing according to one of the Claims 1 to 12, characterized in h- ' net that a removable layer is arranged on the bearing layer is. 14. Material according to claim 13, characterized in that that the removable layer of compressed particles of aluminum or an aluminum alloy or mix. 15. Nat.erial according to claim Ik, characterized in that the removable layer consists of 0 to 13 % silicon, 0 to 7 % copper, 0 to 1.5 % manganese, 0 to 6 % magnesium, 0 to 3 % nickel, 0 to 2 % iron, 0 to 8 % zinc, 0 to 1 % chromium, 0 to 1 % zircon, 0 to 1 % titanium, 0 to 50 % cadmium, 0 to 50 % bismuth, 0 to 50 % antimony 0 to 50 % Lead, 0 to 50 % tin, the remainder aluminum. 16. Material according to claim 14, characterized in that the removable layer consists of about 20 % tin, about 1% copper, the remainder aluminum. 1098 2270 569 17 · Material according to claim 14, characterized in that the removable layer consists of about 20 % lead, the remainder aluminum. 18. Material according to claim Ik, characterized in that the removable layer consists of about 17 % ■ | Lead, about 3 % tin, the remainder aluminum. 19. A method for producing a material for producing a plain bearing according to any one of claims 13 to l8, characterized in that the base layer is made from the respective finely divided starting materials , the storage layer and the removable layer by pressing together, preferably between Pressure rollers, forms, then sintered the three layers and then applied them to the base layer as a carrier ™ serving steel layer is rolled on. 20. The method according to claim 19, characterized in that that the layers are annealed after rolling onto the steel beam. 109822/0569 21. The method according to claim 19 or 20, characterized by d a d u r c h, that one for the production of the material for the bearing layer aluminum or an aluminum alloy melts together with the bearing metal, the melt sprayed and deterred. 22. The method according to claim 21, characterized in that geken nzeichne t- that the melt is sprayed and quenched by means of a liquid or gas jet. 23 · Process for the production of a plain bearing according to one of the Claims 1 to 12, characterized in that one produced according to Claims 19 to 22 is used Cutting or punching material to the appropriate pieces, forming the pieces into a bearing and the removable ones Layer removed. 109822/0569 Blank page