Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D19/00—Casting in, on, or around objects which form part of the product
  • B22D19/08—Casting in, on, or around objects which form part of the product for building-up linings or coverings, e.g. of anti-frictional metal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/008—Continuous casting of metals, i.e. casting in indefinite lengths of clad ingots, i.e. the molten metal being cast against a continuous strip forming part of the cast product
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
  • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars

Definitions

• the invention relates to a method for producing a layer material for sliding elements with a sliding layer of at least one alloy applied to a carrier layer in the form of a metallurgical two- or multi-component system with a miscibility gap (onotectic).
• the invention further relates to a device for performing this method.
• Alloys in the form of metallurgical two-component or multi-component systems with a miscibility gap which are also referred to as dispersion alloys, generally consist of metallic components with widely differing specific weights.
• the heavy components e.g. the Pb in AlPb dispersion alloys tend to segregate, i.e. When the alloy solidifies - according to the state diagram - mixed crystals of a different concentration are deposited first than in the later stage of the cooling process, so that the mixed crystals formed from the melt are not homogeneous.
• the production of AlPb materials for plain bearing purposes under terrestrial conditions by casting technology is therefore carried out by e.g. Gaps in the mixture in the AlPb system made impossible.
• the fine distribution of the lead in the Al matrix required for use as a plain bearing material is not achieved.
• DE-PS 21 30 421 and " DE-OS 22 41 628 a method for producing a composite metal strip, in which molten aluminum passes through an opening in the bottom of the crucible and molten lead in a thin, thread-like stream through the molten aluminum also into the Bottom opening of the crucible is guided.
• the melt mixture of, for example, aluminum and lead formed in the bottom opening of the crucible is then whirled through and mixed by means of gas jets and blown onto the upper surface of the substrate passed by.
• a functional layer formed in this way is still very inhomogeneous, the lead particles, due to their much greater density, tending to segregate and coagulate to a great extent when the swirling stream of melt mixture hits the surface of the substrate.
• DE-OS 17 75 322 describes a plain bearing or material for its production which consists of Al alloys (eg dispersion alloys based on AlPb, AlSn), the Al material which is later plated onto steel as a carrier, is produced by a powder rolling process.
• the AI bearing material made in this way has a line arrangement of the soft minority phase (eg Pb) due to the compression by powder rolling and the subsequent rolling and plating operation.
• Such banded structure is for stressed "Removable load bearings considerable disadvantage, since the formation of the lines due to internal notch effect duration cracks.
• PCT WO 87/04377 describes a process with the aid of which a 1 to 5 mm thick AlPb — Ba-.d is produced and plated onto steel as the carrier material.
• the fine distribution of lead described here is not achieved in practice, however, since the lead plating is scattered in rows and does not become globular even after subsequent heat treatment. In addition, it can be seen that segregation already occurs in strips with a thickness of more than 0.5 mm.
• DE-PS 37 30 862.9-16 wants to avoid this disadvantage by using an AlPb film of 0.5 mm maximum thickness with extremely fine, globular Pb distribution when using a melt-spin method similar to WO 87/04377 claimed and applies the same to a carrier while avoiding rolling operations by ultrasonic welding, soldering and gluing.
• the object of the invention is therefore to provide a method and an apparatus for producing a layer material for sliding elements with a sliding layer made of at least one alloy in the form of a metallurgical two- or multi-component system with a mismatch gap (monotectic) applied to a carrier layer, one in the sliding layer globular fine distribution of the dispersed metal component (the minority phase) in a quasi amorphous metallic matrix.
• Such a layered material is obtained by a process in which the sliding layer is continuously cast from the alloy and immediately after casting in a continuous pass of cooling with, for the prevention of particle growth of the immiscible metallurgical components over particle dimensions of 0.01 to 1 / ⁇ m, preferably ⁇ .1 um, is subjected to sufficiently high solidification speed.
• the high cooling rate freezes a uniform globular distribution of the dispersed metal component (minority phase) in the matrix of the melt. The segregation that occurs with alloys of this type is reduced to a minimum.
• Distribution of the minority phase is equipped with significantly improved properties. This significantly increases the strength of the functional layer. Similarly, the ductility and toughness of the functional layer are improved despite extremely high strength.
• the alloy or the alloys are preferably produced by means of a melt-metallurgical process and, in the process and when they are ready for casting, are kept at a temperature above the separation temperature corresponding to the system and the composition.
• a particularly preferred possibility in the context of the invention to achieve a fine globular distribution of the minority phase in the matrix, which is as uniform as possible, consists in that the alloy or the alloys to be cast have nucleating agents adapted to the respective alloy type, for example P, B , Ti, Si, borides, nitrides and oxides are added in a weight proportion between 0.1 and 3.5%.
• nucleating agents adapted to the respective alloy type for example P, B , Ti, Si, borides, nitrides and oxides are added in a weight proportion between 0.1 and 3.5%.
• Systems with lead as a minority phase are particularly suitable in the process according to the invention, for example AlPb, FePb, CuPb, MnPb, NiPb, possibly also CrPb and CoPb.
• systems with tin, bismuth or antimony as a minority phase such as AlSn, AlBi, AlSb, CrSn.
• the invention offers two basic options:
• the dispersion alloy is cast in the form of a thin layer or a film on a substrate forming the carrier layer, preferably continuously on a strip-shaped substrate.
• the measures according to the invention mentioned above are used to achieve a fine globular distribution of the minority phase in the metal matrix.
• the sliding layer can be poured on in one or more stages. A multi-stage pouring would then provide that first a first thin film is poured on and then immediately and quickly cooled effectively. After the first infused film has solidified, a second film is poured over it and also quickly solidified again. Such a construction of the sliding layer can take place in several stages.
• the individual melted films can have different thicknesses.
• the films can also have different alloy compositions. By using different alloys and / or different cooling conditions, thin layers of different structures can also be formed within the sliding layer.
• sliding layer in the form of a tape or a film is poured free of the carrier layer and after cooling with the aid of a joining process with the help of a laser beam, for example, is continuously applied to the carrier layer.
• a pre-coated tape can also be used as a carrier material for the cast sliding layer film in this case.
• such strips can have a steel backing and an intermediate layer made of one of the following alloys:
• Copper-lead alloys for example Pb 9 to 25%, Sn 1 to 11%, Fe, Ni, M less than or equal to 0.7%, the rest Cu;
• Copper-aluminum alloys for example Al 5 to 8%, balance Cu;
• Aluminum-nickel alloys for example Ni 1 to 5%, Mn 0.5 to 2%, Cu less than or equal to 1%, balance AI;
• Additional elements can be added to the melts to increase the strength of the matrix materials and increase the wear resistance. It has thus been shown that an AIPb dispersion alloy can also be added with about 1 to 4% by weight of silicon, 0.2 to 1% by weight of Mg and 0.1 to 1.5% by weight of Co in order to achieve a to get wear-resistant functional layer. To improve the corrosion resistance of the lead minority phase, it is also advisable to add 0.5 to 3% by weight of tin. For copper-based alloys such as CuPb22, 0.5 to 2% by weight of Sn and 0.2 to 1% by weight of Fe are usually added.
• a binding or diffusion barrier layer between the sliding layer and the intermediate layer for example, made of Ni, Zn, Fe, Co (especially copper-based alloys) as well as NiSn, CuZn, Co, CuSn (especially with aluminum alloys) may be useful.
• a device which is equipped with a crucible for melting and / or keeping an alloy ready for casting in the form of a metallic two-component or one with a miscibility gap - 'i -
• the pouring device for forming a film or sheet-shaped thin strip should be free or designed as a support on a substrate and the cooling device should be a forced-cooled collecting surface for the film to be cast or a forced-cooled abutment surface for the substrate to be poured and on the free surface contain the directional, highly effective cooling units of the cast film or film.
• the device is equipped with strongly forced-cooled rollers, in particular a strongly forced-cooled roller as a ' hanger' for the cast film or carrier for the substrate to be cast.
• a flat-guided guide or transport path can be provided A casting flow device for the molten alloy is arranged across this guide or transport track, the distance between which can be adjusted above the guide track or above a substrate placed on the guide track a sliding layer in a multi-stage construction can be poured onto a substrate in a particularly favorable manner.
• a plurality of such " pouring-flow devices " are arranged one behind the other in the direction of transport and between the pouring-flow device and behind the last one n pouring and flow bars onto the free surface of the use cast film or cooling units that act on the free surface of the cast film.
• Figure 1 is a greatly enlarged partial section of a layer material with a poured sliding layer made of dispersion alloy.
• FIG. 2 shows a greatly enlarged partial section made of a layer material according to another embodiment
• Fig. 3 is a schematic representation of a manufacturing device
• FIG. 4 shows a schematic illustration of a manufacturing device modified compared to FIG. 3;
• Fig. 5 is a schematic representation of another embodiment of the manufacturing device.
• FIG. 6 shows a schematic illustration of a manufacturing device modified compared to FIG. 5;
• Fig. 7 shows another embodiment of the
• Fig. 8 is a greatly enlarged partial section of a with a manufacturing device 7 produced with a soldered sliding layer of dispersion alloy.
• FIG. 1 shows a greatly enlarged partial section made of a layer material 10, with a poured-on sliding layer 13 made of AlPb8Si4SnCu dispersion alloy and an intermediate layer 12 made of AlZn5SiCuPbMg with a carrier material 11 made of steel.
• the functional layer 13 contains a quasi-amorphous aluminum matrix and globular finely distributed lead particles, of which only the larger lead particles 14 in the illustration in FIG. 1 in
• the large amount of lead particles is smaller and is not visible at the magnification chosen in FIG. 1.
• the large amount of lead particles is not least caused by the fact that a nucleating agent adapted to the alloy type, for example P, B, Ti, Si, boride, nitride or oxide, has been added to the dispersion alloy in a proportion by weight of, for example, 2%.
• the nucleating agent was immediately generated a very large amount of very fine lead particles in the dispersion alloy, but they prevented each other from growing during the casting and cooling of the sliding layer 13, so that cooling or quenching at a cooling rate in very rapid
• the segregation of the lead particles could be greatly reduced by the very rapid cooling or quenching of the cast sliding layer 13.
• the crystallization inhibitors glass formers for which, for example, Si, B, P, Fe, Co or Ti come into consideration individually or in mixtures with a weight fraction of 0.2 to 2%, and due to the very rapid cooling the cast sliding layer 13, the crystallization of aluminum that has been typical for aluminum alloys has been considerably reduced.
• the intermediate layer 12 has a structure typical of cast aluminum alloys.
• the example in FIG. 2 is a layer material 10 with a support layer 11 made of steel and a sliding layer 13 as a functional layer made of aluminum / lead dispersion alloy AlPblOSi.7SnCu, ie with a lead content of 10% by weight and a content of 7% by weight. % of silicon, which in this case acts both as a nucleating agent for the minority phase lead as well 'as a crystallization inhibitor in aluminum.
• lead particles dispersed in the quasi-amorphous aluminum matrix of the functional layer 13 are globularly finer
• the silicon is mostly dissolved as a glass former in the quasi-amorphous aluminum matrix and partly as a nucleating agent in the lead minority phase.
• the tin is essentially incorporated into the lead as corrosion protection.
• the intermediate layer 16 consists of a CuPb22Sn dispersion alloy and, in the example shown, has the distribution of the typical of this dispersion alloy Lead particles 17 on.
• FIGS. 3 and 4 One embodiment of the device for carrying out the method for producing a layer material described above with a sliding layer 13 made of alloys with a miscibility gap is shown in two variants in FIGS. 3 and 4.
• the alloy or the dispersion alloy is melted and introduced into a titanium 21 which has an outlet 22 at its lower end for a fine jet 23 of the melt.
• the crucible 21 is supplied with a pressurized gas from the top, which is inert to the melt and also dissolves as little as possible in the melt.
• the crucible 21 is surrounded in the examples shown by an induction coil 25, with which the melt is kept at a predetermined temperature at which it is sufficiently liquid to be pressed through the outlet and form a fine jet 23.
• the crucible 21 can additionally have stirring devices or vibrating devices which continuously mix the melt mixture of the dispersion alloy intensively and keep it in a fine distribution of its mixture components. These mixing devices or vibration devices are not shown in FIGS. 3 and 4 for the sake of simplicity.
• the carrier layer 11 is unwound in the form of a metal strip 40 from a reel and wrapped around a strongly forced-cooled cylinder 26.
• a surface cleaning and deoxidation Device 41 for example a brush device, to ensure that the surface of the metal strip 40 to be coated is free of oxides.
• the metal strip 40 runs through a temperature control device in order to ensure the immediate bonding of the cast alloy to the surface of the metal strip 40.
• the metal strip 40 is guided under an inert gas atmosphere, which is indicated by the inert gas bell 42, until the crucible 21 emerges. The watering itself and the subsequent cooling also take place under the protective gas bell 42 in this example.
• the thin, band-shaped or sheet-like jet 23 of molten alloy or melt mixture of a dispersion alloy pressed out of the crucible strikes the surface of the metal strip 40 at an acute angle * * in the example of FIG. 3.
• Film 20 forms, kept in a quasi-amorphous state, especially when the alloy
• Crystallization inhibitors (glass formers) are added. If a dispersion alloy with a mixture gap of its components is processed, a film 20 results, in which the component of the dispersion alloy forming the matrix is in a quasi-amorphous state, while the component (minority phase) dispersed in this matrix is globally finely distributed in the matrix .
• the melt mixture of a dispersion alloy is placed in a crucible 21 and pressurized in this in accordance with arrow 24 by means of a gaseous medium.
• the crucible 21 at its lower end 22 allows the melt or the melt mixture to enter in a jet "into the gap 30 which is formed between the metal strip 40 guided over a roller 31 and an opposite roller 32. Both rollers 31 and 32 are strong
• the width of the roller gap 30 is set according to the desired thickness of the layer 20 to be produced, as indicated in Figure 4, a small accumulation of melt or melt mixture forms in front of the gap 30 without any significant delay in the transfer at this point the melt or the melt mixture is to enter the gap 30 from the outlet 22 of the crucible 21.
• the two rollers 31 and 32 thus do not exert any appreciable pressure effect on the layer material to be formed, but only a certain smoothing effect on the surface of the layer 20 being formed Furthermore, due to the small accumulation of material at the gap 30, a distribution d he melt or the melt mixture in the axial direction of the rollers 31 and 32, so that tapes of greater width than in the example according to FIG. 3 can also be produced.
• the crucible 21 is arranged in an inclined position with the angle ⁇ , in order in this way the melt or the melt mixture pressurized in the crucible 21 directly into the gap 30 to inject.
• the surface of roller 32 is designed to have virtually no bond with the molten alloy or any of the components of a dispersion alloy to be processed.
• the upper roller 32 is equipped with a strip remover 33.
• a cooling nozzle 34 is first provided which directs a jet of cold gaseous or liquid medium against the exit of the gap 30.
• the metal strip 40 is further cooled by the cooling roller 31 in order to bring about additional cooling of the film 20 from the metal strip 40 or to avoid reheating the film 20 from the metal strip 40.
• the cooling roller 31 is juxtaposed with a third cooling roller 35, which is strongly forced-cooled in order to further cool the film 20 on the side quenched by the roller 32 and the coolant jet from the nozzle 34.
• a fourth cooling roller 36 is provided behind the third cooling roller 35 and takes over the metal strip with the film 20 from the roller 31.
• a likewise cooled deflection roller 38 is juxtaposed with the fourth cooling roller 36.
• the strip of layer material 10 is then removed from the fourth cooling roller 36 by means of a strip remover 39.
• the cooling process is further intensified in the example according to FIG.
• the strip of layer material 10 produced according to one of the working methods according to FIG. 3 or FIG. 4 is then wound up on a reel (not shown).
• a metal strip 40 in the form of a laminate is supplied to the device according to FIG. 3 or 4, which is already coated on the side to be coated with the metal of the intermediate layer.
• the metal strip 40 representing the substrate to be cast is at the speed v in the direction indicated by an arrow indicated transport direction 44 continuously moved over a possibly cooled guide and transport track 45.
• a pouring device 46 belonging to the pouring device is attached at a distance.
• the mounting height of the pouring device 46 above the guiding and transport path 45 is set such that between the lower surface of the pouring device 46 lying essentially parallel to the guiding and transport path 45 and the upper surface of the on the guiding and transport path 45 lying metal strip 40 is a predetermined distance d, such that the alloy melt is held against leakage due to its surface tension in the gap thus formed, as can be seen in the left part of Figure 5.
• the film which forms on the metal strip 40 when leaving the pouring-flow device 46 is produced on the one hand by the cooled metal strip 40 and on the other hand by cooling units possibly directed onto the free surface of the film 20, for example Gas jets or liquid jets cooled very quickly, for example at a cooling rate of 10 2 to 104 K / s.
• a casting device with a pouring-flow device 46 is particularly advantageously suitable for the multi-stage construction of the sliding layer from two or more films 20 successively cast onto the substrate.
• This two-stage or multi-stage construction of the sliding layer offers the advantage that the very thin alloy films 20 cooled accordingly r ⁇ .sch: can be, so that cooling speeds in the size of 10 to 10 K / s can be achieved.
• cooling units for example nozzle arrangements 27 for generating coolant jets 28, can be provided, each directed towards the free surface of the alloy film 20 that has just been formed.
• the pouring device 46 extends across the guide and transport path 45, generally at right angles to the feed direction 44. However, it is also conceivable to insert the pouring device or the pouring device in FIG to arrange an angular position obliquely above the guide and "transport path 45.
• the films 20 formed for coating the substrate or the metal strip 40 are made of the same alloy and in the same thickness.
• a certain structural difference in the two sub-layers of the sliding layer resulting from the films 20 can be expected, because the lower sub-layer is at least partially still when the second film is poured on - -
• the device in its embodiment according to FIGS. 5 and 6 offers particularly favorable control options.
• the defined thickness of the liquid film can be adjusted by regulating the feed rate of the solid, metallic substrate.
• the cooling rate of the cast layer can also be adjusted by regulating the feed rate of the solid metallic substrate.
• the setting of the defined thickness of the liquid film can also be carried out by changing the geometry of the outflow point of the alloy, namely by changing the distance d between the underside of the pouring device 46 and the surface of the metal strip 40 and on the other hand by changing the Dimensions of the pouring device. By setting this distance d between the underside of the pouring device 46 and the surface of the metal strip 40, the rate of cooling of the cast layer or film 20 can also be influenced and adjusted.
• FIG. 7 shows an embodiment of the device in which a film 47 forming the sliding layer is first produced independently of the substrate or metal strip 40 and, after it has cooled and solidified, is combined with the metal strip 40 by joining with the aid of a laser beam.
• the alloy or dispersion alloy is introduced in the molten state into a crucible 21 which has an outlet 22 for a melt jet at its lower end.
• This melt jet hits the surface of a directly strongly force-cooled cylinder 26 and there forms a film 47, which is cooled very quickly by the cylinder 26 and is passed under a nozzle arrangement 27, from which rays 28 of cold gas or cold liquid are directed onto the free surface of the film 47.
• the thickness of the film 47 can be determined by the rotational speed of the cylinder 26 and by the extrusion pressure built up in the interior of the crucible 21 by means of inert gas, as indicated by the arrow 24.
• the dispersion alloy or alloy is poured onto the surface of the cylinder 26 at an angle / r which is set up in such a way that no parts of the alloy spray off when it hits the surface of the cylinder 26.
• the surface of the cylinder 26 is designed such that there is no bond between the cast alloy and the cylinder surface, but only an intense heat transfer.
• Cooling jets 28 are between about 10 K / s and about
• Dispersion alloy with a miscibility gap Dispersion alloy with a miscibility gap
• Foil 47 is transferred to a strongly forced-cooled roller 32.
• This roller 32 is opposed to a roller 31, which is also strongly cooled, so that a
• Gap 30 is formed, in which the film 47 and a __
• band-shaped substrate for example a metal band 40
• a laser beam 48 with an angle OC is directed into this feed gap in such a way that a slight warm-up occurs on the converging surfaces of the foil 47 and the metal strip 40.
• the film 47 and the metal strip 40 are soldered to one another on the heated surfaces by lightly compressing them without any appreciable reduction in thickness.
• the belts thus combined are further cooled between the roller 31 and another cooling roller opposite it and transferred to a fourth cooling roller 36.
• This further cooling roller 36 is juxtaposed with a likewise cooled deflection roller 38.
• the strip of layer material 10 is then removed from the fourth cooling roller 36 by means of a strip remover 39.
• FIG. 8 shows a structure of the layer material 10, which essentially corresponds to that according to FIG. 1, that is to say a layer material with carrier material 11 made of steel, intermediate layer 12 made of AlZn5SiCuPbMg and sliding layer 13 made of AlPb8Si4SnCu dispersion alloy.
• a certain coarsening of structure has occurred in the intermediate layer 12 at the connection surface 49 to the sliding layer 13.
• the sliding layer 13 are in the area of the soldered connection surface 49 to the intermediate layer - __:H-

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Continuous Casting (AREA)
• Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
• Adornments (AREA)
• Sliding-Contact Bearings (AREA)
• Laminated Bodies (AREA)

Applications Claiming Priority (2)

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Citations (8)

• 1989
  • 1989-11-16 ES ES8903918A patent/ES2021906A6/es not_active Expired - Lifetime
  • 1989-11-17 IT IT02241789A patent/IT1236838B/it active IP Right Grant
  • 1989-11-17 PT PT92337A patent/PT92337A/pt not_active Application Discontinuation
  • 1989-11-17 FR FR898915523A patent/FR2639361B1/fr not_active Expired - Lifetime
  • 1989-11-20 WO PCT/DE1989/000726 patent/WO1990005603A1/de unknown

Patent Citations (8)

Non-Patent Citations (3)

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