DE1533037B1 - Process for the powder metallurgical production of thin metal strips - Google Patents

Description

The invention relates to a method for the continuous production of thin metal strips, at the metal particles together with a binder in the form of a layer on at least one side of one flat metallic carrier are applied, in which the layer is also dried, from the carrier removed, heated to a temperature below the melting point of the metal particles, rolled and is then heated again.

It is already known to use metal alloys from be ίο certain metals in the form of blocks, bars, plates or the like. To produce and these shapes to roll down the desired thicknesses. However, this latter process encounters considerable difficulties, especially if the alloy is relatively brittle and therefore has poor ductility having. Foils made from alloys without drawability can be produced by this known method practically cannot be produced at all without cracking occurring.

It is already known to continuously manufacture thin metallic sheets and strips in that a fine metal powder is suspended in a liquid to produce a suspension from which an immersion roller takes up a film, which is dried on the roller and then passed through a A controlled atmosphere furnace is sent through it while being heated to just below the melting point will. The film so sintered is then rolled to the correct dimension and compression and then heat treated to produce the desired strength. With this procedure Relatively strong sheets and metal strips can only be made from such metals and metal alloys are produced which under the conditions described provide a sufficient bond already shrink while drying (Steel magazine, January 9, 1961, p. 31).

Furthermore, a method is known in which metal bodies are produced in that on a Auxiliary body a suspension of one or more metal powder is sprayed on, which is then dried and is subjected to a sintering process, the auxiliary body being subjected to during or after the sintering process is removed chemically, physically or mechanically. With this procedure you can only relatively large moldings are produced, which were previously produced by pressing (German patent specification 586 621).

Finally, a method is also known for forming a permeable body from metal powder, which is firmly connected to a metal carrier. For example, as a thin copper sheet formed metal support, which is tinned in some places and in other places with a composite-repellent layer was provided, a relatively thick layer of sintered metal powder applied and the resulting body sintered, whereupon the metal powder layer by heating was firmly connected to the metal carrier at the tin-plated points. At the unconnected The metal support could then be broken out in places (US Pat. No. 3,049,795).

The invention is now based on the object of creating a method with the help of which very thin Ribbons can also be made from brittle or hard metal powder. This task is carried out at solved the aforementioned method according to the invention in that a layer of a Mixing with the elementary metal particles required for the alloy on the hard carrier is applied that the layer together with the support to form a preliminary metallurgical Composite between the metal particles is rolled while reducing the layer thickness that the layer then peeled from the support and stored at a relatively low temperature to improve the Composite, but without forming an alloy between the metals, is heated that the strip is reduced the thickness is rolled again to form a thin strip and that the thin strip is at is heated at a relatively higher temperature to form the desired alloy.

Further advantages and features of the invention emerge from the following description, which includes an embodiment of the invention. In the drawing shows

F i g. 1 a schematic view of a device for carrying out the method according to the invention, F i g. Fig. 2 is a schematic view showing the changes made to the starting material is subject to during the procedure.

As far as the term "ribbon" is used in the following description, it refers to thin Alloy sheets, the thickness of which is normally about 0.025 to 0.203 mm. The term "powder" means a finely divided substance. The normal particle size is less than 50 microns and it there are essentially no particles that are larger than 100 microns. The exact size of the particles depends on the hardness of the metals used and the shape of the powder particles. Under "Slurry" or "slurry" is understood to mean a liquid medium of considerable viscosity, which in has suspended metal particles in a binder. The term "binder" means long-chain, High molecular weight organic compounds or the like, which are characterized in that their constituents are tough and stringy when shredded and when mixed with a liquid, for example water, swell and act according to the invention so that the metal particles in Suspension are held and bound and there is a corresponding viscosity of the pulp, the then adhered to a smooth surface. As a result, the paste hangs evenly on metal surfaces with whom he is brought into contact. The following binders are merely examples Materials called: methyl cellulose, nonionic cellulose ether, polyethylene oxide, polyvinyl pyrrolidone and the like The intended use of the tape will determine the particular thickness in which it will be produced. In this context it should be mentioned that all drawings are for explanatory purposes only and not for anything are true to scale, as the real dimensions are extremely small.

Briefly summarized broadly the method of making thin ribbons according to the invention a coating on a flexible metallic support through a slurry. the metal powder in a binding agent! contains suspended, whereupon the pulp is then dried by heating, then compacted and is sintered at a relatively low temperature, so that a green bond between the Particles are formed, whereupon a second compression and heating to a relatively high level

3 4

Temperature takes place so that the metals are alloyed. The pulp is a mixture of long-chain, high-quality coatings 29 and 31 are then dried. The molecular, organic binders with water-dry coating; i are denoted by 33 and 32, and powders are required for the desired alloy. The drying of the borrowed metals shown in the drawing. If a band 5 is wet from an alloy :; ßeschichten 29 and 31 acts by being produced, the powder of each of the individual resistance heating of the strip 1, which is fed from a metal of the alloy to the slurry in the ratio desired in the finished electrical power source 33 via conductors 35 and 37 and alloy. By brushing. 8 and 10 power is supplied. The electrical mixture, the particles are heated evenly in the resistance of the carrier 1, the wet loading binder is suspended. The amount of the layers 29 and 31 used during their forward movement and the amount of binder determines the viscosity of the paste, so it converts into the dry state 3!) And 32 so that it adheres when applied to a metal surface. While the thickness of the coating i 2) and 31 the viscosity can be between 1000 and different, for example, a thickness of 4000 cP has been:!. The proportion of solids in the slurry of dried feeds is about 0.127 or can be between 50 and 75 "/". This should 15 0.152 mm to achieve a final B.mddicke that the pulp, ehiclit essentially from 0.038 to 0.051 mm has been found to be satisfactory, evenly in any position of the metal. Then the carrier 1 remains with the dirauf surface. In some, but not all, adhering, dried coatings 1 3D and 32 slats, a conventional wetting agent, for example an aerosol between the rollers 39, 41 of a conventional roller type, advantageously used in the pulp, can pass through it. These rollers 39, 4t press the will. Coatings 39 and 32 together, whereby a flexible thickness is reduced in Fig. 1 of the drawing and the density is increased, as metal carrier 1 is unrolled from a roll 3 and is indicated with 34 and 36 for the purpose of this. The rollers 39, 41 preferably take up a coating from the slurry or cause a reduction in the thickness of the slurry, which is supplied to a dry coating of the order of magnitude of the roller coater, denoted as a whole by 5. Then it becomes 10 to 50% or more. A thick carrier 1 can be rolled up onto a roll 6 again. The 0.064 to 0.076 mm from an original carrier is made of a hard metal, for example a thickness of about 0.152 mm. The dry cold rolled stainless steel. The thickness of the coatings 30 and 32 in the roller mill can be of the order of 0.127 to 1.27 mm. The roller coater 5 has a storage vessel 7, in a green bond between adjacent metal parts of the pulp 9, after thorough mixing, none of the coating is achieved, whereby a for is introduced. The roll coater has two channels 11 and 13 that are sufficient for further treatment according to the invention, through which the pulp is produced to an upper connected metallic body. Zwi-trough 15 or a lower trough 17 is fed. However, if the carrier strip 1 now runs through the roller coater 5 in the direction of FIG. 1 due to the size, shape and hardness of the particles, there is no green bond. It turns out that it runs between the spaced-apart upper composite between the particles and the carrier and the lower rollers 19 rotating in the direction of the arrow are inhibited by the following features: and 21 therethrough. The roller 19 is above the softness of the particles compared to the carrier, top of the belt in the absence of a metering roller 23 located on the certain particle shapes, such as flat, same side of the belt, needle-shaped or small particle size. It is also arranged; both form the long sides of the trough 15. The pressure required for the required reduction. The space between the rollers 19 and 23 on the dried pulp, preferably not so large, determines the amount of the material selected by the roller 19 to the upper 45, that through it the thickness of the Carrier 1 ropes of the carrier strip 1 entrained pulp. is reduced.

In the same way, the roller 21 is above the coating 39 and 32 are dried and arranged, trough 17, and their distance from the metering roller 25, which forms the thickness of the metering roller 25, as shown at 34 and 36, is reduced by roller pressure in the lower side of the trough 17 so they are peeled off from the carrier 1, the amount of which is peeled off by the roller 21 to the bottom 50. The carrier 1 is then on the roll 6 ropes of the carrier I entrained pulp. When wound up. Since the coating Währe id insuran since the rollers 19, 21, 23, rotate in the direction indicated poetry received with the carrier does not bond the direction of arrow 25, then the top and is. this can not be used again with little or no cleaning underside 1, 1 or 15 (FIG. 2) of the carrier with the same or other treatment, moderately with layers of the material located in the table at 15 and 17 The peeling of the compacted, dried 1 fractions coated porridge. The wet layer layers 34 and 35 from the carrier 1 are shown in FIG. 2 with 29 and 31 guide role :! 4 and denoted by a norm il occurring. By changing i'e, - the intervals between mobilizations are made easier. This means that the roller pairs of the two troughs can mean the tendency for two binders rolled together to bend the pulp fed to the carrier and thus the 60 on the roller; i; m stride apart if they do not have the thickness of the coatings 29 and 31 can be changed. stick together.

The next step in the process is preferably the main; -

Lichen the same thickness, but they can also treat the layer 34 differently in an oven 43 and the

be. At this point in time, the charges 1 are shifted to a layer 35 in an Oi'e 1 45, to which they are transferred via roll 1 4

held on the carrier by the binders supplied 65. The ovens 43 and 45 can be conventional

adheres to its surfaces 1A and 1B (FIG. 2). Be heat treatment furnace and an inert or

The thickness of the coating can be reduced in the wet state, such as Arg 11, Wisserstn.T

for example 0.251 mm. or the like. Layers 34 and 35 are at

5 6

heat treated to a temperature sufficient to densify. This resulted in a green network most, if not all, of it contained between the particles. As a result of the small through-binders to evaporate and due to diffusion and sectional size of the metal particles there was no grain growth an improvement in the green bond between these and the carrier. The compacting between the metal particles at least one of the 5 of the coatings was achieved without the metallic, powdery elements in the solid phase, rollers 39, 41 touched the carrier 1 and turned it into to achieve. However, the heating temperature is reduced in its thickness.

kept so low that a substantial homogeneity. The compacted coatings were

ization or alloying of the particles of different leaves the roller frame detached from the carrier and metals of the layers does not take place. During this io the first furnaces 43, 45 are fed, where at one stage, any substantial diffusion of unequal temperature of 760 ° C ^l / ₂ to 1 minute heat-metal particles, which were treated for homogenization and alloying, what was sufficient to the layers would lead to avoided, since this would result in a brittle compression and a significantly better bond between the layers 34 and 36 and to achieve that between the nickel particles. This would make further processing more difficult. In this 15 a shrinkage of 0.051 mm. The partial stage are the coatings in FIG. 2 with sintered tapes were then passed through the rollers 47,

38 and 40. 49, 51 and 53 to the finished thickness of about 0.038 mm

The next step in the process is to roll it into this. However, it can also be used to thin it

At this point, non-brittle layer 38 is compacted to the desired tapes of a final thickness of about 0.025 mm to the final thickness of the tape by producing 20 0.203 mm. These thicknesses normally occur between two pressure rollers 47 and 49 of a conventional soldering tape. Then roller mills were passed through. Similarly, the tapes in other furnaces 55 and 57 ¹ J ₂ to 1 minute is the layer 40 by a pair of pressure rollers long brought to its final thickness of 51 and 53 at higher temperatures of about 871 ° C. heat-treated to homogenize and le- In this process, the reduction is about 5 to 25 yaw through diffusion and grain growth of the three 40% ■ The compacted strips can be achieved with 42 and 44 different metals of the coatings.

designated. A sintering of the above-mentioned nickel powders of the

After the thin strips 42 and 44 on their type, a 255 INCO occurs at about 648 ⁰ C. on the other hand

Having rolled to their final thickness, they are found in furnaces 55, an alloying between nickel, silicon and

and 57 to higher temperatures than in the ovens 43 30 boron powder above 815 ° C quickly takes place. By

and 45 heated. The temperature in the ovens 55 choosing the nickel powder type 255 (or an equivalent and 57 is sufficient to homogenize all the particles, valents) it was therefore possible to use a solid metal band so that the desired alloy results. This manufacture by a first sintering at about 760 ⁰ C and is effected by a substantially complete a second sintering at about 871-926 ° C.

Diffusion between all equal and unequal 35 The soldering tape is very dense, essentially pore-free particles of the metallic components. The thin strips, which are made of metal alloys and melt during the soldering at approximately 1065 ^{° C., are complete.}

denoted at 46 and 48 and can, as at 59 Another solder alloy made according to the invention

and 61 indicated to be wound up; They are very manufactured, made of nickel, silicon and essentially non-porous. The final 40 and chromium particles, so that the boron of the pre-alloying can lead to embrittlement the thin written process is replaced by chromium. the Lead tapes. However, this does not affect harmful weight ratios between the partners nickel, because the machining operations are finished. Silicon and chromium are 71:10: 19.

In the following, the inventive temperatures of this method are those described above as an example Proper process for making a brittle 45 the same except that the alloy formation Solder alloy described. It became a paste for one here at 926 to 982 ° C and the soldering temperature Nickel-based soldering alloy made with powder at 1176 ° C.

made of 4.5% silicon, 3.5% B ° ^{r and} 92% nickel. Further examples are iron and aluminum. These ratios correspond to those of the powder mixtures mentioned, with the iron content 80 to American solder alloy AMS 4778. The metal 50 90% and the aluminum content 20 to 10%, powder were with a polyethylene oxide binder In this case the sintering temperature is up to and water mixed. The nickel used was 482 ⁰ C, and the temperature of the alloy forming a carbonyl (INCO type 255 or equidistant 537 ° C or more.

valent), which with great delicacy, d. H. a Further examples are copper and titanium powder

average particle size from 2 to 14 microns, 55 called mixtures, the weight ratio of which is 90: 10% at low temperature within a short time. Here the sintering temperatures are between the period of time that can be heat treated. This ER 260 and 315 ⁰ C, and the temperature of the alloy also facilitates the subsequent detachment from the carrier. Forming at approximately 537 ^° C or higher. Slurry has been mixed thoroughly and added to the stock The powder mixes given above are examples

vessels 7 and 9 of the roller coater 5 filled, 60 and there is no need to name more, as from whereupon a thin layer of the pulp (about 0.254 mm) above clearly shows which is suitable for the on both sides of a tough, cold-rolled process according to the invention. Stainless steel carrier strip applied It should be noted that the use

became. a wetting agent in the slurry is not required.

The coatings were made by resistance 65 For example, this is not necessary if heating the carrier heated; its thickness was polyethylene oxide, or nonionic cellulose ether 0.127 mm when dry. Then the polyvinylpyrrolidone was used as a long-chain, high-molecular, Dried coating by rolling on 0.064 mm organic compound is used for the slurry.

It should also be mentioned that, although in the example, the coatings 29 and 31 by a roller coater can be applied to the carrier 1, but they can just as easily be applied by pulling the carrier through by a storage container, by brushing or any other suitable means of achieving a uniform coating can be applied on the carrier.

Although the invention has been described in the context of three and two partner alloys it can just as well be used with an alloy from a different number of partners, provided that the particles of some of these components form a green compound and this green compound The composite remains deformable at temperatures below the temperature of the alloy formation.

Claims (14)

Patent claims: 1. A process for the continuous production of thin metal strips, in which metal particles are applied together with a binder in the form of a layer on at least one side of a flat metallic carrier, in which the layer is further dried, removed from the carrier as, to a temperature below the Melting point of the metal particles is heated, waxed and then heated again, characterized in that a layer of a mixture with the elementary metal particles required for the alloy is applied to the hard support, that the layer together with the support to form a preliminary metallurgical bond between the metal particles is rolled while reducing the layer thickness that the Sch ^; is then peeled off from the carrier and heated at a relatively low temperature to improve the bond, but without alloying between the metals, that the strip is rolled again with a reduction in thickness to form a thin strip and that the thin strip is rolled at a relatively higher temperature heated to form the desired alloy. 2. The method according to claim 1, characterized in that both sides of the carrier evenly be coated. 3. The method according to claim 1 or 2, characterized in that the layer made of metal particles of one in the range between 2 and 14 microns in size. 4. The method according to any one of claims 1 to 3, characterized in that the layer consists of a Mixture of nickel, silicon and boron particles with nickel in excess is produced. 5. The method according to claim 4, characterized in that the strip is heated in the first stage to approximately 76O ⁰ C and in the second stage after reaching the final thickness to approximately 871 to 926 ° C. 6. The method according to any one of claims 1 to 3, characterized in that the layer is produced from a mixture of nickel, silicon and chromium particles with nickel in excess. 7. The method according to claim 6, characterized in that. that the tape in the first stage on about 760 "C and in the second stage after reaching the final thickness to about 926 to 982 ° C is heated. 8. The method according to any one of claims 1 to 3, characterized in that the layer consists of a Mixture of iron and aluminum particles with iron in excess is produced. 9. The method according to claim 8, characterized in that the strip ^{is heated in the first stage to approximately 482 °} C. or less and in the second stage, after reaching the final thickness, to approximately 537 ^° C. or more. 10. The method according to any one of claims 1 to 3, characterized in that the layer consists of a Mixture of copper and titanium particles with copper in excess is produced. 11. The method according to claim 10, characterized in that the tape in the first stage at about 260-315 ⁰ C and in the second stage, after reaching the final thickness to about 537 ° C is heated. 12. The method according to any one of claims 1 to 3, characterized in that a layer of a mixture of nickel and titanium particles is made with nickel in excess. 13. The method according to claim 12, characterized in that the tape in the first stage about 510 ° C or less and in the second stage after reaching the final thickness to about Heated to 537 ° C or more. 14. The method according to any one of claims 4,6 and 12, characterized in that nickel is added in the form of carbonyl nickel. 1 sheet of drawings ^CO:; Y 009 531/87