EP3473352B1 - Method for producing a copper profile and copper profile - Google Patents

Description

The invention relates to a method for producing a copper profile, in particular a copper wire, from a matrix element, the matrix element having at least one filament. Furthermore, the invention relates to a copper profile.

Various methods are known for producing a copper wire from a metal matrix composite (MMC). In the melt metallurgical process, fibers or particles are infiltrated by vacuum and / or pressure, particles are stirred into the melt and then further processed by casting and forming processes. Powder metallurgical processes can also be used in which powder mixtures are sintered or sintering or forging of ropes made of metal and non-metal fibers. Coating from a gas phase (PVD / CVD), electrolytic deposition or plasma spraying can also be used.

In general, all of these manufacturing processes require several process steps, such as cast-rolled wire production, coarse wire drawing and / or fine wire drawing.

In addition, the electrical conductivity is significantly reduced by using alloys and / or by reshaping a copper profile. Furthermore, the processing of higher-strength alloys into wires a diameter of <0.3mm is becoming more and more complex due to the low formability.

In the DE 36 38 249 C2 discloses a device for the continuous dew molding of a cast rod, in which a core wire of, for example, 7.15 mm made of metal is moved upwards by means of pinch rollers through a hole in the bottom of a crucible in such a way that another molten metal in the crucible attaches to the core wire and a Cast rod is molded. Thus, the deposit occurs with a solidification direction perpendicular to the core wire axis and below the melt level in the crucible. In addition, only a rod is made of a metal / metal composite material but germ MMC.

From the US 5,736,194 A a method for pressure infiltration of a fiber preform with a matrix material is known, in which a bath with molten metal as the matrix material is arranged within a pressure chamber and the fiber preform is drawn through three different orifices. The first exit opening is immersed in the molten metal bath and thereby directly influences the formation and surface quality of the pre-coated fiber preform.

The US 2003/0029902 A1 discloses a method in which fiber-reinforced metal matrix wires for reinforcing a casting are inserted into the casting mold and the latter is subsequently filled with molten metal.

The WO 96/27 456 A1 discloses a method of producing a metal strand in which a metal band is passed through passed the bottom of a container filled with melt and after the crystallization of the melt is drawn off over rollers arranged above the container. Here, the opening in the bottom is designed as a slot-shaped channel and the belt speed is selected so that a meniscus with conical radii of curvature forms in the region of the mouth of the channel at the bottom of the container to melt, so that the meniscus extends from a two-phase area Part of liquid metal and solid metallic crystals and is located below the liquid level on the start channel. In the US 5 736 199 A describes a method for producing a copper profile.

A disadvantage of the abovementioned processes and the generally known processes for producing fine wires with a diameter of <0.3 mm are the large number of necessary process steps, in particular cast wire rod production, up-casting, coarse wire drawing, medium wire drawing and fine wire drawing as well as multiple heat treatment.

An easy to carry out and inexpensive method for producing a copper wire from metal matrix composite and thus a copper-non-metal composite material is not known from the prior art.

The object of the invention is to improve the prior art.

• Durchführen des Matrixelementes durch eine Öffnung eines mit flüssigem Kupfer gefüllten Kupfertiegels derart, dass flüssiges Kupfer auf dem Matrixelement aufgebracht wird und das aufgebrachte Kupfer auf dem Matrixelement frei von dem flüssigen Kupfer vom gefüllten Kupfertiegel derart erstarrt, dass direkt das Kupferprofil ausgebildet wird.

The object is achieved by a method for producing a copper profile, in particular a copper wire, from a matrix element, the Matrix element has at least one filament, with the following step:

• Passing the matrix element through an opening of a copper crucible filled with liquid copper in such a way that liquid copper is applied to the matrix element and the applied copper on the matrix element solidifies free of the liquid copper from the filled copper crucible in such a way that the copper profile is formed directly.

With the inventive method, a copper matrix composite wire can thus be produced directly in a single process step by passing the matrix element through the copper melt. As a result, the conventional process steps, such as for wire rod, up-casting, coarse wire drawing and / or fine wire drawing, are eliminated.

The method according to the invention therefore produces copper profiles and in particular copper wires made of MMC, which have optimized material properties with regard to tensile strength, electrical conductivity and fatigue strength as well as density. It is particularly advantageous that a copper wire is produced free from forming processes, which provides an optimized electrical conductivity.

An essential idea of the invention is based on the fact that a matrix element is guided through the copper melt by means of an opening in a crucible with copper melt in such a way that the solidification of the copper applied to the matrix element is unaffected by liquid copper in the Crucible takes place and thereby the copper profile is formed directly. A copper matrix wire is thus produced directly in a single process step.

The following terms are explained:

A "copper profile" is in particular an elongated component made of copper and the matrix element. A copper profile has, in particular, the same cross section and / or the same surface quality over its entire length. A copper profile is in particular a wire, in particular fine wire, a strip and / or a rod made of a composite copper matrix element.

A “copper wire” is understood to mean in particular a thin, long and flexible metal and / or copper alloy. A copper wire can in particular have a circular cross-section or another cross-sectional shape. A copper wire can in particular also be a flat, square and / or profile wire. The copper wire has in particular a diameter of 0.1 mm to 30 mm, preferably 0.2 mm to 0.5 mm. The copper wire has in particular a matrix element and thus forms from a copper-non-metal composite material.

A "matrix element" is in particular an elongated element which is free of copper and / or copper alloys or metal. The matrix element has in particular at least one filament.

"Filament" means in particular a single fiber of any length. A filament has in particular an inorganic or organic substance. A filament can be, for example, a textile, glass, carbon and / or ceramic fiber. The filament and / or matrix element preferably has a surface property which attracts melt.

A “copper crucible” is also called a crucible, in particular a container that is open on one side and in particular. Solid copper in particular can be melted in a melting furnace in a copper crucible. The copper crucible has, in particular, liquid copper, through which the matrix element is guided through an opening.

An "opening" is in particular a non-closed point in the bottom of the copper crucible and thus a passage through the bottom of the copper crucible. The opening has in particular any cross section. The opening is preferably adapted to the matrix element being carried out in such a way that liquid copper cannot pass out of the copper crucible through the opening and / or run out. In the case of a wire to be manufactured, the opening is designed, for example, as a round hole and in the case of a tape as an elongated hole.

“Liquid copper” is understood to mean in particular copper and / or copper alloy in the liquid state, so that the liquid copper is flowable.

“Solidification of the applied copper on the matrix element free of the liquid copper in the filled copper crucible” means in particular that copper already applied to the matrix element is not or only slightly influenced by the liquid copper in the filled copper crucible when it solidifies. In this way, a defined cooling and solidification of the melt takes place at the upper end of the meniscus. This effect leads in particular to the formation of the solidification front over the melt surface and parallel to it. The direction of solidification takes place in particular against the direction of movement of the filament.

In a further embodiment of the method, it is carried out by continuous pulling.

By continuously pulling the matrix element through the opening of the copper crucible filled with liquid copper, an endless MMC wire and / or an endless copper profile of any length can be produced. In addition, the copper profile is continuously manufactured with a high, consistent surface quality.

It is particularly advantageous that a specific diameter of the finished copper profile and in particular a very small MMC wire diameter can be produced via a speed during continuous drawing.

Above all, only by pulling the matrix element through the one filled with liquid copper Copper crucible made the copper profile. This is a very cost-effective and one-step process for producing a copper profile from MMC composite material.

Consequently, the method according to the invention can be used in particular to produce a wire with an MMC in which the diameter of which it is manufactured can essentially be freely selected and in particular <0.3 mm. In addition, a quasi-endless wire with any length and at least one filament can be produced.

It is particularly advantageous that an MMC wire is produced directly from a copper melt by pulling a matrix element without further process steps.

“Pulling” is understood in particular to mean the exertion of a force in the direction of a power source. In particular, tensile stress is applied to the matrix element and / or the filament during drawing. When pulling, the matrix element and / or filament in particular is pulled through the opening and the molten copper of the filled copper crucible. Thus, pulling is to be understood in particular in the sense of leading.

In order to achieve optimal solidification of the applied copper on the matrix element, a direction of solidification of the applied copper on the matrix element is aligned along or parallel to a longitudinal axis of the matrix element.

The applied copper thus solidifies along the longitudinal axis of the matrix element, so that a solidification profile can be formed along the matrix element.

The direction of solidification is therefore opposite to the direction of pull, as a result of which the extent of the solidification front and the thickness of the solidified copper on the matrix element can be influenced by the speed at which it is carried out and / or pulled.

It is particularly advantageous if the matrix element with the applied copper is brought out of the copper melt above the liquid level of the liquid copper by carrying out and / or pulling, and the solidification takes place outside the liquid copper above the liquid level.

A "solidification direction" is in particular the direction in which the applied copper solidifies onto the matrix element. If, for example, the matrix element is pulled upwards out of the copper crucible with the filled liquid copper into the surrounding atmosphere, the direction of solidification is in particular opposite to the direction of pull, i.e. towards the melt, and aligned vertically. In particular, a stationary solidification front is established.

Consequently, a continuous, directed solidification process of the applied copper on the matrix element can be implemented.

A "longitudinal axis" is in particular the length of the longest dimension of the matrix element. A longitudinal axis is thus in particular the axis running in the longitudinal direction of the matrix element.

In a further embodiment of the method, the longitudinal axis of the matrix element is aligned vertically, so that a free meniscus made of applied copper forms around the matrix element on and / or above a liquid level of the liquid copper in the filled copper crucible.

A free meniscus made of applied copper is thus formed around the matrix element, the free meniscus having a self-stabilizing round cross section. This reduces or avoids any post-processing steps.

In addition, the trained meniscus means that small particles, such as scale and / or crucible material, can collect on the lower base of the meniscus and sink into the liquid copper in the filled copper crucible, so that the area of the solidification front remains free of particles. As a result, a wire surface is basically formed that is smooth and free of particles.

Furthermore, the solidification of the applied copper on the matrix element can be influenced not only via the drawing speed of the matrix element, but also by deliberately influencing the meniscus. In addition to the design of the copper crucible filled with liquid copper, such as the liquid level of the liquid copper, the design of the opening in the bottom of the crucible, the temperature and viscosity of the liquid copper, the formation and shape of the meniscus, since this is arranged above the liquid level of the liquid copper in the crucible and thus largely in the surrounding atmosphere, by further parameters , such as the ambient temperature, air pressure and the like, as well as influenced by the temperature of the matrix element on the solidification front. In particular, the crucible design and shape as well as the type of filament have a stabilizing effect on the meniscus.

It is particularly advantageous that the meniscus tapers continuously in the direction of drawing to the thickness of the solidified copper on the matrix element.

A “meniscus” is understood in particular to mean a curvature on the surface of a liquid. The meniscus forms in particular on the liquid surface of the liquid copper in the filled copper crucible due to the passage and / or pulling of the matrix element through the liquid copper and the breakthrough of the matrix element through the liquid surface of the liquid copper. Thus, the formation of the meniscus is particularly due to the interaction between the liquid level and the surface of the matrix element with the applied copper. The meniscus in particular has a convex shape at the top of the solidification front and a concave shape at the bottom to the liquid level. In particular is on the solidification front, the curvature of the meniscus maximally and decreases as the liquid level approaches.

A "free meniscus" means in particular that the meniscus itself is not within the liquid copper in the filled copper crucible, but largely in the surrounding atmosphere. The free meniscus is in particular only in contact with the liquid copper liquid level in the filled copper crucible at its lower base.

The "liquid level" is in particular the liquid level of the liquid copper in the filled copper crucible. The liquid level, also called the liquid surface, represents in particular the interface between the liquid copper and the surrounding atmosphere arranged above it.

In order to achieve a uniform application of the copper on the matrix element, the opening is covered by the liquid copper.

Thus, the matrix element is immediately and immediately surrounded by liquid copper when it is introduced into the opening of the copper crucible. Furthermore, the copper melt cannot escape through the opening from the copper crucible due to utilization of the surface tension of the copper melt.

In addition to the surface tension, a leakage of the liquid copper from the copper crucible is also prevented geometric coordination between the matrix element and the opening is achieved.

In a further embodiment of the method, the matrix element has further filaments and / or a bundle of filaments.

The proportion of filaments and / or fibers in the MMC profile and / or wire can thus be increased. Furthermore, multifilaments and tied, twisted, braided and / or otherwise connected filaments in particular can be used in a filament bundle. As a result, the tensile strength and fatigue strength can be increased and the density and weight of the manufactured copper profile and / or wire can be reduced.

In order to set optimal properties of the manufactured copper profile and / or wire, the matrix element has an inorganic fiber, in particular a carbon fiber and / or a silicon carbide fiber.

A "carbon fiber" (also "carbon fiber") is an industrially manufactured fiber from carbon-containing starting material, which is converted into graphite-like carbon by adapted chemical reactions.

A "silicon carbide fiber" is in particular a fiber made of a chemical compound of silicon and carbon belonging to the group of carbides. A silicon carbide fiber is, in particular, a ceramic fiber.

In a further embodiment of the method, a filament or several filaments have a diameter between 3pm and 30pm, especially between 6pm and 20pm.

Consequently, the filament or the filaments and thus the matrix element have a suitable geometry in order in particular to produce fine MMC wires with a final maximum wire diameter of 300 300 μm.

In order to prevent scale formation and / or slagging of the liquid copper melt and to produce optimal surface properties of the copper profile and / or wire, the process is carried out under a protective gas atmosphere.

In particular, the air in the surrounding atmosphere and especially the oxygen in the air can be displaced by the protective gas.

As a result, the quality of the copper profile and / or wire produced can be further increased.

In a further embodiment of the method, a thickness of the copper profile is set by means of a drawing speed of the matrix element and / or a temperature control, in particular a vertical temperature control.

This achieves a defined cooling and solidification of the applied copper on the matrix element and consequently a defined thickness of the copper profile. Above all, the temperature control can support and / or specifically influence a solidification profile in the longitudinal direction of the matrix element and thus in the direction of drawing.

It is particularly advantageous that the thickness of the copper profile can be specifically adjusted via the drawing speed and / or temperature control.

In order to achieve a continuously changing, graduated temperature control along the solidification direction and / or drawing direction, it is advantageous if the temperature control is designed to be vertically variable. This can influence the shape and extent of the meniscus as well as the solidification area.

A "temperature control" is understood to mean in particular a regulation of the temperature. Temperature control can in particular involve cooling and / or heating. The temperature control can in particular be made uniform and / or variable over the length of the matrix element with the applied copper. A “vertical tempering” is understood in particular to mean that the tempering is oriented vertically and thus runs along the longitudinal axis of the matrix element and the direction of solidification. The temperature control has in particular individual heating elements and / or cooling elements. The heating elements as well as the cooling elements can be configured actively and / or passively. As "active heating elements", for example, heat radiators based on gas or electrical energy are used. A "passive Tempering "can take place, for example, by supplying waste heat. Likewise, the cooling elements can be active or passive. As a" passive cooling element ", cooling fins are used, which are arranged in spatial proximity to the matrix element with the applied copper. A" Peltier ", for example, can be used as an" active cooling element " Materials with certain thermal properties, such as heat reflection or heat conduction, can also be used for temperature control.

In a further aspect, the object is achieved by a copper profile, in particular a copper wire, the copper profile being produced using a previously described method.

A copper profile, in particular copper wire, is thus provided, which is manufactured in a single manufacturing step by means of the method according to the invention. It is particularly advantageous that the method according to the invention is used to produce a copper profile which has a very uniform copper cladding of constant thickness and constant properties over any length. Above all, the surface of the copper profile and / or wire is very smooth and free of particles such as scale. Therefore, post-processing steps of the manufactured copper profile and / or wire can be dispensed with. In particular, thin copper wires with a diameter of less than 0.3 mm can be produced in fewer steps than in the prior art.

In a further embodiment of the copper profile, a thickness of the copper profile is <0.3 mm.

A copper profile and / or copper wire made of MMC with a diameter of ≤ 0.3 mm is thus produced in a single process step. As a result, fine wires are produced which cannot be manufactured with these small wire diameters and high surface quality by other manufacturing processes, for example a thawing process.

Figur 1

eine stark schematische Schnittdarstellung eines Kupfertiegels, bei dem ein Siliziumcarbid-Filament gezogen wird, sodass ein MMC-Draht hergestellt ist.

The invention is explained in more detail below using an exemplary embodiment. It shows the only one

Figure 1

a highly schematic sectional view of a copper crucible, in which a silicon carbide filament is drawn, so that an MMC wire is produced.

A crucible 107 has an opening 108 on the bottom. A silicon carbide filament 103 with a diameter of 15 pm is passed vertically upward through the opening 108 by means of a unidirectional unwinding and winding unit, not shown. The crucible 107 is arranged in a melting furnace, not shown, and has a copper melt 105 in its interior. The unidirectional unwinding and winding unit pulls on the silicon carbide filament 103 in the pulling direction 111 and moves it continuously through the opening 108 and the copper melt 105 arranged above it in the crucible 107.

To manufacture an MMC wire 101, the opening 108 has a circular profile with a diameter of 0.2 mm. This ensures that the copper melt 105 does not exit vertically downward through the opening 108 via the opening 108. In addition, the area around the opening 108 has a material with a repellent wetting behavior.

When the silicon carbide filament 103 emerges from a liquid surface of the copper melt 105 into the surrounding atmosphere, a meniscus 113 is formed from molten copper, which is continuously applied to the silicon carbide filament 103. The continuous pulling in the direction of drawing 111 forms a solidification front (transition from liquid to solid copper) at the transition from the meniscus 113 to the regular cross section of the MMC wire 101. By deliberately guiding the meniscus 113, a self-stabilizing round cross section of the applied copper is formed on the silicon carbide filament 103.

By deliberately guiding the meniscus 113, any smaller particles, such as scale, crucible material and the like, collect on a lower base of the meniscus 113 to the copper melt 105, whereby the area of the solidification front remains free of particles. A surface of the manufactured MMC wire 101 is thus achieved which is very uniform and smooth and free of particles.

In the drawing direction 111, after the formation of the meniscus 113, a reheating zone 109 follows, through which the MMC wire 101 is pulled further. The reheating zone 109 has individual heating and cooling elements, via which a corresponding temperature profile is impressed on the meniscus and the MMC wire 101. As a result, a defined solidification profile is impressed on the MMC wire 101 and the surface quality is further improved.

The entire manufacturing process of the MMC wire 101 takes place under a protective gas atmosphere, so that in particular no oxygen diffuses into the manufactured MMC wire 101.

The diameter of the manufactured MMC wire 101 is determined via a drawing speed in the drawing direction 111 and the set temperature profile of the reheating zone 109.

Thus, in a single process step, an MMC wire 101 is continuously manufactured with very high surface qualities and a uniform wire diameter of 130 pm, without further post-treatment steps subsequently being necessary. As a result, an inexpensive and fast manufacturing method for manufacturing MMC wire 101 is provided.

LIST OF REFERENCE NUMBERS

101

MMC wire (metal matrix composite wire)

103

Silicon carbide filament

105

copper smelter

107

melting pot

108

opening

109

reheating

111

drawing direction

113

meniscus

Claims (12)

1. A method for manufacturing a copper profile, in particular a copper wire (101), from a matrix element (103), wherein the matrix element comprises at least one filament, with the following step of

   - passing the matrix element through an opening (108) of a copper crucible (107) filled with liquid copper (105) in such a manner that liquid copper is applied onto the matrix element and the applied copper is solidified on the matrix element, free from the liquid copper in the filled copper crucible, so that the copper profile is directly formed.
2. The method according to claim 1, characterized in that the passing is carried out by continuous drawing.
3. The method according to one of the afore-mentioned claims, characterized in that the opening is covered by the liquid copper.
4. The method according to one of the afore-mentioned claims, characterized in that the matrix element comprises additional filaments and/or a filament bundle.
5. The method according to one of the afore-mentioned claims, characterized in that the matrix element comprises an inorganic fiber, in particular a carbon fiber and/or a silicon carbide fiber.
6. The method according to one of the afore-mentioned claims, characterized in that a filament or several filaments has or have a diameter between 3 µm to 30 µm, preferably between 6 µm and 20 µm.
7. The method according to one of the afore-mentioned claims, characterized in that the matrix element with an outwardly exposed layer or without an outwardly exposed layer, wherein the exposed layer is carried by the filament, forms a contact angle with the liquid copper of 15° to 120°, preferably more than 30°.
8. The method according to one of the afore-mentioned claims, characterized in that the method is carried out in a protective gas atmosphere.
9. The method according to one of the afore-mentioned claims, characterized in that several copper profiles are simultaneously drawn in parallel from the copper crucible.
10. The method according to one of the afore-mentioned claims, characterized in that a thickness of the copper profile is adjusted by means of a drawing speed of the matrix element and/or a tempering (109), in particular a vertical tempering.
11. A copper profile, in particular a copper wire, wherein the copper profile is manufactured by means of a method according to one of the claims 1 to 10.
12. The copper profile according to claim 11, characterized in that a thickness of the copper profile is less than 0.3 mm.

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