EP1973677B1 - Composite electrical conductor and method for producing it - Google Patents

Abstract

An electrical composite conductor includes a CuAg alloy base having an Ag content of 0.08 to 0.12% and a CuMg alloy having a Mg content of 0.1 to 0.7%. The composite conductor further includes a conductor edge and a conductor core, wherein at least one of the edge and the core include the CuMg alloy.

Description

The invention relates to an electrical composite conductor, in particular contact wire, and a manufacturing method thereof.

Various proposals have been made to improve composite conductors (in particular contact wire) in terms of their mechanical strength, although a reduction in the electrical conductivity should not occur. In this case, for example, additional alloying partners have been added to Kupferleitmaterial, which contribute to a mechanical solidification of the conductor material and the participation of example, the electrical conductivity does not decrease significantly.

State of the art

Composite conductors and associated manufacturing methods are known. Different designs have already been proposed for different applications in electrical engineering. Very special applications are required in superconducting technology. Wide applicability for the production of rods, profiles and hollow bodies have found extrusion presses, which are known under the name Conform process (= continuos forming). Older plants are based on an invention, which in the DE 221169C2 are described. In particular, the designation Holton Conform for the procedure has become, since this goes back to a company Holton, of which, for example, the application EP 0494 755 A1 comes. The wrapping of elongated material is called conform cladding. Newer variants of the manufacturing technology can be found for example in EP 0125 788 A2 , The JP-A-02 267 811 discloses an electrical composite conductor having a base alloy of CuAg and a Cu edge.

task

It is the object of the invention to provide the structure of a composite electrical conductor and a manufacturing method thereof to obtain a conductor with maximum electrical conductivity and best mechanical strength.

The solution of the problem is specified in the main claim. Further advantageous developments are formulated in the subclaims. The manufacturing process is defined in a secondary claim.

The invention

The proposed composite conductor excels in its mechanical and electrical properties the materials available so far. At the same time, it is adaptable to a wide range of different requirements. This increases the flexibility of the manufacturing process and the expansion of product diversity.

The invention and thus the composite conductor consists of a base alloy of CuAg with an Ag content of 0.08 to 0.12%, and the edge or the core of the composite conductor consists of an alloy of CuMg with an Mg content of 0.1 to 0.7%.

Further embodiments consist in the following:

The Mg content of the CuMg alloy is preferably 0.5% Mg. Preferably, the silver content in the base alloy is 0.1% Ag.

The area fraction of the alloy present on the core side at the cross section of the composite conductor is between 10 and 80%. Preferably, the area ratio of a CuMg alloy present in the core should be 50%.

The structure of the core may consist of a single or multiple strands of wire.

If several wire strands are present on the core, the wire strands have approximately the same diameter.

The composite conductor can be produced in different cross sections. Such cross sections can be: circular for the production of a round wire, approximately rectangular for the production of a busbar or profiled for a profile wire. As a preferred application of a profile wire trolley wires should be addressed. In this connection reference is made to the standard EN 50149, in which contact wires are standardized.

To produce the composite conductor according to the invention, the known strand-pressing process is proposed. It is the production of rods or wires via extrusion. The jacket material is introduced into (two) peripheral grooves of an extrusion wheel, wherein a flowable, tubular structure is produced by high friction on an abutment, which emerges as casing of the core material from the extruder opening. The core material is inserted through a hollow portal mandrel tangential to the extrusion wheel; the jacket material envelops the core material. The product is then passed through one or more dies and pulled down to final dimensions. It has already been mentioned that suitable extrusion presses are on the market.

The invention utilizes the high strength and good conductivity of CuMg alloys in combination with the high conductivity, moderate hardenability, and good wear characteristics of CuAg alloys. Thus, the physically limited range of conventional contact wires consisting of only one alloy can be significantly extended with the proposed alloying partners in terms of strength and electrical conductivity. In particular, compared to the previously known composite driving wires made of staku (steel-coated copper wire), the proposed composite driving wire, in addition to its better electrical conductivity, is not susceptible to corrosion and also capable of being recycled.

As a contact wire a grooved contact wire can be produced, which contains at least one wire of CuMg 0.1... 0.7 in the core and is surrounded by a jacket of CuAg 0.1. The core wire may be round or more or less adapted to the outer profile of the sheath (Ri profile). The area fraction of the core wire in the cross section of the composite conductor can vary within wide limits. The core wire is characterized in that it is adjusted by means of different degrees of cold work to a desired strength and is introduced with this strength in the composite. By an additional after the Holton-Conform extrusion (for example) applied cold forming a further solidification of the composite trolley wire. Thus, a variability of the adjustable product properties (especially the strength and the electrical conductivity) is possible. Furthermore, depending on the desired properties of the composite trolley wire endprofilnahe production with reduced drawing costs possible.

However, the material pairing is also possible in other forms, where in the core at least one wire of CuAg 0.1 is embedded, and the core is surrounded by a jacket of CuMg 0.1 ... 0.7.

An advantage for the laying properties of the contact wire (low or reduced ripple after rolling off the cable reel) is likely to affect that when using a relatively high degree of cold work after the Holton-Conform process, the solidification of the CuAg shell already in the saturation (thermodynamic Equilibrium) and the overall strength of the jacket is significantly lower than that of the core wire. Furthermore, the homogeneity of the structure of the high strength core wire is much higher than that of a conventional contact wire of a single material, whereby more uniform mechanical properties over the contact wire length can be achieved.

As material properties, it can be estimated that, for example, in the case of an area fraction of the core wire of 25% CuMg 0.5 has a conductivity of 90% IACS (52 MS m ^-1 ) and a tensile strength of at least 435 N / mm ² and at an area fraction of the core wire of 50% CuMg 0.5 a Conductivity of 81% IACS (47 MS m ^-1 ) and a tensile strength of 490 N / mm ² .

manufacturing

By conventional manufacturing method, a core wire (round or as a profile wire) having a defined (high) strength and conductivity is made of a CuMg alloy (e.g., CuMg 0.5). The surface of the core wire or wires is carefully removed from foreign or corrosion layers, for example by chemical treatment. In the case of core wires with an extraneous-free, activated surface, it is ensured that a good material connection to the cladding material can be produced. Surface cleaning is important so that the tight material connection between core wire and sheathing is maintained during the further forming process.

A core wire produced and pretreated in this way is encased in a conform cladding process with the highly conductive material CuAg 0.1. During the process control, it should preferably be prevented that the core wire recrystallizes under the resulting thermal load. The resulting composite wire is brought by further drawing steps in its final profile shape and further solidified. Depending on the required cross-sectional portion of the core wire can be introduced as a round or profile wire. The manufacturing process is to be controlled in such a way that no core wires come to lie in the edge or cladding region near the surface of the composite conductor, so that in the cladding zone of about 10% of the diameter no core wire is present. The cross-sectional reduction in the drawing process has an influence on the final strength of the product. To produce a trolley wire suitable for high speed rail applications, a relatively high cross-sectional reduction is made. Such contact wires are mounted with a particularly high tensile stress, so that they dodge the pressure of a pantograph and ensure a high wave propagation speed of this Anhubes. So it is a high mechanical strength requirement for the application.

It was mentioned that composite conductors according to the invention can also be used as busbars. Busbars are used stationary in electrical distribution systems, so that for this application, the mechanical strength plays only a minor role.

figure description

Fig. 1

den Querschnitt eines Runddrahts mit mehreren Kerndrähten,

Fig. 2

den Querschnitt eines Fahrdrahts mit nur einem Kerndraht und

Fig. 3

den Querschnitt eines Fahrdrahts mit mehreren eingebetteten Drahtsträngen.

The invention is illustrated in three drawings, which show in detail:

Fig. 1

the cross-section of a round wire with several core wires,

Fig. 2

the cross section of a contact wire with only one core wire and

Fig. 3

the cross section of a contact wire with several embedded wire strands.

In the FIG. 1 a round wire 12 is drawn, in which a plurality of core wires 22 are located. The individual wires 22 are distributed irregularly in the material 14 and are spaced from the surface of the round wire, so that a kernerahtfreie edge zone is present. The regularity of the individual wire distribution depends on the manufacturing method used, and is accordingly controllable.

Fig. 2 shows a contact wire 10 (grooved wire or trolley wire) - according to EN 50149, which contains a wire of CuMg 0.1 ... 0.7 in the core 20 and is surrounded by a sheath 14 of CuAg 0.1. The core wire 20 comes from a round wire, which was deformed by the profiling, whereby it has received a pear-shaped cross-section. It is readily understood that the cross-sectional shape of the core wire depends on the magnitude of the deformation and the shape of the extruded starting profile, so that contact wires can be produced, which still have a nearly round core wire.

The area fraction of the core wire in the cross section of the composite conductor can vary within wide limits (10 to 80%). When a CuMg alloy is provided on the core side, the area ratio of this CuMg alloy should preferably be 50%.

Fig. 3 shows a trolley wire 11, which contains a plurality of wire strands 22 in the core, which are distributed more or less regularly. The wire strands 22 are preferably made of a wire supply with a uniform diameter, so that the embedded wire strands have approximately uniform cross section, unless they undergo a different deformation in the manufacturing phase. However, the wire strands may also have non-circular cross-section.

As a numerical example of a contact wire is still specified: Cross section for the core wire 4 mm ² . With a surface portion of the core wires of 50%, a corrugated contact wire (according to the above-mentioned standard) with a cross-section of approximately 120 mm ^{2 would} require approximately 15 core wires.

Claims (9)

1. Electrical composite conductor consisting of a CuAg alloy base having an Ag content of 0,08 % to 0,12 %, in which the edge (14) or the core (20, 22) of the composite conductor (10, 11, 12) consists of a CuMg alloy having an Mg content of 0,1 % to 0,7 %.
2. Composite conductor according to claim 1, characterised in that a proportion of the conductor core (20, 22) in the cross-section of the composite conductor (10, 11, 12) is between 10 % and 80 %.
3. Composite conductor according to either claim 1 or claim 2, characterised in that the core (20, 22) consists of at least one strand (20).
4. Composite conductor according to any one of the preceding claims, characterised in that a plurality of wire strands (22) are arranged in the core and the wire strands (22) have approximately the same cross-section.
5. Composite conductor according to any one of the preceding claims, characterised in that the composite conductor (12) has a round cross-section.
6. Composite conductor according to any one of claims 1 to 4, characterised in that the composite conductor is constructed as a grooved wire (10, 11), in particular as a trolley wire.
7. Composite conductor according to any one of the preceding claims, characterised in that no core wire is present in a cladding region of approximately 10 % of the diameter.
8. Method for producing a composite conductor with an alloy pairing according to claim 1, characterised by the steps of:

   - producing at least one wire strand (22) from a first alloy,

   - introducing at least one wire strand (22) into an extrusion apparatus and providing said strand with a cladding (14) made of a second alloy,

   - pulling the produced composite conductor (10, 11, 12) through a drawing die at least once, thus bringing said conductor into the final profile shape thereof,

   wherein either the first alloy is a CuAg alloy with an Ag content of between 0,08 % and 0,12 % and the second alloy is a CuMg alloy with a Mg content of between 0,1 % and 0,7 %, or the first alloy is a CuMg alloy with a Mg content of between 0,1 % and 0,7 % and the second alloy is a CuAg alloy with an Ag content of between 0,08 % and 0,12 %.
9. Method for producing a composite conductor according to claim 10, characterised in that the surface of the wire strand(s) (22) is freed of a layer of foreign substances before being clad.

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