JPS58150205A - Composite wire and method of producing same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Conventional concentric composite wires are produced by extrusion method, rolling method, wire drawing method, plating method, etc., but the processing conditions for composite wire by the above three methods excluding plating method are as follows. At the bottom, large distortion occurs in the inner layer that becomes the core wire, causing plastic deformation of the core wire and causing it to break. On the other hand, the Notsuki method has drawbacks such as the fact that the outer layer is thin, so the shape of the composite wire must be limited, and furthermore, a wire drawing step is required in the next step. For example, for wires with low tensile strength, such as concentric composite wires with compound superconducting wires as the core or inner layer, the strain applied to the core during processing must be suppressed as much as possible. It is extremely difficult to coat the outer layer with, for example, high-purity aluminum and perform such wire removal using conventional manufacturing techniques.

SUMMARY OF THE INVENTION An object of the present invention is to provide a composite wire system and a method for manufacturing the same, which can minimize the occurrence of distortion to the core wire.

That is, the gist of the present invention is, for example, in a multilayer concentric composite wire such as a three-layer wire, a material having a lower deformation resistance and a lower melting point temperature than the materials forming the inner and outer layers is used as the intermediate layer, and these are used as the intermediate layer material. Composite processing is performed at a temperature above the melting point of.

When carrying out the present invention, it is preferable to prepare the inner layer in advance, provide the outer layer by extrusion, and form the intermediate layer. A method suitable for this purpose is the so-called EET method, in which the superconducting core wire is directly coated with aluminum by extrusion. According to this method, the adhesion properties at the interface are well guaranteed, but when a compound-based superconducting core is used, as mentioned above, the conditions for low distortion processing of the core are further required, and the adhesion at the interface is also ensured. Due to the conflicting demands that the extrusion conditions are also required, the setting range of extrusion conditions is narrow and processing becomes difficult. Therefore, in the present invention, the outer layer made of aluminum is extruded into a pipe shape with intervals from the inner layer made of superconducting wire to prevent distortion, and the entire outer layer is made of a material that guarantees the adhesion of the interface, that is, solder. and the inner layer. In this case, the extrusion temperature of the aluminum needs to be higher than the melting point of the solder in order to eliminate adhesion defects caused by the solder in the intermediate layer.

In processing the composite wire of the present invention, in order to pour molten solder between the outer layer and the inner layer, a downward extrusion structure is used, and as for processing temperature, an alloy or compound layer is formed at the interface between each material, thereby heating the wire. It is important to select various conditions such as extrusion temperature and/or extrusion speed, and product cooling conditions so as not to deteriorate the physical or electrical properties.

The following description will be given based on the embodiments shown in the drawings. FIG. 1 is a cross-sectional view of an aluminum-stabilized composite superconducting wire 4 manufactured according to the present invention, in which the inner layer 1 serving as the core wire is a compound-based superconducting wire prepared in advance, The intermediate layer 2 is made of a material having low deformation resistance and a low melting point, such as solder, and the outer layer 3 is made of high-purity aluminum.

FIG. 2 is a cross-sectional view of the composite wire manufacturing apparatus of the present invention shown in FIG. 1. In FIG. 2, the compound-based superconducting core wire that will become the inner layer 1 is prepared in advance and introduced into the die 6 through the nipple 5 at a constant speed. On the other hand, high-purity aluminum 3, which becomes the outer layer 3, is supplied under pressure to the space defined between the nipple 5 and the die 6, and is extruded from the gap between the die 6 and the outlet of the nipple 5, forming a vibrator that covers the inner layer. The outer layer 3 is formed. On the other hand, molten solder is supplied into the Nisopuru 5 and poured from the nipple 5 so as to fill the gap between the inner layer 1 and the outer layer 3, thereby obtaining the aluminum stabilized superconducting wire 4.

As mentioned above, in manufacturing this composite wire, the intermediate layer 2 can be easily formed by extruding the aluminum outer layer 3 at a temperature higher than the melting temperature of the solder.

In the embodiment shown in FIG. 1, the inner layer 1 is a single concentric compound wire, but the inner layer 1 is a concentric elliptical wire as shown in FIG. 3, or a plurality of single wires or stranded wires as shown in FIG. Furthermore, the material of each layer can be selected from a wide range based on deformation resistance or melting point, etc., and is not limited to only metal. It becomes possible to manufacture special composite wires, which were thought to be impossible with the above technology, that is, by processing the core wires with low distortion. In particular, for compound-based superconducting wires, the weight of the composite wire can be reduced by using aluminum as a stabilizing material.
Compared to conventional copper stabilizing materials, the superconducting properties of the inner layer can be fully utilized.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a composite wire using a compound superconducting wire as a core wire according to the present invention, FIG. 2 is a cross-sectional view of the main part of a composite wire manufacturing apparatus according to the present invention, and FIGS. FIG. 6 is a sectional view showing another embodiment of the composite wire according to the invention. 1... Compound superconducting wire, 2... Solder layer 3...
... High purity aluminum layer 4 ... Aluminum stabilized superconducting composite wire 5 ...
Nipple, 6...Dice, 7...Twisting wire 8
・Combined line 1

Claims (4)

[Claims] (1) A composite wire characterized in that a conductor forming an intermediate layer in a concentric composite wire is formed of a material having a deformation resistance smaller than the deformation resistance of the conductor material forming the inner layer and the outer layer. (2) A claim characterized in that the material forming the inner layer is a compound-based superconducting material, the material forming the intermediate layer is solder, and the material forming the outer layer is high-purity aluminum. Composite line described in item 1. (3) The core wire forming the inner layer is subjected to composite processing at a temperature equal to or higher than the melting point of a material having lower deformation resistance than the inner layer material forming the intermediate layer. 2. Method for manufacturing composite wire as described in section. (4) The method for manufacturing a composite wire according to claim 3, wherein the outer layer is extruded.