JPS62279016A - Billet for extrusion - Google Patents

Abstract

PURPOSE:To reduce the manufacturing cost by inserting >=2 types of wire rod bundles having different internal structures between the front and rear end members of a billet and extruding the above members and bundles as one billet. CONSTITUTION:A wire rod 4a, consisting of a type of Cu covered single core Nb.Ti bar to be used for composition of a superconductive wire, is cut by a prescribed length; many of the cut stocks 4a are inserted into an oxygen free copper tube 5 so as to row up. Then, a circular bulkhead plate 8 is inserted in the tube 5 and wire rods 4b having a different thickness from that of the rods 4a are inserted so as to row up and to form another bundle. A front and a rear end members 6 and 7 are inserted in the front and the rear part of the lined two bundles so as to extrude the bundles and others as one billet. In that method, the superconductive wire or the like having different structures and a small volume is formed by one extrusion work. Therefore, the manufacturing cost of products is reduced.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Industrial Field of Application] The present invention relates to an extrusion billet, particularly an extrusion billet suitable for producing superconducting wires.

[Conventional technology]

In order to manufacture superconducting wires, a method is used in which extrusion billets are extruded into composite wires. below,
As a conventional example, an extrusion billet having a Nb-Ti alloy superconducting wire will be described as an example.

In order for superconducting wires to work stably, many very thin filaments, such as Nb-Ti alloy filaments with a diameter of 10 to 40 μm, are embedded in a normal conductive metal with low electrical resistance, such as oxygen-free copper. A so-called ultra-fine multi-core twisted superconducting wire is manufactured and used by twisting a composite wire like this.

FIG. 2 is a cross-sectional view showing an example of such an Nb-Ti alloy ultrafine multi-core twisted superconducting wire. In the figure, (1
) is a Nb-Ti alloy filament, and (2) is a normally conductive metal such as oxygen-free copper, which makes the composite wire Nb-
A Ti alloy ultrafine multicore superconducting wire (3) is formed. N
The b-Ti alloy ultrafine multicore superconducting wire (3) has b
Therefore, it has a uniform cross section as shown in FIG.

In order to manufacture such a superconducting wire (3), the following method is generally adopted. i.e. copper-coated Nb-
Tip members,
As the rear end member, a copper plate is often welded to form a billet for extrusion. This billet is then extruded into a composite wire, which is further processed to reduce its cross section by swaging, wire drawing, rolling, etc., and is finished into a predetermined shape.

FIG. 3 is a vertical cross-sectional view showing a conventional extrusion billet disclosed in, for example, Japanese Patent Application Laid-Open No. 59-45021. In the figure, (4) is a single-core Nb coated with oxygen-free steel wire. - A wire made of Ti rods, (5) is a pipe made of oxygen-free copper in which a plurality of these wires are arranged inside, (6
) is a conical tip member placed at the tip of the wire (4) to form the billet tip, and (7) is a disc-shaped rear part placed at the rear of the wire (4) to form the billet tip. It is an end member. Here, the front and rear ends mean the front and rear ends of the billet in the extrusion direction.

In order to produce such an extrusion billet, first cut the Nb-Ti alloy wire coated with oxygen-free copper to produce the wire (4), and then insert a large number of wires (4) into the pipe (5). The tip member (6) and the rear end member (7) are then welded to the pipe (5).

For welding, electron beam welding is usually used to maintain a vacuum inside the pipe (5).

The shape of the tip of the tip member (6) is determined by taking into account the type of extrusion method, the constituent material of the billet, the number of wire rods in the billet, the extrusion ratio, etc. The extrusion method may be any forward extrusion type that can extrude composite materials, and depending on the shape of the die, a flat die type where the billet does not taper in the area from the container diameter to the die hole diameter, or a flat die type where the billet does not taper in the area from the container diameter to the die hole diameter, or a rotating part of the die. Tapered die type with conical shape,
Alternatively, there is a hydrostatic extrusion method which is fundamentally different from these extrusion methods.

[Problem that the invention seeks to solve]

Conventional extrusion billets are constructed as described above, so there is no problem when manufacturing one superconducting wire with the same volume from one extrusion billet, but the superconducting wire to be manufactured If the volume of the pipe (
5) It is necessary to shorten the length of the wire rod (4) placed inside.

However, in order to manufacture and extrude such short billets, for example, electron beam welding must be performed in the same way as long billets, and extrusion requires the same manufacturing time and cost as long billets. It takes. Therefore, there was a problem in that the manufactured superconducting wire was extremely expensive.

This invention was made to solve the above-mentioned problems, and it improves production efficiency even when obtaining a superconducting wire with a small volume, does not change current characteristics or other technical characteristics, and is inexpensive. The aim is to obtain an extrusion billet that can be used to manufacture superconducting wires.

[Means for solving problems]

The extrusion billet according to the present invention is an extrusion billet in which a tip member and a rear end member are arranged on both end faces of a wire bundle in which a large number of wire rods are arranged along each other in a pipe, and the wire rod bundle in the pipe is It consists of two or more types arranged in the longitudinal direction.

[For production]

In the extrusion billet of the present invention, for example, a wire bundle configured for manufacturing one type of superconducting wire is inserted into the first half of the pipe, and another superconducting wire with a different internal structure is inserted into the second half. A wire rod bundle configured for manufacturing is inserted, and a leading end member and a trailing end member are arranged to manufacture one billet.

By extruding and cutting this billet in the same manner as in the conventional method, two superconducting wires having a small volume and different types can be manufactured. By adopting such a method, multiple small-volume superconducting wires with different internal configurations can be fabricated into one billet.
The superconducting wire can be manufactured by multiple extrusion processes, and as a result, a superconducting wire whose various properties do not change can be manufactured at low cost.

If we adopt a method of reducing the diameter of the billet in order to manufacture superconducting wires with a small volume, a container with a small diameter must be used, and manufacturing a separate container is not only very troublesome but also economically difficult. This is extremely disadvantageous, and in the case of alloy superconducting wires, it adversely affects its fundamental properties such as critical current value, but the present invention does not have such problems.

[Embodiments of the invention]

FIG. 1 is a longitudinal sectional view of an extrusion billet according to an embodiment of the present invention, and in the figure, the same reference numerals as in FIG. 3 indicate the same or corresponding parts. (4a) is a wire made of a Cu-coated single-core Nb-Ti rod for configuring a type of superconducting wire;
(4b) is a small-diameter Cu-coated single-core Nb-Ti wire arranged for a superconducting wire with a different configuration, with a disk-shaped partition material (8) sandwiched between the oxygen-free copper They are arranged in front and behind a pipe (5) consisting of. The other configurations are the same as in FIG. 3.

To produce the above billet, the wire rod (4a) is cut to a predetermined length in the same manner as in the conventional method, and for example, the outer diameter is 25 mm.
The wires are inserted into a pipe (5) with a diameter of 0 mm to form a wire bundle. Thereafter, one disc-shaped partition wall material (8) is arranged, and further wire rods (4b) having different thicknesses are aligned and inserted to form another wire rod bundle. In this way, one billet is produced and subjected to extrusion processing in the same manner as before.

In this example, the composite rod with a diameter of 7 km extruded as described above has a front part made of Nb4 with a diameter of 2.0 mm.
It was a composite of Cu and Nb4i containing 500 i-wires, and a composite of Cu and Nb-Ti containing 700 Nb-Ti wires with a diameter of 1.1 mm at the rear. After that, it is pulled out.

By performing twisting and heat treatment, two different types of superconducting wires with small volumes were obtained.

By employing the above method, an inexpensive small-volume superconducting wire can be manufactured without changing superconducting properties such as critical current properties.

In the above embodiment, one type of superconducting wire with a small volume is
Although we have described the case of manufacturing from book billets, it is also possible to manufacture three or more types in the same manner. Further, in the above embodiment, the case where both types of superconducting wires were made of Cu and Nb4i was described, but for example, Cu,
It can also be applied to the production of superconducting wires made of Cu-Ni and Nb4i or Q-.
- Not limited to Ti superconducting wire, Ni4i/Ta
It can also be applied to superconducting wires manufactured by so-called composite processing, such as alloy wires, Nb, Sn wires, V, Ga wires, etc.
In particular, in the case of compound superconducting wires such as Nb and Sn superconducting wires, the present invention can also be applied to billets that contain Nb and Sn in separate forms or only one of them.

Furthermore, in the above embodiment, a case was described in which a Cu-coated single-core Nb-Ti wire was inserted in order to produce a billet for extrusion, but as a wire bundle, a large number of Nb/Ti wires and Cu
It is also possible to insert a Cu wire, a Cu wire covered with Cu/Ni, etc. at the same time.

The shape of the wire inserted into the pipe is generally a wire with a hexagonal cross section; however, the same effect can be achieved even if the shape of the wire changes, and the shape of the wire will not change.

After the wire is inserted into the pipe, the gap in the pipe may be filled with the wire, etc. In this case, the shape of the wire, etc. is not limited. The material of the pipe for forming the extrusion billet is also not limited, and may or may not be a composite material.

In the above embodiment, the tip member and the rear end member are welded after filling the metal pipe with the wire bundle. However, after filling the bottomed cylindrical container serving as the rear end member with the wire bundle, the tip member is welded. You may also do so. Further, in the above embodiment, the contact surface between the insertion wire bundle and the tip member or the rear end member is a concave or convex surface, but it is also possible to have a flat surface. In this case, the partition wall material is in the shape of a flat disc. It is preferable that Partition material is not always necessary;
The purpose may be achieved even if the wire (4a) and the wire (4b) are in direct contact with each other.

Further, in the above embodiments, an extrusion billet for producing superconducting wires was described, but the present invention is also applicable to extrusion billets for producing composites other than superconducting wires.

〔Effect of the invention〕

As described above, according to the present invention, since two or more types of wire bundles are arranged in the pipe, even when manufacturing two or more types of superconducting wires with small volumes, the superconducting No change in characteristics or other technical characteristics;
Cheap superconducting wires can be efficiently produced.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of an extrusion billet according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an example of a Nb-Ti superconducting wire, and FIG. 3 is a vertical cross-sectional view of a conventional extrusion billet. It is. In each figure, the same reference numerals indicate the same or corresponding parts, (4a
), (4b) is a wire rod, (5) is a pipe, (6) is a tip member, (7) is a rear end member, and (8) is a partition wall material.

Claims (3)

[Claims] (1) Two or more types of extrusion billets in which a tip member and a rear end member are arranged on both end faces of a wire bundle in which a large number of wire rods are arranged along each other in a pipe, and the wire bundle in the pipe is arranged in the longitudinal direction. A billet for extrusion characterized by consisting of. (2) The billet for extrusion according to claim 1, wherein the wire bundle contains a superconducting material. (3) The billet for extrusion according to claim 1 or 2, characterized in that a partition material is arranged between the bundles of wire rods.