JPH09115357A - Tape form oxide superconducting stranded wire and superconductor using the stranded wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductor capable of reducing an AC loss, restraining the occurrence of a drift current phenomenon, offering flexibility and ensuring more compactness. SOLUTION: A plurality of element wires formed out of an oxide superconductor covered with a first metal are stranded and a first stranded wire is thereby prepared. A second stranded wire formed into square type out of a plurality of the first stranded wires so prepared is covered with a second metal and subjected to thermal treatment to prepare a tape form oxide superconducting stranded wire. Also, this oxide superconducting stranded wire has an internal shape with oxide superconductor filaments stranded to suit the first and the second stranded wire structures, as well as a metallic material with higher mechanical strength than silver unevenly distributed on one plane of a pair of principal planes. Then, a stranded wire material 11 so prepared is spirally wound around a core material 10, with the higher mechanical strength part 6a thereof exposed outside, and an oxide superconductor is thereby formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire and a conductor using an oxide superconductor, and more particularly to a structure of a high temperature superconductor for transmitting a large current by alternating current and a wire for constituting the conductor. .

[0002]

2. Description of the Related Art Oxide superconducting conductors are characterized in that they are in a superconducting state even at a liquid nitrogen temperature or higher, and by cooling with liquid nitrogen, a large current can be transmitted in a compact conductor with low loss.

On the other hand, when an oxide superconducting conductor is applied to an alternating current, an alternating current loss caused by a fluctuating magnetic field during operation,
There are new problems to be overcome, such as the drift phenomenon caused by the difference in impedance between wires, which does not occur in DC applications.

To solve the above problems, for example, in a metal-based superconducting conductor, AC loss is reduced by arranging a barrier layer between filaments, making superconducting filaments extra fine and multi-core, and twisting a wire to reduce the superconducting element wire. We are striving to realize a superconducting conductor capable of transmitting large-capacity and low-loss power by suppressing uneven current flow by adopting a flat-shaped molded twisted-stranded wire structure in which twisted primary twisted wires are further twisted.

If the above problems are overcome, the oxide superconducting conductor can be used under liquid nitrogen, which is higher in temperature than liquid helium, and has a cooling / heat insulating structure as compared with a metal-based superconducting conductor. With the simplification of, there is a possibility of becoming an excellent conductor in terms of compactness.

The present inventors have developed a tape-shaped Bi-based Ag-coated multifilamentary wire in which a high temperature oxide superconductor is multifilamented by using silver as a stabilizer. Since this wire is excellent in bending properties and can be used to manufacture a long wire having a critical current density exceeding 10 ⁴ A / cm ² , application to a superconducting cable conductor is expected. As a high-temperature superconducting cable conductor structure, the present inventors have proposed a structure in which a Bi-based Ag-coated multicore wire is spirally wound in multiple layers on a flexible core material.

[0007]

When an alternating current is passed through a high-temperature superconducting cable conductor, it is important to reduce the AC loss and suppress the drift phenomenon, and the wire rod and the conductor using the oxide superconductor have been described above. Response to the problem is required.

Further, a conductor having an oxide superconductor is desired to have flexibility and a more compact structure.

An object of the present invention is to solve the above problems and to provide a superconducting conductor in which AC loss is reduced and a drift phenomenon is suppressed.

A further object of the present invention is to solve the above problems, to provide a flexible and more compact superconducting conductor.

[0011]

First, according to the present invention,
Provided is a tape-shaped twisted wire material for forming a superconducting conductor which solves the above problems. The tape-shaped superconducting stranded wire of the present invention is formed by twisting a plurality of strands of an oxide superconductor or a powder of its raw material coated with a first metal selected from the group consisting of silver and silver alloys. Tape-shaped oxide superconducting twist obtained by coating a second metal on a second twisted wire obtained by producing a twisted wire It is a line. In this tape-shaped oxide superconducting stranded wire, the filaments of the oxide superconductor formed in the portions corresponding to the strands are twisted according to the twist structure of the portions corresponding to the first and second stranded wires. And has a second shape, and the second metal is
The tape-shaped oxide superconducting stranded wire is made of materials having different mechanical strengths, and has a higher mechanical strength than the first metal of the second metal on one surface side of the pair of main surfaces. The metal material is unevenly distributed.

In the tape-shaped oxide superconducting stranded wire of the present invention, the first metal can be silver, and of the second metals, the metal material having a high mechanical strength is a silver alloy, and the remaining portion. Can be silver.

In the tape-shaped oxide superconducting stranded wire of the present invention, the silver alloy can be an Ag-Mn alloy. Furthermore, the oxide superconductor can be a bismuth-based oxide superconductor. Furthermore, it is preferable that a plurality of oxide superconductor filaments are present in the portion corresponding to the strand.

On the other hand, according to the present invention, there is provided a superconducting conductor using the above-mentioned tape-shaped oxide superconducting stranded wire. This superconducting conductor is a tape-shaped oxide superconducting stranded wire of the present invention,
It is characterized in that a plurality of core materials are spirally wound so that a portion of the second metal having a mechanical strength higher than that of the first metal is arranged outside.

In the superconducting conductor of the present invention, it is preferable that a plurality of tape-shaped oxide superconducting twisted wires be wound around the core material in one layer.

In the superconducting conductor of the present invention, the tape-shaped oxide superconducting stranded wire can be wound around the core material at a bending strain rate of 0.2% or more.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The tape-shaped oxide superconducting stranded wire of the present invention is formed by twisting a plurality of strands of oxide superconductor or powder of a raw material thereof coated with silver or a silver alloy. Such an element wire can be formed, for example, by filling a pipe made of silver or a silver alloy with powder of an oxide superconductor or a raw material thereof and subjecting it to plastic working such as wire drawing. In the preparation of raw powder,
It is possible to obtain a raw material powder by mixing powders of oxides or carbonates of the elements forming the superconductor in a predetermined mixing ratio and sintering, and then pulverizing the sintered product. The obtained strand is usually a round wire. Next, a plurality of the strands are twisted together to form a primary strand. The number of twisted wires may be, for example, 3 twists, 7 twists, or the like, but is not limited thereto. Further, a plurality of primary twisted wires are twisted together to produce a flat-shaped forming twisted wire. As the number of twists, for example, 9 or 15 twists are possible, but the number is not limited to these. The rectangular molding can be performed, for example, by compression molding. In the present invention, a metal is further added to the obtained stranded wire.

The applied metal is composed of materials having different mechanical strengths, and particularly contains the metal material having higher mechanical strength than the above-mentioned first metal, for example, silver. As a metal having high mechanical strength, an Ag-Mn alloy,
Silver alloys such as Ag-Sb alloys can be preferably used, but the present invention is not limited thereto. Further, as the metal having high mechanical strength, stainless steel, aluminum alloy, etc. can be used. When a silver alloy is used as the metal having high mechanical strength, silver is preferable as the metal of the other part. The metal having high mechanical strength can be a part of the rectangular pipe for fitting the above-mentioned twisted-stranded wire. In this case, one surface of the pair of main surfaces of the rectangular pipe is made of metal having high mechanical strength. Further, a metal having high mechanical strength can be applied to the above twisted and stranded wire by fusion bonding. In this case, a metal having high mechanical strength may be fused to one of a pair of main surfaces of the flat-twisted twisted and twisted wire, and then this may be fitted into a flat rectangular pipe. After fitting with a rectangular pipe, a metal having high mechanical strength may be fused to the pipe.

Then, it is usually preferable to subject the stranded wire to which the metal having high mechanical strength is applied to rolling.
After rolling, a tape-shaped stranded wire is obtained. The tape-shaped stranded wire thus obtained is heat-treated for sintering the oxide superconductor. The heat treatment can be performed at a temperature of 800 ° C. or higher, preferably 840 to 850 ° C. Such rolling and heat treatment can be repeated. In the above process, the rolling step is effective in, for example, increasing the orientation of the crystal grains of the Bi-based oxide superconductor having a plate-like crystal structure and strengthening the bond between the crystal grains, It contributes to the improvement of the critical current density of the stranded wire.

By the process described above, a stranded wire having a plurality of filaments made of an oxide superconductor can be obtained. In the obtained twisted wire material, the filaments are respectively formed at the positions corresponding to the strands, and have a structure twisted in a spiral shape in accordance with the above-described twisted wire and twist structure of the twisted wire. . By such twisting, the impedance of each filament is made uniform, so that it is possible to flow a current evenly through each filament even when an alternating current is applied. Further, the coupling current between filaments is also suppressed, which is effective in reducing AC loss.

Further, in the obtained tape-shaped oxide superconducting twisted wire, the metal material having high mechanical strength is unevenly distributed on one surface side of the pair of main surfaces of the tape-shaped twisted wire. Therefore, the tape-shaped stranded wire has a structure in which one surface side is easily bent and the other surface side is hard to be bent. Such a stranded wire material has a characteristic of being resistant to bending strain as described later. By using the wire rod having such a structure for the superconducting conductor, it becomes possible to design a compact conductor having good flexibility, as will be described later.

The conductor of the present invention comprises a plurality of the above-mentioned tape-shaped oxide superconducting stranded wires, which are spirally wound around the core material so that the portion of the metal material having high mechanical strength is arranged outside. Is characterized by. The core material is usually flexible. The core material is usually called a former and is used to hold the tape-shaped superconducting stranded wire at a bending strain rate within a predetermined range. The former has a necessary length for the superconducting cable conductor and is provided at the center of the superconducting cable conductor. For winding the tape wire, the former can be substantially cylindrical or spiral-shaped.
The former generally has a substantially constant diameter over its entire length. The former is, for example, stainless steel,
It can consist of at least one material selected from the group consisting of copper, aluminum, and FRP (fiber reinforced plastic).

Ceramic materials are generally mechanically stronger against compression than against tension. In a multifilamentary wire formed by coating an oxide superconductor, which is a ceramic, with a metal, the resistance to compressive strain at a critical current is better than the resistance to tensile strain. Therefore, place a material with high mechanical strength on one surface side of the wire, and apply a tensile force to that surface,
When the side with high mechanical strength is bent outward, most of the tensile force can be shared by that surface. In this way, the bending strain characteristic of the wire is improved by the amount that the tensile force shared by the superconducting filament is relatively reduced. That is, by using the tape-shaped stranded wire having the above-mentioned structure, it becomes possible to spirally assemble the wire at a bending strain rate of 0.2% or more, that is, to assemble the wire at a short pitch, and to bend the wire. It is possible to design a compact conductor with good flexibility that does not cause the wire rod to loosen when it is damaged. It may be possible to arrange materials with high mechanical strength on both sides to increase the strength, but in the sense of making the conductor compact, only one side where the effect is remarkable, that is, the side to which tension is applied, has the mechanical strength Taking measures to improve is more effective in terms of promoting compactness.

The inventors of the present invention are required to equalize the impedance between the assembled wire rods as a measure against the drift of the high-temperature superconducting cable conductor. This is because one layer of the above-mentioned tape-shaped oxide superconducting stranded wire is used. We thought that it could be realized by making a conductor. In the case of a single-layer conductor, the number of aggregated wire rods is limited, so it is necessary to increase the capacity per wire rod (critical current Ic), that is, increase the wire rod size. At that time, the thickness of the wire also increases, and when a predetermined bending strain is applied along the support material having the outer diameter D, a bending strain larger than that of the wire having a thin wire is applied. Winding pitch P on core material with outer diameter D and thickness t
When the wire is wound spirally, the bending strain rate ε (%) applied to the wire can be described as follows.

Ε = πt × 100 / {(D ² + P ² ) ^0.5 + πt} As a result of the investigation by the present inventors, the decrease in the critical current of the wire wound on the core material is defined by the above equation. It was confirmed that it depends on the bending strain applied in the longitudinal direction of the wire.
Then, it was confirmed that when a tension exceeding 1 kgf / mm ² was applied to the conductor, the decrease in the critical current density of the wire was likely to occur in the region of ε> 0.2%. According to this result,
When the thickness of the wire to be used exceeds 1 mm, the conductor structure has an outer diameter D of 100 mm or more, or a winding pitch, in order to reduce the bending strain to less than 0.2%. Only compact or flexible structures with a loss of 1 m or more can be obtained. However, by winding the stranded wire material according to the present invention around the core material in the above-described structure, a conductor can be formed without lowering the critical current even if the bending strain of the stranded wire material is larger than 0.2%. It became so. Then, by winding the stranded wire material of the present invention in a single layer around the core material, a high-capacity, compact and low-loss high-temperature superconducting conductor has become possible. In such a one-layer conductor, the thickness t of the twisted wire to be wound is ((conductor outer diameter)-(former outer diameter)) / 2.

As described above, 1. 1. Make the wire material a stranded wire structure. 2. Disposing the above-mentioned first metal, for example, a material having higher mechanical strength than silver on one surface of the wire. By considering the three points that the conductor has a single-layer spiral winding structure, it is possible to realize a high-temperature superconducting conductor that can carry a large-capacity alternating current and that has a low current loss.

In the present invention, the oxide superconductor may be a Bi-based, Tl-based, Y-based oxide superconductor, or the like. Bi-based oxide superconductors have a high critical temperature,
It is a preferable material in terms of high current density, low toxicity, and ease of forming a wire.

[0028]

【Example】

Preparation of the superconducting wire (Example _{1) Bi 2 O 3, PbO} , SrCO 3, Ca
Bi: Pb: Sr: C using CO ₃ and CuO
a: Cu = 1.80: 0.30: 1.92: 2.01:
These were blended so that the composition ratio was 3.03. This blended powder was heat-treated multiple times. Note that pulverization was performed after each heat treatment. The powder obtained through such heat treatment and pulverization was further pulverized by a ball mill to obtain submicron powder. This powder was heat-treated at 800 ° C. for 2 hours and then filled in a silver pipe having an outer diameter of 12 mm and an inner diameter of 10 mm. The drawn powder-filled pipe was further fitted into a silver pipe having an outer diameter of 12 mm and an inner diameter of 9 mm to form a 7-core wire, which was drawn to 1 mm to obtain a strand. The obtained strand is shown in FIG. In the wire 1, a stabilizer 2 made of Ag is filled with seven round wires 3. The round wire 3 is obtained by filling a raw material powder of a superconductor into an Ag pipe and drawing it. Seven strands of this element wire were twisted to produce a so-called primary twisted wire. This primary twisted wire is shown in FIG. The primary twisted wire 4 has a structure in which seven strands 1 are twisted together as shown in FIG.

Next, 15 of the obtained primary twisted wires were twisted together. This twisted product is shown in FIG. In this case, 15 primary stranded wires 4 are twisted in a rectangular shape as shown in the figure. The thus twisted pieces were compression-molded to prepare a flat secondary twisted wire.

Next, a rectangular tube as shown in FIG. 4 was prepared. This tube 5 has a thickness of 2 mm, has a rectangular cross section as shown in the drawing, and has a hatched portion 6a,
That is, one (one surface) part of the pair of surfaces 6a and 6b that respectively configure the long sides of the rectangular cross section is made of an Ag-Mn alloy having higher mechanical strength than silver. On the other hand, the other portions 7 and 6b are made of silver. The above-mentioned rectangular secondary stranded wire was fitted into such a tube 5, and this was rolled to form a tape-shaped stranded wire. The tape-shaped stranded wire thus obtained is heat-treated at 845 ° C. for 50 hours,
After further rolling treatment, heat treatment was performed at 840 ° C. for 50 hours.

In the tape-shaped stranded wire obtained by such a method, the filament made of an oxide superconductor is
There are 735 in total. Of these, seven each are spirally twisted in the space forming the primary twisted wire,
Further, 49 filaments each forming the primary twisted wire are spirally twisted in the space forming the secondary twisted wire.

(Comparative Example 1) A flat secondary twisted wire produced in the same manner as in Example 1 was fitted into a flat tube having a thickness of 1 mm and made entirely of silver. In addition, Example 1
In the same manner as above, a rolling treatment is performed, a heat treatment is performed at 845 ° C. for 50 hours, and a rolling treatment is further performed.
Heat treatment was performed for 0 hours.

[Experiments on critical current and winding pitch] Regarding the rectangular twisted wire rods produced in Example 1 and Comparative Example 1, an FRP pipe having an outer diameter of 30 mm and a tension of 1 kgf / m were used.
The spiral winding was carried out at m ² , and the relationship between the critical current and the winding pitch was investigated. The spirally wound state is shown in FIG.
In the figure, a tape-shaped twisted wire material 11 is wound around a pipe 10 in a spiral shape. The dimension P shown in the figure represents the winding pitch, D the outer diameter of the pipe, and t the thickness of the tape-shaped stranded wire. As a result, the wire rod of Comparative Example 1 starts to decrease Ic at a bending strain rate of about 0.2% (corresponding pitch 1.5 m), whereas the wire rod of Example 1 has a bending strain rate of about 0.7%. Until I load (corresponding pitch 0.9m) I
It was confirmed that c did not decrease. Separately, silver and Ag-
When the tensile strength of the oxide high temperature superconducting twisted wire coated with each Mn alloy was measured, when the coating material was Ag, the decrease of Ic started at a tension of about 4 kgf / mm ² , whereas the Ag-Mn alloy In the case of, it was confirmed that the mechanical strength was improved by about 5 times, about 20 kgf / mm ² .

[Confirmation of Effect of Twisted Wire] Ic of the tape-shaped twisted wire material produced in Example 1 and Comparative Example 1 in liquid nitrogen
Was 50A. Ic is 10A by the energization 4-terminal method
The AC loss of the laminated conductor obtained by laminating five tape-shaped Bi-based Ag-coated single-core wires of Example 1 and the wire rod according to Example 1 was measured, and the AC loss of the wire rod according to Example 1 was 5 in the region of 50 A or less. Confirmed to be smaller than.

[Production of Superconducting Conductor] (Example 2) A stranded wire was produced in the same process as in Example 1,
The obtained stranded wire rod was wound around an FRP pipe having an outer diameter of 30 mm at a pitch of 900 mm to be collected, and a one-layer conductor was produced. The outline of the obtained conductor is shown in FIGS. 6 and 7. As shown in FIG. 6, in the conductor 12, the tape-shaped superconducting stranded wire 11 is spirally wound around the FRP pipe 10. As shown in FIG. 7, the FRP pipe 10
Ten tape-shaped superconducting twisted wires 11 are gathered around the circumference of. It should be noted that the portion 6a filled in black in FIG.
Is a portion corresponding to the Ag-Mn alloy of the tube used last in the production of the tape-shaped superconducting stranded wire 11. Therefore, in the conductor 12, the tape-shaped superconducting twisted wire 11 is wound around the pipe so that the portion 6a of the tape-shaped superconducting twisted wire 11 made of Ag-Mn alloy having high mechanical strength is located outside the conductor. Therefore, the outer peripheral portion of the stranded wire material 11 made of silver is directed toward the FRP pipe 10. The Ic of the obtained conductor was 500 A, and no clear decrease in Ic due to the conductor assembly was observed. on the other hand,
A stranded wire rod was manufactured in the same process as in Comparative Example 1, and the obtained wire rod was placed on a FRP pipe having an outer diameter of 30 mm at a pitch of 900 mm.
When a single-layer conductor was produced by winding and winding 0 pieces, Ic of the conductor was 200 A, and it was confirmed that the Ic was lowered due to the spiral bending during the conductor assembly.

(Example 3) A stranded wire was prepared in the same process as in Example 1, and pitch 9 was formed on an FRP pipe having an outer diameter of 30 mm.
Wound 10 pieces at 00 mm to gather, conductor diameter 34 m
A single-layer conductor with m and Ic = 500 A was produced. In addition, the same wire is placed on a FRP pipe with an outer diameter of 26 mm and a pitch of 900
18 pieces are assembled at m, conductor diameter is 34 mm, Ic = 900 A
A two-layer conductor was manufactured. At that time, an insulating layer was provided between the layers. The outline of the obtained two-layer conductor is shown in FIG. 2 layer conductor 1
3, the tape-shaped stranded wire 11 is wound around the FRP pipe 14 in two layers, and the insulating layer 15 is provided between the layers. As a result of investigating the AC loss of these two conductors, 40
Comparing the AC losses when 0 A was energized, no clear difference was seen in the AC loss amount between the two, and the result supported the effectiveness of the single-layer conductor.

(Example 4) A stranded wire was produced in the same process as in Example 1, and pitch 9 was formed on an FRP pipe having an outer diameter of 30 mm.
Wound 10 pieces at 00 mm to gather, conductor diameter 34 m
A single-layer conductor with m and Ic = 500 A was produced. In addition, an Ic = 20A grade 0.2 mm thick Bi-based Ag-coated multi-core wire that does not have a twisted wire structure is used, and an FR having an outer diameter of 30 mm is used.
Collect 30 pieces on a P pipe with a pitch of 900 mm, and
= 600 A single-layer conductor was produced. As a result of investigating the AC loss of the two conductors, comparing the AC losses when energized at 400 A, it is found that the conductor having the same structure as that of Example 1 has a smaller AC loss amount although Ic is slightly lower. confirmed.

In the examples shown above, the flat tube for fitting the secondary twisted wire is a silver alloy having high mechanical strength and a tube forming a tube structure with silver. The material for covering the secondary twisted wire is not limited to this.
Further, the arrangement of the metal having high mechanical strength can be made in various modes, and as an example thereof, the one shown in FIG. 9 can be used. FIG. 9 shows a cross section of a tube that can be used. In the pipe 17, this metallic material 1
Reference numeral 9 is a rectangular tube made of a single material such as silver. The tube 17 is provided with a material 18 having high mechanical strength, for example, a silver alloy or stainless steel, on one surface side thereof by fusion bonding, coating, or the like. With such a structure, even a substance that causes a chemical change when brought into contact with a superconductor can be used as a metal material having high mechanical strength.

It should be considered that the embodiments disclosed herein are illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims described above, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[Brief description of the drawings]

FIG. 1 is a perspective view of an element wire used in the present invention, in which a stabilizer is filled with seven filaments (round wires) made of a superconductor.

FIG. 2 is a perspective view of a primary twisted wire used in the present invention, which is formed by twisting seven strands.

FIG. 3 is a perspective view of a secondary stranded wire formed by twisting 15 primary stranded wires used in the present invention.

FIG. 4 is a perspective view of a flat rectangular tube used in the present invention.

5 is a diagram schematically showing a tape-shaped oxide superconducting stranded wire that is spirally wound around a core material in Example 1 and Comparative Example 1. FIG.

FIG. 6 is a partial perspective view of a superconducting conductor obtained by winding a plurality of tape-shaped oxide superconducting twisted wires in a spiral shape around a core material according to the present invention.

FIG. 7 is a partial cross-sectional view of a superconducting conductor in which a plurality of tape-shaped oxide superconducting twisted wires are spirally wound around a core material according to the present invention.

FIG. 8 is a partial cross-sectional view of a superconducting conductor formed by winding a plurality of tape-shaped oxide superconducting twisted wires in two layers.

FIG. 9 is a cross-sectional view showing another specific example of a tube made of a metal material that can be used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Elementary wire 2 Stabilizing material 3 Round wire 4 Primary stranded wire 5 Tube 6a Surface made of Ag-Mn alloy 6b Surface made of silver 10 FRP pipe 11 Tape-shaped stranded wire material 12 1 layer conductor 13 2 layer conductor 14 FRP pipe 15 Insulation Layer 17 Tube 18 Material with high mechanical strength 19 Metal material

Claims (8)

[Claims] 1. A first stranded wire is prepared by twisting a plurality of strands of an oxide superconductor or a powder of a raw material thereof covered with a first metal selected from the group consisting of silver and silver alloys. A tape-shaped oxide superconducting stranded wire obtained by coating a second metal on a second stranded wire obtained by twisting a plurality of the stranded wires into a rectangular shape and heat-treating the second metal, The filaments of the oxide superconductor formed in the portions corresponding to the strands have a twisted shape according to the twisted structure of the portions corresponding to the first and second twisted wires, and The second metal is composed of materials having different mechanical strengths, and one of the pair of main surfaces of the tape-shaped oxide superconducting stranded wire is provided with one of the second metals, A metal material having a mechanical strength higher than that of the first metal is unevenly distributed. Characterized in that there, the tape-shaped oxide superconducting stranded wire. 2. The first metal is silver, the metal material having high mechanical strength of the second metal is a silver alloy, and the remaining portion is silver. The tape-shaped oxide superconducting stranded wire according to claim 1. 3. The tape-shaped oxide superconducting stranded wire according to claim 2, wherein the silver alloy, which is the metal material having high mechanical strength, is a silver-manganese alloy. 4. The tape-shaped oxide superconducting stranded wire according to claim 1, wherein the oxide superconductor is a bismuth-based oxide superconductor. 5. A plurality of the filaments are present in a portion corresponding to the strands, wherein the filaments are present.
5. The tape-shaped oxide superconducting stranded wire according to any one of 1. 6. A metal material having a plurality of tape-shaped oxide superconducting twisted wires according to claim 1 and having a core material having a mechanical strength higher than that of the first metal among the second metals. A superconducting conductor, characterized in that the superconducting conductor is wound in a spiral shape so that the portion of is placed outside. 7. The superconducting conductor according to claim 6, wherein the plurality of tape-shaped oxide superconducting twisted wires are wound around the core material in one layer. 8. The superconducting conductor according to claim 6, wherein the tape-shaped oxide superconducting stranded wire is wound around the core material at a bending strain rate of 0.2% or more.