JP3178245B2 - Manufacturing method of oxide superconducting wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an oxide superconducting wire, and more particularly, to an oxide superconducting wire in which the heat stress distribution of a wire is made uniform in a heat treatment step, and the straightness of the wire shape and the critical current density are improved. And a method for producing the same.

[0002]

2. Description of the Related Art Oxide superconductors have a high critical temperature and upper critical magnetic field, and exhibit superconducting properties even at temperatures and magnetic fields that metal superconductors cannot. Therefore, widespread application to superconducting equipment is expected. Have been.

On the other hand, recently, an oxide superconducting wire obtained by converting an oxide superconductor into a wire has been attracting attention as being applicable to a power cable, a high magnetic field magnet, and the like, and has been studied by many research institutions around the world. .

[0004] As an oxide superconducting wire, for example, as shown in FIG. 5 , there is an oxide superconductor 1 in which an oxide superconductor 1 is covered with a metal sheath 2. This oxide superconducting wire is formed by coating an oxide superconductor 1 with a metal sheath 2 made of silver, a silver alloy, or the like to form a metal composite conductor, and heat-treating the composite conductor at a predetermined temperature and drawing or rolling. It is manufactured by repeatedly performing plastic working .

[0005]

However, according to the conventional method for manufacturing an oxide superconducting wire, when a metal composite conductor of a metal and an oxide superconductor is subjected to a heat treatment, thermal distortion is caused due to a difference in thermal expansion coefficient between the two. It may occur unevenly in the longitudinal direction. As a result, there arise problems that the direct elongation of the wire shape is reduced and the superconductivity is affected.

It is therefore an object of the present invention, a uniform stress distribution of the wire in the heat treatment process, and a straight extension of the wire-shaped ultrasonic
The oxide superconducting wire capable of improving the conductivity characteristics
It is to provide a manufacturing method .

[0007]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a heat treatment in which a tension is applied to a metal composite conductor.
This is done by doing .

[0008] The tension may be applied to the metal composite conductor by fixing a predetermined portion of the metal composite conductor inside the heat treatment furnace and suspending weights at both ends. May be carried out by winding a metal composite conductor around a pipe arranged at a position above and suspending weights at both ends. Furthermore, the metal composite conductor is wound a plurality of times around a pipe fixed inside the heat treatment furnace so as to hang down by a predetermined length, and the pipe is hung on the hanging portion of the plurality of metal composite conductors and weights are added to both ends. Hanging may be performed.

Further, the tension is applied to the metal composite by winding the metal composite conductor a plurality of times around a pipe fixed inside the heat treatment furnace so as to hang down by a predetermined length. When the hanging portion is sandwiched between a pair of metal plates to converge a plurality of metal composite conductors, and the weight is hung on the hanging metal plate, the allowable tension of the metal composite conductor is increased. This can prevent breakage of the metal composite conductor due to stress during the heat treatment.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for manufacturing an oxide superconducting wire according to the present invention will be described in detail with reference to the accompanying drawings.

First, Bi1.84-Pb0.34-Sr
Powder of 2-Ca2-Cu3-based oxide superconductor is 8 m in outer diameter
m, an Ag pipe having an inner diameter of 6 mm is filled, and this is drawn to obtain a metal composite wire having an outer diameter of 3 mm.

Next, the metal composite wire obtained as described above is placed inside a heat treatment furnace as shown in FIG. In other words, alumina pipes 4A and 4B are respectively passed above and below a treatment 8 provided inside the heat treatment furnace, and as shown in FIG. 2, the alumina pipe 4A is fixed, and the alumina pipe 4B is floated. Then, the metal composite wire 3 is wound around the both sides a plurality of times over a predetermined width, and the weight 9 is hung on both ends thereof.

As shown in FIG. 3, the weight 9 is suspended from the pair of Ag-Pd alloy plates 7 with the end of the metal composite wire 3 sandwiched between the pair of Ag-Pd alloy plates 7. This is performed by passing a stainless steel bolt 5 and further fastening a nut 6 thereto.

Subsequently, the metal composite wire 3 to which the predetermined tension is applied is subjected to a heat treatment at a predetermined temperature, and then the metal composite wire is rolled into a tape shape.

Finally, the metal composite wire rolled into a tape shape is again subjected to a heat treatment in an arrangement as shown in FIG.
Rolling and heat treatment are performed to obtain a tape-shaped oxide superconducting wire.

When the heat treatment is performed while applying tension to the metal composite conductor as described above, the distortion due to the difference in thermal expansion caused by the heat treatment can be reduced, and as a result, the straightness with less lateral displacement, bending, and swelling is excellent. Oxide superconducting wire can be obtained.

Further, in the above embodiment, the upper metal pipe 4A is fixed, and the lower metal pipe 4B is hung by the metal composite wire 3, and the metal composite wire 3 is wound around both. , 4B together with jig stand 8
It may be fixed and wound.

FIG. 4 shows a second embodiment of the present invention. In this embodiment, the heat treatment of the metal composite wire 3 is performed in a state where the metal composite wires 3 are aggregated. That is, a plurality of layers of the metal composite wire 3 are wound around a bolt 11A inserted into the through hole 13A of the refractory brick heat treatment table 13, and this is sandwiched between a pair of Ag-Pd alloy plates 10 from both sides, and nuts are attached to the bolts 11A on both sides. By fastening 12, the metal composite wire 3 is formed into the aggregate 9, the bolt 11 </ b> B is passed through the lower part of the aggregate 9 hanging from the bolt 11, and similarly sandwiched from both sides by a pair of Ag-Pd alloy plates 16, and the two The nut 12 is fastened to the bolt 11B. And Ag
A round bar 15 is passed through a Pd alloy plate 16, a stainless steel weight 14 is hung on the round bar 15, and a heat treatment is performed with tension applied to the entire assembly 9.

In this embodiment, the allowable tension of the metal composite wire 3 can be increased, and breakage of the metal composite wire 3 due to stress during the heat treatment can be prevented.

[0020]

As described in the foregoing, according to the method of manufacturing the oxide superconducting wire of the present invention, since the heat treatment was to heat while applying a tension to the metal composite conductor, the stress distribution of the wire in the heat treatment step Oxide that can be made uniform, has good straightness of wire shape, and has little variation in superconductivity
A superconducting wire can be manufactured. In addition, when the metal composite conductors are aggregated to apply tension to a plurality of metal composite conductors, the allowable tension can be increased, and breakage of the metal composite conductor due to stress during heat treatment can be prevented.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is an explanatory view showing a suspended state of the weight of the metal composite wire.

FIG. 4 is an explanatory view showing a second embodiment of the present invention.

FIG. 5 is a sectional view showing an oxide superconducting wire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oxide superconductor 2 Metal sheath 3 Metal composite wire 4A, 4B Alumina pipe 5 Bolt 6 Nut 7 Ag-Pd alloy plate 8 Jig stand 9 Weight 10 Ag-Pd alloy plate 11A, 11B Bolt 12 Nut 13 Refractory brick heat treatment stand 14 Weight 15 Round bar 16 Ag-Pd alloy plate

Claims (5)

(57) [Claims] 1. An oxide superconducting wire having a predetermined cross-sectional shape by repeatedly covering a periphery of an oxide superconductor with a metal sheath to form a metal composite conductor, and subjecting the metal composite conductor to heat treatment and plastic working repeatedly. In the manufacturing method, the heat treatment is performed by applying tension to the metal composite conductor.
A method for producing an oxide superconducting wire, wherein the method is carried out by heating at a temperature of at least 1 mm. 2. The oxide superconducting wire according to claim 1, wherein the tension is applied to the metal composite conductor by fixing a predetermined portion of the metal composite conductor and suspending weights at both ends inside the heat treatment furnace. Manufacturing method. 3. The method according to claim 1, wherein the tension application to the metal composite conductor is performed by winding the metal composite conductor around pipes arranged above and below inside the heat treatment furnace and suspending weights at both ends. Of manufacturing superconducting wire. 4. A method of applying tension to the metal composite conductor, wherein the metal composite conductor is wound a plurality of times around a pipe fixed inside the heat treatment furnace so as to hang down by a predetermined length, and a plurality of the metal composite conductors are wound. 2. The method for producing an oxide superconducting wire according to claim 1, wherein the method is carried out by suspending a pipe at a suspended portion of the composite conductor and suspending weights at both ends. 5. The method of applying tension to the metal composite conductor is performed by winding the metal composite conductor a plurality of times around a pipe fixed inside the heat treatment furnace so as to hang down by a predetermined length. The wound portion and the suspended portion are each pressed by a pair of metal plates to converge the plurality of metal composite conductors, and a single weight is hung on the metal plate of the suspended portion. Item 10. A method for producing an oxide superconducting wire according to Item 1.