JPH0831368B2 - Superconducting wire manufacturing method - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method of manufacturing a superconducting coil used in a magnet for generating a strong magnetic field, and in particular to a wind-and-wind method in which high-temperature heat treatment is performed after winding to generate a superconductor.・ The present invention relates to a method for manufacturing a superconducting coil by the reactor method.

[Background of the Invention]

Since compound superconducting wires such as Nb ₃ Sn and (NbTi) ₃ Sn have excellent superconducting wire properties such as critical temperature, critical magnetic field, and critical current, they have recently been used as windings for magnets for generating strong magnetic fields. The incarnation has become more frequent.

In order to manufacture the above Nb ₃ Sn compound-based superconducting wire, generally, Sn plating is applied on the Nb core and copper is further coated around the Nb core, or the Nb core is embedded in a Cu-Sn alloy to form a composite wire. After that, a diffusion heat treatment for producing a Nb ₃ Sn superconducting compound is performed.The time for performing this heat treatment is to wind the superconducting wire around the coil into a predetermined shape and then perform the diffusion heat treatment. There is a method of winding a superconducting wire after diffusion heat treatment into a coil to form a magnet having a predetermined shape.

However, compound-based superconducting wires such as Nb ₃ Sn after diffusion heat treatment are not preferable because cracks are likely to occur in the superconducting layer due to molding strain during coil forming, or superconducting properties are likely to deteriorate. And, React method is preferable.

When manufacturing a superconducting wire ring by this method, a method for insulating the outer circumference of the superconducting wire and the exposed portion of the wire is disclosed in JP-A-55-138209 and JP-A-57-103306, respectively. As is known, for example, a method of performing insulation by a glass fiber layer containing an insulating material having a softening temperature equal to or higher than the diffusion heat treatment temperature in an appropriate ratio is known,
This was a rational method because the adjacent superconducting wires could be fixed together via this insulating layer simultaneously with the diffusion heat treatment of the superconducting wires.

However, in the above-mentioned conventional method, there is a problem in the fixing ability between the insulating layer and the wire ring during handling such as transportation from normal temperature to extremely low temperature or during operation. That is, at room temperature, the inorganic material forming the insulating layer is liable to deteriorate in wear resistance and work deterioration due to work, and when operating at low temperature, due to a difference in thermal expansion between the insulating layer and the conductor. There is a possibility that the adhesive surface may easily come off, and in some cases, cracking may occur even due to impact during handling.

[Object of the Invention]

The present invention has been made in view of the above points, and an object thereof is to provide a method for manufacturing a strong superconducting wire ring that does not generate strain in a superconducting wire due to diffusion heat treatment and has little deformation. is there.

[Outline of Invention]

The present invention attaches a compound-based superconducting wire to a metal case, forms an insulating layer mainly composed of mica around the metal case, and winds the metal case in a coil shape while maintaining the shape by a jig to form a superconducting wire ring. After forming, this superconducting wire ring is subjected to diffusion heat treatment while maintaining the shape with the jig equipped with a deformation prevention fixing seat, after which the superconducting wire ring is removed from the jig, grounded, and insulated. The superconducting wire ring is assembled into a jig that has been subjected to a peeling process and integrated, and resin injection is performed to form by heating and fixing, and finally this superconducting wire ring is taken out of the jig and used in a cryopump of a fusion device. It is designed to be incorporated.

According to the above-described manufacturing method, the insulating layer of the superconducting conductor can be integrated, and strain does not occur in the diffusion heat-treated superconducting wire. Therefore, a superconducting wire ring having high electrical and mechanical reliability can be manufactured. You can

Example of Invention

An embodiment of a method for manufacturing a superconducting coil according to the present invention will be described below with reference to the drawings.

1 to 11 show one embodiment of the present invention. Using the superconducting wire single wire 1 made of Nb ₃ Sn before the diffusion heat treatment shown in FIG. 1, it is stranded as shown in FIG. 2 to form a composite multifilament wire 1a. As shown in the figure, it is molded into a substantially rectangular cross section 1b. The composite multifilamentary wire 1b molded in this rectangular cross section is enclosed and integrated in a stainless steel pipe 2 called a jacket having a substantially rectangular cross section as shown in FIG. This stainless steel pipe 2 is about 1.5mm thick and 20mm thick
It is a hollow prism having a square shape and is made of a material that can eliminate the processing strain during winding at the diffusion heat treatment temperature. As shown in FIG. 5, a mica tape 3 on the inner layer and a glass tape 4 on the outer layer are wound around the outer circumference of the stainless steel pipe 2 twice by 1/2 lap winding. It is desirable to use the glass tape 4 that has been treated with silane to improve the adhesiveness with the epoxy resin. Further, the glass tape 4 may be omitted and only the mica tape 3 may be wound. A wire ring 5 made of a stainless steel pipe 2 in which the tapes 3 and 4 are wound and the strand wire 1b is enclosed is attached to a temporary winding core 7 to which a winding reference plate 6 is attached as shown in FIG. Wind up. After the winding is completed, the conductor 5 is restrained by the deformation preventing fixing seat 8 so that the coil is not thermally deformed by the diffusion heat treatment in the next step, and is held so that the shape of the coil is the same as the final finished shape. Keep it.

As described above, the wire ring 5 held by the winding reference plate 6 is mounted on the diffusion heat treatment support frame 9 as shown in FIG. 7, and placed in the center of the furnace for diffusion to diffuse the heat. Perform processing. The temperature of this diffusion heat treatment is to reduce thermal deformation.
600 to 700 ℃. The strain-removed and diffusion-heat treated wire ring 5 is removed from the winding reference plate 6, and the outer circumference of the wire ring 5 is further grounded by a glass tape 10 as shown in FIG. In order to facilitate the removal of the wire ring 5 after curing and molding, the temporary winding core 7 is replaced with the winding core 11 which has been treated with a release agent, and is inserted, and further the winding reference plate 6 and the deformation preventing fixing seat 8 Similarly, the reference plate 12 and the fixed seat 13 which have been treated with a release agent are replaced.

Next, after treating the wire ring 5 with a curing accelerator, a resin such as an epoxy resin is injected, and as shown in FIG.
The molding pressure plate 14 for preventing the deformation is abutted and fixed on the wire ring 5 and then cured by heating. The integral fixing process using the resin may be performed under substantially the same steps and conditions as the known insulating layer forming work. Next, as shown in FIG. 10, the wire ring 5 is removed from the winding core 11, the winding reference plate 12, and the deformation prevention fixing seat 13, and as shown in FIG. 11, both ends of the composite multi-core wire 1b of the wire ring 5 are removed. The superconducting wire wheel is completed by exposing and exposing the mouth.

The superconducting wire ring configured as described above is shown in Figs.
As shown in the figure, for example, a spacer 14 is provided in two stages, and a glass tape 15 is further wound around the outer periphery of the spacer 14 and incorporated into a cryopump of a nuclear fusion device for use.

According to the present embodiment configured as described above, since the conductor is provided with the portion capable of removing strain by heat treatment, the residual strain of the wire ring after diffusion heat treatment is small and deformation can be prevented,
It is possible to prevent characteristic deterioration. In addition, since heat-resistant mica is used as the main insulating material, the diffusion heat treatment
It does not cause thermal decomposition or collapse even at 0 to 700 ° C, has a withstand voltage that is several times that of conventional inorganic insulating materials, and has high insulation properties. Furthermore, a ground insulating layer is provided immediately before the resin is injected into the wire ring, and then a resin such as epoxy is collectively injected and heat-molded, so that the superconducting wire and the insulating layer can be completely integrated, and high rigidity, Since it has scratch resistance and brittleness resistance, it is possible to improve the reliability of shock resistance when handling the wire. Moreover, since the mica pieces which are cheaper than the conventionally used expensive inorganic insulating materials such as quartz glass are used, the cost can be reduced.

[Advantages of the Invention] As described above, according to the present invention, the core wire constituting the superconducting wire ring is enclosed in a metal case made of a material capable of removing processing strain at the time of winding at diffusion heat treatment temperature, and a mica is mainly provided between the windings. Insulating layer and thermal deformation absorption layer by layers are provided,
This is a manufacturing method in which the wire ring is fixed and held during the diffusion heat treatment after the winding is completed to prevent the entire deformation, and after the diffusion heat treatment is earth-insulated and resin injection molding is performed integrally, distortion occurs in the diffusion heat treatment superconducting wire. It is possible to manufacture a wire ring which has little deformation and has excellent electric and mechanical properties, good ground insulation of the whole wire ring, and excellent superconducting properties.

[Brief description of drawings]

1 to 11 are process drawings showing an embodiment of a method for manufacturing a superconducting wire according to the present invention, FIG. 12 is a front view showing an example of a superconducting wire manufactured according to the present invention, and FIG. 12 Figure A-A
It is sectional drawing. 1 ... Superconducting wire, 2 ... Stainless steel pipe, 3 ... Masker tape, 4,10,15 ... Glass tape, 5 ... Wire ring, 6,1
2 ... Winding reference plate, 7,11 ... Winding core, 8,13 ... Deformation prevention fixing seat.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-57713 (JP, A) JP-A-57-164505 (JP, A) Actual development Sho-55-149909 (JP, U) Actual public Sho-58- 52569 (JP, Y2)

Claims (2)

[Claims] 1. A method of manufacturing a superconducting wire wheel, comprising a step of winding a compound superconducting wire into a coil and then performing a diffusion heat treatment, the step of mounting the superconducting wire on a metal case, and mainly comprising mica on the outer periphery of the metal case. A step of forming an insulating layer for forming the insulating layer, a step of winding the metal case on which the insulating layer is formed and on which the superconducting wire is attached while winding the metal case in a coil shape while holding a shape by a jig, and preventing deformation of the superconducting wire ring. The process of diffusion heat treatment while maintaining the shape with a jig equipped with a fixing seat, the superconducting wire ring after this heat treatment is removed from the jig, ground insulation is applied, and after this insulation, it is assembled into the peeled jig. A method of manufacturing a superconducting wire wheel, comprising: a step of injecting and integrating, resin injection, and heat molding; and a step of taking out the molded superconducting wire wheel from the jig. 2. The method for producing a superconducting wire according to claim 1, wherein the compound superconducting wire is made of Nb ₃ Sn.