JPS62267050A - Production of in-situ rod for fiber dispersion type superconducting wire - Google Patents

Abstract

PURPOSE:To obtain an in-situ rod standing in line as dispersing dendritic fibers toward length direction by flowing out the prescribed molten alloy metal from a discharging hole of a crucible bottom and cooling while forming to the rod- shape by rolls having plural grooves. CONSTITUTION:Cu-Nb-Sn alloy or Cu-V-Ga alloy having the prescribed compositions is melt, to produce the in-situ rod 20 for fiber dispersion type superconducting wire. The necessary molten alloy metal Y, which is heated and melted in the crucible 13 under nonoxidizing atmosphere by an induction coil 12 is flowed down continuously from the discharging hole 11 and formed to rod-shape at between the grooving rolls 15, 15 and cooled to obtain the desired rod 20. This rod 20 has the structure which fibers 21 having dendrite of Nb or V is stood in line as dispersing in the matrix of Cu alloy toward length direction of the matrix. In this way, the in-situ rod for fiber dispersion type superconducting wire having excellent workability is produced.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention is applicable to manufacturing fiber-dispersed superconducting wires used in toroidal magnets for nuclear fusion reactors, magnets for particle accelerators, magnets for superconducting generators, etc. The present invention relates to a method of manufacturing the in-situ rod to be used.

"Prior art" Cu Nb Sna base alloy with predetermined components, or
When a Cu-V-Gaa base alloy is produced, a structure in which Nb or V dendrite crystals are dispersed in the copper alloy matrix is present, and an ingot with high workability can be obtained.

When this ingot is strongly processed by wire drawing, etc., as shown in Fig. 6, an ingot is formed in which a large number of filaments 1 of dendrite crystals made of Nb or V are arranged in a dispersed manner in close contact with the copper alloy matrix 2. Zyturrod 3 can be obtained, and this manufacturing method is conventionally known as the so-called in-situ method.

Then, the in-situ rod 3 is subjected to diameter reduction processing to create an in-situ wire 5 of a desired diameter with the filament 4 disposed inside the base 2, and later, by performing a diffusion heat treatment on this in-situ wire 5, the internal Sn and By reacting Nb or ■ with Ga, Nb3Sn or V s
It has been attempted to produce a fiber-dispersed superconducting wire by producing a Ga superconducting intermetallic compound.

``Problem to be Solved by the Invention'' However, when manufacturing a superconducting wire by the method described above, the fibers L generated inside the in-situ rod 3 are oriented in any direction as shown in FIG. In the case of the in-situ wire 5 produced by performing a diameter reduction process to obtain a desired diameter, the diameter reduction process results in a filament 4 with a complex cross-sectional shape in which the fibers l are wavy in a ribbon shape, as shown in FIG. However, due to the deformation, the following problems occurred.

First, in the case of an in-situ wire 5 in which ribbon-shaped filaments 4 are arranged in a complicated manner as shown in FIG. There is a problem that 4 acts as a diffusion barrier for these elements. For this reason, a superconducting intermetallic compound may be non-uniformly generated inside the base 2, causing a problem of anisotropy in the superconducting properties of the manufactured superconducting wire.

Therefore, conventionally, in order to make the cross-sectional shape of the ribbon-like filament 4 relatively circular,
A method has been implemented in which heat treatment is performed by heating at a temperature of .degree. C. for several tens to hundreds of hours.

However, when heat treatment is performed at temperatures as high as 500 to 1000°C for a long time as described above, the metal elements constituting the base 2 and the metal elements constituting the filament 4 react, resulting in a compound with poor workability. There was a problem in that a layer was formed and the workability after the heat treatment deteriorated. In addition,
As mentioned above, performing the heat treatment at high temperature for a long time itself causes a large loss of energy and time, and there is a problem of making the manufacturing process of the superconducting wire complicated and lossy.

In addition, in the method of manufacturing an in-situ rod by subjecting a ternary alloy ingot to wire drawing, there is a limit to the length of the in-situ rod that can be manufactured due to restrictions caused by the size of the ingot. There was a problem in that it was difficult to manufacture rods and it was impossible to manufacture long superconducting wires.

The present invention has been made in view of the above-mentioned problems, and therefore it is possible to omit the heat treatment for circularizing the fibers, which was necessary in the past, to simplify the heat treatment, and to continuously form long fibers in-situ. rods can be made,
A further object of the present invention is to provide a method for manufacturing an in-situ rod for a fiber-dispersed superconducting wire, in which the size of the dendrite fibers produced inside the in-situ rod can be set to a desired diameter.

"Means for Solving the Problems" In order to solve the problems described above, the present invention provides a structure in which at least one metal element out of two or more metal elements constituting a superconducting intermetallic compound constitutes a base. The molten alloy consisting of metal elements is continuously taken out from the outlet at the bottom of the crucible.
The fibers of the dendritic crystals made of the at least one metal element are formed inside the rod-shaped base by a plurality of grooved rolls provided below the outlet and cooled while being formed into a rod shape along the length direction of the base. It is formed by

"Action" The or of dendritic crystals along the length of the in situ rod.
Since rt can be generated, it is possible to make the dendrite fiber into a circular shape even after diameter reduction processing, and the heat treatment for making it circular can be omitted. Furthermore, by continuously flowing out the molten metal from the crucible, long in-situ rods can be easily produced, and by adjusting the speed at which the molten metal is taken up by the rolls, the diameter of the arborescent crystal fibers can be adjusted to a desired size. It can be adjusted to

``Embodiment'' FIGS. 1 to 5 show an embodiment of the present invention, and the method described based on FIGS.
It is possible to manufacture the in-situ rod 20 shown in FIG. A conductive wire T of type Nb5SnH3 can be manufactured.

To manufacture the Onn woven fiber-dispersed Nb3Sn superconducting wire T, first, an in-situ rod 20 shown in FIG. 1 or FIG. 5(A) is manufactured.

To manufacture this in-situ rod 20, first, it has a molten metal outlet 11 at the bottom and an induction coil 12 at the outer periphery.
and prepare Naruppo 13.

The crucible 13 is housed in an airtight casing, which is not shown in the drawings, and the inside of this airtight casing is maintained in a non-oxidizing atmosphere such as an inert gas atmosphere.

Next, a large number of small ingots 14 of Cu and Nb are put into the crucible 13 and heated by the induction coil 12, so that the inside of the crucible I3 is filled with carbon.
Fill the u-Sn alloy molten metal Y. At this time, the ratio of the amount of Cu and Nb to be added is slightly higher than the content ratio of Cu and Nb in the composition of the in-situ rod to be manufactured.
Small lumps of Cu are blended so that the u ratio is high. The reason why a large number of small Cu lumps are mixed is that the melting temperatures of Cu and Nb are significantly different, and at the melting temperature of Nb, part of the Cu vaporizes and the content of Cu in the molten metal Y decreases.
This is to allow the molten metal to contain a proper amount of Cu in consideration of this vaporized content. Here, the Lupo I3 is made of graphite, thoria, beryllia, or the like. The reason for this is that the Nb introduced into Lupo 13 is an active metal, and is intended to prevent Nb from reacting with the elements constituting Lupo I3.

Once the small pieces of Sn and Cu put into the crucible 13 have been sufficiently melted, the molten RAY is continuously poured out from the outlet 11 of the crucible 13 and cooled by water-cooled rolls 15°15. The in-situ rod 20 is manufactured by processing it into a shape.

As shown in FIG. 3, the rolls 15 and 15 are grooved with semicircular grooves 15a formed on their outer peripheral surfaces, and are located directly below the outlet 11 of the Luppo 13. A pair of rolls are arranged with their outer peripheral surfaces facing each other.
, 15, the semi-solidified molten metal flowing out from the outlet of the crucible 13 is passed through and rolled, thereby making it possible to produce the in-situ rod 20. The rate at which the molten metal flows out from the crucible 13 is, for example, 0.5 m/min, and the cooling rate is set at 500°C/sec. Further, in this embodiment, a pair of rolls 15 are provided below the crucible 13, but more rolls may be provided to perform cooling and molding in stages.

By setting the above-mentioned take-up speed and cooling rate and causing the molten metal to flow out of the crucible 13, an in-situ rod 20 having Nb dendritic fibers 21 arranged and densely arranged in the longitudinal direction as shown in FIG. 4 is formed. can be created. Note that the diameter of the fibers 21 can be increased if the speed at which the molten metal is withdrawn from the crucible 13 by the rolls 15.15 is slightly slower than the above-mentioned speed. Therefore, by adjusting the take-up speed, it is possible to manufacture the in-situ rod 20 having a desired diameter of fibers (C21).

Next, the in-situ rod 20 is subjected to an intermediate annealing treatment and its diameter is reduced to form an in-situ line of 20° as shown in FIG. 5(B). Here, this in-situ line 20
Since the fibers 2I are aligned in the longitudinal direction, the fibers 21 do not have a wavy ribbon shape but have a shape close to a circular cross section. Therefore, during the diffusion heat treatment to be performed later, Sn can pass between the fibers 21 and be easily diffused.

Next, a Sn plating layer 23 is formed on the surface of the in-situ wire 20' by electroplating to produce a plated composite wire 24 shown in FIG. 1(C).

Next, a plurality of the plated composite wires 24 are assembled, and a Cu-Sn alloy containing a low concentration of Sn or a C
As shown in FIG. 1(D), this pipe 25 is further covered with a diffusion barrier tube 26 made of Nb or Ta as shown in FIG. 1(E). Further, a stabilizing vibrator 27 made of Cu or AI is attached to one bud 26 to produce a composite wire 28.

Then, the composite wire 28 is subjected to diameter reduction processing to produce a superconducting strand 29 shown in FIG. 1(F) having approximately the same diameter as the superconducting wire T to be manufactured.

Here, in each of the diameter reduction steps described above, processing is performed in a state in which no Nb5Sn superconducting intermetallic compound is generated inside, but since the in-situ rod 20 originally has good workability, problems such as wire breakage may occur. The diameter can be reduced without causing any problems.

Next, the superconducting wire 29 is subjected to diffusion heat treatment (600
The Nb fibers 21 and S
The Sn of the n-plated layer 23 is reacted to generate Nb*Sn, and the fiber-dispersed Nb3Sn superconducting wire T shown in FIG. 1(G) is manufactured. During the diffusion heat treatment, the fibers in the base w, 21
Since the cross section is circular, Sn can be diffused without any problem.

By the way, in the above embodiment, an example in which the present invention was applied to the production of Nb3Sn superconducting wire was explained, but V, G
Of course, the present invention may be applied to other compound-based superconducting wires such as a. In addition, when producing V3Ga superconducting wire, an in-situ rod is produced from Cu-V alloy molten metal, and this is used to sequentially produce a composite rod and further a composite wire, and the composite wire is Ga-plated to form a plated composite wire. A V3Ga superconducting wire can be manufactured by preparing a wire, and if necessary, collecting a large number of plated composite wires and subjecting them to diffusion heat treatment. In addition, in compound-based superconducting intermetallic compounds, T
i, Tas Hf% I n, 5iSAt, Zr
It is known that the critical current characteristics can be improved by adding a third element such as. Therefore, an in-situ rod may be manufactured by adding the third element to the melt 't&Y in the crucible 13 in advance, and a superconducting wire may be manufactured using this in-situ rod.

"Manufacturing Example 1" In order to produce an in-situ rod made of a CuNb alloy containing 30 wt% Nb, Cu small lumps and Nb small lumps with an outer diameter of 5 to 6 III m were mixed with a composition richer in Cu by 4 to 5% than the above composition. The molten metal was continuously poured into a crucible inside an induction coil to avoid melting. The crucible is made of graphite, thoria, beryllia, or the like. After sufficiently melting the small lumps, the melt was taken out from the outlet at the bottom and rolled with a water-cooled grooved roll to an outer diameter of 2.
0mm.

An in situ rod with a length of 10 m was fabricated. At this time, the take-up speed was set to 05 m/min, and the cooling rate was set to 500°C.
/second.

In the in situ rod manufactured as described above, N
The length of the primary arm of “dendritic crystal fiber 2” in b is approximately 30μ.
m, and it was confirmed that each V and vertebra 2I were aligned in the length direction of the in situ rod.

This in-situ rod is subjected to extrusion processing and wire drawing processing,
An in-situ wire with a straight i of 10.1 mm was prepared, and the internal N
When the shape of the b filament was observed, it was confirmed that the cross-sectional shape of the filament was almost circular. And the diameter of this filament is about 40
There were 0 people.

"Effects of the Invention" As explained above, according to the present invention, the following effects are achieved.

(1) In order to create an in-situ rod by flowing out the molten metal from the outlet of the melt and rolling it with rolls, we created an in-situ rod that grows fibers of arborescent crystals that are distributed and aligned in the length direction. Be able to do it. Therefore, when the in-situ rod is subjected to diameter reduction processing and strong processing, in order to avoid deforming the dendrite fibers into a ribbon shape, the cross-sectional shape is circular, and the elements are diffused during the diffusion heat treatment. The effects of making in-situ rods using easily shaped fibers are as follows.

(2) Furthermore, since the direction of the fibers of the dendritic crystals is aligned with the length direction of the in-situ rod, the fibers do not deform into a ribbon shape even after diameter reduction processing, but have a circular cross-sectional shape. First, heat treatment for circularization, which was necessary in the past, is no longer necessary, and the heat treatment process can be simplified accordingly. Furthermore, since the heat treatment can be omitted,
++ Elements and fibers that make up the base that could not be avoided in the past
It is possible to eliminate the reaction of elements that form W. Therefore, a compound layer with poor processability is no longer generated, and processability is improved.

(3) Since the molten metal can be continuously flowed out from the outlet of the crucible, there is an effect that a long in-situ lot can be manufactured easily. Therefore, there is an effect that a long superconducting wire can be manufactured.

(4) Is the melt coming from the outlet? In order to set the cooling rate of the molten metal to a desired value by setting the take-up speed when the molten metal flows out and is taken up to a roll, an in-situ rod having fibers of a desired diameter can be set. It has the effect of being manufacturable.

[Brief explanation of drawings]

1 to 5 show an embodiment of the present invention, in which FIG. 1 is a cross-sectional view showing the manufacturing state of an in-situ rod, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. The figure is a schematic diagram showing the shape of the roll, FIG. 4 is a vertical cross-sectional view of the in-situ rod, and FIGS. Figure 5 (A
) is a cross-sectional view of the in-situ rod, FIG. 5(B) is a cross-sectional view showing the in-situ line, FIG. 5(C) is a cross-sectional view showing the plated composite wire, and FIG. 5(D) is a cross-sectional view showing the in-situ line. A cross-sectional view showing the assembled state inserted into the inside of the pipe,
Figure 5 (E) is a cross-sectional view showing the state in which the tube body and stabilizing pipe are covered on the outside of the pipe, Figure 5 (P) is a cross-sectional view of the superconducting wire, and Figure 5 (G) is the superconducting wire. The cross-sectional views of the line, FIGS. 6 and 7, are for explaining the conventional method, so FIG. 6 is a cross-sectional view of the in-situ lot, and FIG. 7 is an enlarged cross-sectional view of the in-situ line. 11... Outlet, 12... Induction coil, 13... Crucible, 15... Roll,
20...In-situ rod, 21...Fiber, 20°...In-situ wire, T...Superconducting wire.

Claims (1)

[Claims] The superconducting intermetallic compound is made of a rod-shaped base that has fibers of arborescent crystals made of at least one metal element among two or more metal elements constituting the superconducting intermetallic compound, and the interior of the base is treated by diffusion heat treatment. A method for producing an in-situ rod for a fiber-dispersed superconducting wire in which the metal elements diffuse and react to produce a fibrous superconducting intermetallic compound, the method comprising: two or more metal elements constituting the superconducting intermetallic compound; A molten alloy consisting of at least one metal element and a metal element constituting the base is continuously taken out from an outlet at the bottom of the crucible and formed into a rod shape by a plurality of grooved rolls provided below the outlet. An in-situ rod for a fiber-dispersed superconducting wire, characterized in that the in-situ rod for a fiber-dispersed superconducting wire is cooled while cooling to form dendritic crystal fibers made of the at least one metal element inside the rod-shaped base along the length direction of the base. Production method.