JPH07201238A - Manufacture of superconductive wire material and coil - Google Patents

Abstract

PURPOSE:To provide a superconductive wire material having excellent superconductivity characteristics of which characteristics are equalized, and which can be applied to manufacture large-sized conductors or coils by moving an Nb/Al composite wire continuously, while a room temperature is increased to a specified temperature, holding it, and then cooling it to the room temperature. CONSTITUTION:An Nb/Al composite wire comprising Nb metal or Nb alloy and Al metal or Al alloy is sent through a heating furnace to be heated from a room temperature to a specified temperature. This heated composite wire is further sent through the heating furnace to be held at the specified temperature. This composite wire is then sent through a cooling part to be cooled from the specified temperature to the room temperature. Above heating, specified temperature holding, and cooling part passing processes are performed while moving this composite wire continuously, thereby a desired superconductive wire material can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Nb ₃ Al superconducting wire, a Nb ₃ Al superconducting stranded wire and a method for producing a coil, and particularly to a superconducting magnet which can be used for nuclear fusion and other applications. The present invention relates to a method for producing a Nb ₃ Al-based superconducting wire, a Nb ₃ Al-based superconducting stranded wire, and a coil as a superconducting material for high magnetic fields.

[0002]

2. Description of the Related Art Nb ₃ Al-based superconducting materials have good critical current characteristics and strain resistance characteristics in high magnetic fields, and therefore, they are used as fusion reactors that receive a large magnetic force in high magnetic fields and as superconducting materials for power storage. Is expected. Nb which is this intermetallic compound
₃ Al has poor workability and is difficult to be thinned like alloy superconducting materials such as Nb-Ti. Therefore, as a method for obtaining an Nb ₃ Al-based superconducting wire, generally, there is a method in which a metal containing Nb and a metal containing Al are compounded and then wire drawing is performed to obtain a fine wire, which is finally heat-treated. Has been.

Nb ₃ Al is stable only at a high temperature of 1600 ° C. or higher in the binary system of Nb-Al. Therefore, in order to generate Nb ₃ Al at a temperature lower than this, it was necessary to thin each layer of Nb and Al to several tens of nm or less by using the jelly roll method or the like.

[0004]

However, Nb / Al formed by combining a metal containing Nb and a metal containing Al
Since the composite material has poor workability, the filament is deformed unevenly due to thinning. Therefore, the Nb ₃ Al-based superconducting wire obtained by heat treatment of this composite material is
A sufficiently high critical current density could not be obtained.

In addition, since a compound type superconducting material such as Nb ₃ Al cannot avoid deterioration of superconducting characteristics due to strain such as bending, it is coiled before heat treatment. The so-called Wind and React method is adopted. However, as the coil becomes larger, it is difficult to perform uniform heat treatment on the whole.

Further, in order to improve superconducting properties, heat treatment is performed at a temperature as high as possible for a short time to generate Nb ₃ Al having fine crystal grains close to the stoichiometric composition and rapidly cooling to room temperature. It is desirable to maintain this by doing so. However, it has been difficult to apply such heat treatment and cooling to a large coil.

An object of this invention to solve such conventional problems, superior in superconducting properties, characteristics uniform, it is also applicable to the production of large conductor or coil, Nb ₃ Al superconducting wire, Nb ₃ An object is to provide a method for manufacturing an Al-based superconducting stranded wire and a coil.

[0008]

According to the invention of claim 1, N
The method of manufacturing a b ₃ Al-based superconducting wire is made of Nb metal or N
Nb / A consisting of b alloy and Al metal or Al alloy
l a step of passing the composite wire through a heating furnace to raise the temperature from room temperature to a predetermined temperature; a step of further passing the heated Nb / Al composite wire at a predetermined temperature through a heating furnace; The step of further passing the Nb / Al composite wire held at the temperature of 5 to a cooling part to cool it from the predetermined temperature to room temperature, raising the temperature, holding the temperature at the predetermined temperature, and cooling the part. Is characterized by being performed while continuously moving the Nb / Al composite wire.

The cooling portion means a portion for cooling the Nb / Al composite wire from a predetermined temperature to room temperature.

According to a second aspect of the present invention, in the method for producing an Nb ₃ Al-based superconducting wire according to the first aspect of the invention, the time for raising the temperature from room temperature to a predetermined temperature is within 2 minutes.

According to a third aspect of the present invention, in the method for producing an Nb ₃ Al superconducting wire according to the first aspect of the invention, the predetermined temperature is 900 ° C. or higher, and the predetermined temperature is maintained for 20 minutes or less. .

A method for manufacturing an Nb ₃ Al superconducting wire according to a fourth aspect of the present invention is the method according to the first aspect, wherein the predetermined temperature is 800 ° C. or higher, and the material is passed through a cooling unit to cool from the predetermined temperature to room temperature. The cooling time to 800 ° C. is 5 minutes or less.

According to a fifth aspect of the present invention, in the method of manufacturing an Nb ₃ Al superconducting wire according to the first aspect of the present invention, the Nb / Al composite wire that has passed through the cooling section is heated at a temperature lower than a predetermined temperature for a long time. The method further comprises steps.

According to a sixth aspect of the present invention, there is provided a method for producing an Nb ₃ Al-based superconducting wire according to the first aspect of the present invention, wherein the Nb / Al composite wire that has passed through the cooling section is heated at a temperature of 800 ° C. or lower for 10 hours or more. Further comprising the step of:

According to a seventh aspect of the present invention, there is provided a method for producing an Nb ₃ Al-based superconducting wire according to any one of the first to sixth aspects, wherein the Nb / Al composite wire is composed of copper or copper alloy for stabilization. Has been done.

According to an eighth aspect of the present invention, in the method for producing a Nb ₃ Al superconducting wire according to any one of the first to seventh aspects, the Nb / Al composite wire is produced by the jelly roll method.

According to a ninth aspect of the present invention, there is provided a method of manufacturing an Nb ₃ Al-based superconducting wire according to the eighth aspect of the present invention.
The thickness of the Nb layer in the filament of the Al / Al composite wire is 50
It is 0 nm or less.

According to a tenth aspect of the present invention, there is provided a method for manufacturing a Nb ₃ Al superconducting stranded wire, comprising: an Nb metal or an Nb alloy;
A step of passing an Nb / Al composite twisted wire formed by twisting a plurality of Nb / Al composite wires made of a metal or an Al alloy through a heating furnace to raise the temperature from room temperature to a predetermined temperature; / Al composite stranded wire is further passed through a heating furnace to be kept at a predetermined temperature, and Nb / Al composite stranded wire kept at a predetermined temperature is further passed through a cooling unit to reach a room temperature from a predetermined temperature. Cooling step to Nb /, and the step of raising the temperature, the step of maintaining a predetermined temperature, and the step of passing through the cooling unit are Nb /
It is characterized in that it is carried out while continuously moving the Al composite stranded wire.

According to the eleventh aspect of the present invention, there is provided a method for producing a Nb ₃ Al-based superconducting stranded wire, which comprises Nb metal or Nb alloy and Al.
A step of passing an Nb / Al composite wire made of a metal or an Al alloy through a heating furnace to raise the temperature from room temperature to a predetermined temperature; and further passing the heated Nb / Al composite wire through a heating furnace. A step of maintaining the temperature at a predetermined temperature, a step of further passing the Nb / Al composite wire held at the predetermined temperature through a cooling unit to a room temperature from a predetermined temperature, and Nb / Al passing through the cooling unit. A step of collecting a plurality of composite wires and twisting the composite wires is performed. The steps of raising the temperature, maintaining the temperature at a predetermined temperature, and passing the composite wire through the cooling unit are performed by continuously moving the Nb / Al composite wires. It is characterized by being performed while.

According to the twelfth aspect of the present invention, in the method for producing a Nb ₃ Al superconducting twisted wire according to the tenth or eleventh aspect of the invention, the time for raising the temperature from room temperature to a predetermined temperature is within 2 minutes.

According to a thirteenth aspect of the present invention, in the method for producing a Nb ₃ Al superconducting twisted wire according to the tenth or eleventh aspect of the present invention, the predetermined temperature is 900 ° C. or higher, and the predetermined temperature is maintained for 20 minutes. Within.

According to a fourteenth aspect of the present invention, in the method for producing a Nb ₃ Al superconducting twisted wire according to the tenth or eleventh aspect of the present invention, the predetermined temperature is 800 ° C. or higher, and the predetermined temperature is passed through the cooling section. 800 ℃ while cooling to room temperature
The cooling time is up to 5 minutes.

According to a fifteenth aspect of the present invention, there is provided a method for producing a Nb ₃ Al superconducting twisted wire according to the invention of the tenth or eleventh aspect, wherein the Nb / Al composite wire or the Nb / Al composite twisted wire that has passed through the cooling section is used. The method further comprises the step of heating at a temperature lower than a predetermined temperature for a long time.

According to a sixteenth aspect of the present invention, there is provided a method for producing a Nb ₃ Al superconducting twisted wire according to the tenth or eleventh aspect of the invention, wherein the Nb / Al composite wire or the Nb / Al composite wire passed through the cooling section
The method further comprises the step of heating the / Al composite stranded wire at a temperature of 800 ° C. or lower for 10 hours or more.

According to a seventeenth aspect of the present invention, there is provided a method of manufacturing an Nb ₃ Al superconducting coil, which comprises: an Nb metal or an Nb alloy;
l Nb / Al composite wire consisting of metal or Al alloy,
Passing a heating furnace to raise the temperature from room temperature to a predetermined temperature, passing the heated Nb / Al composite wire further to a heating furnace and holding it at a predetermined temperature, and holding it at a predetermined temperature The Nb / Al composite wire that has been passed through a cooling unit to cool it from a predetermined temperature to room temperature; and a step of processing the Nb / Al composite wire that has passed the cooling unit into a coil having a predetermined shape. And a step of raising the temperature, a step of maintaining a predetermined temperature,
The step of passing through the cooling part is characterized by being performed while continuously moving the Nb / Al composite wire.

According to the eighteenth aspect of the present invention, there is provided a method of manufacturing an Nb ₃ Al superconducting coil, which comprises: an Nb metal or an Nb alloy;
a step of passing a Nb / Al composite twisted wire formed by twisting a plurality of Nb / Al composite wires made of a metal or an Al alloy through a heating furnace to raise the temperature from room temperature to a predetermined temperature; The step of further passing the Nb / Al composite stranded wire at a predetermined temperature by passing through a heating furnace, and further passing the Nb / Al composite stranded wire held at the predetermined temperature through a cooling unit to increase the temperature from the predetermined temperature. A step of cooling to room temperature, a step of processing the Nb / Al composite stranded wire that has passed through the cooling part into a coil having a predetermined shape, a step of raising the temperature, and a step of maintaining the temperature at a predetermined temperature;
The step of passing through the cooling section is characterized in that it is performed while continuously moving the Nb / Al composite stranded wire.

According to a nineteenth aspect of the present invention, there is provided a method of manufacturing an Nb ₃ Al-based superconducting coil, comprising: an Nb metal or an Nb alloy;
l Nb / Al composite wire consisting of metal or Al alloy,
Passing a heating furnace to raise the temperature from room temperature to a predetermined temperature, passing the heated Nb / Al composite wire further to a heating furnace and holding it at a predetermined temperature, and holding it at a predetermined temperature The cooled Nb / Al composite wire through a cooling unit to cool it from a predetermined temperature to room temperature; a step of collecting and twisting a plurality of Nb / Al composite wires that have passed through the cooling unit; N passed through the section
a step of processing an Nb / Al composite stranded wire formed by twisting b / Al composite wires into a coil having a predetermined shape, raising the temperature, maintaining the temperature at a predetermined temperature, and cooling the part. The step of passing is Nb / A
It is characterized in that it is performed while continuously moving the l composite line.

According to a twentieth aspect of the present invention, in the method for producing an Nb ₃ Al superconducting coil according to any one of the seventeenth to nineteenth aspects, the time for raising the temperature from room temperature to a predetermined temperature is within 2 minutes.

A manufacturing method of an Nb ₃ Al superconducting coil according to a twenty-first aspect of the present invention is the method according to any one of the seventeenth to nineteenth aspects, wherein the predetermined temperature is 900 ° C. or higher, and the time for holding the predetermined temperature is Within 20 minutes.

The method for producing a Nb ₃ Al superconducting coil according to the invention of claim 22, in any one of the claims 17 to 19, the predetermined temperature is 800 ° C. or higher, predetermined by passing through a cooling section While cooling from temperature to room temperature,
The time for cooling to 800 ° C. is within 5 minutes.

The method of manufacturing an Nb ₃ Al-based superconducting coil according to the twenty- _{third aspect} of the present invention is the method according to any one of the seventeenth to nineteenth aspects of the invention, wherein the Nb / Al composite wire or the Nb / Al composite twisted wire is passed through the cooling section. Is further provided at a temperature lower than a predetermined temperature for a long time.

A method of manufacturing an Nb ₃ Al superconducting coil according to a twenty-fourth aspect of the present invention is the method according to any one of the seventeenth to nineteenth aspects of the invention, wherein the Nb / Al composite wire or the Nb / Al composite stranded wire is passed through a cooling part. At a temperature below 800 ° C
The method further comprises the step of heating for a time or more.

[0033]

Nb according to the present invention₃ Al-based superconducting wire, Nb
₃ Al-based superconducting stranded wire and Nb ₃ Al-based superconducting coil
The manufacturing method is Nb / Al composite wire or Nb / Al composite twist
Pass the wire through a heating furnace to raise it to a specified temperature.
A step and a step of maintaining this temperature for a predetermined time,
The steps of cooling from a predetermined temperature to room temperature are continuous.
Done. Therefore, compared with the case of conventional batch heat treatment
Then, the temperature is raised in a shorter time and the heat treatment is performed at a high temperature for a short time.
It is possible to perform cooling and to cool in a shorter time.

By reacting Nb and Al at a higher temperature, Nb ₃ Al having a stoichiometric composition is produced.

In the conventional batch heat treatment, it took at least several hours to raise the temperature to a high temperature. Therefore before Nb ₃ Al near stoichiometric composition reaches a high temperature which results in a stable, this compositional shift at lower temperatures low with large superconducting properties Nb ₃ Al is generated. In the present invention, Nb / Al composite wire or Nb / A can be used in a very short time.
l Since the temperature of the composite stranded wire can be raised to such a high temperature, N which has a large composition deviation in the temperature raising step.
Nb ₃ A that suppresses the formation of b ₃ Al and has a stoichiometric composition
l can be produced at a high rate.

When the heat treatment is performed at a high temperature, the diffusion rate of Nb and Al increases, so that Nb ₃ Al is produced faster and the crystal grows. According to the present invention, the cooling can be performed in a shorter time as compared with the case of the conventional batch heat treatment. As a result, the heat treatment in the temperature range effective for producing the Nb ₃ Al crystal can be completed in a short time, and the enlargement of the Nb ₃ Al crystal can be suppressed. High Nb ₃ Al is obtained. Further, the composition of the Nb ₃ Al phase generated at a high temperature and close to the stoichiometric composition is maintained at room temperature without shifting in the cooling process.

Further, since the wire is continuously passed through each part for the purpose of temperature rising, holding at high temperature, and quenching step, the heat of the wire due to the temperature distribution in the furnace which has been a problem in the conventional batch heat treatment. Variations in history are eliminated, and uniform characteristics can be obtained over the entire length of the wire.

Further, according to the present invention, the time for raising the temperature of the wire from room temperature to a predetermined temperature is preferably within 2 minutes. If the time required to raise the temperature of the wire to a predetermined temperature becomes long to some extent, enough energy to generate the Nb ₃ Al phase is generated even if the Nb ₃ Al phase passes through the temperature raising process.
It will be given to the b / Al composite wire. However, the Nb ₃ Al phase generated at such a low temperature has a composition in which Al is insufficient as compared with the Nb ₃ Al phase generated at a predetermined temperature, and the critical temperature and the critical magnetic field are low. Also, N
When the b ₃ Al phase is generated during the temperature rising process and the time until it reaches the temperature of the soaking zone becomes longer, the composition ratio of the Nb ₃ Al phase generated at a low temperature is improved to some extent. The crystals are enlarged, and as a result, the grain boundaries that are pinning centers are reduced and the critical current density is lowered. Therefore, it is desirable to shorten the time for raising the temperature from the room temperature to a predetermined temperature as much as possible to suppress the generation of the Nb ₃ Al phase during the temperature rise. Specifically, this purpose can be satisfied by setting the time for raising the temperature from room temperature to a predetermined temperature to within 2 minutes.

Further, according to the present invention, the predetermined temperature is 900 ° C. or higher, and the time for maintaining the predetermined temperature is 10
It is preferably within minutes. At least 90 is required to produce Nb ₃ Al having a close to stoichiometric composition and a high critical magnetic field.
A temperature of 0 ° C or higher is required. Further, in order to suppress the enlargement of crystal grains and obtain a high critical current density, the heat treatment time is preferably 20 minutes or less.

Further, according to the present invention, it is preferable that the cooling time from the predetermined temperature to 800 ° C. is within 5 minutes. In the case of the high temperature heat treatment, which is a feature of the present invention, the diffusion rate of Nb and Al increases, so that Nb ₃ Al is produced faster and crystals grow. In order to suppress the enlargement of Nb ₃ Al crystals and increase the density of pinning centers, it is necessary to finish the heat treatment in a temperature range effective for producing Nb ₃ Al crystals in a short time. Also, if the cooling process becomes too long, deviations from the composition produced at high temperatures will occur. Specifically, this purpose can be achieved by setting the cooling time from the predetermined temperature to 800 ° C. within 5 minutes.

Further, according to the present invention, it is preferable that after passing through the cooling section, heat treatment is further performed at a temperature lower than a predetermined temperature for a long time. Nb ₃ Al, which is a feature of the present invention by heat treatment at high temperature for a short time, is characterized in that it is close to the stoichiometric composition, but since it is a heat treatment for a short time, the regularity of the atomic arrangement in the crystal is not sufficient, It is considered that non-uniform strain remains in the crystal lattice. Therefore, even if the composition is excellent, high superconducting properties cannot be obtained. Further, by performing heat treatment at a temperature lower than a predetermined temperature for a long time, the critical temperature and the critical magnetic field originally possessed by Nb ₃ Al generated at a high temperature can be obtained.

Further, according to the present invention, it is desirable that the heat treatment further performed after passing through the cooling section is 800 ° C. or lower and 10 hours or longer.

Furthermore, according to the present invention, the Nb / Al composite wire may be composited with copper or a copper alloy. In this case, the predetermined temperature is preferably as high as possible within the range where the matrix does not melt.

Further, according to the present invention, the Nb / Al composite wire can be the Nb / Al composite wire produced by the jelly roll method, and even if the thickness of the Nb layer in the filament is about 500 nm. , High characteristics can be obtained.

[0045]

【Example】

[Example 1] First, according to a jelly roll method, an Nb sheet and an Al sheet were wrapped around a copper rod material, and the rolled material was inserted into a copper pipe, followed by wire drawing.
It was molded so that the cross section was hexagonal.

FIG. 1 is a sectional view showing the structure of the hexagonal segment thus manufactured.

Referring to FIG. 1, this hexagonal segment is
A Nb sheet 2 and an Al sheet 3 are alternately wound around a copper matrix 1 arranged at the center, and a copper matrix 4 is formed around the Nb sheet 2 and the Al sheet 3. The copper matrices 1 and 4 serve as a stabilizing material. Further, a portion in which the Nb sheet 2 and the Al sheet 3 are alternately wound and wound, and a copper matrix 1 arranged at the center and the outer periphery,
Diffusion barriers 5 and 6 are formed at the boundaries between the diffusion barriers 5 and 4 by winding only the Nb sheet 2 respectively.

Next, 520 hexagonal segments configured as described above are collected and inserted into a copper pipe, and subjected to a wire drawing process by extrusion, a drawing process, a twisting process, and a molding process, and then Cu / Nb having a cross section of 1.29 mmφ. / Al composite multifilamentary wire was produced.

FIG. 2 shows the Cu / N thus obtained.
It is drawing which shows roughly the structure of a b / Al composite multifilamentary wire.

Referring to FIG. 2, this composite multifilamentary wire is constructed by embedding a large number of filaments 8 in a stabilizing material 7 made of copper. In addition, a stabilizing material 9 made of copper is arranged at the center of each filament 8.

The composite multifilamentary wire thus obtained is subjected to a heat treatment according to the present invention to obtain Nb ₃
An Al superconducting multifilamentary wire was produced. Hereinafter, this heat treatment step will be described in detail with reference to the drawings.

FIG. 3 is a sectional view showing a heat treatment apparatus used in an example heat treatment process according to the present invention.

Referring to FIG. 3, this heat treatment apparatus passes through tubular electric furnace 10, supply reel 13 for feeding composite multifilamentary wire 12 into cooling tank 11, tubular electric furnace 10 and cooling tank 11. Obtained Nb ₃ Al superconducting wire 1
And a take-up reel 15 for taking up 4.

First, Cu / N obtained as described above
The b / Al composite multifilamentary wire 12 was passed through the tubular electric furnace 10. When an arbitrary point of the composite multi-core wire 12 is A. 30 seconds after A entered the tubular electric furnace 10, the temperature of the A was raised from room temperature to 900 ° C., and then the heater and the composite multicore wire 12 of the tubular electric furnace 12 were kept so that the temperature was kept at 900 ° C. for a predetermined time. The feed rate was controlled. Subsequently, the heated wire rod is passed through the cooling tank 11 for 9 seconds in 30 seconds.
After being rapidly cooled from 00 ° C. to 800 ° C. and further cooled to room temperature, it was wound on a take-up reel 15. During the above heating and cooling, the tubular electric furnace 10 and the cooling tank 11 were placed in a nitrogen atmosphere and the composite multifilamentary wire 12 was passed through.

The time during which the wire was kept at a temperature of 900 ° C. in the furnace was set to 1 minute to 30 minutes.

The wire thus obtained was further heat-treated at 750 ° C. for 50 hours in a vacuum electric furnace to obtain a Nb ₃ Al superconducting wire.

[Example 2] Cu / Nb described in Example 1
The / Al composite multifilamentary wire was passed through the tubular electric furnace 10 and the cooling tank 11 in a nitrogen atmosphere in the same manner as in Example 1. In addition,
The heating conditions were changed as follows. That is,
By passing through the tubular electric furnace 10 to the composite multifilamentary wire, the temperature is raised to 1050 ° C. in 30 seconds, and this temperature is maintained for a predetermined time, and then it is passed through a cooling tank to obtain 800 in 30 seconds. It was rapidly cooled to ℃ and further cooled to room temperature.

The time during which the wire was kept at a temperature of 1050 ° C. in the furnace was set to 1 minute to 10 minutes.

The wire thus obtained was heat-treated at 750 ° C. for 50 hours in a vacuum electric furnace in the same manner as in Example 1 to obtain a Nb ₃ Al superconducting wire.

[Example 3] Cu / Nb described in Example 1
The / Al composite multifilamentary wire was passed through the tubular electric furnace 10 and the cooling tank 11 in a nitrogen atmosphere in the same manner as in Example 1. In addition,
The heating conditions were changed as follows. That is,
By passing through the tubular electric furnace 10 to the composite multifilamentary wire, the temperature is raised to 1050 ° C. in a predetermined time, this temperature is maintained for 1 minute, and then the material is passed through a cooling tank for 30 seconds. It was rapidly cooled to 800 ° C and further cooled to room temperature.

The time for heating the wire rod from room temperature to 1050 ° C. was set to 0.5 minutes to 30 minutes.

The wire thus obtained was further heat-treated in a vacuum electric furnace at 750 ° C. for 50 hours in the same manner as in Example 1 to obtain an Nb ₃ Al superconducting wire.

Example 4 Cu / Nb described in Example 1
The / Al composite multifilamentary wire was passed through the tubular electric furnace 10 and the cooling tank 11 in a nitrogen atmosphere in the same manner as in Example 1. In addition,
The heating conditions were changed as follows. That is,
By passing through the tubular electric furnace 10 to the composite multifilamentary wire, the temperature is raised to 1050 ° C. in 30 seconds, this temperature is maintained for 1 minute, and then the cooling water is passed through the tubular electric furnace 10 for 800 seconds in a predetermined time. It was rapidly cooled to ℃ and further cooled to room temperature.

The time for the wire rod to be rapidly cooled from 1050 ° C. to 800 ° C. was set to 0.5 minutes to 15 minutes.

The wire thus obtained was further heat-treated in a vacuum electric furnace at 750 ° C. for 50 hours in the same manner as in Example 1 to obtain an Nb ₃ Al superconducting wire.

Example 5 Cu / Nb described in Example 1
The / Al composite multifilamentary wire was passed through the tubular electric furnace 10 and the cooling tank 11 in a nitrogen atmosphere in the same manner as in Example 1. In addition,
The heating conditions were changed as follows. That is,
By passing through the tubular electric furnace 10 to the composite multifilamentary wire, the temperature is raised to 1050 ° C. in 30 seconds, and this temperature is maintained for 1 minute, and then, passing through a cooling tank, 800 seconds in 30 seconds. It was rapidly cooled to ℃ and further cooled to room temperature.

The wire thus obtained was further heat-treated under a predetermined condition in a vacuum electric furnace in the same manner as in Example 1 to obtain a Nb ₃ Al superconducting wire.

The predetermined conditions were as follows. 90
0 ° C-10 hours, 850 ° C-10 hours, 800 ° C-10
Hours, 750 ° C-10 hours, 750 ° C-50 hours.

[Example 6] Cu / Nb described in Example 1
The / Al composite multifilamentary wire was passed through a tubular electric furnace and a cooling tank in a nitrogen atmosphere in the same manner as in Example 1. The heating conditions were the same as in Example 1. That is, the composite multifilamentary wire is heated to 900 ° C. for 30 seconds,
This temperature was maintained for 5 minutes, and then passed through a cooling bath to cool to 800 ° C. in 30 seconds and further to room temperature. Then, twist this wire with a pitch of 30 mm.
I twisted three pieces together.

The wire thus obtained was further heat-treated at 750 ° C. for 50 hours in a vacuum electric furnace in the same manner as in Example 1 to obtain a Nb ₃ Al superconducting wire.

Example 7 Cu / Nb described in Example 1
The / Al composite multifilamentary wire was passed through a tubular electric furnace and a cooling tank in a nitrogen atmosphere in the same manner as in Example 1. The heating conditions were the same as in Example 2. That is, the temperature of the composite multifilamentary wire is raised to 1050 ° C. in 30 seconds,
By holding this temperature for 1 minute and then passing it through a cooling bath, it was rapidly cooled to 800 ° C. in 30 seconds and further cooled to room temperature. After that, twist this wire with a pitch of 30 m.
3 pieces were twisted together by m.

The wire thus obtained was further heat-treated at 750 ° C. for 50 hours in a vacuum electric furnace in the same manner as in Example 1 to obtain an Nb ₃ Al superconducting wire.

[Embodiment 8] Cu / Nb described in Embodiment 1
Three / Al composite multifilamentary wires were twisted together at a twisting pitch of 30 mm to prepare a composite twisted wire. This composite stranded wire was passed through the tubular electric furnace 10 in a nitrogen atmosphere in the same manner as in Example 1. The heating conditions were the same as in Example 1. That is, by passing the twisted wire through the tubular electric furnace 10, the temperature is raised to 900 ° C. in 30 seconds, the temperature is maintained for 60 seconds, and then the strand is passed through a cooling tank so that It was rapidly cooled to 800 ° C and further cooled to room temperature.

The wire thus obtained was further heat-treated at 750 ° C. for 50 hours in a vacuum electric furnace in the same manner as in Example 1 to obtain a Nb ₃ Al superconducting wire.

[Example 9] Cu / Nb described in Example 1
Three / Al composite multifilamentary wires were twisted together at a twisting pitch of 30 mm to prepare a composite twisted wire. This composite stranded wire was passed through the tubular electric furnace 10 in a nitrogen atmosphere in the same manner as in Example 1. The heating conditions were the same as in Example 1. That is, by passing the twisted wire through the tubular electric furnace 10, the temperature is raised to 1050 ° C. in 30 seconds, the temperature is maintained for 60 seconds, and then the wire is passed through a cooling tank, so that It was rapidly cooled to 800 ° C and further cooled to room temperature.

The wire thus obtained was further heat-treated in a vacuum electric furnace at 750 ° C. for 50 hours in the same manner as in Example 1 to obtain an Nb ₃ Al superconducting wire.

[Example 10] Cu / N described in Example 1
The b / Al composite multifilamentary wire was passed through the tubular electric furnace 10 and the cooling tank 11 in the nitrogen atmosphere in the same manner as in Example 1. The heating conditions were the same as in Example 2. That is, by passing the tubular multi-core wire through the tubular electric furnace 10,
The temperature was raised to 1050 ° C. in 0 seconds, maintained at this temperature for 60 seconds, and then passed through a cooling bath to rapidly cool to 800 ° C. in 30 seconds, and further cooled to room temperature.

For the wire rod thus obtained, 1
Coiled into a circular shape with a diameter of 50 mm, and further heat-treated in a vacuum electric furnace at 750 ° C. for 50 hours to obtain Nb ₃ Al.
I got a superconducting coil.

[Embodiment 11] Cu / N described in Embodiment 1
Three b / Al composite multi-core wires were twisted together at a twist pitch of 30 mm to produce a composite twisted wire. This composite stranded wire was used in Example 1
In the same manner as above, the mixture was passed through a tubular electric furnace and a cooling tank in a nitrogen atmosphere. The heating conditions were the same as in Example 2. That is, it takes 1 for 30 seconds for a composite multicore wire.
The temperature is raised to 050 ° C and kept at this temperature for 1 minute, and then passed through a cooling bath to obtain 800 ° C for 30 seconds.
To room temperature and further to room temperature. Then, three of these wire rods were twisted at a twist pitch of 30 mm.

The composite stranded wire thus obtained was coiled into a circular shape having a diameter of 150 mm, and further heat treated at 750 ° C. for 50 hours in a vacuum electric furnace to obtain Nb.
₃ Al superconducting coil was obtained.

[Example 12] Cu / N described in Example 1
The b / Al composite multifilamentary wire was passed through a tubular electric furnace and a cooling tank in a nitrogen atmosphere in the same manner as in Example 1. The heating conditions were the same as in Example 2. That is, the composite multifilamentary wire is heated to 1050 ° C. in 30 seconds, kept at this temperature for 1 minute, and then passed through a cooling tank to be cooled to 800 ° C. in 30 seconds, and further at room temperature. Cooled down. Then, twist this wire with a pitch of 3
Three strands of 0 mm were twisted together.

The thus-obtained composite stranded wire was coiled into a circular shape having a diameter of 150 mm, further heat-treated at 750 ° C. for 50 hours in a vacuum electric furnace, and Nb
₃ Al superconducting coil was obtained.

[Example 13] Cu / N described in Example 1
The b / Al composite multifilamentary wire was passed through the tubular electric furnace 10 and the cooling tank 11 in the nitrogen atmosphere in the same manner as in Example 1. The heating conditions were the same as in Example 2. That is, by passing the tubular multi-core wire through the tubular electric furnace 10,
By raising the temperature to 1050 ° C. in 30 seconds, maintaining this temperature for 60 seconds, and then passing it through a cooling bath,
It was rapidly cooled to 800 ° C. in seconds, and further cooled to room temperature.

The wire thus obtained was further heat-treated at 750 ° C. for 50 hours in a vacuum electric furnace, and then coiled into a circular shape having a diameter of 150 mm, and N
A b ₃ Al superconducting coil was obtained.

[Comparative Example] Cu / Nb / described in Example 1
Three Al composite multifilamentary wires were twisted together at a twisting pitch of 30 mm to produce a composite twisted wire. This composite stranded wire was heat-treated at 800 ° C. for 10 hours in a vacuum electric furnace to obtain Nb ₃
An Al superconducting stranded wire was obtained.

[Evaluation] With respect to the Nb ₃ Al superconducting wire rods, Nb ₃ Al superconducting stranded wires and coils of Examples 1 to 13 and Comparative Example described above, the critical current density (4.2K, 4.2K,
12T) and the upper critical magnetic field (4.2K) were measured. The results are shown in Table 1 and FIGS.

[0087]

[Table 1]

[0088]

As described above, according to the present invention, Nb ₃ Al-based superconducting wire having uniform characteristics over the entire length and having a high critical current density and an upper critical magnetic field, Nb _{3 is used.}
It is possible to manufacture Al-based superconducting stranded wires and coils.

Further, according to the present invention, Nb-
Since high characteristics can be obtained without refining the Al diffusion pair, the processing rate of the wire can be reduced. Therefore,
Since no breakage occurs, it is advantageous for lengthening,
And productivity is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration of a hexagonal segment formed according to a jelly roll method.

FIG. 2 is a cross-sectional view schematically showing the structure of a Cu / Nb / Al composite multifilamentary wire.

FIG. 3 is a cross-sectional view showing a heat treatment apparatus used in an example heat treatment process according to the present invention.

FIG. 4 is a diagram showing the relationship between holding time and critical current density.

FIG. 5 is a diagram showing a relationship between a holding time and an upper critical magnetic field.

FIG. 6 is a diagram showing a relationship between temperature rising time and critical current density.

FIG. 7 is a diagram showing the relationship between cooling time and critical current density.

[Explanation of symbols]

1 Copper Matrix 2 Nb Sheet 3 Al Sheet 4 Copper Matrix 7 Stabilizer 8 Filament 9 Stabilizer 10 Tubular Electric Furnace 11 Cooling Tank 12 Cu / Nb / Al Composite Multicore Wire 14 Nb ₃ Al Superconducting Wire

Claims (24)

[Claims] 1. A step of passing an Nb / Al composite wire made of Nb metal or Nb alloy and Al metal or Al alloy through a heating furnace to raise the temperature from room temperature to a predetermined temperature, the temperature being raised. A step of further passing the Nb / Al composite wire through the heating furnace to hold it at the predetermined temperature; and a step of passing the Nb / Al composite wire held at the predetermined temperature further through the cooling part to the predetermined temperature. To a room temperature, the step of raising the temperature, the step of maintaining the predetermined temperature, and the step of passing through the cooling unit while continuously moving the Nb / Al composite wire. A method of manufacturing an Nb ₃ Al-based superconducting wire, which is performed. 2. The method for producing an Nb ₃ Al-based superconducting wire according to claim 1, wherein the time for raising the temperature from the room temperature to a predetermined temperature is within 2 minutes. 3. The predetermined temperature is 900 ° C. or higher,
The method for producing an Nb ₃ Al-based superconducting wire according to claim 1, wherein the time for maintaining the predetermined temperature is within 20 minutes. 4. The predetermined temperature is 800 ° C. or higher, and the time for cooling to 800 ° C. is 5 minutes or less among the cooling from the predetermined temperature to room temperature through the cooling unit. 1. The method for producing the Nb ₃ Al-based superconducting wire according to 1. 5. The Nb / Al passed through the cooling section
The composite wire is heated at a temperature lower than the specified temperature for a long time.
The Nb according to claim 1, further comprising a step. ₃ Al-based
Manufacturing method of conductive wire. 6. The Nb / Al passed through the cooling section
The method for producing an Nb ₃ Al-based superconducting wire according to claim 1, further comprising the step of heating the composite wire at a temperature of 800 ° C. or lower for 10 hours or more. 7. The method for producing an Nb ₃ Al superconducting wire according to claim 1, wherein the Nb / Al composite wire is compounded with copper or a copper alloy for stabilization. 8. The method for producing an Nb ₃ Al superconducting wire according to claim 1, wherein the Nb / Al composite wire is produced by a jelly roll method. 9. The method for producing an Nb ₃ Al-based superconducting wire according to claim 8, wherein the thickness of the Nb layer in the filament of the Nb / Al composite wire is 500 nm or less. 10. An Nb / Al composite twisted wire obtained by twisting a plurality of Nb / Al composite wires made of Nb metal or Nb alloy and Al metal or Al alloy is passed through a heating furnace to reach a predetermined temperature from room temperature. A step of raising the temperature to a temperature, a step of further passing the raised Nb / Al composite twisted wire at the predetermined temperature by passing through a heating furnace, and a step of holding the Nb / Al composite twisted wire at the predetermined temperature. A stranded wire, further comprising the step of passing through a cooling unit to cool from the predetermined temperature to room temperature, the step of raising the temperature, the step of maintaining the predetermined temperature, the step of passing the cooling unit. Is carried out while continuously moving the Nb / Al composite stranded wire, the method for producing a Nb ₃ Al superconducting stranded wire. 11. A step of passing an Nb / Al composite wire made of Nb metal or Nb alloy and Al metal or Al alloy through a heating furnace to raise the temperature from room temperature to a predetermined temperature, the temperature being raised. A step of further passing the Nb / Al composite wire through the heating furnace to hold it at the predetermined temperature; and a step of passing the Nb / Al composite wire held at the predetermined temperature further through the cooling part to the predetermined temperature. To a room temperature, a step of collecting and twisting a plurality of the Nb / Al composite wires that have passed through the cooling section, the step of raising the temperature, and the step of maintaining the predetermined temperature. The step of passing the Nb ₃ Al superconducting stranded wire is characterized in that the step of passing through the cooling unit is performed while continuously moving the Nb / Al composite wire. 12. The method for producing a Nb ₃ Al superconducting stranded wire according to claim 10, wherein the time for raising the temperature from the room temperature to a predetermined temperature is within 2 minutes. 13. The method for producing a Nb ₃ Al-based superconducting stranded wire according to claim 10, wherein the predetermined temperature is 900 ° C. or higher, and the time for holding the predetermined temperature is 20 minutes or less. 14. The predetermined temperature is 800 ° C. or higher, and the time for cooling to 800 ° C. is 5 minutes or less among the cooling from the predetermined temperature to room temperature by passing through the cooling unit. 10. The method for producing a Nb ₃ Al-based superconducting stranded wire according to 10 or 11. 15. The Nb / A passed through the cooling section
The method for producing a Nb ₃ Al-based superconducting stranded wire according to claim 10 or 11, further comprising the step of heating the l composite wire or the Nb / Al composite stranded wire at a temperature lower than the predetermined temperature for a long time. 16. The Nb / A passed through the cooling section
further comprising the step of heating the l composite wire or the Nb / Al composite stranded wire at a temperature of 800 ° C. or lower for 10 hours or more,
The method for producing a Nb ₃ Al-based superconducting stranded wire according to claim 10 or 11. 17. A step of passing an Nb / Al composite wire made of Nb metal or Nb alloy and Al metal or Al alloy through a heating furnace to raise the temperature from room temperature to a predetermined temperature, and the temperature is raised. A step of further passing the Nb / Al composite wire through the heating furnace to hold it at the predetermined temperature; and a step of passing the Nb / Al composite wire held at the predetermined temperature further through the cooling part to the predetermined temperature. To a room temperature, a step of processing the Nb / Al composite wire that has passed through the cooling part into a coil having a predetermined shape, the step of raising the temperature, and the holding at the predetermined temperature. a step of the step of passing the cooling unit may be performed while continuously moving the Nb / Al composite wire, the production of Nb ₃ Al superconducting coil Law. 18. A Nb / Al composite twisted wire obtained by twisting a plurality of Nb / Al composite wires made of Nb metal or Nb alloy and Al metal or Al alloy is passed through a heating furnace to reach a predetermined temperature from room temperature. A step of raising the temperature to a temperature, a step of further passing the raised Nb / Al composite twisted wire at the predetermined temperature by passing through a heating furnace, and a step of holding the Nb / Al composite twisted wire at the predetermined temperature. Cooling the stranded wire from a predetermined temperature to room temperature by further passing it through a cooling unit; and processing the Nb / Al composite stranded wire that has passed through the cooling unit into a coil having a predetermined shape. The step of raising the temperature, the step of maintaining the predetermined temperature, and the step of passing through the cooling unit are performed while continuously moving the Nb / Al composite stranded wire. Wherein the method for manufacturing a Nb ₃ Al superconducting coils. 19. A step of passing an Nb / Al composite wire made of Nb metal or Nb alloy and Al metal or Al alloy through a heating furnace to raise the temperature from room temperature to a predetermined temperature, the temperature being raised. A step of further passing the Nb / Al composite wire through the heating furnace to hold it at the predetermined temperature; and a step of passing the Nb / Al composite wire held at the predetermined temperature further through the cooling part to the predetermined temperature. To the room temperature, a step of collecting and twisting a plurality of the Nb / Al composite wires that have passed through the cooling section, and a step of twisting the Nb / Al composite wires that have passed through the cooling section Processing the Nb / Al composite stranded wire into a coil having a predetermined shape, raising the temperature, maintaining the temperature at the predetermined temperature, and passing through the cooling unit. Step A, characterized in that it is performed while continuously moving the Nb / Al composite wire, Nb ₃ manufacturing method of Al-based superconducting coils. 20. The method for manufacturing an Nb ₃ Al superconducting coil according to claim 17, wherein the time for raising the temperature from the room temperature to a predetermined temperature is within 2 minutes. 21. The manufacture of the Nb ₃ Al superconducting coil according to claim 17, wherein the predetermined temperature is 900 ° C. or higher, and the time for holding the predetermined temperature is 20 minutes or less. Method. 22. The predetermined temperature is 800 ° C. or higher, and the cooling time to 800 ° C. is 5 minutes or less while the cooling unit is cooled to the room temperature from the predetermined temperature. Nb ₃ Al according to any one of 17 to 19
-Based superconducting coil manufacturing method. 23. The Nb / A passed through the cooling section.
l a composite wire or Nb / Al composite stranded wire, further comprising the step of heating longer than at low predetermined temperature, method for producing Nb ₃ Al superconducting coil according to any one of claims 17 to 19. 24. The Nb / A passed through the cooling section
further comprising the step of heating the l composite wire or the Nb / Al composite stranded wire at a temperature of 800 ° C. or lower for 10 hours or more,
A method for manufacturing the Nb ₃ Al-based superconducting coil according to claim 17.