JP2006004870A - MANUFACTURING METHOD OF Nb3Al GROUP SUPERCONDUCTING WIRE ROD - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an Nb<SB>3</SB>Al group superconducting wire rod capable of using a core material of a small diameter, shortening rolling time and improving a filling rate of laminated material by applying a method of winding the laminated material from which, a lengthwise laminated material can be obtained. <P>SOLUTION: In manufacturing the Nb<SB>3</SB>Al system superconducting wire rod by the Jelly-roll method, an Nb-containing sheet made of Nb or Nb-base alloy and an Al-containing sheet made of Al or an Al alloy are overlapped on each other and rolled on a core material, which then is turned into a roll-shaped laminated matter with the core material pulled off, into which, one or a plurality of roll-shaped laminated matters likewise made are fitted, one inside another, to make up a primary superconducting wire rod. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for producing a Nb ₃ Sn superconducting wire by Geri roll method, in particular a superconducting energy storage, nuclear fusion coil, useful Nb ₃ Al system as a material such as a high magnetic field generating superconducting magnet The present invention relates to a useful method for producing a superconducting wire.

In superconducting wires used in the field of high magnetic field applications, in addition to high critical current density under high magnetic fields, the development of materials with high strain resistance that can withstand mechanical strain stress caused by electromagnetic force acting on superconducting wires Is desired. Under these circumstances, Nb ₃ Al-based intermetallic compounds are expected to be used in superconducting magnets used for fusion devices, power storage devices, physical properties research, etc., because of their high strain resistance in high magnetic fields. .

As a method for producing an Nb ₃ Al-based intermetallic compound, (A) a rapid heating and quenching method in which a wire is heated and held at a high temperature of 1600 ° C. or higher and then rapidly cooled to obtain an Nb ₃ Al phase; (B) Nb and Al There is known a method (diffusion method) or the like in which Nb ₃ Al phase is obtained by a diffusion reaction between Nb and Al by performing a heat treatment at a temperature of 1000 ° C. or less in a state in which is finely dispersed.

Among the above methods, the Nb ₃ Al phase when the rapid thermal quenching method is applied can stably have a compound having a stoichiometric composition of Nb: Al = 3: 1, and has extremely high superconducting characteristics (under a high magnetic field). High critical current density). However, under a high temperature condition of 1600 ° C. or higher, a stabilizing metal such as Cu or Al that is arranged to enhance the stability of the superconducting wire is melted, so that there is a problem that it is difficult to combine the stabilizing metals. Yes, it has become a big obstacle for practical use.

On the other hand, when the diffusion method is applied, since the heat treatment is performed at a temperature of 1000 ° C. or lower, the composite of the stabilized metal is relatively easy. However, since the treatment temperature is low, the stoichiometric composition (Nb: A compound deviating from Al = 3: 1) is likely to be produced, and the superconducting properties are often inferior. However, in this method, when the diffusion distance into Nb is short, it is known that a good quality Nb ₃ Al phase is generated even at a processing temperature of 1000 ° C. or less. Development of Nb ₃ Al-based superconducting wires is underway.

Various manufacturing methods such as a powder metallurgy method, a tube method, a clad chip extrusion method, and a jellyroll method have been proposed as a method for manufacturing an Nb ₃ Al-based superconducting wire that shortens the diffusion distance of Al to Nb. Of these, the jellyroll method is considered to be the most suitable method for practical use because it is relatively easy to increase the length of the superconducting wire and lengthen it.

  In this jellyroll method, an Nb-containing sheet made of Nb or an Nb alloy and an Al-containing sheet made of Al or an Al alloy are overlapped around a core material made of copper or a copper alloy (or Nb or Nb alloy). After being inserted into a pipe made of Cu or a Cu alloy, a primary superconducting wire is produced by reducing the diameter and bundled together with a Cu wire having the same cross-sectional shape. A wire rod having a multifilament filament is manufactured by inserting into a pipe made of the above and reducing the diameter.

  By the way, in a superconducting wire, it is necessary to make the filament diameter as small as possible in order to prevent AC loss due to fluctuations in current and external magnetic field. There is a problem that it occurs frequently and a long wire cannot be obtained. For this reason, in order to reduce the filament diameter while suppressing the processing rate to such an extent that disconnection does not occur, it is necessary to make the diameter of the roll-shaped laminate around which the raw material sheet is wound as small as possible. Moreover, in order not to deteriorate the characteristic per cross-sectional area of the wire, it is necessary to reduce the diameter of the core material in accordance with the diameter of the roll-shaped laminate. Furthermore, in order to increase the yield, it is necessary to increase the length of the roll laminate.

  That is, in order to improve the characteristics of the superconducting wire manufactured by the gel roll method, it is necessary to wind a wide Nb-containing sheet and an Al-containing sheet around a long and small-diameter core material. At that time, the Nb-containing sheet and the Al-containing sheet to be used are produced by rolling, and the size that can be actually produced can be considerably long in the rolling direction, but the size in the direction perpendicular to the rolling direction is limited. Therefore, when forming a roll-shaped laminate, the Nb-containing sheet and the Al-containing sheet need to be wound in a direction perpendicular to the rolling direction. However, there is a problem that the critical source flow density is lowered.

  For this reason, for example, in Patent Document 1, a Nb-containing sheet and an Al-containing sheet are wound around a core material in a direction perpendicular to the rolling direction to produce a roll laminate, and a plurality of Nb-containing sheets A method has been proposed in which an Al-containing sheet is sandwiched between and connected to the roll laminate to increase the number of layers by lap winding.

  In such a method, there is a problem that the sheets are easily displaced at the winding start portion, and winding slack is likely to occur. Further, in this technique, a plurality of sheets are connected by sandwiching the loose core around the loose core material, and the winding is further continued. As the number (number of windings) increases, there arises a problem that it becomes difficult to wind up neatly. Moreover, as a result, the filling rate of a laminated body will fall. In order to increase such a filling rate, rewinding is performed. However, when such rewinding is performed, there is a problem that manufacturing time is inevitably taken.

In order to avoid rewinding as much as possible and shorten the winding time, the diameter of the core material has to be increased. This core part does not contribute to the critical current, and there is a problem that the critical current density per wire cross-sectional area becomes small.
Japanese Patent Laid-Open No. 10-289624 Patent Claims, etc.

The present invention has been made under such circumstances, and its purpose is to adopt a method of winding a laminate that can use a thin core material and obtain a long laminate, An object of the present invention is to provide a method for producing an Nb ₃ Al-based superconducting wire capable of shortening the winding time and improving the filling rate of the laminate.

The production method of the Nb ₃ Al-based superconducting wire of the present invention that has achieved the above-mentioned object is as follows. In producing the Nb ₃ Al-based superconducting wire by the jelly roll method, an Nb-containing sheet made of Nb or an Nb-based alloy After the Al-containing sheet made of Al or Al alloy is superposed and wound around the core material, the core material is extracted to form a roll-shaped laminate, and one or a plurality of roll-shaped laminates prepared in the same manner therein It has a gist in that an object is manufactured using a primary superconducting wire inserted in a nested manner.

  In the production method of the present invention, it is also useful to bundle one or more primary superconducting wires as described above, insert them into a pipe made of Cu or Cu alloy, and heat-treat them after reducing the diameter. .

Moreover, in the manufacturing method of this invention, it is also useful to employ | adopt the structure in any one of following (1)-(3).
(1) After another roll-shaped laminate is inserted into the roll-shaped laminate in a nested manner, the roll-shaped laminate positioned inside is rewound in the direction opposite to the winding direction, Affix to the inside of the roll laminate.
(2) The roll-shaped laminate located in the outermost layer is formed so that the length in the winding direction of the Nb-containing sheet is longer than the length in the winding direction of the Al-containing sheet. The surplus portion is configured to form the outer peripheral surface of the roll-shaped laminate after being wound.
(3) The roll-shaped laminate formed in the innermost layer is formed so that the length in the winding direction of the Nb-containing sheet is longer than the length in the winding direction of the Al-containing sheet. The surplus portion is configured to form the inner peripheral surface of the roll-shaped laminate after being wound.

In the production method of the present invention, when an Nb ₃ Al-based superconducting wire is produced by the jelly roll method, an Nb-containing sheet made of Nb or an Nb-based alloy and an Al-containing sheet made of Al or an Al alloy are overlapped to form a core. After winding up on the material, the core material is pulled out to form a roll-shaped laminate, and one or a plurality of roll-shaped laminates similarly created therein are used in a primary superconducting wire inserted in a nested manner. Thus, the thickness of the roll laminate inside can be increased, and a superconducting wire exhibiting desired superconducting properties can be obtained. Also, bundle the one or more primary superconducting wires as described above, insert them into a pipe made of Cu or Cu alloy, reduce the diameter of this, and then heat-treat, effectively increasing the number of wires. Can be realized.

  The present inventors have studied from various angles in order to achieve the above object. As a result, the inventors have found that the above object can be achieved brilliantly by adopting the configuration as described above, thereby completing the present invention. Hereinafter, the configuration of the present invention will be described in detail with reference to the drawings.

  In the present invention, it is necessary to superimpose an Nb-containing sheet made of Nb or an Nb-based alloy and an Al-containing sheet made of Al or an Al alloy and wind them around a core material. Is schematically shown in FIG. Moreover, the schematic cross-sectional part of the laminated body after winding up is shown in FIG.

  First, as shown in FIG. 1 (a), an Nb-containing sheet 1a and an Al-containing sheet 1b are overlapped and wound around a core material 1c, and then the core material 1c is pulled out to form a roll-shaped laminate 1 [FIG. a)]. At that time, the length in the winding direction of the Nb-containing sheet 1a is increased [indicated by 1d in FIG. 1 (a)] to form the outer diffusion barrier layer 1d when a roll-shaped laminate is formed. That is, the roll-shaped laminate positioned in the outermost layer is formed so that the length in the winding direction of the Nb-containing sheet is longer than the length in the winding direction of the Al-containing sheet, and the excess of the Nb-containing sheet A part is comprised so that the outer peripheral surface (diffusion barrier layer 1d) of the roll-shaped laminated body after winding may be formed.

  However, the diffusion barrier layer 1d may be formed by processing the Nb-containing material into a pipe shape and disposing the Nb-containing material outside the roll-shaped laminate 1. In this case, the Nb-containing sheet and the Al-containing sheet may have the same winding direction length.

  Next, the Nb-containing sheet 2a and the Al-containing sheet 2b are overlapped and wound around the core material 2c [FIG. 1 (b)], and then the core material 2c is extracted and the roll-shaped laminate 2 [FIG. 2 (b)]. ] Is produced. The outer diameter of the roll laminate 2 is set to be approximately the same as or smaller than the inner diameter of the roll laminate 1 [the diameter of the portion from which the core material 1c is extracted]. And after inserting the roll-shaped laminated body 2 into the inside of the said roll-shaped laminated body 1 in the shape of a nesting, the edge parts, such as the core material 2c, are inserted in the center part space of the roll-shaped laminated body 2, FIG. As shown in the figure, the roll-shaped laminate 2 is applied to the inside of the roll-shaped laminate 1 by spreading in the direction opposite to the winding direction.

In the same manner as described above, the Nb-containing sheet 3a and the Al-containing sheet 3b are overlapped and wound around the core material 3c [FIG. 1 (c)], and then the core material 3c is extracted and the roll-shaped laminate 3 [FIG. (C)] is prepared. At this time, the length in the winding direction of the Nb-containing sheet 3a located inside the winding is made longer than that of the Al-containing sheet, and the inner side surface of the Nb-containing sheet 3a becomes a Nb-containing sheet when wound around the core material 3c. Is done. This inner Nb-containing sheet forms the diffusion barrier layer 3d. That is, the roll-shaped laminate formed in the innermost layer is formed so that the length in the winding direction of the Nb-containing sheet is longer than the length in the winding direction of the Al-containing sheet. A part is comprised so that the internal peripheral surface (diffusion barrier layer 3d) of the roll-shaped laminated body after winding may be formed.
However, as the diffusion barrier layer 3d, the Nb-containing material processed into a pipe shape may be arranged inside the roll-shaped laminate 3 to form the diffusion barrier layer 3d. In this case, the Nb-containing sheet and the Al-containing sheet may have the same winding direction length.

  The outer diameter of the roll laminate 3 is set to be approximately the same as or smaller than the inner diameter of the roll laminate 2 [the diameter after being unrolled at the portion where the core material 1c is removed]. Then, after inserting the roll laminate 2 in a nested manner inside the roll laminate 2, the roll laminate 2 is spread in the same manner as described above, and the roll laminate 3 is attached to the inside of the roll laminate 2. To do so. Finally, the core material 4 [FIG. 2 (d)] made of Cu or Cu alloy (or Nb or Nb alloy) is inserted into the roll-shaped laminate 3 to obtain Nb / Al / as shown in FIG. Cu composite 5 is produced.

  In the example shown above, although the step of inserting the roll laminate in a nested manner showed a configuration twice (that is, a combination of three types of roll laminates 1, 2, and 3), May be at least once, and is not limited to the number of steps. Moreover, when forming a diffusion barrier layer with an Nb-containing sheet, a roll-shaped laminate (corresponding to the roll laminate 1) located on the outermost side and a roll located on the innermost side, regardless of the number of steps. A diffusion barrier layer (corresponding to the diffusion barrier layers 1d and 3d) may be formed on the layered laminate (corresponding to the roll laminate 3).

  Moreover, in the said structure, although each roll-shaped laminated body showed the case where a pair of Nb containing sheet | seat and Al containing sheet | seat were wound, depending on the thickness of each sheet | seat, as shown in FIG. You may employ | adopt the structure wound up. In FIG. 5, the same reference numerals are assigned to the portions corresponding to those in FIG. By adopting such a configuration, it is possible to shorten the winding time.

  In addition, it is preferable that the core material 4 to be finally inserted is slightly larger than the core material 3c in consideration of the fact that the inner diameter of the roll-shaped laminate 3 into which the core material is inserted becomes larger due to winding. By adopting such a configuration, the filling rate of the Nb-containing sheet and the Al-containing sheet can be further increased.

The Nb / Al / Cu composite body 5 obtained in this way is inserted into a Cu or Cu alloy pipe 6 as shown in FIG. Thus, a Nb ₃ Al primary superconducting wire can be obtained.

Next, the primary superconducting wire 7 is made into a hexagonal cross-sectional shape by drawing, and bundled together with a Cu or Cu alloy spacer (not shown) having the same hexagonal cross-sectional shape, and as shown in FIG. It is inserted into an alloy pipe 8 and subjected to extrusion and wire drawing to obtain an Nb ₃ Al multicore superconducting element wire 9 having a cross-sectional shape as shown in FIG.

Finally, the Nb ₃ Al-based superconducting wire 9 is heat-treated at a relatively low temperature (for example, about 700 to 800 ° C.), whereby the reaction proceeds between the Nb-containing sheet and the Al-containing sheet, and the Nb ₃ Al-based superconductivity A body phase is formed and an Nb3Al-based superconducting wire can be obtained.

  In the above configuration, when the roll-shaped laminates 2 and 3 are inserted into a nested shape, the roll-shaped laminates 2 and 3 are rewound and attached to the outer roll-shaped laminates 1 and 2, thereby Although it is preferable that the filling rate can be further increased, the configuration of the present invention can exhibit the effects of the present invention without necessarily performing such rewinding. That is, in the present invention, when configuring the primary super-wire material, it is divided into a plurality of roll-shaped laminates and inserted into the nest, so that the primary super-wire material is composed of one roll-shaped laminate. In comparison with the case where a plurality of Nb-containing sheets and Al-containing sheets are sandwiched between roll-like laminates, winding looseness is less likely to occur, and a higher filling rate can be secured. Moreover, in the roll-shaped laminated body located in the innermost part, even if it uses a core material with a thin diameter [the said FIG.2 (d)], it can wind up effectively. However, from the viewpoint of further increasing the filling rate of each sheet, it is preferable to perform the rewinding as described above.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are not of a nature that limit the present invention, and any design changes may be made in accordance with the gist of the present invention. It is included in the technical scope.

Example Using an Nb sheet of 250 mm × 1000 mm (rolling direction) and an Al sheet of 200 to 250 mm × 1000 mm (rolling direction), the core rods were wound around two SUS core rods. An object (large) was produced.

  On the other hand, a composite sheet in which three Nb sheets and Al sheets of the same material as above are alternately stacked is wound around another SUS core rod, and the roll shape has a diameter so as to enter the inside of the roll-shaped laminate (large). A laminate (small) was prepared and inserted in a nested manner. Then, the end part of the SUS core rod was put inside the roll-shaped laminate (small), and rotated in the direction opposite to the winding direction to perform spreading. A Cu core is inserted into the composite roll laminate thus obtained to produce an Nb / Al / Cu composite, which is inserted into a Cu pipe, and then drawn into a hexagonal cross-sectional shape by wire drawing. A core superconducting wire (primary superconducting wire) was used. A bundle of 102 together with Cu spacers having the same hexagonal cross-section shape was bundled and inserted into a Cu pipe, extruded and drawn, and a multi-core wire having a diameter of 0.8 mm was produced.

The roll laminate winding time at this time was 0.5 hour. The filling rate of the laminate was 690 A / mm ² at a critical current density per non-copper portion of 4.2 k and 12T.

Comparative Example Using an Nb sheet of 250 mm × 1000 mm (rolling direction) and an Al sheet of 200 to 250 mm × 1000 mm (rolling direction), two sheets of Cu core rods were overlapped and wound, and then the same Nb sheet as above A composite sheet in which three Al sheets were alternately stacked was added by sandwiching, and then wound up.

  After the Nb / Al / Cu composite thus obtained was inserted into a Cu pipe, a hexagonal cut single core superconducting wire (primary superconducting wire) was formed by wire drawing. A bundle of 102 together with Cu spacers having the same hexagonal cross-section shape was bundled and inserted into a Cu pipe, extruded and drawn, and a multi-core wire having a diameter of 0.8 mm was produced.

At this time, it was necessary to rewind the roll-shaped laminate to correct the winding deviation, and the time required for winding was 1.5 hours. Moreover, when the critical current density which heat-processed the produced Nb3Al multi-core superconducting wire was measured, the critical current density per non-copper part was 660 A / mm < ² > in 4.2k and 12T.

It is explanatory drawing which showed typically the winding process in this invention. It is explanatory drawing which shows the cross-section of each roll-shaped laminated body. It is a figure explaining the unwinding process in this invention. It is explanatory drawing which shows the cross-section of the composite laminated body produced by this invention. In the winding process of this invention, it is explanatory drawing which showed typically the example in the case of using several overlap sheets. It is a cross sectional view of a Nb ₃ Al based primary superconducting wire manufactured in this invention. It is an assembly schematic diagram of the Nb ₃ Al multicore superconducting wire of the present invention. It is a schematic sectional view showing a configuration example of a Nb ₃ Al-based multi-core superconducting wire manufactured in this invention.

Explanation of symbols

1a, 2a, 3a Nb-containing sheets 1b, 2b, 3b Al-containing sheets 1c, 2c, 3c, 4 Core material 1d, 3d Diffusion barrier layers 1, 2, 3 Rolled laminate 5 Nb / Al / Cu composite 6, 8 Cu or Cu alloy pipe 7 Nb ₃ Al-based primary superconductor 9 Nb ₃ Al-based multi-core superconducting wire

Claims (5)

In manufacturing the Nb ₃ Al-based superconducting wire by the jelly roll method, the Nb-containing sheet made of Nb or Nb alloy and the Al-containing sheet made of Al or Al alloy are overlapped and wound around the core, and then the core Nb ₃ Al, characterized in that Nb ₃ Al is produced by using a primary superconducting wire inserted in a nested manner in the form of one or a plurality of roll-like laminates similarly drawn inside Of manufacturing superconducting wire. The Nb ₃ Al-based superconductivity according to claim 1, wherein one or a plurality of the primary superconducting wires according to claim 1 are bundled, inserted into a pipe made of Cu or Cu alloy, subjected to heat treatment after diameter reduction processing. A manufacturing method of a wire. After another roll-like laminate is inserted into the roll-like laminate in a nested manner, the roll-like laminate located inside is rewound in the direction opposite to the winding direction, and the outer roll-like laminate Nb ₃ Al-based method of manufacturing a superconducting wire according to claim 1 or 2 as pasting the inside. The roll-shaped laminate located in the outermost layer is formed such that the length in the winding direction of the Nb-containing sheet is longer than the length in the winding direction of the Al-containing sheet, and the surplus portion of the Nb-containing sheet is The method for producing an Nb ₃ Al-based superconducting wire according to any one of claims 1 to 3, wherein the method is configured so as to form an outer peripheral surface of the rolled laminate after being wound. The roll-shaped laminate formed in the innermost layer is formed so that the length in the winding direction of the Nb-containing sheet is longer than the length in the winding direction of the Al-containing sheet, and the surplus portion of the Nb-containing sheet is The method for producing an Nb ₃ Al-based superconducting wire according to any one of claims 1 to 4, wherein the method is configured so as to form an inner peripheral surface of a rolled laminate after being wound.

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