JP4009977B2 - Superconducting wire manufacturing method and manufacturing apparatus thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a superconducting wire and a manufacturing apparatus therefor, and more particularly to a method for manufacturing a superconducting wire and a manufacturing apparatus therefor, which manufacture a superconducting wire by applying pressure.
[0002]
[Prior art]
Conventional high-temperature superconducting wires, such as Bi-2223 wires, are known to be aligned in the same direction by processing because the crystal grains are plate-like. Bi-2223 includes three elements of Sr, Ca, and Cu in addition to Bi, and each atomic ratio is typically Bi: Sr: Ca: Cu = 2: 2: 2: 3. However, for Bi = 2, the composition of other elements is allowed to vary within a range of ± 20%. Further, a material containing Pb whose ratio to Bi = 2 is 0.30 to 0.45 is allowed.
[0003]
In order to produce a superconducting wire with better electrical conductivity by orienting these crystal grains in the same direction, intermediate processing such as rolling, pressing or swaging has been performed during the heat treatment of the superconducting powder.
[0004]
FIG. 8 is a schematic side view of a conventional superconducting wire manufacturing apparatus 1. The superconducting wire manufacturing apparatus 1 has a pair of molds 2 and supplies a wire material 3 therebetween.
The die 2 is various rolling means such as a rolling roll, a press means, or a swaging process, or a forging means, and extends this in the length direction and the width direction by applying pressure to the wire material 3.
The wire material 3 is composed of a sheath material 4 and a superconducting powder 5 accommodated in the sheath material 4, and is extended into a strip shape by the pressure from the mold 2, and is formed to have a required thickness and width.
[0005]
However, in the superconducting wire manufacturing apparatus 1 having such a configuration, for example, when the die 2 is rolled by a rolling roll or the like, the wire material 3 extends in the longitudinal direction but hardly extends in the width direction. That is, since the elongation in one direction (longitudinal direction) is large, there is a problem that the growth of crystal grains is hindered.
In the pressing process, the critical current density is relatively high because the wire material 3 extends in the width direction as compared with the rolling process, but the extension in the width direction is not yet sufficient, and the crystal grains are not largely oriented. There is.
Even in the swaging process, there is a problem that it is difficult to uniformly spread the wire material 3 in the length direction and the width direction.
Therefore, the conventional superconducting wire manufacturing apparatus 1 or manufacturing method has a problem that it is difficult to sufficiently obtain a necessary critical current density.
[0006]
[Problems to be solved by the invention]
The present invention has been considered in view of the above problems, and an object of the present invention is to provide a method of manufacturing a superconducting wire capable of improving the critical current density as a superconducting wire and a manufacturing apparatus therefor.
[0007]
In addition, the present invention provides a method of manufacturing a superconducting wire and an apparatus for manufacturing the same capable of sufficiently extending a wire material not only in the longitudinal direction but also in the width direction by rolling, pressing, swaging and other extending processes. Let it be an issue.
[0008]
Moreover, this invention makes it a subject to provide the manufacturing method of the superconducting wire which can orientate the crystal grain of a superconducting wire in the same direction, and its manufacturing apparatus.
[0009]
[Means for Solving the Problems]
That is, the present invention focuses on sandwiching a wire material of a superconducting wire in a metal plate such as copper or stainless steel in an intermediate process such as rolling or pressing and swaging, and processing them together between dies. A first invention is a method for producing a superconducting wire in which a superconducting powder is accommodated in a sheath material and used as a wire raw material, and the wire raw material is extended between molds. A superconducting wire manufacturing method characterized in that the wire material is sandwiched between metal plates that are softer and harder than the sheath material, and then processed by the mold.
[0010]
The thickness of the metal plate can be 0.01 to 5.0 mm.
[0011]
The extending process using the mold and the baking process of the superconducting powder can be repeated.
[0012]
A second invention is a superconducting wire manufacturing apparatus in which a superconducting powder is accommodated in a sheath material and used as a wire material, and the wire material is extended between molds to form a superconducting wire. A superconducting wire manufacturing apparatus characterized in that it has a metal plate that is softer and harder than the sheath material, and is processed by the mold after the wire material is sandwiched between the metal plates.
[0013]
The metal plate is harder than the sheath material and softer than the mold. For example, the Vickers hardness is preferably 70 to 300.
[0014]
In the superconducting wire manufacturing method and manufacturing apparatus according to the present invention, a metal plate that is softer than the mold and harder than the sheath material of the wire material is interposed between the mold and the wire material. Is applied to the sheath material via the metal plate, and a uniform pressure can be applied to the sheath material.
That is, by processing the sheath material (wire material raw material) together with the metal plate, the sheath material (wire material raw material) also extends in the width direction, and as a result, it can be uniformly extended in both the longitudinal direction and the width direction.
Therefore, it becomes possible to orient the crystal grains of the superconducting powder in the same direction and increase the critical current density.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, a superconducting wire manufacturing apparatus 10 according to an embodiment of the present invention will be described with reference to FIGS. However, the same parts as those in FIG. 8 are denoted by the same reference numerals, and detailed description thereof will be omitted.
FIG. 1 is a schematic side view of a superconducting wire manufacturing apparatus 10, and the superconducting wire manufacturing apparatus 10 has a pair of metal plates 11 together with the pair of molds 2.
[0016]
The metal plate 11 is made of a metal material that is softer than the mold 2 and harder than the sheath material 4 of the wire material 3. The mold 2 is made of, for example, tool steel (SKD) or other special hardness steel, and the metal plate 11 is made of copper or stainless steel.
The thickness of the metal plate 11 can be 0.01 to 5.0 mm.
[0017]
In the intermediate processing for extending, the wire material 3 is sandwiched between the metal plates 11, and the wire material 3 is pressed together with the metal plate 11 by the mold 2.
[0018]
In the superconducting wire manufacturing apparatus 10 having such a configuration, for example, a superconducting calcined powder for a Bi-2223 wire, which is a high-temperature superconducting wire, is accommodated in the sheath material 4 as the superconducting powder 5, sandwiched between the metal plates 11, and the mold 2 Apply pressure by.
[0019]
In the press working, the metal plate 11 located between the mold 2 and the wire material 3 is also processed and stretched simultaneously by the compression action, so that the wire material 3 (sheath material 4) is dragged by the extension of the metal plate 11. Can extend greatly in the width direction.
In addition, as shown in the processing procedure of FIG. 2, a superconducting wire can be manufactured by alternately repeating the extending step of applying pressure and the baking step of heating any number of times (for example, three times).
[0020]
3 shows a conventional manufacturing apparatus 1 (FIG. 8) that does not use the metal plate 11 performed by using a press as the mold 2 and a manufacturing apparatus 10 according to the present invention that sandwiches the metal plate 11 (for example, a copper plate). FIG. 2 is a comparative cross-sectional view in the width direction of the wire raw material 3 when pressed, (1) is a state after 100 hours after pressing, and (2) is further sintered after pressing for 50 hours. (3) shows the state after further pressing and firing for 50 hours.
As shown in the figure, in the case of the present invention, it can be seen that the width is greatly increased as compared with the conventional case.
Moreover, it turns out that the thickness of the part of a core (superconducting powder 5) also becomes small, and is oriented largely.
[0021]
Furthermore, in the rolling process, the softer the material, the easier it is to extend in the longitudinal direction, and the more difficult it is to extend in the width direction. In other words, a hard material is easier to extend in the width direction than in the longitudinal direction. For example, the sheath material 4 of the Bi-2223 wire is soft because it is silver (Ag) or a silver alloy, and therefore is easily stretched in the longitudinal direction.
On the other hand, for example, by rolling the wire material 3 together with the metal plate 11 such as a stainless steel plate, the stainless steel metal plate 11 is 3 times or more harder in Vickers hardness than the sheath material 4. The sheath material 4 extends sufficiently in the width direction so as to be dragged while the plate 11 extends in the width direction.
Moreover, force is uniformly applied to the wire material 3 by processing the metal plate 11 therebetween.
[0022]
FIG. 4 shows a conventional manufacturing apparatus 1 (FIG. 8) that uses a rolling roll as the mold 2 and does not use the metal plate 11, and a metal plate 11 (for example, copper and stainless steel) using the manufacturing apparatus 10 according to the present invention. It is comparison sectional drawing of the width direction of the wire raw material 3 when it processes by pinching, Comprising: (1) is a conventional case, (2) is a copper plate as the metal plate 11, (3) is as the metal plate 11 When a stainless steel plate is used, each is shown.
As shown in the figure, in the case of the present invention, it can be seen that both the copper plate and the stainless steel plate can extend in the width direction as compared with the conventional case, and the crystal grains are two-dimensionally grown by uniform processing.
In the case of pressing, it can be seen that when the harder stainless steel plate is used as the metal plate 11, the elongation in the width direction is larger than when the softer copper plate is used.
[0023]
FIG. 5 is a chart showing the critical current density at a temperature of 77 K and a magnetic field of 0 T of the high-temperature superconducting wire (Bi-2223 wire) according to the conventional case and the present invention, and is a metal plate 11 (stainless steel plate and copper plate). The case where each thickness is 2.5 mm is shown.
According to the present invention, it is understood that the critical current density is increased by 1.5 times or more in the case of rolling and pressing as compared with the conventional case.
[0024]
FIG. 6 is a chart showing the critical current density Jc at a temperature of 77 K and a magnetic field of 0 T when the thickness of the metal plate 11 (stainless steel plate and copper plate) to be rolled and pressed is changed from 0.005 to 0.8 mm. The conventional superconducting wire manufacturing apparatus 1 (FIG. 8) is shown as having a zero thickness.
As shown in the figure, according to the present invention, in the range where the thickness of the metal plate 11 is greater than 0.01 mm, the critical current density is increased compared to the conventional manufacturing method by both rolling and pressing. I understand that.
[0025]
FIG. 7 shows the critical current density Jc at a temperature of 77 K and a magnetic field of 0 T when the thickness of the metal plate 11 (stainless steel plate and copper plate) to be rolled and pressed is changed from 1 to 7 mm, as in FIG. It is a figure to show, Comprising: The conventional superconducting wire manufacturing apparatus 1 (FIG. 8) is shown as a case where thickness is zero.
As shown in the figure, according to the present invention, the critical current density is increased in comparison with the conventional manufacturing method by both rolling and pressing in the range where the thickness of the metal plate 11 is less than 5 mm. I understand.
In addition, about the range whose thickness of the metal plate 11 is between 0.08-1 mm, although illustration is abbreviate | omitted in FIG.6 and FIG.7, the above-mentioned of the metal plate 11 interposed between the metal mold | dies 2 is mentioned. In view of the extension assisting action as described above, and since the critical current density in the meantime is a close value when the thickness is 0.08 mm and 1 mm, even if the thickness is within this range, It is considered that the critical current density is increased as compared with the conventional manufacturing method by any processing of the press.
[0026]
【The invention's effect】
As described above, according to the present invention, the metal plate is softer than the mold and harder than the sheath material of the wire material between the metal mold and the wire material. Uniform extension in both the width direction and the width direction is possible, and the critical current density can be increased.
[Brief description of the drawings]
FIG. 1 is a schematic side view of a superconducting wire manufacturing apparatus 10 according to an embodiment of the present invention.
FIG. 2 is a flowchart showing an example of a processing procedure.
3 shows a conventional manufacturing apparatus 1 (FIG. 8) that uses a press as the mold 2 and does not use the metal plate 11, and a manufacturing apparatus 10 according to the present invention sandwiches the metal plate 11 (for example, a copper plate). It is a comparative sectional view of the width direction of the wire material 3 when processed by.
4 shows a conventional manufacturing apparatus 1 (FIG. 8) that uses a rolling roll as the mold 2 and does not use the metal plate 11, and a metal plate 11 (for example, copper and stainless steel) in the manufacturing apparatus 10 according to the present invention. ) Is a comparative cross-sectional view in the width direction of the wire material 3 when processed with a sandwiched between.
FIG. 5 is a chart showing the critical current density Jc at a temperature of 77 K and a magnetic field of 0 T for a high-temperature superconducting wire (Bi-2223 wire) according to the conventional case and the case of the present invention.
FIG. 6 shows the critical current density Jc at a temperature of 77 K and a magnetic field of 0 T when the thickness of the metal plate 11 (stainless steel plate and copper plate) to be rolled and pressed is changed from 0.005 to 0.8 mm, respectively. It is a chart shown.
7 is the same as FIG. 6, and the critical current density Jc at a temperature of 77 K and a magnetic field of 0 T when the thickness of the metal plate 11 (stainless steel plate and copper plate) to be rolled and pressed is changed from 1 to 7 mm. It is a chart which shows each.
FIG. 8 is a schematic side view of a conventional superconducting wire manufacturing apparatus 1;
[Explanation of symbols]
1 Superconducting wire manufacturing equipment (Figure 8)
2 A pair of molds 3 Wire material 4 Sheath material 5 Wire material 3 Superconducting powder 10 Wire material 3 Superconducting wire manufacturing apparatus (embodiment, FIG. 1)
11 A pair of metal plates (for example, copper plate, stainless steel plate)

Claims (4)

A superconducting powder is housed in a sheath material and used as a wire raw material, and a method for producing a superconducting wire that forms a superconducting wire by extending the wire raw material between molds,
A superconducting wire, wherein the wire material and the metal plate are pressed together by the die after the wire material is sandwiched between a pair of metal plates softer than the mold and harder than the sheath material Manufacturing method.     The thickness of the said metal plate makes this 0.01-5.0 mm, The manufacturing method of the superconducting wire of Claim 1 characterized by the above-mentioned.     The method for producing a superconducting wire according to claim 1, wherein the extending step by the mold and the firing step of the superconducting powder are repeated. The superconducting powder is contained in a sheath material and used as a wire material, and a superconducting wire manufacturing apparatus for making a superconducting wire by extending the wire material between molds,
Having a pair of metal plates softer than the mold and harder than the sheath material between the mold and the wire material ,
An apparatus for producing a superconducting wire, wherein the wire material is sandwiched between the metal plates, and the wire material and the metal plate are pressed together by the mold.

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