JPS6215966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for manufacturing a wedge-shaped superconducting shaped stranded wire.

Recently, a shaped stranded superconducting wire as shown in FIG. 1 has been used as a superconducting wire with high current density and high stability.

This superconducting wire has higher stability against magnetic field fluctuations than a single superconducting wire due to the double twist in which the wires are twisted and twisted at a constant pitch. In addition, when using a multi-core wire with several thousand filaments embedded in each wire, a cable made up of these wires contains tens of thousands of filaments. By twisting with a period of , the stability against magnetic field fluctuations is significantly improved and a stabilization line can be obtained. Therefore, it has a high current density and has excellent performance as a magnet winding used in alternating current. In particular, for two-pole and four-pole magnets, the cross-sectional shape of the magnet is a semicircle or a quarter circle, respectively, but with the advancement and rationalization of winding technology, the cross-section of the cable has been shaped into a wedge shape. A method is used in which the stranded wire is wound into a desired cross-sectional shape of the magnet, and the wedge-shaped shape of the formed stranded wire also changes in various ways depending on the size of the magnet.

Conventionally, in order to process this superconducting formed stranded wire into a wedge shape, it was formed all at once during the rolling process. However, in this processing process, in order to process what should originally be rolled into a rectangular shape into a wedge shape, the superconducting strand 1 is
Cracks or thinning occur in the short side portion 2 of the material, deteriorating the characteristic values of superconductivity, and this tendency becomes particularly pronounced as the processing rate increases. On the other hand, it is difficult to make the length of the long side 3 larger than the wire diameter. Therefore, it is difficult to greatly change the ratio of the short side and long side, and the shape is limited to a wedge shape.

In this way, it has been difficult to form a shaped stranded wire consisting of two upper and lower layers of strands to an arbitrary angle.

The present invention has been made as a result of intensive research aimed at improving these drawbacks, and as a result has discovered a method for manufacturing wedge-shaped molded stranded wires having a cross-sectional shape of an arbitrary angle. That is, the method of the present invention includes a superconducting stranded wire obtained by winding and twisting a plurality of superconducting strands around a core metal having a wedge-shaped groove with one side open, and the above-mentioned wedge provided in the core metal. A metal tape with a wedge-shaped cross section attached to the mold-shaped groove is pulled and both are taken out from the core bar, the outer periphery of the metal tape is coated with superconducting stranded wires, and then introduced into a rolling roll and rolled into a wedge shape. It is characterized by:

The method of the present invention uses a metal tape (metal ribbon) as a core material that is tapered at a desired angle at the center, and once the superconducting strands are falsely twisted on the core metal,
The superconducting wire is twisted around the metal ribbon while the false twisted wire is pulled down at the point where it separates from the metal core, and then rolled into a wedge shape. However, in order to directly strand the metal ribbon without using a metal core, the ribbon needs to have a tensile strength higher than that of the stranded wire. Therefore, the reinforcing material that occupies the cross section of the formed stranded wire is required to be large in amount and to have high strength. In order to solve such problems, in the method of the present invention, a groove is provided in the core metal as a guide for allowing the metal ribbon of the core material to pass through, and the superconducting strands are twisted on the core metal while being separated from the core metal. At this point, the outside of the metal ribbon is wrapped with twisted wire and immediately rolled and formed.

Therefore, in the method of the present invention, even if Al or Cu is used as the core material, there is no risk of wire breakage, and since the magnet can be processed into a wedge shape at any angle, it is possible to design and manufacture any magnet. Furthermore, by using Cu and Al as core materials for DC magnet windings, it can also be used as a superconducting wire with a wedge-shaped cross section that has excellent stabilizing properties. On the other hand, by using a core material with high electric resistance and high strength, such as stainless steel, it is possible to obtain a shaped stranded wire that can withstand AC use. In addition, by using the core material, the plastic working of the core material is increased simultaneously with the processing of the superconducting wire during rolling, making it possible to prevent property deterioration due to cracking of the superconducting wire.

In addition, the method of the present invention is particularly one in which a wedge-shaped groove is formed as a core metal. The reason for this is that when the metal tape attached to the core metal and the superconducting strands wound around the outside of the core metal are pulled and the superconducting strands are coated on the outer periphery of the metal tape, an impact is applied to the core metal at the exit of the core metal. There is a risk that the force will be applied and damage the core metal.

However, by providing the opening at the top of the core metal as described above, there is room inside the core metal, so this impact force is alleviated and damage to the core metal is extremely rare. Note that when using a sealed core metal, there is no space inside, so damage to the core metal is significant.To prevent this, it is necessary to increase the thickness of the core metal. Even if the stranded wires are covered, a gap is formed between them due to the influence of the thickness of the core metal, making it impossible to obtain a good superconducting stranded wire. Furthermore, by using a core bar with an opening at the top, the work of inserting the metal tape is made extremely easy.

Next, embodiments of the present invention will be described based on the drawings.

Example As shown in Figure 2, the long side is 1.8 mm, the short side is 1.2 mm, and the width is 7.8 mm.
In order to process wedge-shaped superconducting formed strands 1 of mm,
As shown in the figure, a groove 5 with a long side a of 0.8 mm, a short side b of 0.5 mm, and a width c of 6.0 mm is formed on a core bar 4 with a long side of 1.1 mm, a short side of 0.8 mm, and a width of 7.0 mm.
has been established. Inside this groove, the long side is 0.5 mm as the core material 6,
A wedge-shaped SUS304 tape with a short side of 0.2 mm and a width of 5.0 mm is attached, and the tape is supplied to the stranded wire from its tip.

On the other hand, superconducting wire 1 is placed inside the OFHC with an outer diameter of 0.69φ.
2300 NbTi filaments of 8.3 μΦ are embedded, and 23 of them are wrapped and twisted around a core metal, and the wires are slid over the core metal and coated on the outer periphery of the above tape at the point where it comes off the core metal. This was then rolled to produce a wedge-shaped stranded wire with a diameter of 1.8 x 1.2 x 7.8 mm.

In this case, there were no problems such as overlapping of strands or breakage of the core material during the processing of the formed stranded wire.

When the characteristics of the wedge-shaped superconducting stranded wire obtained by the method of the present invention were measured, it was found to be 5200A (5T), and the deterioration due to the stranding process was 0.8%.

In addition, when using the same 1.8 x 1.2 x 7.8 mmφ as the conventional wedge-shaped superconducting formed stranded wire,
5060A (5T), and 3.5% deterioration was observed.

As described in detail above, the method of the present invention has remarkable effects such as being able to form stranded wires in a wedge shape at any angle and also being able to sufficiently use low-strength Al and Cu as core materials.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a wedge-shaped superconducting formed stranded wire obtained by the conventional method, FIG. 2 is a cross-sectional view of a wedge-shaped superconducting formed stranded wire obtained by the method of the present invention, and FIG. 3 is a core used in the method of the present invention. It shows gold and is shown in Figure 3A.
is a perspective view thereof, and FIG. 3B is a sectional view thereof. 1... Superconducting strand, 2... Short side, 3... Long side,
4...Core metal, 5...Groove, 6...Core material.

Claims (1)

[Claims] 1. A superconducting stranded wire in which a plurality of superconducting strands are wound and twisted around a core metal having a wedge-shaped groove with an open side, and the wedge-shaped groove provided in the core metal. While pulling a metal tape with a wedge-shaped cross section attached to the metal tape, both of them are taken out from the core metal, the outer periphery of the metal tape is coated with superconducting stranded wires, and then introduced into a rolling roll and rolled into a wedge shape. A manufacturing method for wedge-shaped superconducting shaped stranded wires.