A method for preparing NbTi / V artificial pinning superconducting wire using NbTi grooved wire

Abstract

The present application discloses a method for preparing NbTi / V artificial pinning superconducting wires by using NbTi grooved wires, and the method includes the following steps: Step 1: Select NbTi alloy wires, V wires and copper wires; Step 2: Roll the NbTi alloy wires to obtain NbTi flat tapes; Step 3: Use an inlay machine to embed the V wires into the NbTi flat tapes with U-shaped grooves, and draw them through a die to obtain NbTi / V flat tapes; Step 4: Uniformly wrap the copper wires around the NbTi / V flat tapes, and draw them to make the combination tight to obtain NbTi / V / Cu flat tapes; Step 5: Cut the NbTi / V / Cu flat tapes to a fixed length, load them into a return-shaped copper tube according to the structure, and draw them multiple times to obtain NbTi / V / Cu multi-core superconducting wires. The present application belongs to the field of superconducting material processing, and the present application solves the problem that there is an upper limit for the critical current density of the existing preparation of NbTi superconducting wires. The critical current density of the NbTi / V / Cu artificial pinning superconducting wire materials in the present application has been greatly improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of superconducting material processing, and particularly relates to a method for preparing NbTi / V artificial pinning superconducting wire by using NbTi grooved wire. Background Art

[0002] Niobium-titanium superconducting material is a non-ideal type-II superconductor. Introducing a second-phase material of different quality into the niobium-titanium superconducting material to prevent the movement of vortex lines is called a "pinning center". If the pinning effect is strong enough, the vortex motion can become small enough to improve the performance of the superconducting material. Currently, the critical current density of conventional NbTi superconductors is < 3200 A / mm 2 (under 5T magnetic field).

[0003] Through different technological processes, people have introduced various artificially shaped and arranged pinning centers to improve the flux pinning force and critical current density of NbTi superconductors. People use a variety of methods to introduce artificial pinning centers into NbTi composite wires, such as the rod-based method, the gun-dril method, the diffused-layer method, the jelly-roll method, the powder-metallurgy method, the laminated-structure method, etc.

[0004] Traditional NbTi superconductors are all prepared by cold drawing with a drawing machine to produce superconducting wires. The traditional method for preparing NbTi superconductors uses α-Ti in the NbTi alloy as the pinning center. However, since the maximum precipitation amount of α-Ti in the NbTi alloy can only reach 25%, there is an upper limit to the critical current density of the NbTi superconducting wire prepared by the traditional method. After the α-Ti precipitation amount reaches 25%, the maximum critical current density can only reach 3200 A / mm2 (5T). Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing NbTi / V artificial pinning superconducting wire by using NbTi grooved wire, which solves the problem of the upper limit of the critical current density of the NbTi superconducting wire prepared by the prior art.

[0006] The present invention adopts the following technical solution: A method for preparing NbTi / V artificial pinning superconducting wire by using NbTi grooved wire, the method comprising the following steps:

[0007] Step 1, material selection: Select NbTi alloy wire, V wire and copper wire.

[0008] Step 2, making flat tape: Roll the NbTi alloy wire in step 1, and after several rollings, obtain NbTi flat tape, and roll the NbTi flat tape to form a U-shaped groove.

[0009] Step 3: Embedding and drawing: Use an inlaying machine to embed the V wire in step 1 into the NbTi flat tape with a U-shaped groove in step 2, and then draw it through a die to obtain the NbTi / V flat tape.

[0010] Step 4: Wrapping and drawing: Use a braiding machine to evenly wrap the copper wire in step 1 on the surface of the NbTi / V flat tape, and then draw and tightly bond the NbTi / V flat tape wrapped with copper wire on a drawing machine to obtain the NbTi / V / Cu flat tape.

[0011] Step 5: Assembly and drawing: Cut the NbTi / V / Cu flat tape in step 4 to a fixed length, load it into a return-shaped copper tube according to a densely packed structure, and perform several draws on the assembled NbTi / V / Cu multi-core flat wire to obtain the NbTi / V / Cu multi-core superconducting wire.

[0012] Preferably, the diameter of the NbTi alloy wire in step 1 is 3-5 mm, the diameter of the V wire is 0.5-1 mm, and the diameter of the copper wire is 0.1 mm.

[0013] Preferably, the width of the NbTi / V flat tape in step 3 is 1.2-1.5 mm, and the height is 1.0-1.2 mm.

[0014] Preferably, the diameter of the U-shaped groove is 0.5-1 mm.

[0015] Preferably, the width of the NbTi / V / Cu flat tape obtained in step 4 is 1.0-1.2 mm, and the height is 0.6-0.8 mm.

[0016] Preferably, the NbTi alloy wire is rolled on a rolling mill.

[0017] Preferably, the rolling processing rate in step 2 is controlled at 5%-8%.

[0018] Preferably, the range of the fixed length in step 5 is 100 mm to 1000 mm.

[0019] The beneficial effects of the present invention are as follows: The present invention obtains an NbTi flat tape with a U-shaped groove by rolling NbTi, embeds a V wire in the groove of the NbTi flat tape, and then cold-draws the NbTi / V flat tape and braids copper wire on the surface to obtain the NbTi / V / Cu artificial pinning superconducting wire material. The critical current density of the NbTi / V / Cu artificial pinning superconducting wire material obtained by the preparation method of the present invention has been greatly improved. Description of the Drawings

[0020] Figure 1 is a schematic diagram of an NbTi flat tape with a U-shaped groove;

[0021] Figure 2Schematic diagram of embedding V wire into NbTi flat tape with U-shaped groove. Specific implementation mode

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0023] The present application provides a method for preparing NbTi / V artificial pinned superconducting wire by using NbTi grooved wire, including the following steps:

[0024] Step 1, material selection: Select NbTi alloy wire with a diameter of φ3 - 5mm, V wire with a diameter of φ0.5 - 1mm, and copper wire with a diameter of φ0.1mm.

[0025] Step 2, flat tape production: Roll the NbTi alloy wire with a diameter of φ3 - 5mm on a flat tape rolling mill. After multiple passes of rolling (the pass reduction rate is controlled at 5% - 8%), obtain an NbTi flat tape with a width of 1.2 - 1.5mm and a height of 1.0 - 1.2mm. Then roll the NbTi flat tape as Figure 1 shown to form a U-shaped groove with a diameter of φ0.5 - 1mm.

[0026] Step 3, embedding and drawing: Use an embedding machine to embed the V wire into the NbTi flat tape with a U-shaped groove, and obtain an NbTi / V flat tape through drawing with a die. The structure is as Figure 2 shown.

[0027] Step 4, wrapping and drawing: Use a braiding machine to evenly wrap the copper wire with a diameter of φ0.1mm on the surface of the NbTi / V flat tape, and then draw the NbTi / V flat tape wrapped with copper wire on a drawing machine for tight combination to obtain an NbTi / V / Cu flat tape with a width of 1.0 - 1.2mm and a height of 0.6 - 0.8mm.

[0028] Step 5, assembly and drawing: After cutting the NbTi / V / Cu flat tape to a fixed length, load it into a return-shaped copper tube according to a certain structure. Perform multiple passes of drawing on the assembled NbTi / V / Cu multi-core flat wire to obtain an NbTi / V / Cu multi-core superconducting wire.

[0029] Example 1

[0030] Step 1: Select NbTi alloy wire with a diameter of φ3mm, V wire with a diameter of φ0.5mm, and copper wire with a diameter of φ0.1mm.

[0031] Step 2: Roll the NbTi alloy wire with a diameter of φ3mm on a flat strip rolling mill. After multiple passes of rolling (the pass reduction rate is controlled at 5%), obtain a NbTi flat strip with a width of 1.20mm and a height of 1.00mm. Then roll the NbTi flat strip to form a U-shaped groove with a diameter of φ0.5mm.

[0032] Step 3: Use an inlaying machine to embed the V wire into the NbTi flat strip with a U-shaped groove, and obtain a NbTi / V flat strip with a width of 1.10mm and a height of 0.90mm through die drawing.

[0033] Step 4: Use a braiding machine to evenly wrap the copper wire with a diameter of φ0.1mm on the surface of the NbTi / V flat strip, and then draw the NbTi / V flat strip wrapped with copper wire on a drawing machine to achieve a tight combination, obtaining a NbTi / V / Cu flat strip with a width of 1.20 mm and a height of 1.00mm.

[0034] Step 5: Cut the NbTi / V / Cu flat strip to a fixed length and install it into a return-shaped copper tube with an inner hole width of 5.00mm, a height of 4.10mm, and a thickness of 2mm according to a certain structure. Perform multiple passes of drawing on the assembled NbTi / V / Cu multi-core flat wire to obtain a NbTi / V / Cu multi-core superconducting wire.

[0035] For the NbTi / V / Cu multi-core superconducting wire prepared in Example 1, the critical current of the superconducting wire is detected by an instrument, and dividing by the area gives the critical current density. The critical current density can reach 3800 A / mm 2 (under a 5T magnetic field).

[0036] Example 2

[0037] Step 1: Select a NbTi alloy wire with a diameter of φ5mm, a V wire with a diameter of φ1mm, and a copper wire with a diameter of φ0.1mm.

[0038] Step 2: Roll the NbTi alloy wire with a diameter of φ5mm on a flat strip rolling mill. After multiple passes of rolling (the pass reduction rate is controlled at 5%), obtain a NbTi flat strip with a width of 1.50mm and a height of 1.20mm. Then roll the NbTi flat strip to form a U-shaped groove with a diameter of φ1.0mm.

[0039] Step 3: Use an inlaying machine to embed the V wire into the NbTi flat strip with a U-shaped groove, and obtain a NbTi / V flat strip with a width of 1.40mm and a height of 1.10mm through die drawing.

[0040] Step 4: Use a braiding machine to evenly wrap the copper wire with a diameter of φ0.1mm on the surface of the NbTi / V flat strip, and then draw the NbTi / V flat strip wrapped with copper wire on a drawing machine to achieve a tight combination, obtaining a NbTi / V / Cu flat strip with a width of 1.50 mm and a height of 1.20mm.

[0041] Step 5: After cutting the NbTi / V / Cu flat tape to a fixed length, it is loaded into a return-shaped copper tube with an inner hole width of 7.70 mm, a height of 6.10 mm, and a thickness of 3 mm according to a certain structure. The assembled NbTi / V / Cu multi-core flat wire is drawn through multiple passes to obtain the NbTi / V / Cu multi-core superconducting wire.

[0042] For the NbTi / V / Cu multi-core superconducting wire prepared in Example 2, the critical current of the superconducting wire is detected by an instrument, and the critical current density is obtained by dividing it by the area. Through experiments, it is found that the critical current density of the NbTi / V / Cu multi-core superconducting wire can reach 3870 A / mm 2 (under a 5T magnetic field).

[0043] Example 3

[0044] Step 1: Select a NbTi alloy wire with a diameter of φ4 mm, a V wire with a diameter of φ0.8 mm, and a copper wire with a diameter of φ0.1 mm.

[0045] Step 2: Roll the φ4 mm NbTi alloy wire on a flat tape rolling mill. After multiple passes of rolling (the pass reduction rate is controlled at 5%), a NbTi flat tape with a width of 1.30 mm and a height of 1.00 mm is obtained. Then roll the NbTi flat tape to form a U-shaped groove with a diameter of φ0.8 mm.

[0046] Step 3: Use an inlay machine to embed the V wire into the NbTi flat tape with a U-shaped groove, and draw it through a die to obtain a NbTi / V flat tape with a width of 1.40 mm and a height of 1.10 mm.

[0047] Step 4: Use a braiding machine to evenly wrap the φ0.1 mm copper wire on the surface of the NbTi / V flat tape, and then draw and tightly bond the NbTi / V flat tape wrapped with the copper wire on a drawing machine to obtain a NbTi / V / Cu flat tape with a width of 1.30 mm and a height of 1.00 mm.

[0048] Step 5: After cutting the NbTi / V / Cu flat tape to a fixed length, it is loaded into a return-shaped copper tube with an inner hole width of 7.00 mm, a height of 5.50 mm, and a thickness of 3 mm according to a certain structure. The assembled NbTi / V / Cu multi-core flat wire is drawn through multiple passes to obtain the NbTi / V / Cu multi-core superconducting wire.

[0049] For the NbTi / V / Cu multi-core superconducting wire prepared in Example 3, through experiments, it is found that the critical current density of the NbTi / V / Cu multi-core superconducting wire can reach 3842 A / mm 2 (under a 5T magnetic field).

[0050] Through the above embodiments, we can obtain a method for preparing NbTi / V artificial pinning superconducting wire by using NbTi grooved wire. The critical current density of the prepared NbTi / V artificial pinning superconducting wire is > 3200 A / mm 2 (under a 5T magnetic field). The critical current density of the NbTi / V / Cu artificial pinning superconducting wire obtained by the preparation method of the present application has been greatly improved.

[0051] Although the content of the present application has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be regarded as a limitation of the present application. After those skilled in the art have read the above content, various modifications and substitutions of the present application will be obvious. Therefore, the protection scope of the present application should be defined by the appended claims.

Claims

1. A method for preparing NbTi / V artificial pinning superconducting wire using NbTi grooved wire, characterized in that, The method comprises the following steps: Step 1, material selection: Select NbTi alloy wire, V wire and copper wire; Step 2, making flat tape: Roll the NbTi alloy wire in Step 1. After several rollings, obtain NbTi flat tape. Roll the NbTi flat tape to form a U-shaped groove; Step 3: Embedding and drawing: Use an embedding machine to embed the V wire in Step 1 into the NbTi flat tape with a U-shaped groove in Step 2, and draw it through a die to obtain NbTi / V flat tape; Step 4: Wrapping and drawing: Use a knitting machine to evenly wrap the copper wire in Step 1 on the surface of the NbTi / V flat tape, and then draw and tightly bond the NbTi / V flat tape wrapped with copper wire on a drawing machine to obtain NbTi / V / Cu flat tape; Step 5: Assembly and drawing: Cut the NbTi / V / Cu flat tape in Step 4 to a fixed length, load it into a return-shaped copper tube according to a densely packed structure, and draw the assembled NbTi / V / Cu multi-core flat wire several times to obtain NbTi / V / Cu multi-core superconducting wire; The rolling processing rate in Step 2 is controlled within 5% - 8%; The range of the fixed length in Step 5 is 100 mm to 1000 mm.

2. The method for preparing NbTi / V artificial pinned superconducting wire by using NbTi groove wire according to claim 1, characterized in that, The diameter of the NbTi alloy wire in Step 1 is 3 - 5 mm, the diameter of the V wire is 0.5 - 1 mm, and the diameter of the copper wire is 0.1 mm.

3. The method for preparing NbTi / V artificial pinning superconducting wire by using NbTi grooved wire according to claim 1, characterized in that, The width of the NbTi / V flat tape in Step 3 is 1.2 - 1.5 mm, and the height is 1.0 - 1.2 mm.

4. The method for preparing NbTi / V artificial pinned superconducting wire by using NbTi grooved wire according to claim 1, characterized in that, The diameter of the U-shaped groove is 0.5 - 1 mm.

5. The method for preparing NbTi / V artificial pinning superconducting wire using NbTi grooved wire according to claim 1, characterized in that, The width of the NbTi / V / Cu flat tape obtained in Step 4 is 1.0 - 1.2 mm, and the height is 0.6 - 0.8 mm.

6. The method for preparing NbTi / V artificial pinning superconducting wire by using NbTi grooved wire according to claim 2, characterized in that, The NbTi alloy wire is rolled on a rolling mill.

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