Method for preparing NbTi / V artificial pinning superconducting wire by using NbTi slot line

Abstract

The invention discloses a method for preparing an NbTi / V manual pinning superconducting wire by using an NbTi slot line. The method comprises the following steps: step 1, selecting an NbTi alloy wire, a V wire and a copper wire; 2, the NbTi alloy wire is rolled, and an NbTi flat belt is obtained; 3, the V wire is embedded into the NbTi flat belt with the U-shaped groove through an embedding machine, and a NbTi / V flat belt is obtained through mold drawing; 4, the NbTi / V flat belt is evenly wrapped with copper wires, drawing is conducted to enable the combination to be tight, and an NbTi / V / Cu flat belt is obtained; and step 5, cutting off the NbTi / V / Cu flat belt according to a fixed length, loading the NbTi / V / Cu flat belt into a concentric-square-shaped copper pipe according to the structure, and drawing for multiple times to obtain the NbTi / V / Cu multi-core superconducting wire. The invention belongs to the field of superconducting material processing, and solves the problem that the critical current density of a conventional NbTi superconducting wire has an upper limit. The critical current density of the NbTi / V / Cu artificial pinning superconducting wire is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of superconducting material processing, and in particular relates to a method for preparing a NbTi / V artificial pinning superconducting wire by utilizing a NbTi slot wire. Background Art

[0002] Niobium-titanium superconducting materials are non-ideal type II superconductors. A second phase of material with different properties is introduced into the niobium-titanium superconducting material to prevent the movement of the vortex line, which is called the "pinning center". If the pinning effect is strong enough, the vortex motion can become small enough to improve the performance of the superconducting material. At present, the critical current density of conventional NbTi superconductors is less than 3200A / mm 2 (Under 5T magnetic field).

[0003] Through different processes, people have introduced artificial pinning centers of various shapes and arrangements 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 rod-based, gun-dril, diffused-layer, jelly-roll, power-metallurgy, laminated-structure, etc.

[0004] Traditional NbTi superconductors are all cold-drawn by drawing machines to prepare superconducting wires. The NbTi superconductors prepared by traditional methods use α-Ti in NbTi alloys as pinning centers. However, since the maximum amount of α-Ti precipitation in NbTi alloys can only reach 25%, the critical current density of NbTi superconducting wires prepared by traditional methods has an upper limit. When the α-Ti precipitation reaches 25%, the maximum critical current density can only reach 3200A / 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 slot wire, which solves the problem that there is an upper limit on the critical current density of 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 slot wire, the method comprising the following steps: Step 1. Material selection: Select NbTi alloy wire, V wire and copper wire.

[0007] Step 2, making a flat strip: rolling the NbTi alloy wire of step 1, and obtaining a NbTi flat strip after several rollings, and rolling the NbTi flat strip to form a U-shaped groove.

[0008] Step 3: embedding and drawing: using an embedding machine, the V wire of step 1 is embedded into the NbTi flat strip with a U-shaped groove of step 2, and the NbTi / V flat strip is obtained by drawing through a mold.

[0009] Step 4: Wrapping and drawing: Use a braiding machine to evenly wrap the copper wire of step 1 on the surface of the NbTi / V flat strip, and then draw the NbTi / V flat strip wrapped with the copper wire on a drawing machine to tightly combine them to obtain a NbTi / V / Cu flat strip.

[0010] Step 5: Assembling and drawing: The NbTi / V / Cu flat strip of step 4 is cut into a fixed length, and loaded into a circular copper tube according to a densely packed structure. The assembled NbTi / V / Cu multi-core flat wire is drawn several times to obtain a NbTi / V / Cu multi-core superconducting wire.

[0011] 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.

[0012] Preferably, the NbTi / V flat strip in step 3 has a width of 1.2-1.5 mm and a height of 1.0-1.2 mm.

[0013] Preferably, the diameter of the U-shaped groove is 0.5-1 mm.

[0014] Preferably, the NbTi / V / Cu flat strip obtained in step 4 has a width of 1.0-1.2 mm and a height of 0.6-0.8 mm.

[0015] Preferably, the NbTi alloy wire is rolled in a rolling mill.

[0016] Preferably, the rolling processing rate in step 2 is controlled at 5% to 8%.

[0017] Preferably, the sizing range in step 5 is 100 mm to 1000 mm.

[0018] The beneficial effects of the present invention are as follows: the present invention obtains a NbTi flat strip with a U-shaped groove by rolling NbTi, embeds a V wire in the groove of the NbTi flat strip, and then cold-draws the NbTi / V flat strip, and then braids a copper wire on the surface to obtain a NbTi / V / Cu artificial pinning superconducting wire. The critical current density of the NbTi / V / Cu artificial pinning superconducting wire obtained by the preparation method of the present invention is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of NbTi flat ribbon with U-shaped groove; Figure 2 It is a schematic diagram of embedding V-wire into NbTi flat ribbon with U-shaped groove. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0021] The present application provides a method for preparing a NbTi / V artificial pinning superconducting wire using a NbTi slot wire, comprising the following steps: Step 1: Material selection: Select φ3-5mm NbTi alloy wire, φ0.5-1mm V wire and φ0.1mm copper wire.

[0022] Step 2, flat strip making: NbTi alloy wire with a diameter of φ3-5mm is rolled on a flat strip rolling mill, and after multiple rolling passes (the pass processing rate is controlled at 5%-8%), a NbTi flat strip with a width of 1.2-1.5mm and a height of 1.0-1.2mm is obtained. Then the NbTi flat strip is rolled, such as Figure 1 As shown, a U-shaped groove of φ0.5~1mm is formed.

[0023] Step 3: Embedding and drawing: Use an embedding machine to embed the V wire into the NbTi flat strip with a U-shaped groove, and then draw it through a mold to obtain the NbTi / V flat strip. The structure is as follows: Figure 2 shown.

[0024] Step 4: Wrapping and drawing: Use a braiding machine to evenly wrap the φ0.1mm copper wire on the surface of the NbTi / V flat strip, and then draw the NbTi / V flat strip wrapped with the copper wire on a drawing machine to tightly combine them to obtain a NbTi / V / Cu flat strip with a width of 1.0-1.2mm and a height of 0.6-0.8mm.

[0025] Step 5, assembly and drawing: After the NbTi / V / Cu flat strip is cut to a certain length, it is placed into a circular copper tube according to a certain structure. The assembled NbTi / V / Cu multi-core flat wire is drawn for multiple times to obtain a NbTi / V / Cu multi-core superconducting wire.

[0026] Example 1 Step 1: Select φ3mm NbTi alloy wire, φ0.5mm V wire and φ0.1mm copper wire.

[0027] Step 2: Roll the φ3mm NbTi alloy wire on a flat strip rolling mill, and after multiple passes of rolling (the pass processing 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 φ0.5mm U-shaped groove.

[0028] Step 3: Use an embedding machine to embed the V wire into the NbTi flat strip with a U-shaped groove, and draw it through a mold to obtain a NbTi / V flat strip with a width of 1.10 mm and a height of 0.90 mm.

[0029] Step 4: Use a braiding machine to evenly wrap the φ0.1 mm copper wire on the surface of the NbTi / V flat strip, and then draw the NbTi / V flat strip wrapped with the copper wire on a drawing machine to tightly combine them to obtain a NbTi / V / Cu flat strip with a width of 1.20 mm and a height of 1.00 mm.

[0030] Step 5: Cut the NbTi / V / Cu flat strip to a certain length and put it into a round 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. The assembled NbTi / V / Cu multi-core flat wire is drawn multiple times to obtain the NbTi / V / Cu multi-core superconducting wire.

[0031] The critical current density of the NbTi / V / Cu multi-core superconducting wire prepared in Example 1 is obtained by measuring the critical current of the superconducting wire by dividing it by the area. The critical current density can reach 3800A / mm 2 (Under 5T magnetic field).

[0032] Example 2 Step 1. Select φ5mm NbTi alloy wire, φ1mm V wire and φ0.1mm copper wire.

[0033] Step 2: Roll the φ5mm NbTi alloy wire on a flat strip rolling mill, and after multiple passes of rolling (the pass processing 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 φ1.0mm U-shaped groove.

[0034] Step 3: Use an embedding machine to embed the V-wire into the NbTi flat strip with a U-shaped groove, and draw it through a mold to obtain a NbTi / V flat strip with a width of 1.40 mm and a height of 1.10 mm.

[0035] Step 4: Use a braiding machine to evenly wrap the φ0.1 mm copper wire on the surface of the NbTi / V flat strip, and then draw the NbTi / V flat strip wrapped with the copper wire on a drawing machine to tightly combine them to obtain a NbTi / V / Cu flat strip with a width of 1.50 mm and a height of 1.20 mm.

[0036] Step 5: Cut the NbTi / V / Cu flat strip to a certain length and install it into a round copper tube with an inner hole width of 7.70mm, a height of 6.10mm and a thickness of 3mm according to a certain structure. The assembled NbTi / V / Cu multi-core flat wire is drawn multiple times to obtain a NbTi / V / Cu multi-core superconducting wire.

[0037] The critical current density of the NbTi / V / Cu multi-core superconducting wire prepared in Example 2 is obtained by measuring the critical current of the superconducting wire by dividing it by the area. The experiment shows that the critical current density of the NbTi / V / Cu multi-core superconducting wire can reach 3870A / mm 2 (Under 5T magnetic field).

[0038] Example 3 Step 1. Select φ4mm NbTi alloy wire, φ0.8mm V wire and φ0.1mm copper wire.

[0039] Step 2: Roll the φ4mm NbTi alloy wire on a flat strip rolling mill, and after multiple passes of rolling (the pass processing rate is controlled at 5%), obtain a NbTi flat strip with a width of 1.30mm and a height of 1.00mm. Then roll the NbTi flat strip to form a φ0.8mm U-shaped groove.

[0040] Step 3: Use an embedding machine to embed the V-wire into the NbTi flat strip with a U-shaped groove, and draw it through a mold to obtain a NbTi / V flat strip with a width of 1.40 mm and a height of 1.10 mm.

[0041] Step 4: Use a braiding machine to evenly wrap the φ0.1 mm copper wire on the surface of the NbTi / V flat strip, and then draw the NbTi / V flat strip wrapped with the copper wire on a drawing machine to tightly combine them to obtain a NbTi / V / Cu flat strip with a width of 1.30 mm and a height of 1.00 mm.

[0042] Step 5: Cut the NbTi / V / Cu flat strip to a certain length and install it into a round copper tube with an inner hole width of 7.00mm, a height of 5.50mm and a thickness of 3mm according to a certain structure. The assembled NbTi / V / Cu multi-core flat wire is drawn multiple times to obtain a NbTi / V / Cu multi-core superconducting wire.

[0043] The NbTi / V / Cu multi-core superconducting wire prepared in Example 3 has a critical current density of 3842A / mm2. 2 (Under 5T magnetic field).

[0044] Through the above examples, we can conclude that the method of preparing NbTi / V artificial pinned superconducting wire by using NbTi slot wire in this application can prepare NbTi / V artificial pinned superconducting wire with critical current density>3200A / mm2 (Under 5T magnetic field). The critical current density of the NbTi / V / Cu artificial pinned superconducting wire obtained by the preparation method of the present application is greatly improved.

[0045] Although the content of the present application has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present application. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present application can be made. Therefore, the protection scope of the present application should be limited by the appended claims.

Claims

1. A method for preparing a NbTi / V artificial pinned superconducting wire using a NbTi slot 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 a flat strip: rolling the NbTi alloy wire of step 1, and obtaining a NbTi flat strip after several rollings, and rolling the NbTi flat strip to form a U-shaped groove; Step 3: embedding and drawing: using an embedding machine to embed the V wire of step 1 into the NbTi flat strip with a U-shaped groove of step 2, and drawing through a mold to obtain a NbTi / V flat strip; Step 4: Wrapping and drawing: Use a braiding machine to evenly wrap the copper wire of step 1 on the surface of the NbTi / V flat strip, and then draw the NbTi / V flat strip wrapped with the copper wire on a drawing machine to tightly combine them to obtain a NbTi / V / Cu flat strip; Step 5: Assembling and drawing: The NbTi / V / Cu flat strip of step 4 is cut into a fixed length, and loaded into a circular copper tube according to a densely packed structure. The assembled NbTi / V / Cu multi-core flat wire is drawn several times to obtain a NbTi / V / Cu multi-core superconducting wire.

2. The method for preparing a NbTi / V artificial pinning superconducting wire using a NbTi slot 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 slot wire according to claim 1, characterized in that: The width of the NbTi / V flat strip 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 pinning superconducting wire by using NbTi slot 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 by using NbTi slot wire according to claim 1, characterized in that: The NbTi / V / Cu flat strip obtained in step 4 has a width of 1.0-1.2 mm and a height of 0.6-0.8 mm.

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

7. The method for preparing NbTi / V artificial pinning superconducting wire by using NbTi slot wire according to claim 1, characterized in that: The rolling processing rate in step 2 is controlled at 5% to 8%.

8. The method for preparing NbTi / V artificial pinning superconducting wire by using NbTi slot wire according to claim 1, characterized in that: The range of the sizing in step 5 is 100 mm to 1000 mm.

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