Superconducting wire torque measuring method

Abstract

The invention belongs to the technical field of superconducting material detection, and particularly relates to a superconducting wire torque measuring method. The invention discloses a superconducting wire torque measuring method, which comprises the following steps of: annealing a superconducting wire to be detected in an annealing furnace, spraying paint on the surface of the superconducting wire, rolling the superconducting wire, removing paint, and measuring the distance between threads on the surface of a bare wire. And calculating the torque of the superconducting wire according to the distance between the threads, the number of core wires on the outermost layer of the wire and the length of the wire before and after rolling. The torque of the wire rod is measured according to the hardness difference between the superconductor and the base body. The method is simple to operate, wide in application range and high in measurement precision.

Description

Technical Field

[0001] The invention belongs to the technical field of superconducting material detection, and in particular relates to a method for measuring the torque of a superconducting wire. Background Art

[0002] Changes in the magnetic field will induce coupling currents in the multi-core composite superconductor. The coupling currents pass through the matrix between the core wires, forming loops between the superconducting wires, resulting in coupling losses.

[0003] The twisting process improves the performance of the superconducting wire under the external magnetic field and current by optimizing the magnetic field and current distribution of the multi-core superconducting wire, and reduces the energy loss caused by factors such as magnetic flux pinning, vortex motion, eddy current loss, and uneven current distribution. In this way, the superconductor can maintain higher superconductivity, conduct current better, and significantly improve the working efficiency and stability of the superconducting wire. In particular, accurate twisting technology is of great significance for high-precision superconducting applications such as MRI scanners, particle accelerators, and high magnetic field applications. Therefore, it is necessary to accurately measure the torque of the superconducting wire to reduce the coupling loss of the superconducting wire during the magnetic field change process and improve the stability and transmission efficiency of the superconducting current.

[0004] The conventional method for measuring the torque of superconducting wires is the "corrosion-detwist method", which is to use acid to corrode the matrix, leaving the twisted core wire that cannot be corroded, detwist it, and then measure the torque. This method is only applicable to "the matrix can be corroded / the superconductor cannot be corroded" and in actual operation, the manual operation of detwist has a great influence, and the measurement accuracy is average. It is necessary to study a more accurate superconducting wire torque measurement method to adapt to high-precision superconducting applications. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a more environmentally friendly and more accurate superconducting wire torque measurement method. This method uses annealing to adjust the hardness difference between the superconductor and the matrix to make the hardness difference more obvious, and then performs flat rolling on the wire. The cross-sectional shape and size of the wire are adjusted by flat rolling, and the actual torque of the wire is calculated using a rebound mechanism.

[0006] In one aspect, the present invention provides a method for measuring torque of a superconducting wire, the method comprising the following steps: Step 1: Take a wire to be tested, where the number of core wires in the outermost layer of the wire to be tested is counted as n2; Step 2: placing the wire to be inspected into an annealing furnace for annealing to obtain an annealed wire; Step 3: spray paint the annealed wire obtained in step 2, cut a section of the painted wire and measure its length, marking the length as L1; Step 4: Flat-roll the painted wire obtained in step 3, and measure the length of the wire after rolling, marking the length as L2; Step 5: Remove the paint from the wire after rolling in step 4, measure the pitch length between n1 threads on the surface of the bare wire after the paint is removed, and mark the pitch length as L3; Step 6: Calculate the torque based on the measured data; the torque calculation formula is as follows: .

[0007] Furthermore, in the superconducting wire torque measurement method, the wire to be tested in step 1 is a multi-core superconducting wire obtained by twisting and stretching.

[0008] Furthermore, in the superconducting wire torque measurement method, the number of cores of the multi-core superconducting wire is not higher than 100 cores.

[0009] Furthermore, in the superconducting wire torque measurement method, the annealing temperature in step 2 is 200-450° C., and the annealing time is 20-45 min.

[0010] Furthermore, in the superconducting wire torque measurement method, the paint applied in the painting treatment in step three is acetal paint, and the viscosity of the acetal paint is 2300-2700maps.

[0011] Furthermore, in the superconducting wire torque measurement method, the thickness of the paint film after the spray painting is 100-200 microns.

[0012] Furthermore, in the superconducting wire torque measurement method, the height of the plane rolling in step 4 is 1 / 2 to 1 / 3 of the height of the wire after painting.

[0013] Furthermore, in the superconducting wire torque measurement method, the paint removal in step 5 is carried out by soaking in oxalic acid.

[0014] On the other hand, the present invention also provides a computer device, comprising: a processor and a memory, wherein the memory stores at least one program code, and the at least one program code is loaded and executed by the processor to implement the operations performed in the above-mentioned superconducting wire torque measurement method.

[0015] On the other hand, the present invention further provides a computer-readable storage medium, wherein at least one program code is stored in the computer-readable storage medium, and the at least one program code is loaded and executed by a processor to implement the operations performed in the above-mentioned superconducting wire torque measurement method.

[0016] Compared with the prior art, the technical solution provided by the present invention has at least the following beneficial effects or advantages: The present invention applies the annealing process to adjust the hardness difference between the superconducting material and the matrix, making the hardness difference more obvious, and then flat rolling the superconducting wire, adjusting the cross-sectional shape and size of the wire through flat rolling, and using the rebound mechanism to calculate the actual torque of the wire. The superconducting wire torque measurement method is simple to operate, has high measurement accuracy, and has a wide range of applications. It overcomes the measurement limitation of the prior art "corrosion-backtwist method" that is only applicable to "matrix can be corroded / superconductor cannot be corroded", and overcomes the limitations of the prior art that the actual operation is cumbersome, the backtwist manual operation has a large impact, and the measurement accuracy is not high. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the cross section of the wire core in Example 1. Figure 1 1 in the middle is copper; Figure 1 2 in the middle is the core wire of the wire.

[0018] Figure 2 This is a schematic diagram of the pitch measurement between the six threads on the surface of the wire after paint removal in Example 1. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is described below in conjunction with embodiments; however, the present invention is not limited to the following embodiments.

[0020] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0021] The experimental methods and detection methods described in the following embodiments are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0022] Example 1 This embodiment provides a measurement example of the torque of a wire with a copper ratio of 7, a core number of 6, and a finished wire specification of Φ1.856mm.

[0023] The theoretical torque of the wire is 35 mm. The torque measurement method for niobium-titanium (Nb-Ti) and niobium-tin (Nb3Sn) composite superconductors in the GB / T 40296-2021 standard, hereinafter referred to as the "corrosion-detorsion method", is used to measure the torque to be 37 mm. The measurement steps of the torque measurement method provided by the present invention are as follows: Take a 5m sample of wire with a copper ratio of 7, 6 cores, and a finished wire specification of Φ1.856mm as the wire to be tested. Record the number of core wires in the outermost layer of the wire to be tested. The number of core wires in the outermost layer of the wire to be tested is 6, and record n2=6. Put the wire to be tested into an annealing furnace and anneal it at 200℃ for 20min. Then use acetal paint with a viscosity of 2300~2700maps to spray paint the wire. The paint thickness is 100 microns. After spraying, the wire specification is Φ1.956mm. Select a position of 2m (L1) in the middle of the sample for marking, and flat roll the selected wire. The rolling height is H0.800mm. After rolling, the length between the measured marks is 2.10m (L2). Then, oxalic acid was used to remove the paint from the rolled wire until there were obvious threads on the bare wire surface. The spacing between the 6 (n1) threads was measured, which was the pitch. The pitch was recorded and was 30 mm (L3). Figure 1 As shown in the figure, the number of core wires is 6. The pitch between the 6 threads on the surface of the wire after depainting is measured as follows Figure 2 As shown, Figure 2 The six threads are marked as 1, 2, 3, 4, 5, and 6. The distance between the six threads is the pitch, which is 30 mm. The wire torque is calculated according to the wire torque formula.

[0024]

[0025] Where: n2 is the number of core wires in the outermost layer of the wire; L1 is the length of the annealed wire after painting; L2 is the length of the wire after flat rolling; L3 is the pitch length between n1 threads on the surface of the bare wire after depainting; n1 is the number of threads corresponding to the pitch length.

[0026] The torque of this wire is calculated to be 34.3mm.

[0027] The torque of the wire measured by the torque measurement method provided by the present invention is 34.3 mm, which is closer to the theoretical torque of 35 mm of the wire and has higher measurement accuracy than the torque of 37 mm measured by the "corrosion-detorsion method".

[0028] Example 2 The present invention provides a measurement example of wire torque with a copper ratio of 3, a core number of 54, and a finished wire specification of Φ0.895mm.

[0029] The theoretical torque of the wire is 85mm, and the torque measured by the "corrosion-detorsion method" is 88mm. The measurement steps of the torque measurement method provided by the present invention are as follows: Take a 5m sample of wire with a copper ratio of 3, 54 cores, and a finished wire specification of Φ0.895mm as the wire to be tested. Record the number of core wires in the outermost layer of the wire to be tested. The number of core wires in the outermost layer of the wire to be tested is 24, and record n2=24. Put the wire to be tested into an annealing furnace and anneal it at 350℃ for 40min. Then, use acetal paint with a viscosity of 2300~2700maps to spray paint the wire. The paint thickness is 200 microns. After spraying, the wire specification is Φ1.000mm. Select a position of 2m (L1) in the middle of the sample for marking, and flat-roll the wire. The rolling height is H0.400mm. After rolling, the length between the measured marks is 2.05m (L2). Subsequently, oxalic acid was used to remove the paint from the wire until obvious threads appeared on the surface of the bare wire. The spacing between the 7 (n1) threads, i.e. the pitch, was measured and recorded. The pitch was 22 mm (L3). The torque was calculated using the wire torque calculation formula of Example 1.

[0030] The torque of this wire is calculated to be 85.9mm.

[0031] The torque of the wire measured by the torque measurement method provided by the present invention is 85.9 mm, which is closer to the theoretical torque of 85 mm of the wire and has higher measurement accuracy than the torque of 88 mm measured by the "corrosion-detorsion method".

[0032] Example 3 The present invention provides a measurement example of wire torque with a copper ratio of 1.5, a core number of 85 cores, and a finished wire specification of Φ1.400mm.

[0033] The theoretical torque of the wire is 45 mm, and the torque measured by the "corrosion-detorsion method" is 43.6 mm. The measurement steps of the torque measurement method provided by the present invention are as follows: Take a 5m sample of wire with a copper ratio of 1.5, 85 cores, and a finished wire specification of Φ1.400mm as the wire to be tested. Record the number of core wires in the outermost layer of the wire to be tested. The number of core wires in the outermost layer of the wire to be tested is 6, and record n2=6. Put the wire to be tested into an annealing furnace and anneal at 450℃ for 45min. Then, use acetal paint with a viscosity of 2300~2700maps to spray paint the wire. The paint thickness is 200 microns. After spraying, the wire specification is Φ1.600mm. Select a position of 2m (L1) in the middle of the sample for marking, and flat roll the wire. The rolling height is H0.600mm. After rolling, the length between the measured marks is 2.3m (L2). Then use oxalic acid to remove the paint from the wire until there are obvious threads on the bare wire surface. Measure the spacing between 7 (n1) threads, which is the pitch. Record the pitch. The pitch is 52mm (L3). The torque is calculated using the wire torque calculation formula of Example 1.

[0034] The torque of this wire is calculated to be 45.2mm.

[0035] The torque of the wire measured by the torque measurement method provided by the present invention is 45.2 mm, which is closer to the theoretical torque of 45 mm of the wire and has higher measurement accuracy than the torque of 43.6 mm measured by the "corrosion-detorsion method".

[0036] As described above, the basic principle, main features and advantages of the present invention are well described. The above embodiments and descriptions are only descriptions of the preferred embodiments of the present invention, and the present invention is not limited by the above embodiments. Without departing from the spirit and scope of the present invention, various changes and improvements made by ordinary technicians in this field to the technical solution of the present invention should fall within the protection scope determined by the present invention.

Claims

1. A method for measuring torque of a superconducting wire, characterized in that: The steps include: Step 1: Take a wire to be tested, where the number of core wires in the outermost layer of the wire to be tested is counted as n2; Step 2: placing the wire to be inspected into an annealing furnace for annealing to obtain an annealed wire; Step 3: spray paint the annealed wire obtained in step 2, cut a section of the painted wire and measure its length, marking the length as L1; Step 4: Flat-roll the painted wire obtained in step 3, measure the length of the wire after rolling, and mark the length as L2; Step 5: Remove the paint from the wire after rolling in step 4, measure the pitch length between n1 threads on the surface of the bare wire after the paint is removed, and mark the pitch length as L3; Step 6: Calculate the torque based on the measured data; the torque calculation formula is as follows: 。 2. The superconducting wire torque measurement method according to claim 1, characterized in that: The wire to be inspected in step 1 is a multi-core superconducting wire obtained by twisting and stretching.

3. The superconducting wire torque measurement method according to claim 2, characterized in that: The number of cores of the multi-core superconducting wire is not more than 100 cores.

4. The superconducting wire torque measurement method according to claim 1, characterized in that: In the step 2, the annealing temperature is 200-450° C., and the annealing time is 20-45 minutes.

5. The superconducting wire torque measurement method according to claim 1, characterized in that: The paint used in the spray painting treatment in step 3 is acetal paint, and the viscosity of the acetal paint is 2300-2700 maps.

6. The superconducting wire torque measurement method according to claim 5, characterized in that: The paint film thickness after spray painting is 100~200 microns.

7. The superconducting wire torque measurement method according to claim 1, characterized in that: The height of the flat rolling in step 4 is 1 / 2 to 1 / 3 of the height of the wire after painting.

8. The superconducting wire torque measurement method according to claim 1, characterized in that: In the step 5, the paint is removed by soaking in oxalic acid.

9. A computer device, characterized in that: The computer device includes: a processor and a memory, wherein at least one program code is stored in the memory, and the at least one program code is loaded and executed by the processor to implement the operations performed in the superconducting wire torque measurement method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one program code, and the at least one program code is loaded and executed by the processor to implement the operations performed in the superconducting wire torque measurement method according to any one of claims 1 to 8.

Images