A method for detecting a broken core position and a broken core rate of a superconducting wire

Abstract

The application discloses a kind of superconducting wire broken core position and the detection method of broken core rate, it is related to superconducting wire detection technical field, comprising the following steps: to superconducting composite wire is stretched without mould;To the superconducting composite wire after stretching without mould is stretched with mould;To the superconducting composite wire after stretching with mould is monitored and tested on line size on line resistance;According to the result of on-line size monitoring, broken core position is obtained, and according to the result of on-line resistance test, broken core rate is obtained.The present application is combined with stretching without mould, stretching with mould, on-line size monitoring and on-line resistance test, and the broken core position and broken core rate are obtained, the detection comprehensiveness, detection efficiency and detection accuracy of superconducting wire broken core position and broken core rate are improved, and nondestructive testing is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of superconducting wire detection, in particular to a method for detecting the broken core position and broken core rate of superconducting wire. BACKGROUND

[0002] Superconducting wire is widely used in high-energy physics, medical magnetic resonance imaging (MRI), power transmission and other fields, especially in high magnetic field and low temperature environment. Superconducting wire is usually composed of a porous non-superconducting base wire and several superconducting filaments. These filaments may be broken due to various factors such as material defects and improper processing during production. Broken core not only affects superconducting performance, but also may reduce the current carrying capacity of superconducting wire, thereby affecting its application performance. Therefore, accurately detecting the broken core position and broken core rate of superconducting wire is crucial to ensure product quality and safety.

[0003] The existing method for detecting the broken core of superconducting wire is mainly corrosion method, which corrodes the suspected broken core area of superconducting composite wire to observe the actual broken core condition of the area.

[0004] However, the corrosion method has a large degree of damage to superconducting composite wire, cannot achieve 100% detection, and has poor detection comprehensiveness. At the same time, the corrosion method has high operation complexity and low detection efficiency. In addition, the corrosion method cannot accurately locate the broken core position, and has poor detection accuracy. SUMMARY

[0005] The present application provides a method for detecting the broken core position and broken core rate of superconducting wire to solve the problems of poor detection comprehensiveness, low detection efficiency and poor detection accuracy of the existing superconducting wire broken core detection technology.

[0006] In one aspect, the present application provides a method for detecting the broken core position and broken core rate of superconducting wire, comprising the following steps:

[0007] Step one, stretching the superconducting composite wire without a mold.

[0008] Step two, stretching the superconducting composite wire after mold stretching.

[0009] Step three, online size monitoring and online resistance testing of the superconducting composite wire after mold stretching.

[0010] Step four, obtaining the broken core position according to the online size monitoring result and obtaining the broken core rate according to the online resistance testing result.

[0011] In one possible implementation, in step one, the processing amount of the mold-free stretching is 5%-40%.

[0012] In a possible implementation, in step one, the heating temperature of the free-stretching is 300-600℃, the cooling method is water cooling, and the stretching speed is 5-30m / min.

[0013] In a possible implementation, in step two, the single-pass processing rate of the fixed-stretching is 30%.

[0014] In a possible implementation, in step two, the deviation of the theoretical diameter fluctuation of the superconducting composite wire after the fixed-stretching is within ±0.001mm.

[0015] In a possible implementation, in step three, the monitoring area of the online size is 1mm along the axial direction of the wire, and the monitoring area of the online resistance test is 10mm along the axial direction of the wire.

[0016] In a possible implementation, in step four, the core-breaking position according to the online size monitoring result comprises:

[0017] The position with necking phenomenon in the online size monitoring result is taken as the core-breaking position.

[0018] In a possible implementation, the superconducting composite wire comprises a porous non-superconducting base wire and a plurality of superconducting filaments.

[0019] In step four, the core-breaking rate according to the online resistance test result comprises:

[0020] The core-breaking rate is obtained according to the resistance of the area where the core-breaking position is located and the resistance of the non-core-breaking area by using the difference in resistivity between the porous non-superconducting base wire and the superconducting filaments.

[0021] The method for detecting the core-breaking position and the core-breaking rate of the superconducting wire has the following advantages:

[0022] By combining the free-stretching, the fixed-stretching, the online size monitoring and the online resistance test, the core-breaking position and the core-breaking rate are obtained, and the detection comprehensiveness, the detection efficiency and the detection accuracy of the core-breaking position and the core-breaking rate of the superconducting wire are improved.

[0023] By free-stretching the superconducting composite wire, the defects of the superconducting wire itself can be enlarged, and the detection of the core-breaking is facilitated.

[0024] By fixed-stretching the superconducting composite wire after the free-stretching, the core-breaking problem can be effectively exposed. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only constitute some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0026] Figure 1 A flowchart of a method for detecting a broken core position and a broken core rate of a superconducting wire provided by the embodiments of the present application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only constitute some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] As shown in Figure 1 The embodiments of the present application provide a method for detecting a broken core position and a broken core rate of a superconducting wire, comprising the following steps:

[0029] Step one, dieless stretching of a superconducting composite wire.

[0030] Step two, die stretching of the superconducting composite wire after dieless stretching.

[0031] Step three, online size monitoring and online resistance testing of the superconducting composite wire after die stretching.

[0032] Step four, obtaining a broken core position according to the online size monitoring result and obtaining a broken core rate according to the online resistance testing result.

[0033] Illustratively, in step one, the processing amount of the dieless stretching is 5%-40%.

[0034] Illustratively, in step one, the heating temperature of the dieless stretching is 300-600℃, the cooling method is water cooling, and the stretching speed is 5-30m / min.

[0035] Illustratively, in step two, the single pass processing rate of the die stretching is 30%.

[0036] Illustratively, in step two, the deviation of the theoretical diameter fluctuation of the superconducting composite wire after die stretching is set to be within ±0.001mm.

[0037] Exemplarily, in step three, the monitoring area of the online size is 1mm along the axial direction of the wire, and the monitoring area of the online resistance test is 10mm along the axial direction of the wire.

[0038] Exemplarily, in step four, the broken core position obtained according to the online size monitoring result comprises:

[0039] The position with necking phenomenon in the online size monitoring result is taken as the broken core position.

[0040] Exemplarily, the superconducting composite wire comprises a porous non-superconducting base wire and a plurality of superconducting core filaments.

[0041] In step four, the broken core rate obtained according to the online resistance test result comprises:

[0042] The broken core rate is obtained according to the resistance of the area where the broken core position is located and the resistance of the non-broken core area by utilizing the difference in resistivity between the porous non-superconducting base wire and the superconducting core filaments.

[0043] Specifically, the superconducting composite wires in Embodiment 1 to Embodiment 3 are NbTiCu composite wires, each comprising a porous copper base wire and a plurality of NbTi core filaments.

[0044] Embodiment 1:

[0045] This embodiment provides an implementation process for detecting the broken core position and the broken core rate of a superconducting wire with a copper ratio of 1, a core number of 60, and a finished wire diameter of 0.819mm:

[0046] In step one, the superconducting composite wire with a diameter of 1.200mm is subjected to dieless stretching, the processing amount of dieless stretching is 5%, the diameter is stretched to 1.170mm, the heating temperature is 300℃, the cooling method is water cooling, and the stretching speed is 5m / min.

[0047] In step two, the superconducting composite wire after dieless stretching is subjected to 2 times of die stretching, the single pass processing rate of die stretching is 30%, the theoretical diameter after die stretching fluctuates between 0.818-0.820mm, and the theoretical resistance fluctuates between 599.0-599.2μΩ.

[0048] In step three, the superconducting composite wire after die stretching is subjected to online size monitoring and online resistance test.

[0049] In step four, according to the online size monitoring result, the wire diameter at 13546m is 0.806mm, there is obvious necking phenomenon, so the position is determined as the broken core position. The resistance of the area where the broken core position is located is 582.2μΩ, which is less than the theoretical resistance fluctuation, the broken core rate is obtained by utilizing the difference in resistivity between the porous copper base wire and the NbTi core filaments, and the number of broken cores is calculated as 2, and the number of complete core filaments is 58.

[0050] The detection result of Example 1 is verified by using the corrosion method, and the detection result is correct.

[0051] Example 2

[0052] This embodiment provides the implementation process of the broken core position and the broken core rate detection of the superconducting wire with a copper ratio of 7, a core number of 15 cores and a finished wire diameter of 2.016 mm:

[0053] Step one, the superconducting composite wire with a diameter of 4.599 mm is subjected to moldless stretching, the processing amount of moldless stretching is 20%, stretched to a diameter of 4.113 mm, the heating temperature is 450℃, the cooling method is water cooling, and the stretching speed is 15 m / min.

[0054] Step two, the superconducting composite wire after moldless stretching is subjected to 4 times of die stretching, the single pass processing rate of die stretching is 30%, the theoretical diameter fluctuation after die stretching is 2.015-2.017 mm, and the theoretical resistance fluctuation is 59.5-59.7 μΩ.

[0055] Step three, the superconducting composite wire after die stretching is subjected to online size monitoring and online resistance testing.

[0056] Step four, according to the online size monitoring result, the wire diameter at 9842 m is 2.000 mm, there is obvious necking phenomenon, so the position is determined as the broken core position. The resistance of the area where the broken core position is located is 59.1 μΩ, which is less than the theoretical resistance fluctuation, the broken core rate is obtained by using the resistance rate difference of the multi-hole copper-based wire and the NbTi core wire, and the broken core number is calculated as 1 branch, and the complete core wire number is 14 branches.

[0057] The detection result of Example 2 is verified by using the corrosion method, and the detection result is correct.

[0058] Example 3

[0059] This embodiment provides the implementation process of the broken core position and the broken core rate detection of the superconducting wire with a copper ratio of 2, a core number of 85 cores and a finished wire diameter of 0.873 mm:

[0060] Step one, the superconducting composite wire with a diameter of 2.300 mm is subjected to moldless stretching, the processing amount of moldless stretching is 40%, stretched to a diameter of 1.782 mm, the heating temperature is 600℃, the cooling method is water cooling, and the stretching speed is 30 m / min.

[0061] Step two, the superconducting composite wire after moldless stretching is subjected to 4 times of die stretching, the single pass processing rate of die stretching is 30%, the theoretical diameter fluctuation after die stretching is 0.872-0.874 mm, and the theoretical resistance fluctuation is 407.2-407.4 μΩ.

[0062] Step three, on-line size monitoring and on-line resistance testing are performed on the superconducting composite wire after the die stretching.

[0063] Step four, according to the on-line size monitoring result, the wire diameter at 9842m is 0.865mm, and there is obvious necking phenomenon, so the position is determined as the broken core position. The resistance of the area where the broken core position is located is 396.8μΩ, which is less than the theoretical resistance fluctuation. The broken core rate is obtained by using the resistance rate difference between the porous copper-based wire and the NbTi core wire, and the number of broken cores is calculated to be 5, and the number of complete core wires is 80.

[0064] The detection result of example 3 is verified by using the corrosion method, and the detection result is correct.

[0065] The examples of the present application combine the moldless stretching, die stretching, on-line size monitoring and on-line resistance testing to obtain the broken core position and the broken core rate, and improve the detection comprehensiveness, detection efficiency and detection accuracy of the broken core position and the broken core rate of the superconducting wire.

[0066] The moldless stretching of the superconducting composite wire can magnify the defects of the superconducting wire itself, and facilitate the detection of the broken core.

[0067] The die stretching of the superconducting composite wire after the moldless stretching can effectively expose the broken core problem.

[0068] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to the embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the preferred embodiments and all the changes and modifications falling within the scope of the present application.

[0069] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A method for detecting the location and rate of core breakage in superconducting wires, characterized in that, Includes the following steps: Step 1: Perform moldless stretching on the superconducting composite wire; Step 2: Perform fixed-mold stretching on the superconducting composite wire after moldless stretching; Step 3: Perform online dimensional monitoring and online resistance testing on the superconducting composite wire after it has been stretched in the fixed mold; Step 4: Obtain the location of the broken core based on the online size monitoring results, and obtain the broken core rate based on the online resistance test results; In step one, the processing amount of the moldless stretching is 5%-40%; In step one, the heating temperature for the moldless stretching is 300-600℃, the cooling method is water cooling, and the stretching speed is 5-30m / min; In step two, the single-pass processing rate of the fixed-die stretching is 30%. In step four, obtaining the location of the broken core based on the online dimensional monitoring results includes: The location where necking is observed in the online dimensional monitoring results is taken as the core breakage location; The superconducting composite wire includes a porous non-superconducting baseline and several superconducting core wires; In step four, obtaining the core breakage rate based on the online resistance test results includes: By utilizing the resistivity difference between the porous non-superconducting baseline and the superconducting core wire, the core breakage rate is obtained based on the resistance of the region where the core breakage occurred and the resistance of the non-core breakage region.

2. The method for detecting the location and rate of core breakage in a superconducting wire according to claim 1, characterized in that, In step two, the theoretical diameter fluctuation of the superconducting composite wire after fixed-mold stretching is set to be within ±0.001mm.

3. The method for detecting the location and rate of core breakage in a superconducting wire according to claim 1, characterized in that, In step three, the online dimension monitoring area is 1 mm along the wire axis, and the online resistance test monitoring area is 10 mm along the wire axis.

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