High-performance superconducting switch line and preparation method thereof

Abstract

The invention discloses a high-performance superconducting switch line and a preparation method, and relates to the technical field of superconducting wire preparation, and the preparation method comprises the following steps: S1, placing a plurality of Nb rods, printing oxygen-free copper into a cylinder, filling gaps between adjacent Nb rods with the cylinder to prepare a CuNb composite ingot, adding oxygen-free copper covers at two ends of the composite ingot, and sealing and welding to form a composite sheath; s2, a CuNb composite rod is prepared and drilled, and a CuNb composite pipe is obtained; s3, preparing a subcomponent of the enhanced internal tin method Nb3Sn superconducting wire; and S4, preparing a final blank, and drawing and twisting the final blank to obtain the high-performance superconducting switch wire rod. And S5, sampling the wire rod, performing heat treatment, and testing a critical current value and a residual resistance ratio of the wire rod after the wire rod is discharged from the furnace. On the basis of an internal tin method Nb3Sn preparation process, the enhanced internal tin method Nb3Sn superconducting switch line of which the comprehensive performance is comprehensively improved compared with that of an NbTi superconducting switch line is prepared, and the residual resistance ratio is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of superconducting wire preparation. Background Art

[0002] Superconducting switch wires are an indispensable and important component of manufacturing large scientific devices such as superconducting magnets. At present, the switch wires used in various scientific projects in the world are mainly copper-nickel-based NbTi superconducting wires, which mainly face the problem of low critical current values ​​under high background magnetic field conditions. Therefore, it is crucial to design, develop and mass-produce superconducting switch wires with higher performance. The common copper-nickel-based NbTi superconducting switch wires have low critical current values ​​under high background magnetic field conditions (the upper critical magnetic field is only 11.5T), while the critical current value of Nb3Sn wires (the upper critical magnetic field is above 25T) under high background magnetic field conditions is higher than that of NbTi superconducting wires. In addition, another important performance requirement of superconducting switch wires is that the residual resistance ratio of the wire is 1~10. The residual resistance ratio of copper-nickel-based NbTi superconducting switch wires is mainly determined by their copper-nickel matrix.

[0003] For the internal tin method Nb3Sn wire, how to significantly improve the low-temperature resistance of the wire matrix, achieve a significant reduction in the residual resistance ratio, and meet the performance indicators of the switch line. Obtaining a superconducting switch line with a high critical current value, a low residual resistance ratio, and not prone to brittle fracture is an urgent problem to be solved. Summary of the invention

[0004] The purpose of the present invention is to solve the above technical problems and provide a high-performance superconducting switch wire and a preparation method thereof, and the comprehensive performance of the prepared switch wire is greatly improved.

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions: A method for preparing a high-performance superconducting switch line, S1, vertically placing a plurality of Nb rods on a circular base. Using 3D printing technology, printing oxygen-free copper into a cylinder with the same specifications as the circular base, and filling the gaps between adjacent Nb rods to make a CuNb composite ingot, adding oxygen-free copper caps at both ends of the composite ingot and performing electron beam sealing welding to obtain a CuNb composite sheath; S2, heating, heat-insulating, and extruding the CuNb composite sheath obtained in step S1 to obtain a CuNb composite rod, and drilling holes in batches at the center of the CuNb composite rod to obtain a CuNb composite tube; S3, cold-extrude the SnTi alloy ingot into a SnTi alloy tube, insert a Ta rod of matching size into the SnTi alloy tube to obtain a SnTi / Ta composite rod, and then insert the obtained SnTi / Ta composite rod into the CuNb composite tube obtained in step S2 to obtain an enhanced internal tin method Nb3Sn superconducting wire subcomponent, draw the obtained internal tin method Nb3Sn superconducting wire subcomponent, and cut the drawn internal tin method Nb3Sn superconducting wire subcomponent into multiple equal lengths and evenly arrange them; S4. Load the plurality of inner tin method Nb3Sn superconducting wire subcomponents obtained in step S3 into an oxygen-free copper tube to obtain a final billet, and draw and twist the final billet to finally obtain a high-performance superconducting switch wire. S5. Samples are taken from the high-performance superconducting switch wire obtained in step S4, and heat treated. After being taken out of the furnace, the critical current value and the residual resistance ratio are tested.

[0006] Furthermore, in step S1, the number of Nb rods is 100-150, the specification of the Nb rods is φ9mm-φ12mm, and the specification of the printed CuNb composite ingot is φ280mm-φ300mm.

[0007] Furthermore, in step S2, the extrusion temperature is 700° C. to 900° C., and the insulation time is 60 min to 90 min.

[0008] Furthermore, the outer diameter of the CuNb composite rod obtained in step S2 is φ52 mm to φ75 mm, and the drill hole diameter is φ30 mm to φ35 mm, and the drill hole diameter is 1.0 mm larger than that of the SnTi / Ta composite rod.

[0009] Furthermore, in step S3, the SnTi ingot is cold extruded into a SnTi alloy tube with an outer diameter of φ29mm~φ34mm and an inner hole diameter of φ10mm~φ15mm. The outer diameter of the Ta rod used is φ9.5mm~φ14.5mm. The Ta rod is inserted into the SnTi alloy tube to obtain a SnTi / Ta composite rod. The SnTi / Ta alloy rod is inserted into the CuNb composite tube obtained in step S2 to obtain an enhanced internal tin method Nb3Sn superconducting wire subcomponent, and the enhanced internal tin method Nb3Sn superconducting wire subcomponent is drawn, and the inner tin method Nb3Sn superconducting wire subcomponent obtained after drawing has a side size of 5mm~15mm.

[0010] Furthermore, in step S4, the outer diameter of the oxygen-free copper tube is φ60 mm to φ75 mm, and the inner diameter of the oxygen-free copper tube is φ45 mm to φ60 mm.

[0011] Furthermore, in step S4, the final billet is drawn, and then twisted and finally stretched to obtain the Nb3Sn superconducting wire, wherein the twisting pitch is 15mm~40mm.

[0012] Furthermore, in step S5, the wire sample is heat treated by a standard internal tin method Nb3Sn heat treatment process, and the critical current value and residual resistance ratio of the sample are tested after it is taken out of the furnace.

[0013] The beneficial effects of the present invention are as follows: 1. The present invention discloses a high-performance superconducting switch wire and a preparation method thereof. An enhanced internal tin method Nb3Sn superconducting switch wire with comprehensive performance improved over that of NbTi superconducting switch wire is prepared based on the internal tin method Nb3Sn preparation process. The traditional Ta barrier layer is removed so that the Sn element diffuses into the oxygen-free copper matrix during the heat treatment process, which significantly improves the low-temperature resistance of the wire matrix and meets the requirements of the superconducting switch for high resistance characteristics. Ta rod reinforcement is introduced into the core of the subcomponent to effectively improve the brittleness problem of the Nb3Sn wire after heat treatment. The process system successfully solves the contradiction between high resistance and high current carrying capacity of superconducting switch wires through the collaborative innovation of materials, structures and processes, and has important application value in the fields of cutting-edge equipment such as nuclear magnetic resonance and particle accelerators. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic cross-sectional view of a CuNb composite sheath of the present invention.

[0015] Figure 2 This is a schematic cross-sectional view of a subcomponent of an internal tin method Nb3Sn superconducting wire of the present invention.

[0016] Figure 3 This is a schematic cross-sectional view of an internal tin method Nb3Sn superconducting wire of the present invention.

[0017] Reference numerals: 1. Nb rod; 2. oxygen-free copper; 3. SnTi alloy tube; 4. Ta rod; 5. internal tin method Nb3Sn superconducting wire subcomponent; 6. oxygen-free copper tube. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0019] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] like Figures 1 to 3 As shown, a high-performance superconducting switch line is disclosed. The high-performance superconducting switch line structure includes a SnTi / Ta composite rod, a CuNb composite tube, and an oxygen-free copper tube 6 from the inside to the outside, wherein the SnTi / Ta composite rod includes a Ta rod 4 located in the center and a SnTi alloy tube 3 located at the periphery, and the Nb rod 1 and the oxygen-free copper 2 in the CuNb composite tube are interlocked, and the SnTi / Ta composite rod is inserted into the CuNb composite tube to form an inner tin method Nb3Sn superconducting wire subelement 5.

[0021] like Figures 1 to 3 As shown, this embodiment provides a method for preparing a high-performance superconducting switch line, comprising the following steps: S1. Place multiple Nb rods 1 vertically on a circular base. Use 3D printing technology to print oxygen-free copper 2 into a cylinder with the same specifications as the circular base, and fill the gaps between adjacent Nb rods 1 to make a CuNb composite ingot. Add oxygen-free copper caps to both ends of the composite ingot and perform electron beam sealing welding to obtain a CuNb composite sheath; S2, heating, heat-insulating, and extruding the CuNb composite sheath obtained in step S1 to obtain a CuNb composite rod, and drilling holes in batches at the center of the CuNb composite rod to obtain a CuNb composite tube; S3, cold-extrude the SnTi alloy ingot into a SnTi alloy tube 3, insert a Ta rod 4 of a size matching the SnTi alloy tube 3 to obtain a SnTi / Ta composite rod, and then insert the obtained SnTi / Ta composite rod into the CuNb composite tube obtained in step S2 to obtain an enhanced internal tin method Nb3Sn superconducting wire subcomponent 5, draw the obtained internal tin method Nb3Sn superconducting wire subcomponent 5, and cut the drawn internal tin method Nb3Sn superconducting wire subcomponent 5 into multiple equal lengths and evenly arrange them; S4. Load the plurality of internal tin method Nb3Sn superconducting wire subcomponents 5 obtained in step S3 into the oxygen-free copper tube 6 to obtain a final billet, and draw and twist the obtained final billet to finally obtain a high-performance superconducting switch wire. S5. Samples are taken from the high-performance superconducting switch wire obtained in step S4, and heat treated. After being taken out of the furnace, the critical current value and the residual resistance ratio are tested.

[0022] Furthermore, in step S1, the number of Nb rods 1 is 100-150, the specification of Nb rods 1 is φ9mm-φ12mm, and the specification of the printed CuNb composite ingot is φ280mm-φ300mm.

[0023] Furthermore, in step S2, the extrusion temperature is 700° C. to 900° C., and the holding time is 60 min to 90 min.

[0024] Furthermore, the outer diameter of the CuNb composite rod obtained in step S2 is φ52 mm~φ75 mm, and the drill hole diameter is φ30 mm~φ35 mm, which is 1.0 mm larger than that of the SnTi / Ta composite rod.

[0025] Furthermore, in step S3, the SnTi ingot is cold extruded into a SnTi alloy tube 3 with an outer diameter of φ29mm~φ34mm and an inner hole diameter of φ10mm~φ15mm. The outer diameter of the Ta rod 4 used is φ9.5mm~φ14.5mm. The Ta rod 4 is inserted into the SnTi alloy tube 3 to obtain a SnTi / Ta composite rod. The SnTi / Ta alloy rod is inserted into the CuNb composite tube obtained in step S2 to obtain an enhanced internal tin method Nb3Sn superconducting wire subcomponent 5, and the enhanced internal tin method Nb3Sn superconducting wire subcomponent 5 is drawn. After drawing, the internal tin method Nb3Sn superconducting wire subcomponent 5 has a side size of 5mm~15mm.

[0026] Furthermore, in step S4, the outer diameter of the oxygen-free copper tube 6 is φ60 mm to φ75 mm, and the inner diameter of the oxygen-free copper tube 6 is φ45 mm to φ60 mm.

[0027] Furthermore, in step S4, the final billet is drawn, and then twisted and finally stretched to obtain the Nb3Sn superconducting wire, wherein the twisting pitch is 15 mm to 40 mm.

[0028] Furthermore, in step S5, the wire sample is heat treated by a standard internal tin method Nb3Sn heat treatment process, and the critical current value and residual resistance ratio of the sample are tested after it is taken out of the furnace.

[0029] The following is an explanation of the specific process: Embodiment 1: Step 1, 100 Nb rods 1 with a specification of φ9 mm are placed vertically on a circular base with a specification of φ280 mm. Using 3D printing technology, oxygen-free copper 2 is printed into a cylinder with the same specifications as the circular base, and the gaps between adjacent Nb rods 1 are filled to form a CuNb composite ingot, and oxygen-free copper caps are added to both ends of the composite ingot and electron beam sealing is performed to obtain a CuNb composite sheath; Step 2, heating the CuNb composite sheath obtained in step S1 to 700° C. and keeping the temperature for 60 min, extruding to obtain a CuNb composite rod, and drilling a hole with a specification of φ30 mm at the center of the CuNb composite rod to obtain a CuNb composite tube; Step 3, cold-extrude the SnTi alloy ingot into a SnTi alloy tube 3 with a specification of φ29 / φ10 mm, insert a φ9.5 mm Ta rod 4 into the SnTi alloy tube 3 to obtain a SnTi / Ta composite rod, and then insert the obtained SnTi / Ta composite rod into the CuNb composite tube obtained in step 2 to obtain an enhanced internal tin method Nb3Sn superconducting wire subcomponent 5, draw the obtained internal tin method Nb3Sn superconducting wire subcomponent 5, and cut the drawn internal tin method Nb3Sn superconducting wire subcomponent 5 into multiple equal lengths and evenly arrange them. The opposite side dimension of the internal tin method Nb3Sn superconducting wire subcomponent 5 obtained after drawing is 5 mm.

[0030] Step 4, load the multiple internal tin method Nb3Sn superconducting wire subcomponents 5 obtained in step 3 into the φ60 / φ45mm oxygen-free copper tube 6 to obtain the final billet, and draw and twist the final billet to finally obtain a high-performance superconducting switch wire with a wire specification of 0.5mm and a torque of 15mm. Step 5, taking samples from the high-performance superconducting switch wire obtained in step 4, and heat treating them, and testing their critical current value and residual resistance ratio after they are taken out of the furnace.

[0031] The test results of the sample low temperature performance are as follows:

[0032] In this embodiment 1, a superconducting switch wire with a length of 3000 m is successfully prepared by using a preparation method of a high-performance superconducting switch wire. Its critical current value is greatly improved, and its residual resistance ratio also meets relevant technical requirements.

[0033] Embodiment 2: Step 1, 125 Nb rods 1 with a specification of φ10 mm are placed vertically on a circular base with a specification of φ300 mm. Using 3D printing technology, oxygen-free copper 2 is printed into a cylinder with the same specifications as the circular base, and the gaps between adjacent Nb rods 1 are filled to form a CuNb composite ingot, and oxygen-free copper caps are added to both ends of the composite ingot and electron beam sealing is performed to obtain a CuNb composite sheath; Step 2, heating the CuNb composite sheath obtained in step S1 to 800° C. and keeping the temperature for 80 minutes, extruding to obtain a CuNb composite rod, and drilling a hole with a specification of φ32 mm at the center of the CuNb composite rod to obtain a CuNb composite tube; Step 3, cold-extrude the SnTi alloy ingot into a SnTi alloy tube 3 with a specification of φ31 / φ12 mm, insert a φ11 mm Ta rod 4 into the SnTi alloy tube 3 to obtain a SnTi / Ta composite rod, and then insert the obtained SnTi / Ta composite rod into the CuNb composite tube obtained in step 2 to obtain an enhanced internal tin method Nb3Sn superconducting wire subcomponent 5, draw the obtained internal tin method Nb3Sn superconducting wire subcomponent 5, and cut the drawn internal tin method Nb3Sn superconducting wire subcomponent 5 into multiple equal lengths and evenly arrange them. The opposite side dimension of the internal tin method Nb3Sn superconducting wire subcomponent 5 obtained after drawing is 10 mm.

[0034] Step 4, load the multiple internal tin method Nb3Sn superconducting wire subcomponents 5 obtained in step 3 into the φ65 / φ50mm oxygen-free copper tube 6 to obtain the final billet, and draw and twist the final billet to finally obtain a high-performance superconducting switch wire with a wire specification of 0.7mm and a torque of 20mm. Step 5, taking samples from the high-performance superconducting switch wire obtained in step 4, and heat treating them, and testing their critical current value and residual resistance ratio after they are taken out of the furnace.

[0035] The test results of the sample low temperature performance are as follows:

[0036] In this embodiment 2, a superconducting switch wire with a length of 3800 m is successfully prepared by using a preparation method of a high-performance superconducting switch wire. Its critical current value is greatly improved, and its residual resistance ratio also meets the relevant technical requirements.

[0037] Example 3: Step 1, 150 Nb rods with a specification of φ12 mm are placed vertically on a circular base with a specification of φ320 mm. Using 3D printing technology, oxygen-free copper is printed into a cylinder with the same specifications as the circular base, and the gaps between adjacent Nb rods are filled to form a CuNb composite ingot. Oxygen-free copper caps are added to both ends of the composite ingot and electron beam sealing is performed to obtain a CuNb composite sheath; Step 2, heating the CuNb composite sheath obtained in step S1 to 900° C. and keeping the temperature for 90 minutes, extruding to obtain a CuNb composite rod, and drilling a hole with a specification of φ35 mm at the center of the CuNb composite rod to obtain a CuNb composite tube; Step 3, cold-extrude the SnTi alloy ingot into a SnTi alloy tube with a specification of φ35 / φ15 mm, insert a φ14.5 mm Ta rod into the SnTi alloy tube to obtain a SnTi / Ta composite rod, and then insert the obtained SnTi / Ta composite rod into the CuNb composite tube obtained in step 2 to obtain an enhanced internal tin method Nb3Sn superconducting wire subcomponent, draw the obtained internal tin method Nb3Sn superconducting wire subcomponent, and cut the drawn internal tin method Nb3Sn superconducting wire subcomponent into multiple equal lengths and evenly arrange them. The opposite side dimension of the internal tin method Nb3Sn superconducting wire subcomponent obtained after drawing is 15 mm.

[0038] Step 4, loading the multiple internal tin method Nb3Sn superconducting wire subcomponents obtained in step 3 into a φ75 / φ60mm oxygen-free copper tube to obtain a final billet, and drawing and twisting the final billet to finally obtain a high-performance superconducting switch wire with a wire specification of 0.8mm and a torque of 40mm. Step 5, taking samples from the high-performance superconducting switch wire obtained in step 4, and heat treating them, and testing their critical current value and residual resistance ratio after they are taken out of the furnace.

[0039] The test results of the sample low temperature performance are as follows:

[0040] In this embodiment 3, a superconducting switch wire with a length of 4500 m is successfully prepared by using a preparation method of a high-performance superconducting switch wire. Its critical current value is greatly improved, and its residual resistance ratio also meets relevant technical requirements.

[0041] The present invention discloses a high-performance superconducting switch wire and a preparation method thereof. Based on the preparation process of Nb3Sn by the internal tin method, an enhanced internal tin method Nb3Sn superconducting switch wire with comprehensive performance improved compared with NbTi superconducting switch wire is prepared. By removing the traditional Ta barrier layer, the Sn element is diffused into the oxygen-free copper 2 matrix during the heat treatment process, which significantly improves the low-temperature resistance of the wire matrix, and the RRR value is reduced to the range of 5-10, meeting the requirements of the superconducting switch for high resistance characteristics. The Ta rod 4 reinforcement is introduced into the core of the subcomponent, which effectively improves the brittleness problem of the Nb3Sn wire after heat treatment. The process system successfully solves the contradiction between high resistance and high current carrying capacity of superconducting switch wires through the collaborative innovation of materials, structures and processes, and has important application value in the fields of cutting-edge equipment such as nuclear magnetic resonance and particle accelerators.

[0042] It should be noted that the component connection relationships not specifically mentioned in this application are assumed to adopt the existing technology. Since they do not involve the invention and are widely used in the existing technology, the structural connection relationships are not described in detail.

Claims

1. A method for preparing a high-performance superconducting switch line, characterized in that: The steps include: S1. Prepare a CuNb composite sheath by vertically placing a plurality of Nb rods (1) on a circular base, using 3D printing to print oxygen-free copper (2) into a cylinder with the same specifications as the circular base, and using the cylinder to fill the gaps between adjacent Nb rods (1) to form a CuNb composite ingot, adding oxygen-free copper covers to both ends of the composite ingot and performing electron beam sealing welding to obtain a CuNb composite sheath; S2, heating, heat-insulating, and extruding the CuNb composite sheath obtained in step S1 to obtain a CuNb composite rod, and drilling holes in batches at the center of the CuNb composite rod to obtain a CuNb composite tube; S3, cold-extruding the SnTi alloy ingot into a SnTi alloy tube (3), inserting a Ta rod (4) of a size matching the SnTi alloy tube (3) to obtain a SnTi / Ta composite rod, and then inserting the obtained SnTi / Ta composite rod into the CuNb composite tube obtained in step S2 to obtain an enhanced internal tin method Nb3Sn superconducting wire subcomponent (5), drawing the enhanced internal tin method Nb3Sn superconducting wire subcomponent (5), and cutting the drawn internal tin method Nb3Sn superconducting wire subcomponent (5) into a plurality of equal lengths and arranging them evenly; S4, placing the plurality of enhanced internal tin method Nb3Sn superconducting wire subcomponents (5) obtained in step S3 into an oxygen-free copper tube (6) to obtain a final billet, and drawing and twisting the final billet to finally obtain a high-performance superconducting switch wire; S5. Samples are taken from the high-performance superconducting switch wire obtained in step S4, and heat treated. After being taken out of the furnace, the critical current value and the residual resistance ratio are tested.

2. The method for preparing a high-performance superconducting switch line according to claim 1, characterized in that: The number of Nb rods (1) in step S1 is 100 to 150, the specification of the Nb rods (1) is φ9 mm to φ12 mm, and the specification of the CuNb composite ingot obtained by printing is φ280 mm to φ300 mm.

3. The method for preparing a high-performance superconducting switch line according to claim 1, characterized in that: In the step S2, the extrusion temperature of the CuNb composite sheath is 700° C. to 900° C., and the heat preservation time is 60 min to 90 min.

4. The method for preparing a high-performance superconducting switch line according to claim 1, characterized in that: The outer diameter of the CuNb composite rod obtained in step S2 is φ52mm-φ75mm, the diameter of the drilled hole at the center of the CuNb composite rod is φ30mm-φ35mm, and the drilled hole diameter is 1.0mm larger than that of the SnTi / Ta composite rod.

5. The method for preparing a high-performance superconducting switch line according to claim 1, characterized in that: In the step S3, the SnTi ingot is cold extruded into a SnTi alloy tube (3) with an outer diameter of φ29 mm to φ34 mm and an inner hole diameter of φ10 mm to φ15 mm. The Ta rod (4) used has an outer diameter of φ9.5 mm to φ14.5 mm. The Ta rod (4) is inserted into the SnTi alloy tube (3) to obtain a SnTi / Ta composite rod. The SnTi / Ta alloy rod is inserted into the CuNb composite tube obtained in step S2 to obtain an enhanced internal tin method Nb3Sn superconducting wire subcomponent (5). The enhanced internal tin method Nb3Sn superconducting wire subcomponent (5) is drawn. After drawing, the internal tin method Nb3Sn superconducting wire subcomponent (5) has a side dimension of 5 mm to 15 mm.

6. The method for preparing a high-performance superconducting switch line according to claim 1, characterized in that: In step S4, the outer diameter of the oxygen-free copper tube (6) is φ60 mm to φ75 mm, and the inner diameter of the oxygen-free copper tube (6) is φ45 mm to φ60 mm.

7. The method for preparing a high-performance superconducting switch line according to claim 1, characterized in that: In step S4, the final billet is drawn, and then twisted and finally stretched to obtain the Nb3Sn superconducting wire, wherein the twisting pitch is 15mm~40mm.

8. The method for preparing a high-performance superconducting switch line according to claim 1, characterized in that: In step S5, the wire sample is heat treated by a standard internal tin method Nb3Sn heat treatment process, and the critical current value and residual resistance ratio of the sample are tested after it is taken out of the furnace.

9. A high-performance superconducting switch line, characterized in that: The high-performance superconducting switch wire structure is prepared by the preparation method described in any one of claims 1 to 8, and includes a SnTi / Ta composite rod, a CuNb composite tube, and an oxygen-free copper tube (6) from the inside to the outside, wherein the SnTi / Ta composite rod includes a Ta rod (4) located in the center and a SnTi alloy tube (3) located at the periphery, and the Nb rod (1) and the oxygen-free copper (2) in the CuNb composite tube are interlocked, and the SnTi / Ta composite rod is inserted into the CuNb composite tube to form an inner tin method Nb3Sn superconducting wire subcomponent (5).

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