A method for preparing a superconducting composite long wire

Abstract

The present invention discloses a method for preparing a superconducting composite long wire, comprising: smelting Cu, Mn and a copper alloy to obtain a Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube; placing an Nb tube and an NbTi rod in the alloy tube to make a single core rod; combining the single core rod with an oxygen-free copper rod in the oxygen-free copper tube to obtain a secondary composite rod; combining the secondary composite rod with an oxygen-free copper rod in the oxygen-free copper tube to obtain a tertiary composite rod; and drawing the tertiary composite rod to obtain a tertiary superconducting composite wire. The present invention obtains an alloy resistive matrix by alloying, thereby improving the long-wire processing capability of copper-manganese-based niobium-titanium superconducting wire without reducing the critical current density and AC loss. The oxidation resistance of the single core rod is significantly improved, the thickness of the oxide layer after hot extrusion is significantly reduced, and the number of peeling times is effectively reduced during the processing process. This can effectively improve the deformation uniformity of the superconducting core wire and thus increase the critical current density, and can also increase efficiency and reduce costs.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting wires, and in particular to a method for preparing a superconducting composite long wire. Background Art

[0002] The field of practical superconductivity is developing rapidly. In various large scientific devices, fast pulse superconducting accelerator magnets are core components with high central magnetic fields and high magnetic field change rates, which easily cause high AC losses. Therefore, high critical current density and low loss NbTi superconducting wires are needed. Previously, a good match between high critical current density and low AC loss has been achieved by "replacing Cu with a CuMn alloy resistive matrix" and "designing a new superconducting wire structure." However, the wire still has the problem of long-wire processing, which seriously limits the mass production and application of NbTi / CuMn / Cu wires. Generally, when the length of a single superconducting wire is greater than 1000m, it can be considered to have long-wire processing capabilities. Summary of the Invention

[0003] The embodiments of the present invention provide a method for preparing a long superconducting composite wire, which is used to solve the problem of long wire processing difficulties in the prior art NbTi / CuMn / Cu wire, which seriously limits the batch preparation and application of NbTi / CuMn / Cu wire.

[0004] In one aspect, an embodiment of the present invention provides a method for preparing a superconducting composite long wire, comprising:

[0005] Cu, Mn and any one of CrCu, CuFe, CuZr, CuAg and CuTi are smelted to obtain a Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube;

[0006] Placing a Nb tube and a NbTi rod in the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube to form a single core rod;

[0007] Combining the single core rod and the oxygen-free copper rod in an oxygen-free copper tube to obtain a secondary composite rod;

[0008] Combining the secondary composite rod and the oxygen-free copper rod in the oxygen-free copper tube to obtain a tertiary composite rod;

[0009] The tertiary composite rod is subjected to a drawing process to obtain a tertiary superconducting composite wire.

[0010] In a possible implementation, smelting Cu, Mn and any one of CrCu, CuFe, CuZr, CuAg and CuTi to obtain a Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube includes:

[0011] Using the Cu and Mn plus any one of CrCu, CuFe, CuZr, CuAg and CuTi as raw materials, an initial Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube is obtained by vacuum induction melting, pouring, heating, extruding, drawing and vacuum annealing;

[0012] The initial Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube is subjected to a solid solution treatment to obtain the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube.

[0013] In one possible implementation, placing a Nb tube and a NbTi rod in the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube to form a single core rod includes:

[0014] One end of the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube is sealed by a cover made of the same alloy;

[0015] The Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube with one end sealed, the alloy cover of the same material at the other end of the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube, the Nb cylinder and the NbTi rod are sequentially cleaned, assembled, degassed, vacuum electron beam welded, hot extruded, drawn, peeled, hexagonally formed and cut to length to obtain a single core rod.

[0016] In one possible implementation, combining the single core rod and the oxygen-free copper rod in an oxygen-free copper tube to obtain a secondary composite rod includes:

[0017] Cleaning the oxygen-free copper tube, the upper and lower covers of the oxygen-free copper tube, the plurality of single core rods, and the plurality of oxygen-free copper rods;

[0018] Arranging a plurality of the single core rods in the oxygen-free copper tube according to the superconducting wire structure;

[0019] inserting the oxygen-free copper rod into the gap between the plurality of single core rods to obtain a composite ingot;

[0020] The composite ingot is subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, drawing, peeling and cutting to a predetermined length in sequence to obtain a secondary composite rod.

[0021] In a possible implementation, combining the secondary composite rod and the oxygen-free copper rod in the oxygen-free copper tube to obtain a tertiary composite rod includes:

[0022] Arranging a plurality of the secondary composite rods in the oxygen-free copper tube according to the superconducting wire structure;

[0023] inserting the oxygen-free copper rod into the gap between the plurality of secondary composite rods to obtain a tertiary composite ingot;

[0024] The tertiary composite ingot is subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, drawing, peeling and cutting to a fixed length in sequence to obtain a tertiary composite rod.

[0025] In a possible implementation, the drawing of the tertiary composite rod to obtain a tertiary superconducting composite wire includes:

[0026] The tertiary composite rod is subjected to cold drawing and aging heat treatment to obtain a tertiary composite wire.

[0027] In a possible implementation, the cold drawing process has multiple passes.

[0028] The method for preparing a superconducting composite long wire in the present invention has the following advantages:

[0029] (1) The Cu-Mn-(Cr / Fe / Zr / Ag / Ti) resistive matrix is ​​obtained by alloying and prepared into a tube for use in a single-core ingot sheath. This can significantly improve the long-line processing capability of the copper-manganese-based niobium-titanium superconducting wire without reducing the critical current density or increasing the AC loss, thus achieving mass application, increasing the yield rate and reducing production costs.

[0030] (2) Compared with the previous NbTi / CuMn single core rod, the oxidation resistance of the NbTi / Cu-Mn-(Cr / Fe / Zr / Ag / Ti) single core rod is significantly improved, and the thickness of the oxide layer after hot extrusion is significantly reduced. The number of peeling times can be effectively reduced during the processing process, which can not only effectively improve the deformation uniformity of the superconducting core wire and thus increase the critical current density, but also further save production time, increase efficiency and reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A flow chart of a method for preparing a superconducting composite long wire provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] Figure 1 A flow chart of a method for preparing a superconducting composite long wire provided in an embodiment of the present invention; an embodiment of the present invention provides a method for preparing a superconducting composite long wire, comprising:

[0035] Cu, Mn and any one of CrCu, CuFe, CuZr, CuAg and CuTi are smelted to obtain a Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube;

[0036] Placing a Nb tube and a NbTi rod in the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube to form a single core rod;

[0037] Combining the single core rod and the oxygen-free copper rod in an oxygen-free copper tube to obtain a secondary composite rod;

[0038] Combining the secondary composite rod and the oxygen-free copper rod in the oxygen-free copper tube to obtain a tertiary composite rod;

[0039] The tertiary composite rod is subjected to a drawing process to obtain a tertiary superconducting composite wire.

[0040] The method of smelting Cu, Mn and any one of CrCu, CuFe, CuZr, CuAg and CuTi to obtain a Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube comprises:

[0041] Using the Cu and Mn plus any one of CrCu, CuFe, CuZr, CuAg and CuTi as raw materials, an initial Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube is obtained by vacuum induction melting, pouring, heating, extruding, drawing and vacuum annealing;

[0042] The initial Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube is subjected to a solid solution treatment to obtain the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube.

[0043] The method of placing a Nb tube and a NbTi rod in the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube to form a single core rod comprises:

[0044] One end of the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube is sealed by a cover made of the same alloy;

[0045] The Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube with one end sealed, the alloy cover of the same material at the other end of the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube, the Nb cylinder and the NbTi rod are sequentially cleaned, assembled, degassed, vacuum electron beam welded, hot extruded, drawn, peeled, hexagonally formed and cut to length to obtain a single core rod.

[0046] Combining the single core rod and the oxygen-free copper rod in the oxygen-free copper tube to obtain the secondary composite rod comprises:

[0047] Cleaning the oxygen-free copper tube, the upper and lower covers of the oxygen-free copper tube, the plurality of single core rods, and the plurality of oxygen-free copper rods;

[0048] Arranging a plurality of the single core rods in the oxygen-free copper tube according to the superconducting wire structure;

[0049] inserting the oxygen-free copper rod into the gap between the plurality of single core rods to obtain a composite ingot;

[0050] The composite ingot is subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, drawing, peeling and cutting to a predetermined length in sequence to obtain a secondary composite rod.

[0051] Combining the secondary composite rod and the oxygen-free copper rod in the oxygen-free copper tube to obtain a tertiary composite rod includes:

[0052] Arranging a plurality of the secondary composite rods in the oxygen-free copper tube according to the superconducting wire structure;

[0053] inserting the oxygen-free copper rod into the gap between the plurality of secondary composite rods to obtain a tertiary composite ingot;

[0054] The tertiary composite ingot is subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, drawing, peeling and cutting to a fixed length in sequence to obtain a tertiary composite rod.

[0055] The drawing process of the tertiary composite rod to obtain the tertiary superconducting composite wire comprises:

[0056] The tertiary composite rod is subjected to cold drawing and aging heat treatment to obtain a tertiary composite wire.

[0057] The cold drawing has multiple passes.

[0058] For example, a Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy is used as the resistive matrix of a low-loss superconducting wire, and the alloying element content ranges as follows: Mn element content is 0.5% to 5%, Cr or Fe or Zr or Ag or Ti element content is 0.01% to 1%, and the balance is Cu. To ensure purity and content, the alloying elements are added in the form of MnCu, CuCr or CuFe or CuZr or CuAg or CuTi master alloys;

[0059] The microstructure of the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube before solution treatment is a recrystallized structure, and the precipitated phase in the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy is completely dissolved back into the matrix through solution treatment, aiming to re-regulate the precipitation of the precipitated phase during the aging process. The solution parameters of the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube are as follows: solution temperature of 800-1050°C, solution time of 1-5h, and cooling method of water cooling;

[0060] The thickness of each component required for the single core rod is as follows: the thickness of the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube is 15-60 mm, the thickness of the Nb tube is 0.5-2 mm, and the thickness of the NbTi rod is 100-300 mm. Finally, the NbTi / Cu-Mn-(Cr / Fe / Zr / Ag / Ti) single core rod is formed, where Cu-Mn-(Cr / Fe / Zr / Ag / Ti) represents an alloy of Cu, Mn and any one of CuCr, CuFe, CuZr, CuAg or CuTi, and NbTi / Cu-Mn-(Cr / Fe / Zr / Ag / Ti) represents a composite sheath structure of the NbTi rod and the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy.

[0061] The processing parameters for single-core hot extrusion are: extrusion temperature 600~900℃, holding time 2~8h, extrusion ratio 5~20. During the cold drawing process, peeling only needs 1~2 times;

[0062] The hot isostatic pressing processing parameters of the secondary composite rod are as follows: hot isostatic pressing temperature is 500~800℃, holding time is 2~8h;

[0063] The hot extrusion processing parameters of the secondary composite rod are: extrusion temperature of 600~900℃, holding time of 2~8h, extrusion ratio of 5~20;

[0064] The aging heat treatment parameters of the three-composite line are: aging temperature is 300~500℃, the number of aging times is 2~8 times, the aging time each time is 10~80h, and the cooling method is furnace cooling.

[0065] In one possible embodiment, Example 1:

[0066] Step 1, prepare a CuMnCr alloy tube with high oxidation resistance: using Cu source, Mn source, and CuCr master alloy as raw materials, obtain the CuMnCr alloy tube through vacuum induction melting, pouring, heating, extrusion, drawing, vacuum annealing and other processes. The alloy element content range is as follows: Mn element content is 0.5%~5%, Cr element content is 0.01%~1%, and the balance is Cu. The CuMnCr alloy tube is then solution treated to dissolve all the precipitated phases back into the matrix, and used as the initial organizational state for low-loss superconducting wires. The solution parameters are as follows: solution temperature is 1050°C, solution time is 5, and cooling method is water cooling;

[0067] Step 2, prepare NbTi / CuMnCr single core rod: the thickness of CuMnCr alloy tube is 60mm, the thickness of Nb tube is 2mm, and the thickness of NbTi rod is 300mm. The CuMnCr alloy tube, upper and lower covers, high-purity Nb tube, and NbTi rod are sequentially cleaned, assembled, degassed, vacuum electron beam welded, hot extruded, multi-pass cold drawing with peeling, hexagonal forming, and cut to length to obtain NbTi / CuMnCr single core rod. The extrusion temperature is 900℃, the holding time is 8h, and the extrusion ratio is 15. Peeling is only required 1~2 times during the cold drawing process;

[0068] Step 3, prepare NbTi / CuMnCr / Cu secondary composite rods: clean the oxygen-free copper tube and upper and lower covers, as well as a specified number of NbTi / CuMnCr single-core rods and oxygen-free copper rods, arrange the single-core rods in the oxygen-free copper tube according to the structural design, and fill the gaps in the oxygen-free copper tube with oxygen-free copper rods. The composite ingot is then subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, multi-pass cold drawing with peeling, and cut to length to obtain NbTi / CuMnCr / Cu secondary composite rods. The hot isostatic pressing temperature is 800°C, and the holding time is 8h. The extrusion temperature is 800°C, the holding time is 8h, and the extrusion ratio is 15;

[0069] Step 4: Preparation of the NbTi / CuMnCr / Cu tertiary composite wire: The oxygen-free copper tube, NbTi / CuMnCr / Cu secondary composite rod, and oxygen-free copper rod are cleaned. The NbTi / CuMnCr / Cu secondary composite rod is arranged in the oxygen-free copper tube according to the structural design, and the oxygen-free copper rod is used to fill the gaps in the oxygen-free copper tube. A combination of cold drawing and multiple aging heat treatments is used to obtain the NbTi / CuMnCr / Cu tertiary composite wire. The aging temperature is 500°C, and the number of aging cycles is 6, each aging time is 75 hours, and the cooling method is furnace cooling.

[0070] In a possible embodiment, embodiment 2:

[0071] Step 1, prepare a CuMnFe alloy tube with high oxidation resistance: using Cu source, Mn source, and CuFe intermediate alloy as raw materials, obtain a CuMnFe alloy tube through vacuum induction melting, pouring, heating, extrusion, drawing, vacuum annealing and other processes. The alloy element content range is as follows: Mn element content is 0.5%~5%, Fe element content is 0.01%~1%, and the balance is Cu. The CuMnFe alloy tube is then solution treated to dissolve all the precipitated phases back into the matrix, and used as the initial organizational state for low-loss superconducting wires. The solution parameters are as follows: solution temperature is 1000℃, solution time is 4h, and cooling method is water cooling;

[0072] Step 2, prepare NbTi / CuMnFe single core rod: the thickness of the CuMnFe alloy tube is 45mm, the thickness of the Nb tube is 1.5mm, and the thickness of the NbTi rod is 200mm. The CuMnFe alloy tube, upper and lower covers, high-purity Nb tube, and NbTi rod are sequentially cleaned, assembled, degassed, vacuum electron beam welded, hot extruded, multi-pass cold drawing with peeling, hexagonal forming, and cut to length to obtain the NbTi / CuMnFe single core rod. The extrusion temperature is 850°C, the holding time is 7h, and the extrusion ratio is 13. Peeling is only required 1 to 2 times during the cold drawing process;

[0073] Step 3, prepare NbTi / CuMnFe / Cu secondary composite rods: clean the oxygen-free copper tube and upper and lower covers, as well as a specified number of NbTi / CuMnFe single-core rods and oxygen-free copper rods, arrange the single-core rods in the oxygen-free copper tube according to the structural design, and fill the gaps in the oxygen-free copper tube with oxygen-free copper rods. The composite ingot is then subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, multi-pass cold drawing with peeling, and cut-to-length cutting to obtain NbTi / CuMnFe / Cu secondary composite rods. The hot isostatic pressing temperature is 750°C, and the holding time is 6h. The extrusion temperature is 850°C, the holding time is 7h, and the extrusion ratio is 15;

[0074] Step 4: Preparation of the NbTi / CuMnFe / Cu tertiary composite wire: Clean the oxygen-free copper tube, NbTi / CuMnFe / Cu secondary composite rod, and oxygen-free copper rod. Arrange the NbTi / CuMnFe / Cu secondary composite rod in the oxygen-free copper tube according to the structural design, and fill the gaps in the oxygen-free copper tube with oxygen-free copper rod. Combined with cold drawing and multiple aging heat treatments, the NbTi / CuMnFe / Cu tertiary composite wire is finally obtained. The aging temperature is 450°C, and the number of aging cycles is 6, each aging time is 30 hours, and the cooling method is furnace cooling.

[0075] In one possible embodiment, Example 3:

[0076] Step 1, prepare a CuMnZr alloy tube with high oxidation resistance: using Cu source, Mn source, and CuZr master alloy as raw materials, obtain the CuMnZr alloy tube through vacuum induction melting, pouring, heating, extrusion, drawing, vacuum annealing and other processes. The alloy element content range is as follows: Mn element content is 0.5%~5%, Zr element content is 0.01%~1%, and the balance is Cu. The CuMnZr alloy tube is then solution treated to dissolve all the precipitated phases back into the matrix, and used as the initial organizational state for low-loss superconducting wires. The solution parameters are as follows: solution temperature is 1000℃, solution time is 4h, and cooling method is water cooling;

[0077] Step 2, prepare NbTi / CuMnZr single core rod: the thickness of CuMnZr alloy tube is 30mm, the thickness of Nb tube is 1mm, and the thickness of NbTi rod is 150mm. The CuMnZr alloy tube, upper and lower covers, high-purity Nb tube, and NbTi rod are sequentially cleaned, assembled, degassed, vacuum electron beam welded, hot extruded, multi-pass cold drawing with peeling, hexagonal forming, and cut to length to obtain NbTi / CuMnZr single core rod. The extrusion temperature is 850℃, the holding time is 6h, and the extrusion ratio is 13. Peeling is only required 1~2 times during the cold drawing process;

[0078] Step 3, prepare NbTi / CuMnZr / Cu secondary composite rods: clean the oxygen-free copper tube and upper and lower covers, as well as a specified number of NbTi / CuMnZr single-core rods and oxygen-free copper rods, arrange the single-core rods in the oxygen-free copper tube according to the structural design, and fill the gaps in the oxygen-free copper tube with oxygen-free copper rods. The composite ingot is then subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, multi-pass cold drawing with peeling, and cut-to-length cutting to obtain NbTi / CuMnZr / Cu secondary composite rods. The hot isostatic pressing temperature is 750°C, and the holding time is 6h. The extrusion temperature is 850°C, the holding time is 7h, and the extrusion ratio is 15;

[0079] Step 4: Preparation of the NbTi / CuMnZr / Cu tertiary composite wire: Clean the oxygen-free copper tube, NbTi / CuMnZr / Cu secondary composite rod, and oxygen-free copper rod. Arrange the NbTi / CuMnZr / Cu secondary composite rod within the oxygen-free copper tube according to the structural design, and fill the gaps in the oxygen-free copper tube with oxygen-free copper rod. Combined with cold drawing and multiple aging heat treatments, the NbTi / CuMnZr / Cu tertiary composite wire is finally obtained. The aging temperature is 450°C, and the number of aging cycles is 6, each aging time is 30 hours, and the cooling method is furnace cooling.

[0080] In a possible embodiment, Example 4:

[0081] Step 1, prepare a CuMnAg alloy tube with high oxidation resistance: using Cu source, Mn source, and CuAg master alloy as raw materials, obtain the CuMnAg alloy tube through vacuum induction melting, pouring, heating, extrusion, drawing, vacuum annealing and other processes. The alloy element content range is as follows: Mn element content is 0.5%~5%, Ag element content is 0.01%~1%, and the balance is Cu. The CuMnAg alloy tube is then solution treated to dissolve all the precipitated phases back into the matrix, and used as the initial organizational state for low-loss superconducting wires. The solution parameters are as follows: solution temperature is 1000℃, solution time is 4h, and cooling method is water cooling;

[0082] Step 2, prepare NbTi / CuMnAg single core rod: the thickness of the CuMnAg alloy tube is 30mm, the thickness of the Nb tube is 1mm, and the thickness of the NbTi rod is 150mm. The CuMnAg alloy tube, upper and lower covers, high-purity Nb tube, and NbTi rod are sequentially cleaned, assembled, degassed, vacuum electron beam welded, hot extruded, multi-pass cold drawing with peeling, hexagonal forming, and cut to length to obtain the NbTi / CuMnAg single core rod. The extrusion temperature is 850°C, the holding time is 6h, and the extrusion ratio is 13. Peeling is only required 1 to 2 times during the cold drawing process;

[0083] Step 3, prepare NbTi / CuMnAg / Cu secondary composite rods: clean the oxygen-free copper tube and upper and lower covers, as well as a specified number of NbTi / CuMnAg single-core rods and oxygen-free copper rods, arrange the single-core rods in the oxygen-free copper tube according to the structural design, and fill the gaps in the oxygen-free copper tube with oxygen-free copper rods. The composite ingot is then subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, multi-pass cold drawing with peeling, and cut to length to obtain NbTi / CuMnAg / Cu secondary composite rods. The hot isostatic pressing temperature is 750°C, and the holding time is 6h. The extrusion temperature is 850°C, the holding time is 7h, and the extrusion ratio is 15;

[0084] Step 4: Preparation of NbTi / CuMnAg / Cu tertiary composite wire: Clean the oxygen-free copper tube, NbTi / CuMnAg / Cu secondary composite rod, and oxygen-free copper rod. Arrange the NbTi / CuMnAg / Cu secondary composite rod in the oxygen-free copper tube according to the structural design, and fill the gaps in the oxygen-free copper tube with oxygen-free copper rod. Combined with cold drawing and multiple aging heat treatments, the NbTi / CuMnAg / Cu tertiary composite wire is finally obtained. The aging temperature is 450°C, and the number of aging cycles is 6, each aging time is 30 hours, and the cooling method is furnace cooling.

[0085] In a possible embodiment, Example 5:

[0086] Step 1, prepare a CuMnTi alloy tube with high oxidation resistance: using Cu source, Mn source, and CuTi master alloy as raw materials, obtain the CuMnTi alloy tube through vacuum induction melting, pouring, heating, extrusion, drawing, vacuum annealing and other processes. The alloy element content range is as follows: Mn element content is 0.5%~5%, Ti element content is 0.01%~1%, and the balance is Cu. The CuMnTi alloy tube is then solution treated to dissolve all the precipitated phases back into the matrix, and used as the initial organizational state for low-loss superconducting wires. The solution parameters are as follows: solution temperature is 800℃, solution time is 1h, and cooling method is water cooling;

[0087] Step 2, prepare NbTi / CuMnTi single core rod: the thickness of the CuMnTi alloy tube is 30mm, the thickness of the Nb tube is 1mm, and the thickness of the NbTi rod is 150mm. The CuMnTi alloy tube, upper and lower covers, high-purity Nb tube, and NbTi rod are sequentially cleaned, assembled, degassed, vacuum electron beam welded, hot extruded, multi-pass cold drawing with peeling, hexagonal forming, and cut to length to obtain the NbTi / CuMnTi single core rod. The extrusion temperature is 600°C, the holding time is 2h, and the extrusion ratio is 5. Peeling is only required 1 to 2 times during the cold drawing process;

[0088] Step 3, prepare NbTi / CuMnTi / Cu secondary composite rods: clean the oxygen-free copper tube and upper and lower covers, as well as a specified number of NbTi / CuMnTi single-core rods and oxygen-free copper rods, arrange the single-core rods in the oxygen-free copper tube according to the structural design, and fill the gaps in the oxygen-free copper tube with oxygen-free copper rods. The composite ingot is sequentially degassed, vacuum electron beam welded, hot isostatically pressed, hot extruded, multi-pass cold drawn with peeling, and cut to length to obtain NbTi / CuMnTi / Cu secondary composite rods. The hot isostatic pressing temperature is 500°C, and the holding time is 2h. The extrusion temperature is 600°C, the holding time is 2h, and the extrusion ratio is 5;

[0089] Step 4: Prepare the NbTi / CuMnTi / Cu tertiary composite wire: Clean the oxygen-free copper tube, NbTi / CuMnTi / Cu secondary composite rod, and oxygen-free copper rod. Arrange the NbTi / CuMnTi / Cu secondary composite rod in the oxygen-free copper tube according to the structural design, and fill the gaps in the oxygen-free copper tube with oxygen-free copper rod. Combined with cold drawing and multiple aging heat treatments, the NbTi / CuMnTi / Cu tertiary composite wire is finally obtained. The aging temperature is 300°C, the number of aging cycles is two, each aging time is 10 hours, and the cooling method is furnace cooling.

[0090] In a possible embodiment, the parameters of Comparative Example 1 are the same as those of Example 1, except that the alloy raw material in Comparative Example 1 is a CuMn alloy.

[0091] In a possible embodiment, the parameters of Comparative Example 2 are the same as those of Example 2, except that the alloy raw material in Comparative Example 1 is a CuMn alloy.

[0092] In a possible embodiment, the parameters of Comparative Example 3 are the same as those of Example 3, except that the alloy raw material in Comparative Example 1 is a CuMn alloy.

[0093] The critical current and loss performance of the NbTi superconducting wires prepared in Examples 1 to 5 and Comparative Examples 1 to 3 were tested, and the lengths of the superconducting wires were counted. The results are summarized in Table 1:

[0094] Table 1 Physical properties and lead lengths of low-loss NbTi superconducting wires under the same conditions in the examples and comparative examples

[0095]

[0096] As shown in Table 1, the low-loss NbTi superconducting wire produced using the method of the present invention significantly improves the long-line processing capability of low-loss NbTi superconducting wire, effectively increasing the yield rate of superconducting wire and significantly reducing production costs, without compromising critical current density or loss performance. Furthermore, it improves the oxidation resistance of single core rods, reduces the number of stripping operations, and improves the uniformity of core wire deformation, thereby increasing the critical current density of the superconducting wire.

[0097] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including all changes and modifications that fall within the scope of the present invention and the preferred embodiments.

[0098] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a superconducting composite long wire, characterized in that: include: Cu, Mn and any one of CrCu, CuFe, CuZr, CuAg and CuTi are smelted to obtain a Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube; Placing a Nb tube and a NbTi rod in the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube to form a single core rod; Combining the single core rod and the oxygen-free copper rod in an oxygen-free copper tube to obtain a secondary composite rod; Combining the secondary composite rod and the oxygen-free copper rod in an oxygen-free copper tube to obtain a tertiary composite rod; Drawing the tertiary composite rod to obtain a tertiary superconducting composite wire; The method of smelting Cu, Mn and any one of CrCu, CuFe, CuZr, CuAg and CuTi to obtain a Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube comprises: Using the Cu and Mn plus any one of CrCu, CuFe, CuZr, CuAg and CuTi as raw materials, an initial Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube is obtained by vacuum induction melting, pouring, heating, extruding, drawing and vacuum annealing; performing a solid solution treatment on the initial Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube to obtain the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube; The method of placing a Nb tube and a NbTi rod in the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube to form a single core rod comprises: One end of the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube is sealed by a cover made of the same alloy; The Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube with one end sealed, the alloy cover of the same material at the other end of the Cu-Mn-(Cr / Fe / Zr / Ag / Ti) alloy tube, the Nb tube and the NbTi rod are sequentially cleaned, assembled, degassed, vacuum electron beam welded, hot extruded, drawn, peeled, hexagonally formed and cut to length to obtain a single core rod.

2. The method for preparing a superconducting composite long wire according to claim 1, characterized in that: Combining the single core rod and the oxygen-free copper rod in the oxygen-free copper tube to obtain the secondary composite rod comprises: Cleaning the oxygen-free copper tube, the upper and lower covers of the oxygen-free copper tube, the plurality of single core rods, and the plurality of oxygen-free copper rods; Arranging a plurality of the single core rods in the oxygen-free copper tube according to the superconducting wire structure; inserting the oxygen-free copper rod into the gap between the plurality of single core rods to obtain a composite ingot; The composite ingot is subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, drawing, peeling and cutting to a predetermined length in sequence to obtain a secondary composite rod.

3. The method for preparing a superconducting composite long wire according to claim 2, characterized in that: Combining the secondary composite rod and the oxygen-free copper rod in the oxygen-free copper tube to obtain a tertiary composite rod includes: Arranging a plurality of the secondary composite rods in the oxygen-free copper tube according to the superconducting wire structure; inserting the oxygen-free copper rod into the gap between the plurality of secondary composite rods to obtain a tertiary composite ingot; The tertiary composite ingot is subjected to degassing, vacuum electron beam welding, hot isostatic pressing, hot extrusion, drawing, peeling and cutting to a fixed length in sequence to obtain a tertiary composite rod.

4. The method for preparing a superconducting composite long wire according to claim 3, characterized in that: The drawing process of the tertiary composite rod to obtain the tertiary superconducting composite wire comprises: The tertiary composite rod is subjected to cold drawing and aging heat treatment to obtain a tertiary composite wire.

5. The method for preparing a superconducting composite long wire according to claim 4, characterized in that: The cold drawing has multiple passes.

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