Preparation method of high-performance superconducting switch wire
By installing Ta rods and performing CuNb composite cover processing during the subcomponent of Nb3Sn superconducting wire, the problem of low critical current value and brittle breaking of copper-nickel-based NbTi superconducting wire under high background magnetic field was solved, and a high-performance superconducting switch wire was prepared.
Patent Information
- Application Number
- CN202510356152.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-07-11
AI Technical Summary
The existing copper-nickel-based NbTi superconducting switch lines have a low critical current value under high background magnetic field conditions, and the inner tin method Nb3Sn superconducting wire is easily broken after heat treatment, making it difficult to meet the requirements of high-performance superconducting switch lines.
In the process of preparing the subcomponents of the Nb3Sn superconducting wire, a Ta rod is installed in the center, and through CuNb composite cover, extrusion, drawing and twisting, etc., an enhanced inner tin method Nb3Sn superconducting wire is formed to avoid brittle breakage, and to increase the critical current value and reduce the residual resistance ratio.
The prepared superconducting switch wires are not easily brittle and broken, the critical current value is significantly improved, the residual resistance ratio meets the technical requirements, and the performance is significantly better than the existing technology.
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Figure CN120299816A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of the preparation of superconducting wire materials, and particularly relates to a method for preparing a high-performance superconducting switch wire material. Background Art
[0002] The superconducting switch wire is an indispensable important component for manufacturing large-scale scientific devices such as superconducting magnets. Currently, the switch wires used in various scientific projects internationally are mainly copper-nickel-based NbTi superconducting wires, which mainly face the problem of a relatively low critical current value under high background magnetic field conditions.
[0003] Common copper-nickel-based NbTi superconducting switch wires have a relatively low critical current value under high background magnetic field conditions (the upper critical magnetic field is only 11.5 T), while the critical current value of Nb3Sn wire materials (the upper critical magnetic field is above 25 T) is higher than that of NbTi-based superconducting wires under high background magnetic field conditions. In addition, another important performance requirement for superconducting switch wires is that the residual resistance ratio of the wire materials is 1-10. The residual resistance ratio of copper-nickel-based NbTi superconducting switch wires is mainly determined by their copper-nickel matrix. For the internal tin method Nb3Sn wire materials, the existing technology removes its Ta barrier layer during the composite wire preparation stage, enabling the Sn element to diffuse into the oxygen-free copper matrix during the heat treatment process, significantly increasing the low-temperature resistance of the wire material matrix, achieving a significant decrease in the residual resistance ratio, and meeting the performance indicators of the switch wire. However, the internal tin method Nb3Sn superconducting wire materials are extremely brittle and prone to fracture after heat treatment. Summary of the Invention
[0004] In order to solve the above problems, the present invention provides a method for preparing a high-performance superconducting switch wire material. During the preparation of the sub-elements of the Nb3Sn superconducting wire material, a Ta rod is installed in the center, and a superconducting switch wire that is not easily brittle, has a high critical current value, and a low residual resistance ratio can be obtained.
[0005] In order to achieve the above purpose, the present invention adopts the following technical solutions:
[0006] A method for preparing a high-performance superconducting switch wire material, comprising the following steps:
[0007] S1. Printing multiple Nb rods and oxygen-free copper into an integrated structure to obtain a CuNb composite sheath;
[0008] S2. Heating, insulating, and extruding the CuNb composite sheath to obtain a CuNb composite rod;
[0009] S3. Drilling a hole in the center of the CuNb composite rod to obtain a CuNb composite tube;
[0010] S4. Insert a SnTi / Ta composite rod into the CuNb composite tube to obtain a sub-component of Nb3Sn superconducting wire; the SnTi / Ta composite rod is obtained by extruding a SnTi alloy ingot into a SnTi alloy tube and then inserting a Ta rod into the SnTi alloy tube.
[0011] S5. Load multiple sub-components of Nb3Sn superconducting wire into an oxygen-free copper tube to obtain the final billet.
[0012] S6. Perform drawing and twisting on the final billet to obtain high-performance superconducting switch wire.
[0013] Preferably, S1 is specifically as follows: Place multiple Nb rods vertically on a circular base, use oxygen-free copper as the matrix, and adopt 3D printing technology to print the oxygen-free copper and Nb rods into an integral structure. The Nb rods are dispersedly distributed in the oxygen-free copper matrix. The bottom diameter of the formed cylinder is equal to the diameter of the circular base to form a CuNb composite ingot. Weld oxygen-free copper caps at both ends of the composite ingot to obtain a CuNb composite sheath.
[0014] Preferably, the number of the Nb rods is 100 - 150, and the specification of the CuNb composite ingot is Φ280mm - Φ320mm.
[0015] Preferably, in S2, the heating temperature is 700°C - 900°C, and the heat preservation time is 60min - 90min.
[0016] Preferably, in S3, the outer diameter of the CuNb composite tube is Φ52mm - Φ75mm, and the inner diameter is Φ30mm - Φ35mm.
[0017] Preferably, in S4, the inner diameter of the CuNb composite tube is 1.0mm larger than the outer diameter of the SnTi / Ta composite rod.
[0018] Preferably, in S4, the SnTi ingot is processed by cold extrusion. The outer diameter of the extruded SnTi alloy tube is Φ29mm - Φ34mm, the inner diameter is Φ10mm - Φ15mm, and the outer diameter of the Ta rod is Φ9.5mm - Φ14.5mm.
[0019] Preferably, in S4, the sub-component of the Nb3Sn superconducting wire is drawn and cut to obtain a sub-component of the Nb3Sn superconducting wire with an opposite side dimension of 5mm - 15mm.
[0020] Preferably, in S5, the outer diameter of the oxygen-free copper tube is Φ60mm - Φ75mm, and the inner diameter is Φ45mm - Φ60mm.
[0021] Preferably, in S6, the twisting pitch is 15mm - 40mm.
[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: In order to solve the problem of easy brittle fracture of the inner-tin Nb3Sn superconducting wire after heat treatment, a Ta rod is installed in the center during the preparation of the sub-components of the Nb3Sn superconducting wire. The superconducting switch wire prepared by this method is not easily brittle and has a high critical current value and a low residual resistance ratio. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 It is a schematic cross-sectional view of the CuNb composite sheath of the present invention;
[0024] Figure 2 It is a schematic cross-sectional view of the sub-components of the inner-tin Nb3Sn superconducting wire of the present invention;
[0025] Figure 3 It is a schematic cross-sectional view of the inner-tin Nb3Sn superconducting wire of the present invention;
[0026] Among them, 1. Nb rod; 2. Oxygen-free copper; 3. SnTi alloy tube; 4. Ta rod; 5. Sub-components of the inner-tin Nb3Sn superconducting wire; 6. Oxygen-free copper tube. DETAILED DESCRIPTION OF THE INVENTION
[0027] The following further details the present application in conjunction with the drawings and embodiments. The following further details the specific embodiments of the present invention, but the present invention is not limited to these embodiments. Any improvement or substitution based on the basic spirit of this embodiment still falls within the scope protected by the claims of the present invention.
[0028] The preparation method of the high-performance superconducting switch wire provided by the present invention includes the following steps:
[0029] S1. Printing multiple Nb rods 1 and oxygen-free copper 2 into an integral structure to obtain a CuNb composite sheath; specifically: vertically placing 100 - 150 Nb rods 1 on a circular base, using oxygen-free copper 2 as the matrix, and adopting 3D printing technology to print oxygen-free copper 2 and Nb rods 1 into an integral structure. The Nb rods 1 are dispersedly distributed in the oxygen-free copper 2 matrix. The bottom diameter of the formed cylinder is equal to the diameter of the circular base, and a CuNb composite ingot with a specification of Φ280mm - Φ320mm is made. Adding oxygen-free copper caps at both ends of the composite ingot and performing electron beam sealing welding to obtain a CuNb composite sheath. The cross-sectional view thereof is referred to Figure 1 . For the structure of the CuNb composite sheath of the present invention, except for the niobium rods, the rest is oxygen-free copper.
[0030] S2. Heating and insulating the CuNb composite sheath, and then extruding to obtain a CuNb composite rod; wherein, the heating temperature is 700°C - 900°C, and the insulation time is 60 min - 90 min.
[0031] S3. Drill a hole in the center of the CuNb composite rod to obtain a CuNb composite tube; the outer diameter of the CuNb composite tube is Φ52 mm to Φ75 mm, and the inner diameter is Φ30 mm to Φ35 mm.
[0032] S4. Insert a SnTi / Ta composite rod into the CuNb composite tube to obtain the enhanced inner-tin method Nb3Sn superconducting wire sub-component 5, and its cross-sectional view is referred to Figure 2 ; draw the obtained inner-tin method Nb3Sn superconducting wire sub-component 5, cut the drawn inner-tin method Nb3Sn superconducting wire sub-component 5 into multiple equal-length pieces and arrange them evenly. The opposite side dimension of the inner-tin method Nb3Sn superconducting wire sub-component 5 obtained after drawing is 5 mm to 15 mm; the inner diameter of the CuNb composite tube is 1.0 mm larger than the outer diameter of the SnTi / Ta composite rod;
[0033] The SnTi / Ta composite rod is obtained by cold-extruding a SnTi alloy ingot into a SnTi alloy tube 3 with an outer diameter of Φ29 mm to Φ34 mm and an inner diameter of Φ10 mm to Φ15 mm, and then inserting a Ta rod 4 into the SnTi alloy tube 3. The outer diameter of the Ta rod 4 is Φ9.5 mm to Φ14.5 mm.
[0034] S5. Load the multiple inner-tin method Nb3Sn superconducting wire sub-components 5 obtained in S4 into an oxygen-free copper tube 6 with an outer diameter of Φ60 mm to Φ75 mm and an inner diameter of Φ45 mm to Φ60 mm to obtain the final billet;
[0035] S6. Draw and twist the final billet to obtain a high-performance superconducting switch wire, that is, an inner-tin method Nb3Sn superconducting wire, and its cross-sectional view is referred to Figure 3 ; the wire specifications are Φ0.5 mm to Φ0.8 mm, the length is 3000 m to 4000 m, and the twist pitch is 15 mm to 40 mm.
[0036] The following is illustrated with specific embodiments.
[0037] Example 1
[0038] A method for preparing a high-performance superconducting switch wire includes the following steps:
[0039] S1. Vertically place 100 Nb rods with a diameter of Φ9 mm on a circular base with a diameter of Φ280 mm. Using oxygen-free copper as the matrix, adopt 3D printing technology to print oxygen-free copper into a cylinder with the same specifications as the circular base. The Nb rods are dispersedly distributed in the oxygen-free copper matrix to make a CuNb composite ingot with a diameter of Φ280 mm. Add oxygen-free copper caps at both ends of the composite ingot and seal them by electron beam welding to obtain a CuNb composite sheath.
[0040] S2. Heat the CuNb composite sheath obtained in step S1 to 700 °C and hold for 60 min, then extrude to obtain a CuNb composite rod.
[0041] S3. Drill a hole with a diameter of Φ30 mm at the center of the CuNb composite rod to obtain a CuNb composite tube.
[0042] S4. Cold extrude the SnTi alloy ingot into a SnTi alloy tube with an outer diameter of Φ29 and an inner diameter of Φ10 mm, insert a Ta rod with a diameter of Φ9.5 mm 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 S3 to obtain a sub-component of the enhanced internal tin process Nb3Sn superconducting wire. Draw the obtained sub-component of the internal tin process Nb3Sn superconducting wire, cut the drawn sub-component of the internal tin process Nb3Sn superconducting wire into multiple equal-length pieces and arrange them evenly. The opposite side dimension of the drawn sub-component of the internal tin process Nb3Sn superconducting wire is 5 mm.
[0043] S5. Load the multiple sub-components of the internal tin process Nb3Sn superconducting wire obtained in S4 into an oxygen-free copper tube with an outer diameter of Φ60 mm and an inner diameter of Φ45 mm to obtain the final billet.
[0044] S6. Draw and twist the final billet to obtain a high-performance superconducting switch wire; the wire specification is Φ0.5 mm and the twist pitch is 15 mm.
[0045] Take samples from the high-performance superconducting switch wire obtained in S6, perform heat treatment, and test its critical current value and residual resistance ratio after being taken out of the furnace. The results are shown in Table 1:
[0046] Table 1 Test results of the low-temperature performance of the samples
[0047] Wire number Ic@8T RRR NbTi type 61.4 2 <![CDATA[Internal Tin Process Nb3Sn Type]]> 1054.3 1
[0048] In Example 1, a superconducting switch wire with a length of 3000 m was successfully prepared. As can be seen from Table 1, its critical current value has been greatly improved, and its residual resistance ratio also meets the relevant technical requirements.
[0049] Example 2
[0050] A method for preparing a high-performance superconducting switch wire, comprising the following steps:
[0051] S1. Vertically place 125 Nb rods with a diameter of Φ10 mm on a circular base with a diameter of Φ300 mm. Using oxygen-free copper as the matrix, adopt 3D printing technology to print oxygen-free copper into a cylinder with the same specifications as the circular base. The Nb rods are dispersed in the oxygen-free copper matrix to form a CuNb composite ingot with a diameter of Φ300 mm. Add oxygen-free copper caps at both ends of the composite ingot and seal them by electron beam welding to obtain a CuNb composite sheath.
[0052] S2. Heat the CuNb composite sheath obtained in step S1 to 800 °C and hold for 80 min, then extrude to obtain a CuNb composite rod.
[0053] S3. Drill a hole with a diameter of Φ32 mm at the center of the CuNb composite rod to obtain a CuNb composite tube.
[0054] S4. Cold-extrude the SnTi alloy ingot into a SnTi alloy tube with an outer diameter of Φ31 and an inner diameter of Φ12 mm. Insert a Ta rod with a diameter of Φ11 mm into the SnTi alloy tube to obtain a SnTi / Ta composite rod. Then insert the obtained SnTi / Ta composite rod into the CuNb composite tube obtained in S3 to obtain a sub-component of the enhanced internal tin method Nb3Sn superconducting wire. Draw the obtained sub-component of the internal tin method Nb3Sn superconducting wire, cut the drawn sub-component of the internal tin method Nb3Sn superconducting wire into multiple equal-length pieces and arrange them evenly. The opposite side dimension of the drawn sub-component of the internal tin method Nb3Sn superconducting wire is 10 mm.
[0055] S5. Load the multiple sub-components of the internal tin method Nb3Sn superconducting wire obtained in S4 into an oxygen-free copper tube with an outer diameter of Φ65 mm and an inner diameter of Φ50 mm to obtain a final billet.
[0056] S6. Draw and twist the final billet to obtain a high-performance superconducting switch wire; the wire specification is Φ0.7 mm and the twist pitch is 20 mm.
[0057] Take samples from the high-performance superconducting switch wire obtained in S6 and perform heat treatment. After taking out of the furnace, test its critical current value and residual resistance ratio. The results are shown in Table 2:
[0058] Table 2 Test results of the low-temperature performance of the samples
[0059] Wire number Ic@8T RRR NbTi type 85.9 1 <![CDATA[Internal Tin Process Nb3Sn Type]]> 1453.4 1
[0060] In Example 2, a superconducting switch wire with a length of 3800 m was successfully prepared. As can be seen from Table 2, its critical current value has been greatly improved, and at the same time its residual resistance ratio also meets the relevant technical requirements.
[0061] Example 3
[0062] A method for preparing a high-performance superconducting switch wire, comprising the following steps:
[0063] S1. Vertically place 150 Nb rods with a diameter of Φ12mm on a circular base with a diameter of Φ320mm. Using oxygen-free copper as the matrix and 3D printing technology, print oxygen-free copper into a cylinder with the same specifications as the circular base. The Nb rods are dispersed in the oxygen-free copper matrix to form a CuNb composite ingot with a diameter of Φ320mm. Add oxygen-free copper caps at both ends of the composite ingot and seal them by electron beam welding to obtain a CuNb composite sheath.
[0064] S2. Heat the CuNb composite sheath obtained in step S1 to 900 °C and hold for 90 min, then extrude to obtain a CuNb composite rod.
[0065] S3. Drill a hole with a diameter of Φ35mm at the center of the CuNb composite rod to obtain a CuNb composite tube.
[0066] S4. Cold extrude the SnTi alloy ingot into a SnTi alloy tube with an outer diameter of Φ35mm and an inner diameter of Φ15mm. Insert a Ta rod with a diameter of Φ14.5mm into the SnTi alloy tube to obtain a SnTi / Ta composite rod. Then insert the obtained SnTi / Ta composite rod into the CuNb composite tube obtained in S3 to obtain a reinforced inner-tin method Nb3Sn superconducting wire sub-component. Draw the obtained inner-tin method Nb3Sn superconducting wire sub-component, cut the drawn inner-tin method Nb3Sn superconducting wire sub-component into multiple equal-length pieces and arrange them evenly. The opposite side dimension of the drawn inner-tin method Nb3Sn superconducting wire sub-component is 15mm.
[0067] S5. Load multiple inner-tin method Nb3Sn superconducting wire sub-components obtained in S4 into an oxygen-free copper tube with an outer diameter of Φ75mm and an inner diameter of Φ60mm to obtain the final billet.
[0068] S6. Draw and twist the final billet to obtain a high-performance superconducting switch wire; the wire specification is Φ0.8mm and the twist pitch is 40mm.
[0069] Take samples from the high-performance superconducting switch wire obtained in S6 and perform heat treatment. After furnace cooling, test its critical current value and residual resistance ratio. The results are shown in Table 3:
[0070] Table 3 Test results of the low-temperature performance of the samples
[0071] Wire number Ic@8T RRR NbTi type 100.3 1 <![CDATA[Internal Tin Process Nb3Sn Type]]> 1662.1 1
[0072] In Example 3, a superconducting switch wire with a length of 4500m was successfully prepared. As can be seen from Table 3, its critical current value has been greatly improved, and its residual resistance ratio also meets the relevant technical requirements.
[0073] Preparation method of high-performance superconducting switch wire. Based on the internal tin method for Nb3Sn preparation process, an enhanced internal tin method Nb3Sn superconducting switch wire with comprehensively improved performance compared to NbTi superconducting switch wire is prepared. A Ta rod is installed in the center during the preparation of the sub-components of the Nb3Sn superconducting wire. The superconducting switch wire prepared by this method is not easily brittle and has a high critical current value and a low residual resistance ratio. The data in Tables 1, 2, and 3 that are not examples of the present invention all come from the prior art.
[0074] The above are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.
[0075] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is only limited by the appended claims.
Claims
1. A preparation method of a high-performance superconducting switch wire, characterized in that, It includes the following steps: S1. Print multiple Nb rods and oxygen-free copper into an integral structure to obtain a CuNb composite sheath; S2. Heat and keep the CuNb composite sheath at a certain temperature, and then extrude it to obtain a CuNb composite rod; S3. Drill a hole in the center of the CuNb composite rod to obtain a CuNb composite tube; S4. Insert an SnTi / Ta composite rod into the CuNb composite tube to obtain a Nb3Sn superconducting wire sub-component; the SnTi / Ta composite rod is obtained by extruding an SnTi alloy ingot into an SnTi alloy tube and then inserting a Ta rod into the SnTi alloy tube; S5. Load multiple Nb3Sn superconducting wire sub-components into an oxygen-free copper tube to obtain a final blank; S6. Draw and twist the final blank to obtain a high-performance superconducting switch wire.
2. The preparation method of the high-performance superconducting switch wire according to claim 1, characterized in that, Specifically, S1 is as follows: Vertically place multiple Nb rods on a circular base, use oxygen-free copper as the matrix, and adopt 3D printing technology to print oxygen-free copper and Nb rods into an integral structure. The Nb rods are dispersedly distributed in the oxygen-free copper matrix. The bottom diameter of the formed cylinder is equal to the diameter of the circular base to make a CuNb composite ingot. Weld oxygen-free copper caps at both ends of the composite ingot to obtain a CuNb composite sheath.
3. The preparation method of the high-performance superconducting switch wire according to claim 2, characterized in that, The number of the Nb rods is 100 - 150, and the specification of the CuNb composite ingot is Φ280mm - Φ320mm.
4. The preparation method of the high-performance superconducting switch wire according to claim 1, characterized in that In S2, the heating temperature is 700°C - 900°C, and the heat preservation time is 60min - 90min.
5. The preparation method of the high-performance superconducting switch wire according to claim 1, wherein In S3, the outer diameter of the CuNb composite tube is Φ52mm - Φ75mm, and the inner diameter is Φ30mm - Φ35mm.
6. The preparation method of the high-performance superconducting switch wire according to claim 1, characterized in that, In S4, the inner diameter of the CuNb composite tube is 1.0mm larger than the outer diameter of the SnTi / Ta composite rod.
7. The preparation method of the high-performance superconducting switch wire according to claim 1, characterized in that, In S4, the SnTi ingot is extruded by the cold extrusion method. The outer diameter of the extruded SnTi alloy tube is Φ29mm - Φ34mm, and the inner diameter is Φ10mm - Φ15mm. The outer diameter of the Ta rod is Φ9.5mm - Φ14.5mm.
8. The preparation method of the high-performance superconducting switch wire according to claim 1, characterized in that, In S4, the Nb3Sn superconducting wire sub-component is drawn and cut rectilinearly. The opposite side dimension of the obtained Nb3Sn superconducting wire sub-component is 5mm - 15mm.
9. The preparation method of the high-performance superconducting switch wire according to claim 1, characterized in that, In S5, the outer diameter of the oxygen-free copper tube is Φ60mm - Φ75mm, and the inner diameter is Φ45mm - Φ60mm.
10. The preparation method of the high-performance superconducting switch wire according to claim 1, characterized in that, In S6, the twist pitch is 15mm - 40mm.