A special grinding brush head for NbTi alloy surface treatment and its preparation method

Abstract

The present invention discloses a special grinding brush head for NbTi alloy surface treatment. To obtain NbTi alloy filaments, a multi-core NbTi / Cu composite wire is first prepared by an assembly method. Then, the NbTi / Cu composite wire stretched to corresponding specifications is subjected to an etching operation to remove the copper matrix. Finally, the clean NbTi alloy filaments obtained by etching are pressed to finally prepare a grinding brush head. The above content forms a preparation method for a special grinding brush head for NbTi alloy surface treatment, which solves the problems of uneven thickness, low grinding accuracy, and easy loss of Fe chips and impurities in traditional steel wire brush heads. It completely eliminates the problem that the surface quality of NbTi alloy seriously affects the performance of NbTi / Cu superconducting wires.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, in particular to a special grinding brush head for NbTi alloy surface treatment and a treatment method thereof. Background Art

[0002] Currently, NbTi superconductors are widely used in fields such as MRI, MCZ, NMR, nuclear fusion reactors, and accelerators due to their mature manufacturing processes and stable performance. NbTi alloys not only possess excellent superconducting properties, with a critical temperature Tc of approximately 9.5K, but also exhibit good processing characteristics and a high upper critical magnetic field Hc2, attracting widespread attention in the superconducting field.

[0003] The production of superconducting wire using NbTi alloy involves multiple steps, including forging, extrusion, and wire drawing. These processes can introduce defects such as Fe inclusions and dents to the NbTi alloy surface. Surface quality is crucial for the subsequent performance of the superconducting wire and the subsequent magnet winding process. Therefore, polishing the NbTi alloy surface is often required during the production process. However, conventional steel wire brushes commonly used in the prior art suffer from uneven wire thickness, low polishing accuracy, and the tendency to lose Fe chips. This makes it impossible to guarantee the performance of the subsequent superconducting wire or the quality of the subsequent magnet winding. Summary of the Invention

[0004] The purpose of the present invention is to provide a special grinding brush head for NbTi alloy surface treatment, so as to solve the problems raised in the above background technology that the ordinary steel wire brush heads generally used in the prior art have uneven steel wire thickness, low grinding accuracy and easy Fe chips falling off, and the problem that the performance of the subsequent superconducting wire and the quality of the subsequent wound magnets cannot be guaranteed during use.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] On the one hand, the embodiments of the present application provide a method for preparing a special grinding brush head for NbTi alloy surface treatment, comprising the following steps:

[0007] Obtaining an assembled multi-core NbTi / Cu composite ingot;

[0008] The assembled NbTi / Cu composite ingots are welded by electron beam welding to obtain welded NbTi / Cu composite ingots;

[0009] The welded NbTi / Cu composite ingot is heated, extruded and drawn in sequence to obtain a mm-grade multi-core NbTi / Cu composite wire;

[0010] The multi-core NbTi / Cu composite wire was corroded to obtain mm-scale NbTi alloy filaments;

[0011] performing a pressing process on the NbTi alloy filament to obtain the NbTi alloy filament;

[0012] The NbTi alloy filaments are evenly arranged and installed on the filament cover to obtain a grinding brush head.

[0013] Further preferably, when obtaining the assembled multi-core NbTi / Cu composite ingot, it is necessary to calculate the specifications of the multi-core NbTi / Cu composite ingot assembly materials according to the required size of the NbTi alloy filaments, and design the NbTi / Cu composite ingot assembly drawing, and the multi-core NbTi / Cu composite ingot assembly materials include oxygen-free copper tubes, upper covers, lower covers, NbTi / Cu single core rods and copper plug rods.

[0014] Further preferably, when obtaining the assembled multi-core NbTi / Cu composite ingot, the oxygen-free copper tube, the upper cover, the lower cover, the NbTi / Cu single core rod and the copper insert rod need to be cleaned and dried, and the NbTi / Cu single core rod is neatly arranged in the oxygen-free copper tube, the gap between the NbTi / Cu single core rod and the oxygen-free copper tube is filled with the copper insert rod, and the two ends of the oxygen-free copper tube are sealed by the upper cover and the lower cover respectively, and it is also necessary to ensure that no foreign matter is introduced during the assembly process.

[0015] Further preferably, when the assembled NbTi / Cu composite ingot is welded by electron beam welding, six-point positioning is first performed, and then repeated sealing is performed, and when electron beam welding is performed, the vacuum degree is less than 10 -5 mbar.

[0016] Further preferably, when the welded NbTi / Cu composite ingots are heated in sequence, they are heated by a resistance furnace and extruded after heating; when the welded NbTi / Cu composite ingots are drawn in sequence, multiple aging heat treatments are required, and the vacuum degree of the heat treatment furnace is less than 0.1 Pa during the aging heat treatment, and the temperature of the NbTi / Cu composite ingot is monitored.

[0017] Further preferably, when the multi-core NbTi / Cu composite wire is corroded, the multi-core NbTi / Cu composite wire needs to be coiled and fixed at at least two points by a Nb3Sn wire, and then placed in a dilute nitric acid solution. After the copper matrix on the surface of the multi-core NbTi / Cu composite wire completely disappears, it is rinsed and dried to obtain mm-level NbTi alloy filaments.

[0018] Further preferably, when the NbTi alloy filaments are pressed, NbTi alloy filaments of different lengths are obtained according to the size of the mold.

[0019] Further preferably, the NbTi alloy filaments are evenly arranged and installed on the wire cover, and polishing brush heads of different specifications are obtained through different arrangement methods and densities.

[0020] On the other hand, an embodiment of the present application further provides a special grinding brush head for NbTi alloy surface treatment, which is prepared using the above-mentioned preparation method.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] It solves the problems of uneven thickness, low grinding precision and easy loss of Fe chips and impurities in traditional steel wire brush heads, and eliminates the problems of NbTi alloy surface quality seriously affecting the performance of NbTi / Cu superconducting wires.

[0023] On the one hand, the raw materials for preparing NbTi alloy filaments can be prepared by designing the specifications and quantity of NbTi / Cu single core rods required for assembling NbTi / Cu composite ingots, so as to prepare specific brush heads with strict requirements on the diameter specifications and quantity of NbTi wires; on the other hand, the residual NbTi / Cu composite wires in the production process can be used as the raw materials for preparing NbTi wire brush heads, thereby achieving the effect of recycling. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a flow chart of a method for preparing a special grinding brush head for NbTi alloy surface treatment provided by the present invention; DETAILED DESCRIPTION

[0025] 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.

[0026] See also Figure 1 , the present invention provides a technical solution:

[0027] A method for preparing a special grinding brush head for NbTi alloy surface treatment comprises the following steps:

[0028] S100, obtaining an assembled multi-core NbTi / Cu composite ingot;

[0029] In the present invention, when obtaining an assembled multi-core NbTi / Cu composite ingot, it is necessary to calculate the specifications of the multi-core NbTi / Cu composite ingot assembly materials based on the required size of the NbTi alloy filaments, and design an NbTi / Cu composite ingot assembly diagram. The multi-core NbTi / Cu composite ingot assembly materials include an oxygen-free copper tube, an upper cover, a lower cover, a NbTi / Cu single-core rod, and a copper insert. When obtaining an assembled multi-core NbTi / Cu composite ingot, it is also necessary to clean and dry the oxygen-free copper tube, the upper cover, the lower cover, the NbTi / Cu single-core rod, and the copper insert, and neatly arrange the NbTi / Cu single-core rod in the oxygen-free copper tube. The gap between the NbTi / Cu single-core rod and the oxygen-free copper tube is filled with a copper insert, and the two ends of the oxygen-free copper tube are sealed by the upper cover and the lower cover, respectively. In addition, it is also necessary to ensure that no foreign matter is introduced during the assembly process.

[0030] S110, welding the assembled NbTi / Cu composite ingot by electron beam welding to obtain a welded NbTi / Cu composite ingot;

[0031] In the present invention, when the assembled NbTi / Cu composite ingot is welded by electron beam welding, six-point positioning is first performed, and then repeated sealing welding is performed. When electron beam welding is used, the vacuum degree is less than 10 -5 mbar.

[0032] S120, sequentially heating, extruding, and drawing the welded NbTi / Cu composite ingot to obtain a mm-grade multi-core NbTi / Cu composite wire;

[0033] In the present invention, when the welded NbTi / Cu composite ingots are heated in sequence, they are heated by a resistance furnace and extruded after heating; when the welded NbTi / Cu composite ingots are drawn in sequence, multiple aging heat treatments are required, and the vacuum degree of the heat treatment furnace is less than 0.1 Pa during the aging heat treatment, and the temperature of the NbTi / Cu composite ingots is monitored.

[0034] S130, performing corrosion treatment on the multi-core NbTi / Cu composite wire to obtain mm-level NbTi alloy filaments;

[0035] In the present invention, when the multi-core NbTi / Cu composite wire is subjected to corrosion treatment, the multi-core NbTi / Cu composite wire needs to be coiled and fixed at at least two points by Nb3Sn wire, and then placed in a dilute nitric acid solution. After the copper matrix on the surface of the multi-core NbTi / Cu composite wire completely disappears, it is rinsed and dried to obtain mm-level NbTi alloy filaments.

[0036] S140, pressing the NbTi alloy filaments to obtain NbTi alloy filaments;

[0037] In the present invention, when the NbTi alloy filaments are subjected to a pressing process, NbTi alloy filaments of different lengths are obtained according to the size of the mold.

[0038] S150. Evenly arrange the NbTi alloy filaments and install them on the filament cover to obtain a grinding brush head.

[0039] In the present invention, NbTi alloy filaments are evenly arranged and installed on the filament cover, and polishing brush heads of different specifications are obtained through different arrangement modes and densities. Example 1

[0040] According to the required size of NbTi alloy filaments of Φ0.5mm, the specifications of the materials for assembling the multi-core NbTi / Cu composite ingot are calculated, and a 55-core NbTi / Cu composite ingot is designed. Specifically, the size of the NbTi / Cu single-core rod required for assembling the multi-core NbTi / Cu composite ingot can be calculated by the diameter of the final formed NbTi core wire and the processing rate existing in the drawing process of the wire. First, the oxygen-free copper tube, upper cover, lower cover, single-core rod and copper plug rod that have been cleaned and dried are assembled. During assembly, the NbTi / Cu single-core rod is neatly arranged in the oxygen-free copper tube. The gap between the NbTi / Cu single-core rod and the oxygen-free copper tube is filled with the copper plug rod. The two ends of the oxygen-free copper tube are sealed by the upper cover and the lower cover respectively. It is ensured that no foreign inclusions are introduced during the assembly process. Then, the assembled 55-core NbTi / Cu composite ingot is welded by electron beam welding. The vacuum degree during welding must be guaranteed to be less than 10 -5 mbar, welding begins with six-point positioning, followed by repeated sealing to ensure weld quality. The welded 55-core NbTi / Cu composite ingot is uniformly heated in a resistance furnace and then extruded to produce a NbTi / Cu composite rod. Surface scale is removed by peeling. The NbTi / Cu composite rod undergoes multiple aging heat treatments during subsequent drawing. During these treatments, the furnace vacuum must be less than 0.1 Pa, and the material temperature must be continuously monitored. Sufficient lubrication is also required during the drawing process, resulting in a Φ5.5mm 55-core NbTi / Cu composite wire. A section of Nb3Sn wire, which is difficult to corrode, is then cut and wound around the coiled NbTi / Cu composite wire. The sample to be corroded is placed in a dilute nitric acid solution. Once the copper matrix on the NbTi core wire has completely disappeared, the sample is rinsed and dried to produce a 0.5mm NbTi alloy filament. The prepared clean NbTi core wire is pressed and evenly arranged on a wire cover with an outer diameter of 64 mm and an aperture of 16 mm to prepare a high-purity NbTi alloy surface treatment special grinding brush head with a wire length of 40 mm, which is suitable for 100-type angle grinders. Example 2

[0041] Based on the required size of NbTi alloy filaments of Φ0.7mm, the specifications of the multi-core NbTi / Cu composite ingot assembly materials are calculated, and a 55-core NbTi / Cu composite ingot is designed. First, the cleaned and dried oxygen-free copper tube, upper cover, lower cover, single core rod and copper plug rod are assembled. During assembly, the NbTi / Cu single core rod is neatly arranged in the oxygen-free copper tube. The gap between the NbTi / Cu single core rod and the oxygen-free copper tube is filled with the copper plug rod. The two ends of the oxygen-free copper tube are sealed by the upper cover and the lower cover respectively. During the assembly process, it is ensured that no foreign inclusions are introduced. Then, the assembled 55-core NbTi / Cu composite ingot is welded by electron beam welding. The vacuum degree during welding must be guaranteed to be less than 10 -5 mbar, the welding is first performed with 6-point positioning, and then repeated sealing is performed to ensure the quality of the weld. The welded 55-core NbTi / Cu composite ingot is placed in a resistance furnace for uniform heating, and then extruded to obtain a 55-core NbTi / Cu composite rod. The oxide scale produced on the surface of the 55-core NbTi / Cu composite rod is removed by peeling operation. In the subsequent drawing process, multiple aging heat treatments are required. During the aging heat treatment process, the vacuum degree of the heat treatment furnace must be less than 0.1Pa, and the material temperature must be continuously monitored. It is also necessary to ensure sufficient lubrication during the drawing process to prepare a Φ6.8mm 55-core NbTi / Cu composite wire. Then, a section of Nb3Sn wire that is difficult to corrode is cut and wound on the 55-core NbTi / Cu composite wire after coiling. The sample to be corroded is placed in a dilute nitric acid solution. After the copper matrix on the surface of the 55-core NbTi / Cu composite wire disappears completely, the sample is rinsed and dried to obtain a 0.7mm NbTi alloy filament. The prepared clean NbTi alloy filament is pressed.

[0042] The pressed NbTi alloy filaments are evenly arranged on a wire cover with an outer diameter of 70 mm and an aperture of 22 mm to prepare a high-purity NbTi alloy surface treatment special grinding brush head with a wire length of 45 mm, which is suitable for 125-type angle grinders. Example 3

[0043] Based on the required size of NbTi alloy filaments of Φ0.8mm, the specifications of the multi-core NbTi / Cu composite ingot assembly materials are calculated, and a 55-core NbTi / Cu composite ingot is designed. First, the cleaned and dried oxygen-free copper tube, upper cover, lower cover, single core rod and copper plug rod are assembled. During assembly, the NbTi / Cu single core rod is neatly arranged in the oxygen-free copper tube. The gap between the NbTi / Cu single core rod and the oxygen-free copper tube is filled with the copper plug rod. The two ends of the oxygen-free copper tube are sealed by the upper cover and the lower cover respectively. During the assembly process, it is ensured that no foreign inclusions are introduced. Then, the assembled 55-core NbTi / Cu composite ingot is welded by electron beam welding. The vacuum degree during welding must be guaranteed to be less than 10 -5 mbar, the welding is first performed with 6-point positioning, and then repeated sealing is performed to ensure the quality of the weld. The welded 55-core NbTi / Cu composite ingot is placed in a resistance furnace for uniform heating, and then extruded to obtain a 55-core NbTi / Cu composite rod. The oxide scale produced on the surface of the composite rod is removed by peeling operation. Multiple aging heat treatments are required during the subsequent drawing process. During the aging heat treatment process, the vacuum degree of the heat treatment furnace must be less than 0.1Pa, and the material temperature must be continuously monitored. It is also necessary to ensure sufficient lubrication during the drawing process to prepare a Φ7.8mm 55-core NbTi / Cu composite wire. Then, a section of Nb3Sn wire that is difficult to corrode is cut and wound around the 55-core NbTi / Cu composite wire after coiling. The sample to be corroded is placed in a dilute nitric acid solution. After the copper matrix on the surface of the 55-core NbTi / Cu composite wire completely disappears, the sample is rinsed and dried to obtain a 0.8mm NbTi alloy filament. The prepared clean NbTi alloy filament is pressed.

[0044] The pressed NbTi alloy filaments are evenly arranged on a wire cover with an outer diameter of 96 mm and an aperture of 22 mm to prepare a high-purity NbTi alloy surface treatment special grinding brush head with a wire length of 50 mm, which is suitable for 150-type angle grinders. Example 4

[0045] On the one hand, the raw materials for preparing NbTi alloy filaments can be prepared by designing the specifications and quantity of NbTi / Cu single core rods required for assembling NbTi / Cu composite ingots, so as to prepare specific brush heads with strict requirements on the diameter specifications and quantity of NbTi wires; on the other hand, the residual NbTi / Cu composite wires in the production process can be used as the raw materials for preparing NbTi wire brush heads, thereby achieving the effect of recycling.

[0046] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description. It is intended that all variations within the meaning and range of equivalents of the claims be embraced herein, and any reference signs in the claims should not be construed as limiting the claims to which they relate.

[0047] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a special grinding brush head for NbTi alloy surface treatment, characterized in that: The following steps are involved: Obtaining an assembled multi-core NbTi / Cu composite ingot, calculating specifications of the multi-core NbTi / Cu composite ingot assembly materials based on the required size of the NbTi alloy filaments, and designing an NbTi / Cu composite ingot assembly drawing, wherein the multi-core NbTi / Cu composite ingot assembly materials include an oxygen-free copper tube, an upper cover, a lower cover, a NbTi / Cu single core rod, and a copper insert; The assembled NbTi / Cu composite ingots are welded by electron beam welding to obtain NbTi / Cu composite ingots; The welded NbTi / Cu composite ingot is heated, extruded and drawn in sequence to obtain a multi-core NbTi / Cu composite wire; The multi-core NbTi / Cu composite wire is subjected to corrosion treatment, the multi-core NbTi / Cu composite wire is coiled, and the multi-core NbTi / Cu composite wire is fixed at at least two points by winding a Nb3Sn wire around the wire, and then placed in a dilute nitric acid solution. After the copper matrix on the surface of the multi-core NbTi / Cu composite wire completely disappears, the wire is rinsed and dried to obtain NbTi alloy filaments; The NbTi alloy filaments are pressed to obtain NbTi alloy filaments, wherein the NbTi alloy filaments are pressed to obtain NbTi alloy filaments of different lengths according to the size of the mold; The NbTi alloy filaments are evenly arranged and installed on the filament cover to obtain a grinding brush head.

2. The method for preparing a special grinding brush head for NbTi alloy surface treatment according to claim 1, characterized in that: When obtaining the assembled multi-core NbTi / Cu composite ingot, the oxygen-free copper tube, upper cover, lower cover, NbTi / Cu single core rod and copper insert rod need to be cleaned and dried, and the NbTi / Cu single core rod is neatly arranged in the oxygen-free copper tube. The gap between the NbTi / Cu single core rod and the oxygen-free copper tube is filled with the copper insert rod. The two ends of the oxygen-free copper tube are sealed by the upper cover and the lower cover respectively. During the assembly process, it is also necessary to ensure that no foreign matter is introduced.

3. The method for preparing a special grinding brush head for NbTi alloy surface treatment according to claim 1, characterized in that: When the assembled NbTi / Cu composite ingot is welded by electron beam welding, six-point positioning is first performed, and then repeated sealing welding is performed. When electron beam welding is performed, the vacuum degree is less than 10 -5 mbar.

4. The method for preparing a special grinding brush head for NbTi alloy surface treatment according to claim 1, characterized in that: When the welded NbTi / Cu composite ingots are heated sequentially, they are heated by a resistance furnace and extruded after heating; when the welded NbTi / Cu composite ingots are drawn sequentially, multiple aging heat treatments are required, and the vacuum degree of the heat treatment furnace is less than 0.1 Pa during the aging heat treatment, and the temperature of the NbTi / Cu composite ingot is monitored.

5. The method for preparing a special grinding brush head for NbTi alloy surface treatment according to claim 1, characterized in that: The NbTi alloy filaments are evenly arranged and installed on the filament cover, and polishing brush heads of different specifications are obtained through different arrangement methods and densities.

6. A special grinding brush head for NbTi alloy surface treatment, characterized by: The polishing brush head is prepared by the preparation method according to any one of claims 1 to 5.

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