Production process of magnetic pole copper bar for wind power

Abstract

The invention relates to the technical field of copper bar production, and provides a production process of a magnetic pole copper bar for wind power, which comprises the following steps: selecting a cathode copper plate with the purity of more than or equal to 99.95% as a raw material, removing an oxide layer, impurities and two-pole defect parts on the surface of the copper plate, cleaning the copper plate, manufacturing a copper rod by adopting an up-drawing continuous casting machine, cutting the up-drawing continuous casting copper rod into fixed-length sections of 1-2m, and carrying out continuous casting. Surface oxide skin is removed, and annealing treatment is conducted at the temperature of 300-400 DEG C if necessary; the copper rod is fed into a continuous extrusion unit, the continuous extrusion unit comprises an extrusion die, a driving device and a temperature control system, the extrusion speed is 5.5-6.5 rpm, the temperature of an outlet of the die is controlled to range from 500 DEG C to 580 DEG C in the extrusion process, and the copper bar is formed through extrusion. Impurity-containing areas at the two poles of the copper bar are removed, high-purity raw materials are selected, and trace cerium elements are added in cooperation with upward continuous casting, so that the conductivity of the copper bar is remarkably improved; and in the continuous extrusion process, the hardness of the copper bar is synchronously improved through precise linkage control of the die outlet temperature and the extrusion speed in combination with a graded cooling strategy.

Description

Technical Field

[0001] This invention relates to the field of copper busbar production technology, specifically to the production process of magnetic pole copper busbars for wind power. Background Technology

[0002] Against the backdrop of the global energy structure transitioning towards clean energy, wind power, as an important form of renewable energy utilization, has seen its installed capacity grow rapidly and continuously. Wind turbines operate in complex outdoor environments for extended periods, enduring strong winds, temperature variations, and humidity fluctuations, which places stringent demands on the performance of their core components. Among these, the copper pole busbars within the generator, as key components for power transmission and magnetic field formation, directly impact the operating efficiency and lifespan of wind turbines due to their conductivity, mechanical strength, and environmental adaptability.

[0003] Currently, the production of copper pole blocks for wind power mainly employs traditional processes, namely, forming through smelting, rolling, and drawing. However, existing technologies have significant shortcomings: to ensure high conductivity, high-purity copper is typically selected, but high-purity copper is relatively soft, resulting in low hardness of the copper pole blocks. This makes them prone to deformation under electromagnetic forces during high-speed motor operation, affecting magnetic field stability. Conversely, increasing hardness by adding alloying elements significantly reduces conductivity, making it difficult to balance both performance requirements. The core reason for this contradiction lies in the difficulty of precisely controlling the internal microstructure of copper during the rolling and drawing processes in traditional methods. This makes it impossible to simultaneously ensure the ordered arrangement of copper atoms (ensuring high conductivity) and uniform grain refinement (achieving high hardness), resulting in copper pole blocks that cannot meet the synergistic requirements of wind power equipment for high conductivity and high hardness. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a manufacturing process for magnetic pole copper busbars used in wind power. This process solves the problem that in existing technologies, high-purity copper is typically selected to ensure the high conductivity of the copper busbars. However, high-purity copper is relatively soft, resulting in low hardness of the copper busbars. This makes them prone to deformation due to electromagnetic forces when the motor is running at high speed, affecting the stability of the magnetic field. If alloying elements are added to increase the hardness, the conductivity of the copper busbars will be significantly reduced, making it difficult to balance the performance of both materials.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a manufacturing process for copper pole busbars for wind power, comprising the following steps: S1: Select cathode copper plates with a purity of ≥99.95% as raw materials, remove the oxide layer, impurities and electrode defects from the surface of the copper plates, clean the copper plates, and then use an upward continuous casting machine to form copper rods. S2: Cut the continuously cast copper rod into 1-2 meter long sections, remove the surface oxide scale, and anneal at 300-400℃ if necessary; feed the copper rod into the continuous extrusion unit, which includes an extrusion die, a drive device and a temperature control system. The extrusion speed is 5.5-6.5 rpm, and the die outlet temperature is controlled at 500-580℃ during the extrusion process to form copper busbars. S3: The extruded copper busbar is cooled by a cooling unit, which includes a primary cooling section and a secondary cooling section. When the copper busbar thickness is ≤3.55mm, it directly enters the secondary cooling section, where the cooling water temperature is 40-45℃. When the copper busbar thickness is >3.55mm, it first passes through the primary cooling section and then enters the secondary cooling section. The primary cooling section is protected by inert gas with a protection distance of 100-300mm. S4: Use a high-precision saw to cut the continuously extruded copper busbars into fixed lengths with a length tolerance of ≤ ±0.5mm; use a grinding wheel or cloth wheel to polish the surface of the copper busbars to make the surface roughness Ra ≤ 0.8μm, and perform passivation treatment if necessary; S5: The hardness and conductivity of the finished copper busbars are tested. If they pass the test, the copper busbars are packaged using moisture-proof and oxidation-proof composite materials and then put into storage.

[0006] Preferably, in step S1, the width of the impurity-containing areas at both poles of the copper plate being removed is 5-10 cm, the inner wall of the crystallizer of the upward continuous casting machine is provided with a silicon nitride coating with a thickness of 5-10 μm, and trace amounts of rare earth elements, namely cerium, are added to the copper liquid during upward continuous casting, with an addition amount of 0.01-0.03 wt%.

[0007] Preferably, in the preparation of the copper rod in S1, the pretreated copper plate is put into an industrial frequency induction furnace and smelted at 1100-1150℃ under inert gas protection. Through the upward continuous casting method, a solid copper rod with a diameter of 8-20mm is continuously pulled upward under the conditions of crystallizer water temperature of 30-40℃ and traction speed of 10-20m / min.

[0008] Preferably, in step S2, the output torque of the drive device is 1200-1500 N·m.

[0009] Preferably, in step S2, the extrusion speed is... With mold exit temperature Satisfy the association relationship: ,in .

[0010] Preferably, in step S2, the continuous extrusion unit further includes an online temperature measurement module that provides real-time feedback on the mold outlet temperature and adjusts the rotation speed of the drive device.

[0011] Preferably, in step S3, the inert gas in the primary cooling section is argon with a purity ≥99.99% and a gas flow rate of 10-15 L / min; the cooling water in the secondary cooling section is deionized water with a conductivity ≤10 μS / cm and a cooling time of 10-15 s.

[0012] Preferably, in step S4, a diamond saw blade is used for sawing, and an aluminum oxide grinding wheel is used for polishing.

[0013] Preferably, in step S5, the hardness is tested using a Brinell hardness tester, and the conductivity is tested using an eddy current conductivity meter.

[0014] Preferably, in step S5, the items need to be placed in a constant temperature and humidity workshop for 24 hours before being put into storage, and the workshop is equipped with an anti-static grounding device.

[0015] This invention provides a manufacturing process for copper pole blocks used in wind power. It offers the following advantages: 1. This invention significantly improves the conductivity of copper busbars by removing impurity-containing areas at both ends of the copper plate and selecting high-purity raw materials, combined with the addition of trace amounts of cerium during continuous casting. During continuous extrusion, the hardness of the copper busbars is simultaneously improved by precisely controlling the mold exit temperature and extrusion speed, combined with a staged cooling strategy. This effectively solves the technical contradiction of balancing high conductivity and high hardness in traditional processes, and fully meets the stringent requirements for conductivity efficiency and deformation resistance of wind turbines during high-speed operation.

[0016] 2. This invention achieves automated production processes by utilizing online temperature measurement and closed-loop speed regulation of the drive device in the continuous extrusion unit; it significantly shortens the production cycle by reducing redundant processes such as multiple annealing and grinding in traditional processes through a graded cooling strategy; at the same time, the special coating on the inner wall of the crystallizer extends the service life of the mold, and the combination of high-precision sawing and grinding reduces the scrap rate.

[0017] 3. This invention achieves precise control of parameters throughout the entire process, significantly reducing the fluctuation range of key indicators such as the dimensional tolerance and surface roughness of the copper busbar, thus solving the problem of large performance dispersion of products using traditional processes. The combination of passivation treatment and moisture-proof and anti-oxidation packaging with constant temperature and humidity static storage process significantly improves the corrosion resistance of the copper busbar in complex outdoor environments, making it suitable for the complex outdoor working conditions of wind power equipment. Attached Figure Description

[0018] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example

[0020] Please see the appendix Figure 1 This invention provides a manufacturing process for copper pole busbars used in wind power, including the following steps: S1: Select cathode copper plates with a purity of ≥99.95% as raw materials, remove the oxide layer, impurities and electrode defects from the surface of the copper plates, clean the copper plates, and then use an upward continuous casting machine to form copper rods. S2: Cut the upper continuous casting copper rod into fixed length sections of 1-2 meters, remove the surface oxide scale, and anneal at 300-400℃ if necessary; feed the copper rod into the continuous extrusion unit, which includes an extrusion die, a drive device and a temperature control system. The extrusion speed is 5.5-6.5 rpm, and the die outlet temperature is controlled at 500-580℃ during the extrusion process to form copper busbars. S3: The extruded copper busbar is cooled by a cooling unit, which includes a primary cooling section and a secondary cooling section. When the copper busbar thickness is ≤3.55mm, it directly enters the secondary cooling section, where the cooling water temperature is 40-45℃. When the copper busbar thickness is >3.55mm, it first passes through the primary cooling section and then enters the secondary cooling section. The primary cooling section is protected by inert gas with a protection distance of 100-300mm. S4: Use a high-precision saw to cut the continuously extruded copper busbars into fixed lengths with a length tolerance of ≤ ±0.5mm; use a grinding wheel or cloth wheel to polish the surface of the copper busbars to make the surface roughness Ra ≤ 0.8μm, and perform passivation treatment if necessary; S5: The hardness and conductivity of the finished copper busbars are tested. If they pass the test, the copper busbars are packaged using moisture-proof and oxidation-proof composite materials and then put into storage. Specifically, high-purity cathode copper plates can reduce the impact of impurities on conductivity. Surface oxide scale is removed using a belt sander with a sanding pressure of 0.3 MPa to prevent oxide scale from entering the extrusion die and causing inclusions on the copper busbar surface. When copper rods are stored for more than 72 hours, an oxide film easily forms on the surface. Therefore, they need to be annealed at 300-400℃ in a box-type annealing furnace, held at that temperature for 2 hours, and then air-cooled. This process can eliminate internal stress from cold working, improve plasticity, and prevent cracking during extrusion. The difference in cooling methods stems from the influence of copper busbar thickness on heat dissipation: copper busbars with a thickness ≤3.55mm have a small heat capacity and can be cooled from 500-580℃ to below 100℃ in only 10-15 seconds, allowing them to directly enter the secondary cooling section for rapid shaping and to avoid oxidation; copper busbars with a thickness >3.55mm will experience a temperature difference exceeding 200℃ if directly water-cooled, easily generating thermal stress and causing cracking. Therefore, they first undergo a primary cooling section to prevent oxide scale formation on the copper busbar surface; a protection distance of 100-300mm allows the copper busbar temperature to drop from 500-580℃ to 300-350℃ before entering the secondary cooling section for final cooling.

[0021] In step S1, the width of the impurity-containing areas at both poles of the copper plate is 5-10 cm. The inner wall of the crystallizer of the upward continuous casting machine is coated with a silicon nitride coating with a thickness of 5-10 μm. During the upward continuous casting, trace amounts of rare earth elements are added to the copper liquid. The rare earth element is cerium, and the amount added is 0.01-0.03 wt%. In the preparation of the copper rod in S1, the pretreated copper plate is put into an industrial frequency induction furnace and melted at 1100-1150℃ under inert gas protection. Through the upward continuous casting method, under the conditions of crystallizer water temperature of 30-40℃ and traction speed of 10-20 m / min, a solid copper rod with a diameter of 8-20 mm is continuously pulled upward. Specifically, the defective parts at both poles need to be removed longitudinally along the edge of the copper plate for 5-10cm. Because the copper plate poles are prone to accumulating impurities such as lead and iron during electrolysis, this operation can improve the purity of the copper plate. The cleaning is done using an ultrasonic cleaner with a neutral surfactant as the cleaning agent. The water temperature is 50℃ and the cleaning time is 5 minutes to ensure that there is no oil residue on the surface. During the upward continuous casting, the silicon nitride coating (5-10μm) on the inner wall of the crystallizer can reduce the adhesion between the copper liquid and the crystallizer and extend the life of the crystallizer. Adding 0.01-0.03wt% of cerium to the copper liquid can refine the copper rod grains and inhibit the formation of brittle compounds between oxygen and copper, thereby improving the tensile strength of the copper rod. During smelting, a temperature range of 1100-1150℃ ensures complete melting of the copper plate while avoiding excessive evaporation and loss of the molten copper due to excessively high temperatures. Matching the crystallizer water temperature of 30-40℃ with a traction speed of 10-20m / min controls the cooling rate of the copper rod, ensuring uniform internal structure without defects such as shrinkage cavities or porosity. The resulting 8-20mm diameter solid copper rod has a straightness of ≤0.5mm / m.

[0022] In step S2, the output torque of the drive device is 1200-1500 N·m, and the extrusion speed is... With mold exit temperature Satisfy the association relationship: ,in , The continuous extrusion unit also includes an online temperature measurement module that provides real-time feedback on the die exit temperature and adjusts the drive unit speed. Specifically, the drive unit's output torque of 1200-1500 N·m can match the extrusion pressure (300-500 MPa) required for the plastic deformation of the copper rod, ensuring that the material fully fills the mold cavity. The relationship between extrusion speed and mold exit temperature... ,in Strictly adhere to the following: When T=500℃, v=6.5rpm (maximum speed); when T=580℃, v=5.5rpm (minimum speed). Through the online temperature measurement module, the infrared thermometer provides real-time temperature feedback, and the drive device automatically adjusts the speed to ensure that the copper busbar is formed in the 500-580℃ range. At this temperature, the yield strength of copper is ≤80MPa, making it easy to form and preventing overheating.

[0023] In step S3, the inert gas in the primary cooling section is argon with a purity ≥99.99% and a flow rate of 10-15 L / min; the cooling water in the secondary cooling section is deionized water with a conductivity ≤10 μS / cm and a cooling time of 10-15 s. Specifically, the argon flow rate in the primary cooling section is 10-15 L / min, which needs to be adjusted according to the width of the copper busbar to ensure that the gas curtain completely covers the surface of the copper busbar; the deionized water in the secondary cooling section has a conductivity of ≤10 μS / cm, which can prevent calcium and magnesium ions in the water from forming scale on the surface of the copper busbar and thus affecting subsequent conductivity. The cooling time is 10-15 s, which is controlled by the conveyor belt speed to ensure that the copper discharge temperature is ≤60℃.

[0024] In step S4, diamond saw blades are used for sawing and alumina grinding wheels are used for polishing and grinding. In step S5, Brinell hardness tester is used for hardness testing and eddy current conductivity tester is used for conductivity testing. Before being put into storage, the equipment needs to be placed in a constant temperature and humidity workshop for 24 hours. The workshop is equipped with an anti-static grounding device. Specifically, the copper busbars are placed in a constant temperature and humidity workshop for 24 hours before being put into storage to eliminate micro-deformation caused by temperature changes after packaging; the workshop has an anti-static grounding device with a grounding resistance of ≤4Ω to prevent static electricity from attracting dust in the air and to ensure the cleanliness of the copper busbar surface.

[0025] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A manufacturing process for copper pole blocks for wind power, characterized in that, Includes the following steps: S1: Select cathode copper plates with a purity of ≥99.95% as raw materials, remove the oxide layer, impurities and electrode defects from the surface of the copper plates, clean the copper plates, and then use an upward continuous casting machine to form copper rods. S2: Cut the continuously cast copper rod into 1-2 meter long sections, remove the surface oxide scale, and anneal at 300-400℃ if necessary; feed the copper rod into the continuous extrusion unit, which includes an extrusion die, a drive device and a temperature control system. The extrusion speed is 5.5-6.5 rpm, and the die outlet temperature is controlled at 500-580℃ during the extrusion process to form copper busbars. S3: The extruded copper busbar is cooled by a cooling unit, which includes a primary cooling section and a secondary cooling section. When the copper busbar thickness is ≤3.55mm, it directly enters the secondary cooling section, where the cooling water temperature is 40-45℃. When the copper busbar thickness is >3.55mm, it first passes through the primary cooling section and then enters the secondary cooling section. The primary cooling section is protected by inert gas with a protection distance of 100-300mm. S4: Use a high-precision saw to cut the continuously extruded copper busbars into fixed lengths with a length tolerance of ≤ ±0.5mm; use a grinding wheel or cloth wheel to polish the surface of the copper busbars to make the surface roughness Ra ≤ 0.8μm, and perform passivation treatment if necessary; S5: The hardness and conductivity of the finished copper busbars are tested. If they pass the test, the copper busbars are packaged using moisture-proof and oxidation-proof composite materials and then put into storage.

2. The manufacturing process for wind power magnetic pole copper busbars according to claim 1, characterized in that, In step S1, the width of the impurity-containing areas at both poles of the copper plate to be removed is 5-10 cm. The inner wall of the crystallizer of the upward continuous casting machine is coated with a silicon nitride coating with a thickness of 5-10 μm. During the upward continuous casting, trace amounts of rare earth elements are added to the copper liquid. The rare earth element is cerium, and the amount added is 0.01-0.03 wt%.

3. The manufacturing process for wind power magnetic pole copper busbars according to claim 1, characterized in that, In the preparation of copper rods in S1, the pretreated copper plate is put into an industrial frequency induction furnace and smelted at 1100-1150℃ under inert gas protection. Through the upward continuous casting method, solid copper rods with a diameter of 8-20mm are continuously pulled upward under the conditions of crystallizer water temperature of 30-40℃ and traction speed of 10-20m / min.

4. The manufacturing process for wind power magnetic pole copper busbars according to claim 1, characterized in that, In step S2, the output torque of the drive device is 1200-1500 N·m.

5. The manufacturing process for wind power magnetic pole copper busbars according to claim 1, characterized in that, In step S2, the extrusion speed With mold exit temperature Satisfy the association relationship: ,in .

6. The manufacturing process for wind power magnetic pole copper busbars according to claim 1, characterized in that, In step S2, the continuous extrusion unit also includes an online temperature measurement module that provides real-time feedback on the mold outlet temperature and adjusts the rotation speed of the drive device.

7. The manufacturing process for wind power magnetic pole copper busbars according to claim 1, characterized in that, In step S3, the inert gas in the primary cooling section is argon with a purity ≥99.99% and a flow rate of 10-15 L / min; the cooling water in the secondary cooling section is deionized water with a conductivity ≤10 μS / cm and a cooling time of 10-15 s.

8. The manufacturing process for wind power magnetic pole copper busbars according to claim 1, characterized in that, In step S4, a diamond saw blade is used for sawing, and an aluminum oxide grinding wheel is used for polishing.

9. The manufacturing process for wind power magnetic pole copper busbars according to claim 1, characterized in that, In step S5, the hardness is tested using a Brinell hardness tester, and the conductivity is tested using an eddy current conductivity meter.

10. The manufacturing process for wind power magnetic pole copper busbars according to claim 1, characterized in that, In step S5, the product needs to be placed in a constant temperature and humidity workshop for 24 hours before being put into storage. The workshop is equipped with an anti-static grounding device.

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