Preparation method of copper bar

Abstract

The invention relates to the technical field of copper bar preparation, and provides a copper bar preparation method which comprises the following steps: step 1, raw material preparation: preparing an electrolytic copper plate, and sequentially carrying out polishing, acid pickling and clean water cleaning on the electrolytic copper plate to remove a surface oxide layer and impurities; step 2, smelting: drying an electrolytic copper plate, adding the electrolytic copper plate into a smelting furnace, adding polymerized carbon blocks into the smelting furnace and a middle partition bin after the electrolytic copper plate is liquefied, and adding graphite flakes with the covering thickness of more than 20cm into a heat preserving furnace for covering; 3, drainage is conducted, specifically, the copper liquid is guided to a heat preservation furnace, and the temperature of the heat preservation furnace is kept; and 4, upward casting is conducted, a traction casting machine is used for traction, the high-purity oxygen-free copper rod is led out, and cooling forming is conducted through a crystallizer. According to the method, the oxygen content of a finished product is effectively reduced, the tensile strength, ductility and toughness of the copper bar are improved, and oxidation of the molten copper is reduced to the maximum extent by precisely regulating and controlling the temperature of the smelting furnace and the temperature of the heat preservation furnace and cooperating with the synergistic effect of the polymerized carbon blocks and the graphite flakes.

Description

Technical Field

[0001] This invention relates to the field of copper busbar preparation technology, specifically a method for preparing copper busbars. Background Technology

[0002] Copper busbars, commonly known as copper bars, are a major type of copper processed material. They possess high mechanical properties, good electrical and thermal conductivity, excellent corrosion resistance, electroplating and brazing properties, a beautiful metallic luster, and good formability and processing performance. Therefore, various power transmission and distribution equipment and electrical appliances made from copper busbars are widely used in the power industry.

[0003] Traditional copper busbar manufacturing processes, particularly continuous extrusion, have inherent drawbacks. Uncontrollable overflow during extrusion can easily lead to delamination of the copper busbar, resulting in insufficient tensile strength, ductility, and toughness. Therefore, a novel method for manufacturing copper busbars is needed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing copper busbars, which solves the problem that the traditional copper busbar preparation process has inherent defects in continuous extrusion, where uncontrollable overflow during extrusion can easily lead to delamination of the copper busbar, resulting in insufficient tensile strength, ductility, and toughness.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a copper busbar includes the following steps: Step 1: Raw material preparation. Prepare electrolytic copper plates and grind, pickle, and clean them with water in sequence to remove the surface oxide layer and impurities. Step 2: Smelting. After the electrolytic copper plate is dried, it is added to the smelting furnace. After the electrolytic copper plate is liquefied, polymerized carbon blocks are added to the smelting furnace and the intermediate compartment. The heat preservation furnace is covered with graphite flakes with a thickness of more than 20cm. Step 3: Draining the copper liquid to the holding furnace to maintain its temperature; Step 4: Upward casting. A high-purity oxygen-free copper rod is drawn out using a traction casting machine and cooled and shaped in a crystallizer. Step 5: Annealing and cold rolling. The high-purity oxygen-free copper rod undergoes a first offline annealing treatment. After the treatment is completed, it is cold rolled using four-roll rolling. After the cold rolling is completed, a second offline annealing treatment is performed to obtain the rod blank. Step 6: Extrusion of the billet. The billet is placed in a continuous extrusion press for extrusion to obtain copper billet. The copper billet coming out of the extrusion die is cooled by cooling water and then wound up. Step 7: Drawing and shaping. The billet is drawn to obtain a flat copper busbar with an arc shape.

[0006] Preferably, the copper content of the electrolytic copper plate in step one is not less than 99.98%, and the structure is a single layer.

[0007] Preferably, the carbon content of the polymerized carbon block in step two is greater than 98%, and the thickness of the coating on the copper liquid surface is at least 5 cm.

[0008] Preferably, the temperature of the smelting furnace in step two is maintained at 1155℃~1170℃ to ensure that the copper raw material is completely melted and the fluidity of the copper liquid meets the requirements.

[0009] Preferably, in step four, the traction speed of the traction casting machine is 550 mm / min to 2250 mm / min, the inlet water temperature of the crystallizer is controlled at 25℃ to 35℃, and the outlet water temperature of the crystallizer is controlled at 35℃ to 50℃.

[0010] Preferably, in step five, the offline annealing temperature is 550℃~630℃, and the time is controlled between 3h and 7h.

[0011] Preferably, in step five, the deformation amount of a single cold rolling pass is controlled at 10% to 40%, and the total deformation amount of cold rolling is controlled at 60% to 80%.

[0012] Preferably, in step six, the cooling water is deionized water, with 4wt% to 9.5wt% of industrial alcohol and an appropriate amount of passivation solution added.

[0013] Preferably, in step seven, the drawing rate is controlled at 18% to 35%, the error is controlled within ±0.10mm, and the copper busbar dimensional accuracy error is controlled within ±0.15mm.

[0014] Preferably, in step two, the graphite flakes have a particle size of at least 200 mesh and are dry and free of impurities.

[0015] This invention provides a method for preparing copper busbars. It has the following beneficial effects: 1. The method provided by this invention effectively reduces the oxygen content of the finished product, improves the tensile strength, ductility and toughness of the copper busbar, and minimizes copper oxidation by precisely controlling the temperature of the smelting furnace and the holding furnace, in conjunction with the synergistic effect of polymerized carbon blocks and graphite flakes.

[0016] 2. The optimized combination of cold rolling and annealing processes in this invention eliminates internal stress in the material, refines the grain structure, and gives the prepared copper busbar excellent tensile strength, ductility and toughness, enabling the copper busbar to meet the needs of various industrial equipment for high-performance copper busbars.

[0017] 3. This invention significantly improves the dimensional accuracy and surface quality of copper busbars through precise control of details such as cooling medium and drawing rate. Furthermore, the cooling system using deionized water combined with industrial alcohol and passivation solution ensures uniform shrinkage of the copper busbars during the cooling process, enabling the copper busbars prepared by this method to be suitable for various environments. Attached Figure Description

[0018] Figure 1 This is a flowchart of the method 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 method for preparing a copper busbar, comprising the following steps: Step 1: Raw material preparation. Prepare electrolytic copper plates with a copper content of not less than 99.98% and a single-layer structure. Grind, pickle, and clean with water in sequence to remove the surface oxide layer and impurities. Step 2: Smelting. After the electrolytic copper plate is dried, it is added to the smelting furnace. After the electrolytic copper plate is liquefied, polymeric carbon blocks are added to the smelting furnace and the intermediate compartment. The holding furnace is covered with graphite flakes with a thickness of more than 20cm. The polymeric carbon blocks have a carbon content of more than 98% and a coverage thickness of at least 5cm on the surface of the copper liquid. The temperature of the smelting furnace is maintained at 1155℃~1170℃ to ensure that the copper raw material is completely melted and the fluidity of the copper liquid meets the requirements. Step 3: Draining the copper liquid to the holding furnace to maintain its temperature; Step 4: Upward casting. A high-purity oxygen-free copper rod is drawn out using a traction casting machine and cooled and shaped in a crystallizer. The traction speed of the traction casting machine is 550 mm / min to 2250 mm / min. The inlet water temperature of the crystallizer is controlled at 25℃ to 35℃, and the outlet water temperature of the crystallizer is controlled at 35℃ to 50℃. Step 5: Annealing and Cold Rolling. The high-purity oxygen-free copper rod undergoes a first offline annealing treatment. After the treatment, it is cold rolled using four-roll rolling. After cold rolling, a second offline annealing treatment is performed to obtain the rod blank. The offline annealing temperature is 550℃~630℃, and the time is controlled between 3h and 7h. The deformation amount per cold rolling pass is controlled between 10% and 40%, and the total deformation amount is controlled between 60% and 80%. Step 6: Extrusion of the billet. The billet is placed in a continuous extrusion press for extrusion to obtain copper billet. The copper billet coming out of the extrusion die is cooled by cooling water and then wound up. The cooling water is deionized water with 4wt% to 9.5wt% industrial alcohol and an appropriate amount of passivation solution added. Step 7: Drawing and forming. The billet is drawn to obtain a flat copper busbar with an arc. The drawing rate is controlled at 18% to 35%, the error is controlled within ±0.10mm, and the dimensional accuracy error of the copper busbar is controlled within ±0.15mm.

[0021] Experimental Example Based on the copper busbar preparation method provided in the above embodiments, the prepared copper busbar was subjected to the following experiments: Three copper busbars were prepared by the preparation method provided in the experimental examples, and one common copper busbar product was used for comparison. The experimental results are as follows Through experiments, the hydrogen embrittlement levels of the finished products in Examples 1 to 3 of this experiment can be maintained at levels one to two, while those of the comparative examples are at levels three to five. This shows that the copper busbars prepared by this method have excellent tensile strength, ductility and toughness, and belong to high-performance and long-life copper busbars.

[0022] 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 method for preparing a copper busbar, characterized in that, Includes the following steps: Step 1: Raw material preparation. Prepare electrolytic copper plates and grind, pickle, and clean them with water in sequence to remove the surface oxide layer and impurities. Step 2: Smelting. After the electrolytic copper plate is dried, it is added to the smelting furnace. After the electrolytic copper plate is liquefied, polymerized carbon blocks are added to the smelting furnace and the intermediate compartment. The heat preservation furnace is covered with graphite flakes with a thickness of more than 20cm. Step 3: Draining the copper liquid to the holding furnace to maintain its temperature; Step 4: Upward casting. A high-purity oxygen-free copper rod is drawn out using a traction casting machine and cooled and shaped in a crystallizer. Step 5: Annealing and cold rolling. The high-purity oxygen-free copper rod undergoes a first offline annealing treatment. After the treatment is completed, it is cold rolled using four-roll rolling. After the cold rolling is completed, a second offline annealing treatment is performed to obtain the rod blank. Step 6: Extrusion of the billet. The billet is placed in a continuous extrusion press for extrusion to obtain copper billet. The copper billet coming out of the extrusion die is cooled by cooling water and then wound up. Step 7: Drawing and shaping. The billet is drawn to obtain a flat copper busbar with an arc shape.

2. The method for preparing a copper busbar according to claim 1, characterized in that, In step one, the copper content of the electrolytic copper plate is not less than 99.98%, and the structure is a single layer.

3. The method for preparing a copper busbar according to claim 1, characterized in that, The polymerized carbon block in step two has a carbon content greater than 98% and covers the copper liquid surface with a thickness of at least 5 cm.

4. The method for preparing a copper busbar according to claim 1, characterized in that, In step two, the temperature of the smelting furnace is maintained at 1155℃~1170℃ to ensure that the copper raw material is completely melted and the fluidity of the copper liquid meets the requirements.

5. The method for preparing a copper busbar according to claim 1, characterized in that, In step four, the traction speed of the traction casting machine is 550 mm / min to 2250 mm / min, the inlet water temperature of the crystallizer is controlled at 25℃ to 35℃, and the outlet water temperature of the crystallizer is controlled at 35℃ to 50℃.

6. The method for preparing a copper busbar according to claim 1, characterized in that, In step five, the offline annealing temperature is 550℃~630℃, and the time is controlled between 3h and 7h.

7. The method for preparing a copper busbar according to claim 1, characterized in that, In step five, the deformation amount of a single cold rolling pass is controlled at 10% to 40%, and the total deformation amount of cold rolling is controlled at 60% to 80%.

8. The method for preparing a copper busbar according to claim 1, characterized in that, In step six, deionized water is used for cooling, and 4wt% to 9.5wt% of industrial alcohol and an appropriate amount of passivation solution are added.

9. The method for preparing a copper busbar according to claim 1, characterized in that, In step seven, the drawing rate is controlled at 18% to 35%, the error is controlled within ±0.10mm, and the copper busbar dimensional accuracy error is controlled within ±0.15mm.

10. The method for preparing a copper busbar according to claim 1, characterized in that, In step two, the graphite flakes must have a particle size of at least 200 mesh and be dry and free of impurities.

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