Manufacturing method of copper-aluminum composite strip with inclined surface penetration type composite structure

Abstract

The present invention provides a copper-aluminum composite strip with an inclined through-wall composite structure and a method for manufacturing the same, which belongs to the technical field of bimetallic composite materials. [Solution] The present invention involves unwinding copper and aluminum strips with acute-angle composite surfaces side by side, applying traction to the beginning and end of the copper and aluminum strips, fixing the starting positions of the copper and aluminum strips relative to each other, and adjusting the direction of the traction force to bond the composite surfaces of the copper and aluminum strips together. The resulting strip is then subjected to online heating, hot pressing, and rolling to form a copper-aluminum-copper parallel composite with a through-hole structure. The through-hole structure is then heat-treated, cold-rolled, surface-cleaned and passivated, straightened, and cut to obtain a copper-aluminum composite strip with an inclined through-hole structure. The copper-aluminum composite strip with an inclined through-hole structure described in the present invention has advantages such as a simple structure, low processing difficulty, good bonding strength, interface uniformity, stability, consistency, and good conductivity, making it widely applicable to conductive connections between copper and aluminum materials.

Description

[Technical Field]

[0001] The present invention relates to the technical field of bimetallic composite materials, and in particular to a copper-aluminum composite strip having an inclined through-plane composite structure and a method for manufacturing the same. [Background technology]

[0002] Currently, conductive connecting parts are widely used in electronic and electrical components, and conductive connecting parts often connect dissimilar materials during assembly. However, some dissimilar materials are not suitable for welding. To solve the problem of welding dissimilar materials and save material costs, material processing companies usually adopt layered composite or side composite solutions. Among them, layered composite materials have problems such as difficulty in recycling scrap during production and low recycling value, while side composite can generally be achieved by methods such as electron beam welding and rolled composite. However, electron beam welding has structural defects, and rolled composite has problems such as difficulty in large-scale production or poor joint strength, making it difficult to meet market demand.

[0003] The patented invention, application number 202311209411.7, entitled "Method for Manufacturing a Copper-Aluminum Composite Strip with Side Combination and Wedge-Shaped Structure," also produces a copper-aluminum composite strip with a strongly bonded side composite structure. However, the copper-aluminum composite strip produced by this patent has four turning points at the bonding interface. The sharp corners at these turning points represent abrupt changes in geometry, which can easily interrupt the stress transmission path. According to the principles of elastic mechanics, stress streamlines cannot smoothly transition as they pass through the sharp corners, resulting in abrupt changes. This distortion of the streamlines results in stress peaks, or stress concentrations, in localized regions that are several times higher than the average stress. Furthermore, the sharp corners are more likely to leave microscopic defects during processing. Therefore, this wedge-shaped interface structure poses a risk of delamination and cracking during manufacturing and use. Furthermore, because the wedge-shaped composite structure has a large angle at some of the interfaces, the normal component of the force received by the bonding interface during hot-rolling bonding is small, and the amount of strain required to ensure good bonding strength at the interface is insufficient. This makes products that require bending within the bonding area prone to bending and cracking. Furthermore, the wedge-shaped composite structure is difficult to process, and it is difficult to ensure shape consistency each time it is processed, which can lead to unstable composite strength due to structural inconsistencies. As described above, the copper-aluminum composite strip manufactured according to this patent has a complex material structure, making processing and bonding difficult, and can cause problems such as stress concentration at the tip of the bonding interface, which can affect the bonding strength of the materials. Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a copper-aluminum composite strip with an inclined surface composite structure that overcomes the shortcomings of the conventional side composite technology and has the advantages of low processing difficulty, good bonding strength, uniform interface, high consistency, and good conductivity, and can be widely used in conductive connecting members between copper and aluminum materials, as well as a manufacturing method thereof. [Means for solving the problem]

[0005] To achieve the above object, the present invention adopts the following technical solutions. The present invention provides a method for manufacturing a copper-aluminum composite strip having an inclined surface through-type composite structure, (1) preparing copper and aluminum strip materials; (2) processing the composite end of the copper strip and the aluminum strip into an acute-angle composite surface; (3) Rewinding the copper strip and aluminum strip with the acute angle composite surface side by side, applying a pulling force to the beginning and end of the copper strip and aluminum strip, fixing the starting positions of the copper strip and aluminum strip relative to each other, and adjusting the direction of the pulling force so that the composite surfaces of the copper strip and aluminum strip are bonded to each other; (4) respectively online heating the copper strip and the aluminum strip, and hot pressing and rolling the copper strip to form a through-hole composite material having a copper-aluminum-copper parallel composite structure; (5) heat treating, cold rolling, surface cleaning, passivation, straightening and cutting the through-hole composite material to obtain a copper-aluminum composite strip with an inclined-plane through-hole composite structure.

[0006] Furthermore, in step (1), the copper strip has a width of 20 mm to 100 mm and a thickness of 1 mm to 15 mm, and the aluminum strip has a width of 20 mm to 100 mm and a thickness of 1 mm to 15 mm.

[0007] Furthermore, in step (2), the sharp-angled composite surface is manufactured by conventional metal working methods, including but not limited to mechanical cutting, extrusion, and profile rolling.

[0008] In step (3), the copper strip and the aluminum strip are rewound side by side and washed, which is a common method used in metal processing, including but not limited to mechanical and chemical cleaning, and focuses on the strip surface, especially the inclined surface joining interface, to ensure cleanliness of the interface.

[0009] Furthermore, in step (4), the copper strip is heated to a temperature of 400°C to 700°C for a heating time of 2 to 4 minutes.

[0010] Furthermore, in step (4), the aluminum strip is heated to a temperature of 300°C to 500°C and kept at that temperature for 2 to 4 minutes.

[0011] In the present invention, by heating the copper strip and the aluminum strip online, respectively, the rapid solid solution diffusion of copper and aluminum at high temperatures is promoted, thereby improving the strength of the copper-aluminum bonding interface.

[0012] Furthermore, in step (4), the rolling temperature of the hot pressing and rolling combined process is 300°C to 650°C, the rolling speed is 8mpm to 12mpm, and the hot rolling reduction is controlled to 40% to 60% by reducing gas protection.

[0013] This invention uses a hot pressing and rolling combined process to achieve atomic-level precision bonding of the copper strip and aluminum strip at the bonding interface. The copper and aluminum atoms dissolve and diffuse into each other under high temperature and pressure, achieving copper-aluminum composite processing and inclined surface interfacial bonding between the copper and aluminum strip. During the rolling process, the inclined surface composite interface of the copper and aluminum strips is deformed by traction force and downward pressure, which effectively increases the interfacial bonding strength and the structural strength of the composite material.

[0014] Furthermore, in step (5), the heat treatment includes an annealing treatment, the annealing temperature is controlled to 300°C to 600°C, and the annealing temperature retention time is controlled to 10 minutes to 30 minutes depending on the thickness of the material.

[0015] Furthermore, in step (5), the cold rolling includes a cold rolling process, in which the rolling speed is controlled at 80 mpm to 150 mpm, and the deformation amount is controlled at 30% to 70% according to the performance requirements of the finished product.

[0016] Furthermore, in step (4), the thickness of the copper-aluminum composite strip with the inclined surface through-type composite structure is 0.3 mm to 4.0 mm, which can be manufactured according to different product requirements.

[0017] The present invention further provides a copper-aluminum composite belt having an inclined plane through-composite structure produced according to the above method. [Effects of the Invention]

[0018] Compared with the prior art, the present invention has the following beneficial effects: The bonding interface of the copper-aluminum composite strip with an inclined surface through-type composite structure manufactured according to the present invention has an inclined surface shape, a simple structure, low material processing difficulty, good structural consistency, a smooth interface, and no areas where stress is likely to concentrate, such as sharp corners or transitions, and is less likely to leave fine defects during the processing process.

[0019] The inclined surface composite used in this invention has a small angle (less than 40%) between the interface and the surface, and the vertical component of the force that the bonding interface receives during the hot pressing and compounding process is large, providing sufficient pressure and strain to ensure the bonding strength of the interface, resulting in high bonding strength.The bonding surface has a symmetrical inclined surface structure with a copper:aluminum ratio of 1:1, and the copper:aluminum ratio is appropriate, resulting in excellent material conductivity.

[0020] The copper-aluminum composite strip having an inclined surface through-type composite structure manufactured by the present invention has excellent bending performance, and can achieve crack-free bending, especially for products that require bending within the bonding area.

[0021] The present invention uses copper and aluminum strips with special angled inclined surface structures on the side edges to work together, thereby reducing the difficulty of processing the materials and making it advantageous for batch production. It also has the characteristics of producing less processing waste, making it easy to sort and recycle, and being environmentally friendly.

[0022] The present invention uses a large-scale drawing and hot-rolling combined process to deform the strip material in the longitudinal direction and limit the lateral expansion of the copper and aluminum, thereby effectively increasing the strength of the bonding interface between the copper and aluminum. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram of the copper-aluminum constrained positioning of the present invention. [Figure 2] 1 is a schematic diagram of a composite structure of a copper-aluminum composite strip having an inclined surface-through composite structure of the present invention. [Figure 3] 1 is a metallographic diagram (copper on the left and aluminum on the right) of a cross section of a copper-aluminum composite strip having an inclined-surface-penetrating composite structure according to Example 1 of the present invention. [Figure 4] 1 is a metallographic diagram (copper on the left and aluminum on the right) for detecting the strength of a copper-aluminum composite strip having an inclined-surface-penetrating composite structure according to Example 1 of the present invention when bent at 90°. DETAILED DESCRIPTION OF THE INVENTION

[0024] In order to clarify the purpose, technical solution and advantages of the present invention, the technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present invention, not all of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments that can be obtained by those skilled in the art without creative work fall within the protection scope of the present invention.

[0025] The test or experimental methods described in the following examples are conventional unless otherwise specified. The raw materials and auxiliary materials described are obtained from conventional commercial sources or prepared by conventional methods unless otherwise specified.

[0026] Example 1 A method for manufacturing a copper-aluminum composite strip having an inclined-plane through-type composite structure includes the following steps: (1) Prepare copper strip and aluminum strip materials, and process the composite ends of the copper strip and aluminum strip into acute-angle composite surfaces. The copper strip has a width of 100 mm, a thickness of 5.0 mm, and a width of the inclined surface of 3 mm. The aluminum strip has a width of 40 mm, a thickness of 5.0 mm, and a width of the inclined surface of 4 mm. (2) The surface of the strip is mechanically cleaned using a brush, polished to remove 30 μm to 100 μm of the surface of the strip, mill scale is polished to expose the new metal layer, soft burrs on the edges are removed, and after washing with a water flow of 20 m / s, the surface of the material is dried with a 2.0 MPa compressed air knife, and then the remaining moisture on the surface of the material is dried in a drying box at 90 ° C, resulting in the cleaned copper strip and aluminum strip. (3) The cleaned copper strip and aluminum strip are rewound side by side, and a pulling force is applied to the beginning and end of the copper strip and aluminum strip to fix the starting positions of the copper strip and aluminum strip relative to each other, and the pulling force direction is adjusted so that the composite surfaces of the copper strip and aluminum strip are bonded to each other. (4) The copper strip and the aluminum strip are heated online, respectively. The heating temperature of the copper strip is controlled at (680±5)℃, the heat-holding time is 2.0 minutes, and the temperature of the aluminum strip is controlled at (430±5)℃, the heat-holding time is 2.0 minutes. Then, the hot pressing and rolling are performed. The hot pressing and rolling temperature is controlled at (500±5)℃, the hot rolling speed is 10.5mpm, and the hot rolling reduction is 56%, thereby forming a through-type composite material with a copper-aluminum-copper parallel composite structure. (5) The through-type composite material is annealed, cold-rolled, surface cleaned and passivated, straightened, and cut. The annealing temperature is controlled at 450°C, the annealing time is controlled at 25 minutes, the rolling speed is controlled at 100 mpm, and the deformation amount is controlled at 30%, to obtain a copper-aluminum composite strip with a thickness of 1.2 mm and an inclined through-type composite structure.

[0027] Figure 3 is a metallographic diagram of the finished copper-aluminum composite strip with an inclined-surface-through composite structure manufactured in Example 1. As can be seen from Figure 3, the bonding interface of the copper-aluminum composite strip is uniform, smooth, and defect-free.

[0028] FIG. 4 shows the interfacial metallographic structure of the bonded region of the finished copper-aluminum composite strip with an inclined-surface-through composite structure manufactured in Example 1 after a 90° bending test. As can be seen from FIG. 3, no delamination or cracks were observed at the bonded interface of the copper-aluminum composite strip after strain, and the bond strength of the product was good.

[0029] The electrical conductivity of the copper-aluminum composite strip with an inclined-surface-through composite structure manufactured in Example 1 was tested, and the results are shown in Table 1. Measurement method and equipment: Resistivity samples were prepared and tested using a conventional strip resistivity measurement method. Three parallel experiments were performed using the copper strip and aluminum strip described in Example 1, and the measurement equipment was a digital milliohm meter: TEGAM. [Table 1]

[0030] Example 2 A method for manufacturing a copper-aluminum composite strip having an inclined-plane through-type composite structure includes the following steps: (1) Prepare copper strip and aluminum strip materials, and process the composite ends of the copper strip and aluminum strip into acute-angle composite surfaces. The copper strip has a width of 85 mm, a thickness of 12 mm, and a width of the inclined surface of 15 mm. The aluminum strip has a width of 85 mm, a thickness of 12 mm, and a width of the inclined surface of 15 mm. (2) The surface of the strip is mechanically cleaned using a brush, polished to remove 30 μm to 100 μm of the surface of the strip, mill scale is polished to expose the new metal layer, soft burrs on the edges are removed, and after washing with a water flow of 2.5 m / s, the surface of the material is dried with a compressed air knife at 2.0 MPa, and then the remaining moisture on the surface of the material is dried in a drying box at 90 ° C, resulting in cleaned copper strip and aluminum strip. (3) The cleaned copper strip and aluminum strip are rewound side by side, and a pulling force is applied to the beginning and end of the copper strip and aluminum strip to fix the starting positions of the copper strip and aluminum strip relative to each other, and the pulling force direction is adjusted so that the composite surfaces of the copper strip and aluminum strip are bonded to each other. (4) The copper strip and the aluminum strip are heated online, respectively. The heating temperature of the copper strip is controlled at (640±5)℃, the heat-holding time is 4.0 minutes, and the temperature of the aluminum strip is controlled at (430±5)℃, the heat-holding time is 4.0 minutes. Then, the hot pressing and rolling are performed. The temperature of the hot pressing and rolling is controlled at (530±5)℃, the hot rolling speed is 9.5mpm, and the hot rolling reduction is 60%, thereby forming a through-type composite material with a copper-aluminum-copper parallel composite structure. (5) The through-type composite material is annealed, cold-rolled, surface cleaned and passivated, straightened, and cut. The annealing temperature is controlled at 580°C, the annealing time is controlled at 30 minutes, the rolling speed is controlled at 100 mpm, and the deformation amount is controlled at 42%, resulting in a copper-aluminum composite strip with a thickness of 2.78 mm and an inclined-plane through-type composite structure.

[0031] The bonded interface of the finished product in Example 2 is uniform and smooth, without defects, and without phenomena such as delamination or cracks. The electrical conductivity of the finished product reaches 82.10% IACS, and the electrical conductivity performance is excellent.

[0032] The above is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make some improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered to fall within the protection scope of the present invention.

Claims

1. (1) preparing copper strip and aluminum strip materials; (2) processing the composite ends of the copper strip and the aluminum strip in the width direction into a smooth, acute-angle composite surface; (3) Rewinding the copper strip and aluminum strip with the acute-angle composite surface in a widthwise direction, fixing the start positions of the copper strip and aluminum strip relative to each other, applying a pulling force in the longitudinal direction of the strip material, and adjusting the direction of the pulling force so that the acute-angle composite surfaces of the copper strip and aluminum strip are bonded to each other; (4) online heating the copper strip at a heating temperature of 400°C to 700°C for 2 to 4 minutes, and the aluminum strip at a heating temperature of 300°C to 500°C for 2 to 4 minutes, and then hot pressing and rolling the bonded acute-angle composite surfaces in the longitudinal direction while applying pressure in the thickness direction of the strips to form a through-type composite material having a copper-aluminum-copper parallel composite structure; (5) heat treating the through-type composite material, cold rolling it longitudinally while applying pressure through the strip thickness, and then surface cleaning, passivating, straightening, and cutting it to obtain a copper-aluminum composite strip with an inclined-plane through-type composite structure. A method for producing a copper-aluminum composite strip having an inclined surface penetration type composite structure, characterized in that:

2. In step (1), the copper strip has a width of 20 mm to 100 mm and a thickness of 1 mm to 15 mm, and the aluminum strip has a width of 20 mm to 100 mm and a thickness of 1 mm to 15 mm.

2. The method for producing a copper-aluminum composite strip having an inclined surface-penetrating composite structure according to claim 1.

3. In step (4), the rolling temperature of the hot pressing and rolling combined process is 300°C to 650°C, and the rolling speed is 8 mpm to 12 mpm.

2. The method for producing a copper-aluminum composite strip having an inclined surface-penetrating composite structure according to claim 1.

4. In step (4), during the hot pressing and rolling combined process, the hot rolling reduction ratio is controlled to 40% to 60% by reducing gas protection; 2. The method for producing a copper-aluminum composite strip having an inclined surface-penetrating composite structure according to claim 1.

5. In step (5), the heat treatment includes an annealing treatment.

2. The method for producing a copper-aluminum composite strip having an inclined surface-penetrating composite structure according to claim 1.

6. In step (5), the cold rolling includes a cold rolling treatment.

2. The method for producing a copper-aluminum composite strip according to claim 1.

7. In step (4), the thickness of the copper-aluminum composite strip having an inclined surface through-type composite structure is 0.3 mm to 4.0 mm; 2. The method for producing a copper-aluminum composite strip according to claim 1.

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