A copper-aluminum composite sheet and a method for manufacturing the same

Abstract

The application discloses a copper-aluminum composite sheet and a preparation method thereof. The preparation method comprises the following steps: obtaining a copper-aluminum composite blank through explosion welding, and then cutting and processing two composite sheets with the same size specifications to be back-to-back welded and combined, adopting a copper surface centering mode, and finally performing cold rolling processing on the combined composite sheet under a suitable rolling mill device to obtain the copper-aluminum composite sheet. The preparation method can effectively overcome the warping deformation problem often occurring in the rolling process of a single copper-aluminum composite sheet, and realizes high-quality combination of the copper sheet and the aluminum sheet. The copper-aluminum composite sheet prepared by adopting the preparation method has a good appearance forming, no microcracks and no warping deformation on the surface, and has excellent mechanical properties, and is suitable for the new energy material field, and is especially suitable for new energy industry pole products.

Description

Technical Field

[0001] This invention belongs to the field of layered metal composite material processing technology, specifically relating to a copper-aluminum composite thin plate and its preparation method. Background Technology

[0002] Dissimilar metal composites are made by combining different types of metals through special processes, possessing unique properties and advantages. This type of material has broad application prospects in fields such as new energy. With the increasing demands for material performance in new energy vehicles and other sectors, the demand for copper-aluminum composite plates in the new energy vehicle industry is growing rapidly. Currently, the main manufacturing processes for copper-aluminum composite plates include explosive welding and rolling.

[0003] Explosive welding utilizes the instantaneous high temperature and pressure generated by an explosive detonation to cause metal plates to collide. During this collision, a high-speed jet removes impurities from the surfaces of the two plates, achieving a metallurgical bond under extremely high pressure. This method is particularly suitable for surface bonding between dissimilar layered metal materials. However, this method faces technical limitations regarding the thickness of the cladding material. Typically, the thickness of the cladding metal in a single explosive welding operation should be 3–15 mm. The cladding material should not be too thick or too thin, making it generally suitable for the composite preparation of medium-thick cladding plates, but not for the composite preparation of thin plates. Furthermore, due to its working principle, the explosive bonding process currently relies heavily on manual operation, making full mechanization and automation difficult, resulting in relatively low production efficiency.

[0004] Rolling is a pressure processing method in which metal billets are passed through the gap between a pair of rotating rolls (of various shapes). Due to the compression of the rolls, the cross-section of the material is reduced and the length is increased. This process is stable, efficient, and suitable for mass production. However, during the rolling of a single copper-aluminum composite plate, the uneven elongation of copper and aluminum causes the aluminum layer to flow faster under pressure, while the copper layer flows slower. This can easily lead to "C-shaped" warping deformation of the plate, affecting the normal progress of the rolling process and, in severe cases, causing the process to be interrupted.

[0005] Therefore, how to prepare a high-quality copper-aluminum composite sheet with excellent comprehensive mechanical properties is an urgent problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to solve the aforementioned problems in the prior art and provide a method for preparing high-performance copper-aluminum composite thin plates. This method first obtains a copper-aluminum composite plate blank through explosive welding, then cuts and processes two composite plates of identical dimensions and welds them back-to-back, centering the copper surface. Finally, the assembled composite plate is cold-rolled using suitable rolling mill equipment. This effectively overcomes the warping and deformation problems that often occur during the rolling process of single copper-aluminum composite plates, achieving high-quality copper-aluminum composites. The copper-aluminum composite thin plates prepared using this method possess excellent comprehensive mechanical properties and are suitable for use in the field of new energy materials, especially for products such as electrode posts in the new energy industry.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] This invention provides a method for preparing a copper-aluminum composite thin plate, comprising the following steps:

[0009] S1. Explosive welding technology is used to perform explosive welding composite processing on aluminum plate and copper plate to obtain copper-aluminum composite billet. Then, the copper-aluminum composite billet is leveled, inspected and cut to obtain qualified copper-aluminum composite sheet.

[0010] S2. Using the principle of rolling processing technology, the copper-aluminum composite plate obtained in step S1 is rolled to reduce its thickness, resulting in the desired copper-aluminum composite thin plate. The specific process is as follows:

[0011] 1) Perform cold cutting on the copper-aluminum composite plate, and then combine two copper-aluminum composite plates of the same size back to back. The copper side should be in the center and the aluminum side should be facing outwards, with the two copper sides touching tightly. Then weld the outer edges of the copper material in the middle, intermittently along the length and fully welded along the width. All welds must be firmly and reliably welded.

[0012] 2) The copper-aluminum composite plate assembled in step 1) is rolled according to the set rolling process parameters. After rolling is completed, the weld is removed to obtain the copper-aluminum composite thin plate.

[0013] Furthermore, in step S1, the aluminum plate is made of pure aluminum or aluminum alloy, and the copper plate is made of pure copper or copper alloy.

[0014] In some specific embodiments, in step S1, the aluminum plate is made of 1060 pure aluminum and the copper plate is made of T2 copper.

[0015] In some specific embodiments, in step S1, the aluminum plate is the base layer with a thickness of ≥7mm; the copper plate is the cladding layer with a thickness of 3-8mm.

[0016] In some specific embodiments, in step S1, the length of the aluminum plate and the copper plate are both 800-1500mm, and the width is both 300-600mm.

[0017] Furthermore, step S1 specifically includes the following steps:

[0018] The surfaces of the aluminum and copper plates to be welded are pre-treated by surface polishing and cleaning to meet the requirements of the explosive bonding process.

[0019] The pretreated aluminum plate is placed horizontally on a flat foundation. Spacer columns for explosive welding are evenly spaced along the edge and middle of the aluminum plate surface. Then, the pretreated copper plate is placed on the spacer columns, with the polished surface of the aluminum plate facing up and the polished surface of the copper plate facing down. Finally, a protective layer is laid on the copper plate, and an explosive layer is laid on the protective layer and detonated by a detonator. The explosive residue and the protective layer are removed to obtain a copper-aluminum composite billet.

[0020] The prepared copper-aluminum composite billet is first leveled, then ultrasonic flaw detector is used to test the bonding of the composite interface, and poor bonding areas are marked. The qualified copper-aluminum composite sheet is then cut and processed by mechanical cold working.

[0021] In some specific embodiments, the spacing between the spacer columns used in explosive welding is 100-150mm, and the protective layer is a 1-2mm thin wooden board.

[0022] In some specific implementations, in step 1), the copper-aluminum composite plate is cold-cut into strips, and the specific specifications are determined according to the capacity of the rolling equipment.

[0023] It should be noted that when combining two cut and processed copper-aluminum composite panels of the same size back to back in step 1), if the panels are not flat, they need to be leveled first.

[0024] In some specific embodiments, in step 1), conventional arc welding MAG welding is used to weld the outer edges of the copper material in the middle. The welding process parameters are: current 220-250A, voltage 29-30V, welding speed 12-15cm / min, shielding gas flow rate 15-20L / min, welding 100mm every 100mm along the length direction, and full welding in the width direction.

[0025] In some specific embodiments, in step 2), the rolling is a multiple small-scale rolling process with the following rolling parameters: the maximum single-pass rolling pressure is controlled to be 5%-20% of the thickness of the copper-aluminum composite plate, the total deformation is controlled to be below 80%, and the rolling speed is controlled to be within 20m / min.

[0026] This invention combines and welds two copper-aluminum composite plates and then rolls them, which can constrain the elongation and plastic deformation of copper and aluminum during the rolling process. The copper surface is centered, which can make the warping deformation cancel each other out, thereby achieving consistent elongation of copper and aluminum and thus avoiding warping deformation of the plate.

[0027] Copper-aluminum composite sheet prepared according to the preparation method described above.

[0028] The copper-aluminum composite sheet adopts a layered composite connection structure with a thickness of 3-8mm, wherein the copper sheet has a thickness of 1-3mm and the aluminum sheet has a thickness of 2-6mm.

[0029] The beneficial effects of this invention are:

[0030] The method for preparing copper-aluminum composite thin plates provided by this invention fully utilizes and combines the advantages of explosive welding and rolling processes, and employs an advanced combined welding technology to successfully avoid the "C-shaped" warping deformation of the plate caused by the inconsistent elongation of copper and aluminum during the rolling process. Through the combination and optimization of the "explosive + rolling" process, not only can copper-aluminum composite thin plates be successfully prepared, but this method also boasts mature technology, simple operation, high production efficiency, and ease of mass production.

[0031] The copper-aluminum composite sheet prepared by the method of this invention has a good appearance and is free from microcracks and warping deformation. It has excellent mechanical properties and is suitable for use in the field of new energy materials, especially for products such as poles in the new energy industry. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the assembly of rolled blanks for copper-aluminum composite plates. Detailed Implementation

[0033] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0034] The aluminum plate used in the following examples and comparative examples is a 1060 pure aluminum plate, and the copper plate is a T2 copper plate.

[0035] Example 1

[0036] 1) Obtain an aluminum plate with a length of 1500mm, a width of 450mm, and a thickness of 7mm, and a copper plate with a length of 1500mm, a width of 450mm, and a thickness of 6mm. Perform surface polishing and pre-cleaning treatment on the surfaces to be welded to meet the requirements of the explosive bonding process.

[0037] 2) Place the pretreated aluminum plate horizontally on a flat foundation. Arrange special gap columns for explosive welding evenly along the edge and middle of the aluminum plate surface. The spacing between the gap columns is 150mm. Then place a copper plate (polished and ground surface facing down) on the gap columns. Finally, lay a 1.5mm thin wooden board on the copper plate. Lay an explosive layer on the thin wooden board and detonate it with a detonator. Remove the explosive residue and the thin wooden board to obtain the copper-aluminum composite billet.

[0038] 3) The prepared copper-aluminum composite billet is first leveled, and then the bonding of the composite interface is detected by ultrasonic flaw detector. The poor bonding areas are marked and drawn, and the qualified copper-aluminum composite plate workpiece is cut by mechanical cold working.

[0039] 4) Cold cut the copper-aluminum composite plate workpiece into strip-shaped copper-aluminum composite plates with a specification of 250*400mm;

[0040] 5) Combine two cut copper-aluminum composite plates of the same size back to back (if the plate surface is not flat, it needs to be leveled first), with the copper side in the middle and the aluminum side facing outward (the two copper sides should be tightly attached with almost no gap). Then, use traditional arc welding MAG welding to weld the outer edge of the copper material in the middle. The welding process parameters are: current 230A, voltage 30V, welding speed 15cm / min, shielding gas flow rate 18L / min, weld 100mm every 100mm along the length direction, and fully weld along the width direction. All welds must be firmly and reliably welded.

[0041] 6) The assembled copper-aluminum composite plate is rolled in 8 passes on a rolling mill. The specific rolling process parameters are as follows: the maximum downward pressure per single pass is controlled at 9.8% of the plate thickness, the total deformation is controlled at 63%, and the rolling speed is controlled at 5m / min. After rolling, the weld is removed to obtain the final finished copper-aluminum composite thin plate.

[0042] The copper-aluminum composite sheet prepared in this embodiment has a copper plate thickness of 2.2 mm and an aluminum plate thickness of 2.6 mm. It has a good appearance and is free of microcracks and warping deformation. Its shear strength is 72 MPa.

[0043] Comparative Example 1

[0044] Compared with Example 1, the difference in this comparative example is that the number of rolling passes is 4, the maximum reduction in a single rolling pass is controlled at 26.3% of the plate thickness, and other conditions remain unchanged. The relevant performance results of the obtained copper-aluminum composite thin plate are shown in Table 1.

[0045] Example 2

[0046] Copper-aluminum composite thin plates were prepared according to the method of Example 1. The differences between this example and Example 1 are as follows: in step 1), the thickness of the copper plate is 4 mm and the thickness of the aluminum plate is 10 mm; in step 6), the number of rolling passes is 9, and the maximum reduction in a single rolling pass is 14.6% of the plate thickness. The relevant performance results of the obtained copper-aluminum composite thin plates are shown in Table 1.

[0047] Comparative Example 2

[0048] Compared with Example 2, the main difference in this comparative example is that the aluminum surface is centered when the copper-aluminum composite plates are combined. The relevant performance results of the obtained copper-aluminum composite thin plates are shown in Table 1.

[0049] Example 3

[0050] Copper-aluminum composite thin plates were prepared according to the method of Example 1. The differences between this example and Example 1 are as follows: in step 1), the thickness of the copper plate is 4 mm and the thickness of the aluminum plate is 8 mm; in step 6), the number of rolling passes is 13, the maximum reduction per rolling pass is 14.5% of the plate thickness, and the rolling speed is 10 m / min. The relevant performance results of the obtained copper-aluminum composite thin plates are shown in Table 1.

[0051] Comparative Example 3

[0052] Compared with Example 3, the main difference in this comparative example is that the aluminum surface is centered when the copper-aluminum composite plates are combined. The relevant performance results of the obtained copper-aluminum composite thin plates are shown in Table 1.

[0053] Example 4

[0054] Copper-aluminum composite thin plates were prepared according to the method of Example 1. The main differences between this example and Example 1 are: in step 1), the thickness of the copper plate is 6 mm and the thickness of the aluminum plate is 10 mm; in step 6), the maximum reduction in a single rolling pass is 19.7% of the plate thickness, and the rolling speed is 15 m / min. The relevant performance results of the obtained copper-aluminum composite thin plates are shown in Table 1.

[0055] Comparative Example 4

[0056] Compared with Example 4, the difference in this comparative example is that the number of rolling passes is 5, the maximum reduction in a single rolling pass is controlled at 28.6% of the plate thickness, and other conditions remain unchanged. The relevant performance results of the obtained copper-aluminum composite thin plate are shown in Table 1.

[0057] Example 5

[0058] Copper-aluminum composite thin plates were prepared according to the method of Example 1. The differences between this example and Example 1 are as follows: in step 1), the thickness of the copper plate is 5 mm and the thickness of the aluminum plate is 14 mm; in step 6), the number of rolling passes is 11, the maximum reduction per rolling pass is 14.8% of the plate thickness, and the rolling speed is 20 m / min. The relevant performance results of the obtained copper-aluminum composite thin plates are shown in Table 1.

[0059] Comparative Example 5

[0060] Compared with Example 5, the main difference in this comparative example is that the rolling speed is 30 m / min. The relevant performance results of the obtained copper-aluminum composite sheet are shown in Table 1.

[0061] Table 1. Relevant process parameters and performance results of copper-aluminum composite thin plates

[0062]

Claims

1. A method for preparing a copper-aluminum composite thin plate, comprising the following steps: S1. Explosive welding technology is used to perform explosive welding composite processing on aluminum plate and copper plate to obtain copper-aluminum composite billet. Then, the copper-aluminum composite billet is leveled, inspected and cut to obtain qualified copper-aluminum composite sheet. S2. Using the principle of rolling processing technology, the copper-aluminum composite plate obtained in step S1 is rolled to reduce its thickness, resulting in the desired copper-aluminum composite thin plate. The specific process is as follows: 1) Perform cold cutting on the copper-aluminum composite plate, and then combine two copper-aluminum composite plates of the same size back to back. The copper side should be in the center and the aluminum side should be facing outwards, with the two copper sides touching tightly. Then weld the outer edges of the copper material in the middle, intermittently along the length and fully welded along the width. All welds must be firmly and reliably welded. 2) The copper-aluminum composite plate assembled in step 1) is rolled according to the set rolling process parameters. After rolling is completed, the weld is removed to obtain the copper-aluminum composite thin plate. Step S1 specifically includes the following steps: The surfaces of the aluminum and copper plates to be welded are pre-treated by surface polishing and cleaning to meet the requirements of the explosive bonding process. The pretreated aluminum plate is placed horizontally on a flat foundation. Spacer columns for explosive welding are evenly spaced along the edge and middle of the aluminum plate surface. Then, the pretreated copper plate is placed on the spacer columns, with the polished surface of the aluminum plate facing up and the polished surface of the copper plate facing down. Finally, a protective layer is laid on the copper plate, and an explosive layer is laid on the protective layer and detonated by a detonator. The explosive residue and the protective layer are removed to obtain a copper-aluminum composite billet. The prepared copper-aluminum composite billet is first leveled, then the bonding of the composite interface is detected by ultrasonic flaw detector, the poor bonding area is marked, and the qualified copper-aluminum composite plate is cut by mechanical cold working. In step 1), conventional arc welding MAG welding is used to weld the outer edges of the copper material in the middle. The welding process parameters are: current 220-250 A, voltage 29-30V, welding speed 12-15cm / min, shielding gas flow rate 15-20L / min, welding 100mm every 100mm along the length direction, and full welding in the width direction. In step 2), the rolling is a multiple small-pressure rolling process. The rolling process parameters are: the maximum pressure per single pass is controlled to be 5%-20% of the thickness of the copper-aluminum composite plate, the total deformation is controlled to be below 80%, and the rolling speed is controlled to be within 20m / min. In step S1, the aluminum plate is the base layer with a thickness of ≥7mm; the copper plate is the cladding layer with a thickness of 3-8mm. The copper-aluminum composite sheet adopts a layered composite connection structure, and its thickness is 3-8mm. The thickness of copper plates is 1-3mm, and the thickness of aluminum plates is 2-6mm.

2. The preparation method according to claim 1, characterized in that, In step S1, the aluminum plate is made of pure aluminum or aluminum alloy, and the copper plate is made of pure copper or copper alloy.

3. The preparation method according to claim 1, characterized in that, In step S1, the aluminum plate is made of 1060 pure aluminum and the copper plate is made of T2 copper.

4. A copper-aluminum composite sheet prepared by the preparation method according to any one of claims 1 to 3.

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