Continuous casting and rolling process for copper-aluminum composite board

Abstract

The invention relates to a continuous casting and rolling process for a copper-aluminum composite board. The process comprises the following steps of: putting an aluminum ingot into a smelting furnace, melting the aluminum ingot into molten aluminum, loading a coiled copper strip onto an uncoiling machine at the top of a die-casting machine, preparing for continuous die-casting, and manufacturing a copper-aluminum composite board strip; a liquid outlet of the smelting furnace is opened, rollers on the die-casting machine and an uncoiler are started, molten aluminum is output from the liquid outlet of the smelting furnace, enters a material groove and flows into a material nozzle through the material groove, the molten aluminum is conveyed to the position between the rollers of the die-casting machine through the material nozzle, meanwhile, a copper strip is also conveyed to the position between the rollers of the die-casting machine, and a copper-aluminum composite plate strip is formed through rotation of the rollers in a die-casting mode; the rollers on the die-casting machine comprise the upper roller and the lower roller, the copper strip is fed along the surface of the upper roller, and the conveying speed of the copper strip is consistent with the rotating speed of the upper roller. According to the process, the input speed of the copper strip and the rotating speed of the upper roller are set to be consistent, so that the copper-aluminum contact length and time are changed, mutual diffusion of metal can be effectively controlled, and the bonding strength of the copper-aluminum composite plate is improved.

Description

Technical field:

[0001] The invention relates to the technical field of continuous die-casting technology, and more specifically to a continuous casting and rolling technology for copper-aluminum composite plates. Background technology:

[0002] Cu / Al layered composite materials are widely used in conductive materials such as power batteries, substations, and distribution cabinets, especially as an indispensable material for power battery tab materials. At present, the main methods for preparing Cu / Al layered composite materials are continuous casting, rolling composite method, explosive composite method, high-speed torsion composite method and casting and rolling composite method.

[0003] In the continuous casting method, the copper melt is first cast into a plate under nitrogen protection, and then the aluminum alloy melt is cast on the surface of the copper plate and solidified to form a composite plate blank. At high temperature, the copper and aluminum interact with each other to finally form a metallurgical bond. However, due to the violent interface reaction, the hard and brittle compound layer is thick, the interface bonding strength is poor, and the interface conductivity is poor;

[0004] Rolling cladding is a method of laminating copper plates and aluminum alloy plates, exposing the fresh metal surface at the interface of copper and aluminum through rolling deformation to achieve metallurgical bonding. Rolling cladding has high production efficiency and is easy to automate. However, the rolling cladding process has high requirements for the rolling mill and material surface, and the interface bonding strength is low. Currently, it can only be used for copper-aluminum layered composite conductive materials with low interface bonding requirements.

[0005] The explosive composite method uses the powerful energy generated by the explosion of explosives to act on the materials, causing huge pressure between the plates, instantly destroying the oxide film on the contact surface and exposing fresh metal. Under the action of huge pressure, atoms interact with each other to achieve bonding. Its characteristics are high interface composite strength and strong bonding, but the thickness of each layer of the composite material is difficult to control, the production environment is harsh, the risk is relatively high, the production cost is high, and continuous production is not possible.

[0006] The high-speed torsion composite method is also called friction welding. It is a method of placing an aluminum plate and a copper plate on a high-speed rotating machine, rotating the materials in different directions, and making the two metals rub against each other on the contact surface, embedding and mixing with each other to achieve composite. It was the main preparation method for power battery tab materials before the emergence of the casting and rolling composite process. The Cu / Al composite plate prepared by this method has no obvious composite interface, and the two metals are mixed at the interface with great peeling strength. There is no need to process the interface. However, this method is not suitable for mass production, the operation is more complicated, and the production efficiency is low.

[0007] The casting and rolling composite method, also known as the continuous die-casting method, is a method in which the copper strip is sent from the top of the casting nozzle into the casting and rolling area during the aluminum alloy casting and rolling process. The copper strip first contacts the aluminum alloy melt, and the aluminum alloy melt solidifies under the cooling effect of the casting roller and the copper strip, and deforms together with the copper strip to form a well-bonded copper-aluminum layered composite material. This method has the advantages of low equipment investment and low production cost. It is a low-cost, high-quality copper-aluminum layered composite material preparation technology. Its emergence has greatly reduced the production cost of copper-aluminum layered composite materials; however, the copper-aluminum casting and rolling composite process currently used is based on the ordinary aluminum alloy casting and rolling process. The contact time between copper and aluminum is extremely short, the mutual diffusion is insufficient, and the interface strength is difficult to guarantee. Summary of the invention:

[0008] The purpose of the invention is to address the deficiencies of the prior art and to provide a continuous casting and rolling process for copper-aluminum composite plates, which sets the input speed of the copper strip and the rotation speed of the upper rolling roller to be consistent, thereby changing the contact length and time of the copper and aluminum, and can effectively control the mutual diffusion of the metals, thereby achieving the purpose of controlling the interface bonding strength and conductivity, and further improving the bonding strength through subsequent thermal deformation, thereby improving the organizational properties of the material.

[0009] A continuous casting and rolling process for a copper-aluminum composite plate, the process comprising:

[0010] S1: Conduct quality inspection on raw materials used to make copper-aluminum composite panels, mainly aluminum ingots and copper strips; at the same time, ensure that all related equipment involved in production are in qualified production status;

[0011] S2: Put the aluminum ingot into the smelting furnace to melt into aluminum liquid, and load the coiled copper strip onto the unwinder at the top of the die casting, ready for continuous die casting to produce copper-aluminum composite plates and strips;

[0012] S3: Open the liquid outlet of the smelting furnace, start the rollers on the die-casting machine and start the unwinder. The aluminum liquid is output from the liquid outlet of the smelting furnace into the material trough, and flows into the material nozzle through the material trough. The material nozzle conveys the aluminum liquid to between the rollers of the die-casting machine. At the same time, the copper strip is also conveyed to between the rollers of the die-casting machine. The copper-aluminum composite plate and strip are die-casted by the rotation of the rollers.

[0013] S4: The rollers on the die-casting machine include an upper roller and a lower roller that are opposite to each other. The copper strip is fed along the surface of the upper roller, and the conveying speed of the copper strip is consistent with the rotation speed of the upper roller.

[0014] Preferably, a fan-shaped guide area is formed between the nozzle and the copper strip on the lower side of the upper rolling roller, and fan-shaped aluminum liquid is arranged in the guide area; a first cooling channel is arranged in the nozzle, and the cooling of the aluminum liquid in the guide area is controlled by controlling the flow rate and temperature of the cooling water in the nozzle.

[0015] Preferably, an oil discharge hole is provided on the nozzle surface in the guide area, and an oil inlet channel connected to the oil hole is provided in the nozzle. Oil enters through the oil inlet channel, and oil flows out of the oil outlet hole to form an oil film on the nozzle surface, thereby lubricating the contact surface between the aluminum liquid and the nozzle.

[0016] Preferably, the rotational speed of the upper roller and the rotational speed of the lower roller on the die-casting machine are different, and the rotational speed ratio of the upper roller to the lower roller is between 1.05 and 1.25.

[0017] Preferably, a second cooling channel is provided in the upper roller, and the upper roller is cooled with high intensity by cooling water through the second cooling channel, the cooling water pressure is not less than 0.6 MPa, and the water temperature is not higher than 35°C;

[0018] The lower roller is subjected to low-intensity cooling.

[0019] The beneficial effects of the invention are:

[0020] This process sets the input speed of the copper strip and the rotation speed of the upper roller to be consistent, thereby changing the contact length and time of copper and aluminum, which can effectively control the mutual diffusion of the metals, thereby achieving the purpose of controlling the interface bonding strength and conductivity, and further improving the bonding strength and the organizational properties of the material through subsequent thermal deformation. Description of the drawings:

[0021] Figure 1 It is a schematic diagram of the state during the die-casting process of the invention.

[0022] In the figure: 1. Lower roller; 2. Upper roller; 3. Feed nozzle; 4. Copper strip; 5. Molten aluminum; 6. Copper-aluminum composite plate and strip. Specific implementation method:

[0023] Embodiment: A continuous casting and rolling process for a copper-aluminum composite plate, the process comprising:

[0024] S1: Quality inspection of raw materials for making copper-aluminum composite panels, mainly quality inspection of aluminum ingots and rolled copper strips; at the same time, ensure that all related equipment involved in production are in qualified production status;

[0025] S2: putting the aluminum ingot into a smelting furnace to melt it into aluminum liquid, loading the coiled copper strip onto an unwinder at the top of the die casting, preparing for continuous die casting to produce a copper-aluminum composite plate strip 6;

[0026] S3: Open the liquid outlet of the smelting furnace, start the rollers on the die-casting machine and start the unwinding machine, the aluminum liquid 5 is output from the liquid outlet of the smelting furnace into the material trough, and flows into the material nozzle 3 through the material trough, and the material nozzle 3 conveys the aluminum liquid 5 to between the rollers of the die-casting machine, and at the same time, the copper strip 4 is also conveyed to between the rollers of the die-casting machine, and the copper-aluminum composite plate strip 6 is die-casted by the rotation of the rollers; Figure 1 As shown,

[0027] S4: The rollers on the die-casting machine include an upper roller 2 and a lower roller 1 which are opposite to each other. The copper strip 4 is fed in along the surface of the upper roller 1 , and the conveying speed of the copper strip 4 is consistent with the rotation speed of the upper roller 1 .

[0028] A fan-shaped flow guide area is formed between the nozzle 3 and the copper strip 4 on the lower side of the upper roller 2, and a fan-shaped aluminum liquid 5 is arranged in the flow guide area; a first cooling flow channel is arranged in the nozzle, such as Figure 1 As shown, the first cooling channel includes a group of interconnected cooling inlet holes 31 and cooling outlet holes 32, and the cooling of the aluminum liquid in the guide area is controlled by controlling the flow rate and temperature of the cooling water in the nozzle.

[0029] An oil discharge hole is provided on the surface of the nozzle 3 in the guide area, and an oil inlet channel connected to the oil hole is provided in the nozzle 3. Oil enters through the oil inlet channel, and oil flows out of the oil outlet hole to form an oil film on the surface of the nozzle 3 to lubricate the contact surface between the aluminum liquid 5 and the nozzle 3.

[0030] The rotation speed of the upper roller 2 on the die-casting machine is different from the rotation speed of the lower roller 1, and the rotation speed ratio of the upper roller 2 to the lower roller 1 is between 1.05 and 1.25.

[0031] The upper roller 2 is provided with a second cooling channel, and the upper roller 2 is cooled with high intensity by cooling water based on the second cooling channel. Figure 1 As shown, a circle of cooling diversion holes 22 is arranged near the outer wall of the upper roller 2, and a main cooling hole 21 connected to the cooling diversion hole 22 is arranged in the middle of the upper roller 2. Cooling water enters through the main cooling hole 21 and is then discharged from the cooling diversion hole 22. The cooling water pressure is not less than 0.6MPa and the water temperature is not higher than 35°C.

[0032] The lower roller 1 is subjected to low-intensity cooling, and the lower roller 1 may also not be subjected to cooling treatment. As shown in FIG1 , a cooling channel is provided inside the lower roller 1 .

[0033] Working principle: In this process, the linear speed of the copper strip 5 conveying is designed to be consistent with the linear speed of the upper roller 2 surface rotation, which can effectively extend the contact length and time between the copper strip 5 and the aluminum liquid 5, and the contact part is designed to be fan-shaped, which can further extend the contact time. In addition, by using the cooling channels on the upper roller 2 and the nozzle 3, the temperature of the upper roller 2 and the nozzle 3 can be effectively controlled to further improve the mutual diffusion between the metals and improve the bonding strength of the two materials in the copper-aluminum composite plate 6.

[0034] The embodiments are used to illustrate the invention, not to limit the invention. Any person skilled in the art may modify the embodiments without violating the spirit and scope of the invention, and therefore the scope of protection of the invention shall be as set forth in the claims of the invention.

Claims

1. A continuous casting and rolling process for a copper-aluminum composite plate, the process comprising: S1: Conduct quality inspection on raw materials used to make copper-aluminum composite panels, mainly aluminum ingots and copper strips; at the same time, ensure that all related equipment involved in production are in qualified production status; S2: Put the aluminum ingot into the smelting furnace to melt into aluminum liquid, load the coiled copper strip onto the unwinder at the top of the die casting, prepare for continuous die casting, and produce copper-aluminum composite plates and strips; S3: Open the liquid outlet of the smelting furnace, start the rollers on the die-casting machine and start the unwinder. The aluminum liquid is output from the liquid outlet of the smelting furnace into the material trough, and flows into the material nozzle through the material trough. The material nozzle conveys the aluminum liquid to between the rollers of the die-casting machine. At the same time, the copper strip is also conveyed to between the rollers of the die-casting machine. The copper-aluminum composite plate and strip are die-casted by the rotation of the rollers. S4: The rollers on the die-casting machine include an upper roller and a lower roller that are opposite to each other. The copper strip is fed along the surface of the upper roller, and the conveying speed of the copper strip is consistent with the rotation speed of the upper roller.

2. The continuous casting and rolling process of a copper-aluminum composite plate according to claim 1, characterized in that: A fan-shaped guide area is formed between the nozzle and the copper strip on the lower side of the upper rolling roller, and fan-shaped aluminum liquid is arranged in the guide area; a first cooling channel is arranged in the nozzle, and the cooling of the aluminum liquid in the guide area is controlled by controlling the flow rate and temperature of the cooling water in the nozzle.

3. The continuous casting and rolling process of a copper-aluminum composite plate according to claim 2, characterized in that: An oil discharge hole is arranged on the nozzle surface in the guide area, and an oil inlet channel connected to the oil hole is arranged in the nozzle. Oil enters through the oil inlet channel, and oil flows out of the oil outlet hole to form an oil film on the nozzle surface, thereby lubricating the contact surface between the aluminum liquid and the nozzle.

4. The continuous casting and rolling process of a copper-aluminum composite plate according to claim 1, characterized in that: The rotation speed of the upper roller and the rotation speed of the lower roller on the die-casting machine are different, and the rotation speed ratio of the upper roller to the lower roller is between 1.05 and 1.

25.

5. The continuous casting and rolling process of the copper-aluminum composite plate according to claim 1, characterized in that: The upper roller is provided with a second cooling channel, and the upper roller is cooled with high intensity by cooling water through the second cooling channel, the cooling water pressure is not less than 0.6MPa, and the water temperature is not higher than 35°C; The lower roller is subjected to low-intensity cooling.

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