Preparation method of electric heating short-distance copper-aluminum composite board

Abstract

The invention discloses a preparation method of an electric heating short-distance type copper-aluminum composite board, which comprises the following steps of: preparing a protection tunnel, arranging a feed port and a discharge port at the front end and the rear end of the protection tunnel, pulling an aluminum plate strip and a copper plate strip into the protection tunnel, and enabling the aluminum plate strip to be in sliding contact with a high potential in the protection tunnel, an aluminum plate strip is used as a base strip to be overlapped with a copper plate strip in a deviation rectifying mode to form a pre-rolled plate strip, a roller of a rolling mill makes contact with a low potential, then inert gas and hydrogen are continuously introduced into a protection tunnel, the pre-rolled plate strip is electrified through the high potential and the low potential, and the pre-rolled plate strip is heated through low voltage and large current; and sealing at the feed port and the discharge port through continuous flame, rolling the pre-rolled plate strip into a composite plate strip under the traction of a rolling mill, annealing the composite plate strip, and performing cold rolling to obtain the copper-aluminum composite board. Compared with the prior art, oxide generation can be effectively reduced, the plate strip heating efficiency is improved, and the quality stability of the copper-aluminum composite plate obtained through hot rolling compounding is high.

Description

Technical Field

[0001] The invention belongs to the field of metal processing, and in particular relates to a method for preparing an electric heating short-distance copper-aluminum composite plate. Background Art

[0002] Copper-aluminum composite materials are materials formed by combining copper and aluminum through a specific processing technology. Its structure can be layered, for example, the copper layer and the aluminum layer are closely attached together through explosive compounding, rolling compounding and other methods to form a "sandwich" structure; it can also be dispersed particles, that is, aluminum particles are evenly dispersed in the copper matrix, or vice versa. This composite material combines the advantages of copper and aluminum, and has good electrical conductivity, high strength, good toughness, good thermal conductivity, corrosion resistance and other characteristics. It is widely used in power, electronics, machinery manufacturing and other industries.

[0003] At present, the preparation methods of copper-aluminum composite plates and strips mainly adopt solid-solid composite method and liquid-solid composite method. The solid-solid composite method is mainly produced by explosive composite method, cladding welding method, composite ingot hot rolling method, rolling and pressing method. These production methods have the disadvantages of complex process, high production cost, low composite strength and unstable product quality. The liquid-solid composite method is mainly produced by composite casting method and continuous casting and rolling method, which requires special equipment and has extremely high technical requirements.

[0004] In view of the above problems, patent document CN112934965B discloses a copper-aluminum warm-rolled composite plate and its preparation method and application, which discloses placing a copper strip on a heated first aluminum-containing plate The surface of the strip is subjected to the first warm rolling composite under protective conditions to obtain a plate blank, and then the plate blank is annealed and cold rolled in sequence to obtain a copper-aluminum warm-rolled composite plate, which has a high composite rate and good composite strength. However, in actual operation, it was found that there are some problems with this preparation method: first, during the heating and transfer process of the first aluminum-containing strip, it will contact the outside world to generate too much oxide on its surface; second, during the heating of the first aluminum-containing strip to the transfer process under protective conditions for the first warm rolling composite, the temperature will drop over time, and the heating efficiency is low; excessive oxide generation and low heating efficiency will lead to poor quality stability of the hot-rolled composite copper-aluminum composite plate. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of interface oxides and heating efficiency in the existing copper-aluminum composite plate preparation method, and to provide an electric heating short-distance copper-aluminum composite plate preparation method that can effectively reduce oxide generation and improve plate and strip heating efficiency.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for preparing an electrothermal short-distance copper-aluminum composite plate, comprising the following steps: S1: Prepare a protection tunnel, seal the front and rear ends of the protection tunnel, and respectively set a feeding port and a discharging port at its front and rear ends. A pay-off reel is provided in front of the feeding port, a rolling mill is provided at the discharging port, and a take-up reel is provided behind the rolling mill; S2: Place aluminum coils and copper coils on the pay-off reel, unwind them into aluminum strip and copper strip, and draw the aluminum strip and copper strip into the protection tunnel. Inside the protection tunnel, the aluminum strip contacts a high potential, and with the aluminum strip as the base band, it is corrected and laminated with the copper strip to form a pre-rolled strip. Then draw the pre-rolled strip into contact with the rolls of the rolling mill, and the rolls of the rolling mill contact a low potential. Then continuously introduce inert gas and hydrogen into the protection tunnel; S3: Apply electricity to the pre-rolled strip through the high potential and low potential, heat the pre-rolled strip with low voltage and high current, and seal the feeding port and discharging port inside the protection tunnel with continuous flames. The pre-rolled strip is rolled into a composite strip under the traction of the rolling mill, and the composite strip is drawn to the take-up reel and connected to it. Under the action of the pay-off reel and the take-up reel, front and rear tensions are established for the strip, and the prefabricated strip is continuously rolled to form a composite strip. The composite strip is cold-rolled into copper-aluminum composite sheets after annealing.

[0007] Optionally, in S1, a waste roll is provided below the outlet of the rolling mill, and the waste roll rotates synchronously with the rolls of the rolling mill. In S3, draw the waste strips cut off from both sides of the composite sheet coming out of the rolling mill, connect them to the waste roll, and the waste roll continuously rotates to collect the waste strips.

[0008] Optionally, in S1, a cooling tunnel is provided between the rolling mill and the take-up reel. In S3, draw the composite strip through the cooling tunnel and connect it to the take-up reel.

[0009] Optionally, in S2, the volume flow ratio of the inert gas to the hydrogen introduced is 2:0.8 - 1.2; Optionally, in S3, the low voltage is 20 - 25V, and the high current is 10 - 12.5KA.

[0010] Optionally, in S1, the distance between the discharging port and the rolls of the rolling mill is 2 - 8 cm.

[0011] Principle of the present invention: First, a high potential is slidably contacted with an aluminum strip, and a low potential is connected to the roll of a rolling mill. When an electric current is applied to the strip through the high potential and the low potential, an electric current will pass through the strip between the roll and the high potential. The current heats the strip. Since the strip is continuously moving forward, the aluminum strip near the high potential is preheated. After preheating, the aluminum strip moves forward and is corrected and laminated with the copper strip to form a pre-rolled strip. At this time, the resistance increases and the electron density increases, and the temperature of the pre-rolled strip further rises. Then the pre-rolled strip continues to move forward and contacts the roll. At this time, the resistance further increases and the electron density further increases. The temperature of the pre-rolled strip rises to an appropriate value and is immediately rolled into a composite strip. Through this form of heating, the temperature rises relatively gently, the heat loss is small, a better heating efficiency can be achieved, and the requirements for equipment are not high. In addition, heating the composite sheet material with low voltage and large current can effectively improve the heating efficiency, optimize the material properties, reduce the cost, reduce the arc radiation, and improve the safety, and the operation is simple; Second, the strip to be heated is placed in a relatively airtight protection tunnel. By continuously injecting inert gas and hydrogen into the protection tunnel, the protection tunnel is filled with inert gas and hydrogen, and the inert gas and hydrogen overflow out of the protection tunnel through the gaps of the protection tunnel to form a positive pressure barrier to prevent the external oxygen-containing air from entering the protection tunnel. At the same time, at the inlet and outlet of the protection tunnel, it is sealed by continuous flames to burn oxygen, further preventing the external oxygen-containing air from entering the protection tunnel. In addition, the hydrogen diffused in the protection tunnel can reduce the oxides on the surface of the sheet material. In a high-temperature environment, this reduction will be accelerated. By using this method, the generation of oxides can be reduced at each node.

[0012] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention can effectively reduce the generation of oxides, improve the heating efficiency of the strip, and the quality stability of the copper-aluminum composite sheet hot-rolled and compounded is relatively high. Specific embodiments

[0013] Example 1. For the convenience of understanding the technical solution, the present invention will be further described below. A method for preparing an electrothermal short-pitch copper-aluminum composite sheet includes the following steps: S1: Prepare a protection tunnel, seal the front and rear ends of the protection tunnel, and respectively set an inlet and an outlet at the front and rear ends thereof. The sizes of the inlet and the outlet match the strip. A pay-off reel is provided in front of the inlet, a rolling mill is provided at the outlet, the distance between the outlet and the roll of the rolling mill is 2-8 cm, and a take-up reel is provided behind the rolling mill; S2: Place the aluminum coil and copper coil on the uncoiler. Uncoil them into aluminum strip and copper strip. Manually pull the aluminum strip and copper strip into the protection tunnel. The aluminum strip and copper strip enter the protection tunnel from different feeding ports. Inside the protection tunnel, the aluminum strip makes sliding contact with a high potential. With the aluminum strip as the base, it is corrected and laminated with the copper strip to form a pre-rolled strip. Pull the pre-rolled strip into contact with the rolls of the rolling mill. The rolls of the rolling mill make sliding contact with a low potential. Then, continuously introduce inert gas and hydrogen into the protection tunnel. The volume flow ratio of the inert gas to hydrogen introduced is 2:0.8 - 1.2, and the hydrogen flow rate is set at 30 - 100 L / h. S3: Apply electricity to the pre-rolled strip through the high potential and low potential to heat the pre-rolled strip with low voltage and high current. The low voltage is 20 - 25 V, and the high current is 10 - 12.5 KA. Seal the feeding port and discharging port inside the protection tunnel with continuous flames. The pre-rolled strip is pulled forward by the rolling mill and rolled into a composite strip. Manually pull the composite strip to the coiler and establish a connection with it. Under the action of the uncoiler and coiler, front and rear tensions are established for the strip, and the prefabricated strip is continuously rolled to form a composite strip. The composite strip is cold-rolled into a copper-aluminum composite sheet after annealing.

[0014] Since after the prefabricated strip is rolled, excess waste strips will be cut off at both sides. If not processed, it will affect the forward movement of the composite strip. Therefore, a waste roller is provided below the outlet of the rolling mill. The waste roller rotates synchronously with the rolls of the rolling mill. Manually pull the waste strips cut off from both sides of the composite material coming out of the rolling mill and connect them to the waste roller. The waste roller rotates continuously to collect the waste strips.

[0015] Since the composite strip coming out of the rolling mill has a high temperature, in order to facilitate subsequent safe coiling, its temperature needs to be appropriately reduced. Therefore, a cooling tunnel is provided between the rolling mill and the coiler. Manually pull the composite strip through the cooling tunnel and establish a connection with the coiler.

[0016] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. Preparation method of electrothermal short-distance copper-aluminum composite plate, characterized in that: The following steps are involved: S1: prepare a protection tunnel, seal the front and rear ends of the protection tunnel, and respectively set a feed port and a discharge port at the front and rear ends thereof, a uncoiler is set in front of the feed port, a rolling mill is set at the discharge port, and a coiler is set behind the rolling mill; S2: placing the aluminum coil and the copper coil on the unwinding machine, unwinding them into aluminum strips and copper strips, pulling the aluminum strips and the copper strips into the protection tunnel, in which the aluminum strips are in contact with a high potential, and the aluminum strips are used as the base strips to correct the deviation and overlap with the copper strips to form pre-rolled strips, pulling the pre-rolled strips into contact with the rollers of the rolling mill, and the rollers of the rolling mill are in contact with a low potential, and then continuously introducing inert gas and hydrogen into the protection tunnel; S3: The pre-rolled strip is energized by high potential and low potential, and the pre-rolled strip is heated by low voltage and high current, and is sealed by continuous flame at the feed port and discharge port in the protection tunnel. The pre-rolled strip is rolled into a composite strip under the traction of the rolling mill, and the composite strip is pulled to the winder to establish a connection with it. Under the action of the unwinder and winder, the front and rear tensions are established for the strip, and the prefabricated strip is continuously rolled to form a composite strip, which is cold-rolled into a copper-aluminum composite plate after annealing.

2. The preparation method of the electrothermal short-pitch copper-aluminum composite plate according to claim 1, characterized in that: In S1, a scrap roller is provided below the mill outlet, and the scrap roller rotates synchronously with the mill rollers. In S3, the scrap strips cut off on both sides of the composite sheet coming out of the mill are pulled and connected to the scrap roller, and the scrap roller rotates continuously to collect the scrap strips.

3. The preparation method of the electrothermal short-pitch copper-aluminum composite plate according to claim 1, characterized in that: In S1, a cooling tunnel is provided between the rolling mill and the coiler, and in S3, the pulled composite strip is connected to the coiler through the cooling tunnel.

4. The preparation method of the electrothermal short-pitch copper-aluminum composite plate according to claim 1, characterized in that: In S2, the volume flow ratio of the inert gas to the hydrogen is 2:0.8~1.

2.

5. The preparation method of the electrothermal short-pitch copper-aluminum composite plate according to claim 1, characterized in that: In S3, the low voltage is 20~25V and the high current is 10~12.5KA.

6. The preparation method of the electrothermal short-pitch copper-aluminum composite plate according to claim 1, characterized in that: In S1, the distance between the discharge port and the rolling mill rolls is 2~8cm.