Copper aluminum composite strips are widely used in the field of batteries, but in fact, they are not just commonly used. In many ways, copper aluminum composite strips are gradually replacing copper for use. Below, we will explain in detail the application and production process of copper aluminum composite strips.

Production process of copper aluminum composite strip

We all know that the copper aluminum composite strip generates pressure through rolling, causing at least two layers of metal plates to undergo plastic deformation, causing the surface of the gold layer to crack, the inner layer to activate and clean the metal to be exposed, and metallurgical bonding occurs between the plates and surfaces. Through thermal diffusion, the bonding is further stabilized and strengthened during subsequent heat treatment processes. Asynchronous rolling composite, cold rolling composite, and hot rolling composite all belong to the rolling composite method. Usually, surface treatment is carried out first, followed by rolling and lamination, and finally heat treatment is carried out. When using this method, the boundary should have some roughness and be kept clean, which helps with thermal diffusion, plastic deformation, and sufficient pressure.

The surface treatment of copper aluminum composite strip includes the establishment of film covering method, mechanical method, and chemical method. Generally, the combination of mechanical method and chemical method is used to improve the treatment effect. There are three main steps in rolling composite, namely cold rolling composite, heating, and secondary rolling. Its advantages include high efficiency, simple process, and high composite strength. Research has shown that composite materials have good strength, and scientific heat treatment at 60-430 ° C can reduce the degree of influence of metal compounds on their properties.

Application of Copper Aluminum Composite Strip

1. The common application of copper aluminum composite strip is to wrap a layer of copper on the surface of aluminum plate to form a composite material called copper aluminum composite strip. The red copper strip not only has a great demand, but also has a wide range of applications. After replacing it with copper aluminum composite strip, it can be applied in multiple fields such as signal transmission and power transmission, with broad prospects, laying the foundation for the development of such industries. At present, China mainly produces copper aluminum composite strips through processes such as casting and rolling, mold casting and composite, and explosive composite rolling and composite. Each method has different characteristics and advantages.

2. The corresponding method should be selected based on the characteristics of the product. Usually, the rolling composite method can achieve the goal of large-scale industrial production. The United States first developed the controlled atmosphere rolling composite technology and produced corresponding equipment, which can produce copper aluminum rolling composite plates and strips through the strip method, with ideal production efficiency.

3. There are many types of copper aluminum composite tapes, so their application range is also quite extensive. The advantages of British Chinese aluminum based copper clad laminate mainly include good rigidity, stable size, flat sheet, good electromagnetic shielding, easy mechanical processing, good heat dissipation, and low thermal resistance. It is widely used in printed circuit boards of electronic components, televisions, motorcycles, automobiles, and other industries.

4. Copper aluminum composite strip is used as a transition joint for copper aluminum bus bars and a conductive plate for power supply parts, which will not cause surface arcing or overheating. It is not only cheap, but also can extend the lifespan of the conductive plate, reduce electrical energy loss, and have stable conductivity. The advantages of copper aluminum composite strip in solar water heaters mainly include corrosion resistance, long service life, strong pressure resistance, high heat collection efficiency, and good thermal performance. For new types of solar water heaters, it can be used as a heat collection component. Relevant data shows that the better performing solar water heaters usually use tube plate flat plate collectors. Replacing it with copper aluminum composite strip can significantly reduce unit accumulation.

Copper aluminum composite materials include copper clad aluminum composite wires, copper aluminum composite plates and strips, and copper aluminum composite joint materials.

There are many processing methods for copper aluminum composite materials, which can be roughly divided into two categories: solid-solid phase composite method and liquid-solid phase composite method. The solid-solid composite method includes rolling composite, explosive composite, extrusion drawing composite, etc., while the liquid-solid composite method includes core filling continuous casting, double crystallizer continuous casting, etc.

1. Rolling composite method:

(1) The basic principle of rolling composite method: Under the action of rolling pressure, two or more layers of metal plates undergo plastic deformation at the same time, causing the surface metal layer to crack and expose clean and activated metal, thereby forming metallurgical bonding between the plate surfaces. In the subsequent heat treatment process, thermal diffusion is used to further strengthen and stabilize the interface bonding.

(2) The rolling composite method can be divided into hot rolling composite, cold rolling composite, and asynchronous rolling composite. The process is generally divided into three steps: surface treatment, rolling composite, and heat treatment. The key to the rolling composite method process is: clean and with a certain roughness interface; Sufficient pressure and plastic deformation; Suitable thermal diffusion.

(3) The surface treatment before copper aluminum rolling composite can be divided into chemical method, mechanical method, and establishment coating method. In order to achieve better surface treatment results, a combination of chemical and mechanical methods has become a commonly used method. The copper aluminum rolling composite process is generally cold rolling composite heating hot rolling (secondary rolling), which has the advantages of high composite strength, simple process, and high efficiency. Two situations were found in the heat treatment process of copper aluminum rolling composite materials: firstly, the thermal movement and diffusion of copper aluminum atoms cause the matrix metal to change from point bonding to surface bonding, thereby improving the bonding strength and eliminating residual stress during composite rolling; Secondly, as the temperature increases, both copper and aluminum undergo recrystallization, and the composite interface thickens, resulting in the formation of hard and brittle intermetallic compounds, leading to a sharp deterioration in bonding strength and bending performance.. X. K. Peng et al. studied the effects of rolling temperature, heat treatment process, and reduction on the properties of copper aluminum composite plates. The results showed that composite materials with good bonding strength can be obtained at a rolling temperature of 430 ℃ and a reduction of 60%. Reasonable heat treatment processes can reduce the impact of intermetallic compounds on interface properties.

(4) At present, it is generally believed that the copper aluminum rolling composite process consists of three stages, namely the physical contact stage, the contact surface activation stage, and the diffusion stage. The composite mechanism can be summarized as follows: the surface layer of copper aluminum ruptures, fresh aluminum particles squeeze into the copper crack and come into contact with each other, and under certain conditions, surface atoms are activated to form activation centers, causing atomic bonding between fresh particles; During the subsequent heat treatment process, point bonding is transformed into surface bonding through diffusion or recrystallization, with a certain depth of diffusion.

2. Explosive composite method:

(1) The principle of explosive composite method: The explosive composite method utilizes the energy generated by the explosion of explosives to generate a strain rate of up to 106-107/s and a high pressure of 104MPa at the collision point of two metal plates in microseconds, thereby achieving the welding and composite of dissimilar metals.

(2) Characteristics of explosive bonding method: Due to the extremely short duration of loading pressure and interface high temperature, it hinders the chemical reaction between each component metal. The thickness of the welding zone is generally within tens of micrometers, making it suitable for welding between most metal pairs. Its characteristic is that it can achieve composite metal combinations with extremely significant differences in material performance; It can avoid the formation of brittle intermetallic compounds; Strong flexibility, able to achieve the composite of various irregular parts; Composite materials have high bonding strength. Its disadvantages include low mechanization, poor working conditions, and certain risks. Copper aluminum explosive composite plates have high bonding strength due to the presence of metal plastic deformation and melting in the bonding zone, the mutual diffusion of copper and aluminum atoms near the interface, and the occurrence of metallurgical processes in the bonding zone; The interfacial shear strength is around 75MPa, and the separation strength can reach up to 106MP.

Article source: Internet

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