Introduction to copper-aluminum composite strips, including production technology, applications, processing methods, etc.
Copper-aluminum composite strips are widely used in the battery field. In fact, it is not just the same. In many aspects, copper-aluminum composite strips are gradually replacing copper. Let's explain in detail the application and production process of copper-aluminum composite strips.
Copper-aluminum composite strip manufacturing process
We all know that the copper-aluminum composite strip is subjected to pressure generated by rolling, causing at least two layers of metal plates to undergo plastic deformation, causing the surface of the gold layer to rupture, and the activated and clean metal in the inner layer to be exposed. A metallurgical bond is produced, which is bonded by thermal diffusion and further stabilizes and strengthens the bond during subsequent heat treatment. Asynchronous rolling cladding, cold rolling cladding and hot rolling cladding all belong to rolling cladding methods. Surface treatment is usually performed first, followed by rolling and compounding, and finally heat treatment. The interface used when using this method should have some roughness and be kept clean, which is helpful for heat diffusion, plastic deformation and pressure. big.
The surface treatment of copper-aluminum composite strips includes the establishment of coating methods, mechanical methods and chemical methods. Generally, the treatment effect is improved by combining mechanical methods and chemical methods. There are three main steps in rolling cladding, namely cold rolling cladding, heating and secondary rolling. Its advantages include high efficiency, simple process, and high composite strength. Research shows that composite materials have better strength, and scientific heat treatment operations of 60-430°C can reduce the impact of metal compounds on the performance.
Application of copper and aluminum composite strips
1. The more common copper-aluminum composite tape application is a composite material formed by wrapping a layer of copper on the surface of an aluminum plate. It is a copper-aluminum composite tape. Copper tape not only has great demand, but also has a wide range of applications. After replacing it with copper-aluminum composite tape, it can be used in many fields such as signal transmission and power transmission. It has broad prospects and lays the foundation for the development of such industries. Left the basics. At present, my country mainly produces copper-aluminum composite strips through processes such as casting-rolling, die-casting cladding, explosive cladding, and rolling cladding. Each method has different characteristics and advantages.
2. The corresponding method should be selected based on the characteristics of the product. Under normal circumstances, the rolling cladding method can achieve the goal of large-scale industrial production. The United States first developed the controlled atmosphere rolling cladding technology and produced matching equipment to produce copper-aluminum rolled cladding panels through the strip method. belt, the production efficiency is ideal.
3. There are many types of copper-aluminum composite tapes, so their applications are also wide. The advantages of Yingzhong aluminum-based copper-clad laminates include good rigidity, stable dimensions, flat sheets, good electromagnetic shielding, easy machining, good heat dissipation, and low thermal resistance. They are widely used in electronic components, televisions, and motorcycles. Printed circuit boards in cars, automobiles, etc. are widely used.
4. The copper-aluminum composite strip is used as the transition joint of the copper-aluminum busbar and the conductive plate in the power supply part. It will not cause surface arcing or overheating. It is not only low in price, but also can extend the life of the conductive plate, reduce power loss, and has stable conductivity. performance. The advantages of copper-aluminum composite strips for solar water heaters mainly include corrosion resistance, long service life, strong pressure resistance, high heat collection efficiency, good thermal performance, etc. For new solar water heaters, it can be used as a heat collecting element. Relevant data shows Among solar water heaters with better performance, tube-sheet flat plate collectors are usually used. Replacing them with copper-aluminum composite strips can significantly reduce unit area.
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. Solid-solid phase compounding methods include rolling compounding, explosion compounding, extrusion drawing compounding, etc. Liquid-solid phase compounding methods include core-filled continuous casting, double-mold continuous casting, etc.
1. Rolling composite method:
(1) Basic principle of rolling composite method: Under the action of rolling pressure, two or more layers of metal plates are plastically deformed at the same time, and the surface metal layer is broken, exposing clean and activated metal, thereby forming a metallurgical bond between the plate surfaces. The interface bonding is further strengthened and stabilized through thermal diffusion during subsequent heat treatment.
(2) The rolling cladding method can be divided into hot rolling cladding, cold rolling cladding and asynchronous rolling cladding. The process is generally divided into three steps: surface treatment, rolling compound and heat treatment. The key to the rolling composite method is: clean and rough interface; sufficient pressure and plastic deformation; suitable heat diffusion.
(3) Surface treatment before copper-aluminum rolling composite can be divided into chemical method, mechanical method and film-building method. In order to obtain better surface treatment effects, a combination of chemical and mechanical methods has become a common 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. During the study of the heat treatment process of copper-aluminum rolling composite materials, two situations were found: First, the thermal movement and diffusion of copper and aluminum atoms caused the base metal to change from point bonding to surface bonding, thus increasing the bonding strength and also increasing the residual stress during composite rolling. Second, as the temperature increases, both copper and aluminum recrystallize, the composite interface thickens, and hard and brittle intermetallic compounds are generated, resulting in a sharp deterioration in bonding strength and bending properties. . X.K.Peng et al. studied the effects of rolling temperature, heat treatment process and reduction on the performance of copper-aluminum composite panels. The results show that composite materials with better bonding strength can be obtained when the rolling temperature is 430°C and the reduction is 60%. Reasonable heat treatment The process 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 and aluminum breaks, fresh aluminum particles squeeze into the copper cracks and contact each other. Under certain conditions, surface atoms are activated to form an activation center, causing atomic bonds to occur between the fresh particles; during subsequent heat treatment, Point bonding is transformed into surface bonding through diffusion or recrystallization, and has a certain diffusion depth.
2. Explosive compounding method:
(1) Principle of the explosive composite method: The explosive composite method uses the energy generated by the explosion of explosives to produce a strain rate of up to 106~107/s and a high pressure of 104MPa at the collision point of two metal plates within microseconds, thereby achieving welding and composite of dissimilar metals.
(2) Characteristics of the explosive recombination method: Due to the extremely short duration of the loading pressure and interface high temperature, which hinders the chemical reaction between the component metals, the thickness of the welding zone is generally within tens of microns, so it is suitable for welding between most metal pairs. . Its characteristics are that it can composite metal combinations with extremely different material properties; it can avoid the generation of brittle intermetallic compounds; it has strong flexibility and can realize the composite of various special-shaped parts; and the composite material has high bonding strength. Its shortcomings are low degree of mechanization, poor working conditions, and certain risks. Copper-aluminum explosive composite panels have high bonding strength. The reason is that there is plastic deformation and melting of metal in the bonding area, mutual diffusion of copper and aluminum atoms near the interface, and a metallurgical process occurs in the bonding area. The interface shear strength is about 75MPa, and separation Intensity*** up to 106MP.
