The Study On The Electrical Properties And The Cold Rolling Technique For Copper And Aluminum Composite Laminates

According to the problems of pure copper with high cost as bus-bars in the electricity and the shortage of the copper resource, the clad rolling technique of copper and aluminum composite laminates has been studied for substituting the pure copper bus-bars. The Cu/Al cold rolling composite technique, the treatment before and after the cold rolling composite and the influence parameters of cold rolling and heat-treatment to the electric and mechanical properties of clad plate have been studied systematically. With the help of software ANSYS, the characteristics of electricity curl in the clad plate has been analyzed as well. The last, designing to the Cu/Al cladding rolling machine has been made in this paper.The results show that the press ratio of Cu and Al plates, the surface treatment to the Cu and Al before cladding rolling and the heat-treatment after cladding rolling have obviously effect on the Cu/Al composite. The scrubbing before cladding rolling can improve the surface of the Cu and Al; the heat-treatment after cladding rolling can enhance the diffusion between the interfaces, forming a perfect transition layer, which can intensify the effect of cladding. Compared with the Cu and Al without scrubbing and later heat-treatment, the ones with scrubbing and the heat-treatment after cladding rolling can increase the stripping strength 100% to 200%. The etch washing to Cu and alkaline cleaning to Al have little impact on the cladding rolling, so in some case this procedure can be canceled.When loaded with current, the Cu/Al clad plate had a phenomenon that the density of current in the surface is higher than that interior, moreover the higher frequent the current is the stronger trend become. That provides a theory instruction for the substitute the pure copper busbar with Cu/Al clad plate. The test of Cu/Al clad plate has a good electric properties. The surface conductivity is 53 MS/m; The surface electrical resistivity is 0.018868 μ Ω . m; The total conductivity is 33.7MS/m; the total electrical resistivity is 0.029664 μ Ω. m. Allowingfor the "conductor skin effect", the electrical properties of Cu/Al clad plate will be better than the Al bus-bar and close to the pure copper bus-bar.At the same time, to the problems of the producing Cu/Al cold rolling cladding plate, a special device has been designed. Measures by applying force on the Cu strip cooperated with the compression roll are taken to control the off tracking; using the shaping mill roll to control the shape of the Cu clad plate. The results show that the thoughts are right and the shape and compound strength have a great improvement.