Research On Rolling Theory And Process Of Copper/Aluminum Bimetal Clad Plate

In industrial and civil, copper and aluminum have good thermal conductivity, electrical conductivity. So, the two kinds of materials are more widely used. However, with the development of the industry both in China and abroad, the material needs to have some characteristics of good heat dissipation, electrical conductivity, welding ability, corrosion resistance, easy processing and light weigh. So, the material can satisfy the need of the current society, where aluminum plate with easily forming, low density and good corrosion resistance was composited with copper plate with high strength and good thermal conductivity.In this paper, by introducing the stress field and velocity field of slip line method, the effects of rolling technology on clad plate were predicted and analyzed. At the same time, initial blank size prediction method was established about copper/aluminum bimetal clad plate. Finally, some effects of reduction rate and annealing time on copper/aluminum bimetal clad plate were studied through some experiments. The main research results are as follows:(1) The deformation process of cold rolling copper/aluminum bimetal clad plate can be divided into four parts. In the part I, II and III, the speeds of the corresponding nodes are different on the contact surfaces of copper/aluminum plate, and the values of differences decrease gradually in the bonding process. In the part IV, the speeds of the corresponding nodes are basically identical, and the strain variable quantity on interface is mostly equal, so, synchronous deformation occurs on the interface. In the symmetry rolling process, residual stress of bonding surface after rolling increases with the increase of rolling velocity and the synchronicity of metal flow on bonding surface decreases, which are not conducive to bonding. So, the circumferential velocity of rollers is less than 750 mm/s. In the bonding process of synchronous rolling with non-equal sized rollers, when the diameter ratio is 1.4~1.6, the synchronicity of metal flow on bonding surface is enhanced near the exit of deformation area and residual stress of bonding surfaces is less, which are conducive to bonding. In the bonding process of asymmetrical rolling with non-equal sized rollers, when the circum-ferential velocity rate is 1.2, the synchronicity of metal flow on bonding surface is enhanced near the exit of deformation area and the residual stress of bonding surfaces is less, which are conducive to bonding. In the symmetry rolling process, with the increase of rolling reduction rate, the synchronicity of metal flow is enhanced on bonding surface near the exit of deformation area, which is conducive to bonding.(2) The average ?? of the revised deformation rate is affected by the thickness ratio H1/H2 between Al plate and Cu plate before rolling and the total thickness deformation rate ?total. With the increase of total thickness deformation rate ?total, the revised deformation rate ?? iis gradually decreased. Under the conditions of known thicknesses of aluminum plate and copper plate after rolling and the total deformation rate, using the average ?? of the corresponding revised deformation rate, the thicknesses of Al and Cu plates as well as their lengths relations can be ensured. Under the same reduction rate, the initial thickness ratio is greater between Al plate and Cu plate, the thickness distribution is more uneven in each layer after rolling in the rolling direction.(3) Under the same annealing process, with the total reduction rate increased, peeling strength of clad plate increases gradually. When the reduction rate is more than 61%, there forms intermediate layer with better continuity in the interface. When annealing time is 50 minutes, under the 380?, there is good bonding in interface and intermetallic compound is less.The processes of cold rolling copper/aluminum bimetal clad plate were compared, by numerical analysis method, and the reasonable processes parameters were concluded. Initial blank sizes were researched about copper/aluminum bimetal clad plate through theory and experiment. Reasonable reduction rate and annealing time were obtained by experimental contrast. To a certain extent, it has a certain reference significance to the subsequent study of cold rolling copper/aluminum bimetal clad plate and practical production.