| In recent years,the rise of new energy vehicles,microelectronics and other industries has promoted the rapid rise of the demand for copper and copper alloy strip in China,and the requirements for the quality of copper strip products have become increasingly harsh.Shape is an important quality index of cold rolled copper strip.Since the shape of copper strip will change dynamically during annealing after rolling,it is necessary to fully consider this change and set a reasonable target curve of shape in advance.In this paper,the influence of different annealing process parameters and different incoming material parameters on the evolution of residual stress in the annealing process is analyzed,which provides theoretical support for the accurate and reasonable setting of the plate shape target curve.Firstly,based on the traditional creep theory,the influence of initial hardening degree,recovery and recrystallization behavior on the release of residual stress in cold rolled copper strip was considered.Based on the high temperature annealing stress release model of copper strip as the theoretical basis,ABAQUS finite element software was used to establish the finite element model of copper strip annealing,and SIGINI subroutine was used to apply the initial residual stress to the copper strip.Then,the CREEP subroutine is used to write the high-temperature stress release model of copper strip annealing,simulate the annealing process of copper strip,obtain the evolution rule of residual stress,analyze the influence rule of different annealing process parameters on the evolution of residual stress in copper strip,and then obtain the range of annealing process parameters that can achieve the best annealing effect.Secondly,under certain annealing conditions,the influences of different incoming parameters,such as initial hardening degree,incoming plate width,incoming plate thickness and initial plate shape,on the evolution of residual stress in the annealing process of cold rolled copper strip were analyzed.The quantitative relationship between the thickness of the incoming plate and the shape of the target plate(the maximum difference between positive and negative stress)was determined on the premise that the residual stress after annealing was reduced to below the threshold.Finally,the temperature field simulation was carried out to obtain the temperature curve of the copper coil with time.The curve was re-imported into the flat thin strip model to simulate the evolution of residual stress.Finally,the law of eliminating the radial(length direction)residual stress of the copper strip coil was obtained.Combined with the actual annealing temperature and time in the factory and the finite element simulation results in this paper,the cold rolling and annealing experiments of copper strip were carried out to verify the correctness of the simulation results in this paper. |
