Research On The Formability Of Rolled Copper Clad Steel Plate

Copper clad steel plate has a wide range of applications in the fields of automotive,refrigeration,weapons and building decoration for combining the high conductivity and corrosion resistance of copper with the high strength,hardness and remarkable weldability of steel.Substituting copper products with copper clad steel plates can reduce the consumption of copper resources,making the material and project cost drop greatly.Copper clad steel plate is generally fabricated by electroplating,explosion and rolling methods,but the former two methods can cause environmental and noise pollution.In order to comply with the green production mode,research on the mechanical behavior and formability of rolled copper clad steel plate was deeply carried out,providing theoretical foundations and experimental supports for its industrial production and market application.In this paper,copper clad steel plate was selected as the research material,which was fabricated by the processes of cold rolling,diffuse annealing and cold-finished rolling.The anisotropy and formability were further studied,and the 550~800? annealing treatment was carried out so as to achieve the purposes of controlling interfacial bonding strength and improving the workability and formability.In this paper,the microstructure,interface characteristics and element distribution of copper clad steel plate were observed by metallographic microscope,scanning electron microscopy(SEM)and electron probe microanalysis(EPMA).The tensile and reverse bending properties of copper clad steel plate were studied by universal testing machine.The formability was studied by cupping test.The obtained results were as follows:During annealing process,the mutual diffusion phenomenon of alloy elements was presented at the clad,forming the Fe-Cu solid solution layer.The diffusion layer thickness was increased with the elevated diffusion temperature and prolonged holding time,and the effect of the holding time on elements diffusion was remarkable.When the holding time was too long,a large number of oxygen would gather in the interface,forming oxides and voids,resulting in negative influences on the mechanical properties of the plate.The ferrite grain size of steel layer was increased,while the tensile strength and yield strength were decreased with higher temperature.The changes of strength were not obvious with the increasing holding time annealed at 600?.The mechanical properties of copper clad steel plate showed obvious anisotropy.Especially,the strength was the highest at 45 degrees and the plasticity was the best at 90degrees.Annealing treatment could elevate the strain hardening exponent,improving the workability and formability of the plate.The strength of copper clad steel plate was slightly lower than that of single layered steel plate,but the plasticity was greatly improved.It was found that the presence of copper cladding resulted in more severe anisotropy in the strength and plasticity of the composite plates when annealing temperature changed from650? to 800?.Compared with the original copper clad steel plate,with the increase of annealing temperature,the percentage elongation after fracture,the number of bending and the cupping test value of the cladding plate had the same trend of increasing firstly and then decreasing.The maximum values were obtained at 600?,and the plasticity and forming performance of the composite plates were the best.