| Electromagnetic forming can significantly improve the forming limit of materials,but the existing technology is mainly applied to high conductivity materials,and the energy utilization rate of the forming process is low.How to improve the energy utilization of electromagnetic forming and form high resistance materials is an urgent problem to be solved.In this paper,the current assisted electromagnetic forming method is proposed,which can further effectively improve the plastic deformation effect of high conductivity aluminum alloy,improve the energy rate,and form high-strength steel sheet with low conductivity,expanding the application range of electromagnetic forming.The effects of die and current introduction method on the current distribution and deformation behavior of 5052 aluminum alloy sheet with high conductivity were analyzed by finite element simulation and experiment.The results show that the steel mold commonly used in traditional electromagnetic forming will weaken the effect of current assisted electromagnetic forming.After improvement,the steel mold is replaced by the epoxy plate mold with good insulation,and the bridge structure is used to form a current loop with the plate,which can significantly enhance the current density and electromagnetic force in the deformation area of the plate,and finally improve the forming height of the part,and the energy utilization ratio is increased by 69%.By simulating 3KV current assisted electromagnetic forming and3.9kv electromagnetic forming processes,the same part height is obtained,which is verified with the experimental results.The microstructure evolution of 5052 aluminum alloy under the two forming processes is studied.Compared with electromagnetic forming,the primary strain and secondary strain of current assisted electromagnetic forming increased by53.8% and 27.4% respectively,and the elongation increased by 160%.From the point of view of microstructure evolution,the reason is that the current can reduce the dislocation density,make the dislocations oriented,and improve the plasticity and formability of the material.The current assisted electromagnetic forming process of DP600 highstrength steel with low conductivity was studied.Considering the change of temperature rise,the coupled simulation of thermal,electrical and mechanical multi physical fields of high-strength steel was realized.It showed that the current assisted electromagnetic forming improved the deformation temperature of the material and the forming effect.Compared with the former two,current assisted electromagnetic forming can improve the plasticity and elongation of the material,and does not need the driving sheet,which reduces the material loss,and can achieve a higher forming effect than the driving forming with a lower current peak value. |
