Experimengts And Deformation Law Of Magnetic Pulse Flanging Of Sheet Metal

The flanging process of aluminum and copper alloys sheets has been widely applied in the realm of aviation and aerospace engineering.To ensure the welding quality and high welding strength between the box and tubes,the flanging of the hole on the box parts are necessary.However,the conventional flanging technique requires large-tonnage punching machine and complicated modes,in addition,the metal pieces have to be heat treated between the working stages in order to decrease the deformation resistance,therefore,the production efficiency is limited and the cost is high.The use of electromagnetic pulse hole flanging has the adva ntages of simplified forming die,high forming accuracy and speed.This makes the electromagnetic pulse forming suitable for the small batch manufacture.Therefore the research of flanging driven by electromagnetic pulse force has a great significance in the engineering industry.In this investigation,the finite element numerical simulation technology is used to analyze and optimize the whole flanging process on metal sheet,and the effect of the main processing parameters on the deformation law and t he forming quality are studied.Based on the simulation results,electromagnetic pulse flanging experiment of circular/non-circular holes on several metal sheets,namely 5A06 aluminum alloy,QCr0.8 copper alloy and LY19 aluminum alloy,are conducted.The design and improvement of the coil and mode for the magnetic pulse flanging are also discussed.On the basis of circular hole flanging of 5A06 aluminum alloy and QCr0.8 copper alloy sheets,it is concluded that high pulsing voltage leads to higher flanging height and severe thickness reduction.The flanging quality of sheet with large deformation area can be improved by multiple magnetic pulsing.The processing parameters of 5A06 aluminum alloy and QCr0.8 copper alloy are determined.On the basis of non-circular hole flanging of LY19 aluminum alloy,it is found that the area close to the hole edge is of the maximum radial tensile stress and circumferential compression stress,the thickness reduction is most pronounced,the material close to the straight edge flows toward the corner,the material close to the upper corner of the mode is of two tension strain and one compress strain,the use of lubricants can alleviate local material thinning,reducing the rupture of hole edge.