Research On Process And Application Of Electromagnetic Punching On AA5182 Aluminum Alloy For Vehicle Body

Electromagnetic punching(EMP)is a novel type of high-efficiency and highspeed punching technology,which is mainly suitable for thin metal plates with good electrical conductivity.Aluminum alloy is the most widely employed in the automotive and aerospace fields because of its excellent properties.This paper investigated the electromagnetic punching on AA5182 aluminum alloy in the aspect of punching process parameter and mechanism.And then the hole,which was punched by EMP,was applied to discuss the electromagnetic pulse flanging.Firstly,the electromagnetic punching of process parameters was explored.The main process parameters were discharge energy,sheet thickness and die shapes,and then the holes quality was analyzed from the dimensional accuracy,the hole of inner wall,micro-cross section and work hardening etc.The experimental results showed that as the discharge energy increases,the dimensional accuracy and inner wall smoothness of the punch parts were constantly getting better.Under different die shapes,the punching quality of special-shaped holes was different in terms of punching inner wall and cross-sectional micro-morphology.The inner wall of the long axis of square and ellipse was smoother,and the short axis of ellipse and triangle were rougher.The quality of blanking under different plate thicknesses was different in terms of blanking inner wall,dimensional accuracy and work hardening.The inner wall of 0.8mm plate was smoother,the density of dimples was higher,and the average diameter and depth of dimples were relatively small.The 1.0 mm and 1.2 mm plates would have smoother and rougher inner walls,sparse dimples,and larger average diameter and depth of dimples.Secondly,Numerical simulation of magnetic pulse punching was carried out by finite element software,and the magnetic flux distribution,induced current distribution,sheet stress distribution and sheet fracture process of magnetic pulse punching were analyzed.The results showed that the gap between the coil and the plate was the place where the magnetic flux density was the largest,and the plate would has the largest induced current value within the coil diameter range.The equivalent stress cloud chart shows that the equivalent stress near the surface of the sheet and the edge of the die was the largest.The punching process showed that the strain of the sheet was very small in the elastic deformation stage,and the parabolic shape of the rollover zone gradually became obvious in the plastic deformation stage.When the fracture separation reached a certain extent,the sheet would undergo brittle fracture.Finally,based on the prefabricated holes obtained by EMP,the magnetic pulse flanging test was carried out.The research result showed that the inner wall of the flanging piece was smooth and the outer wall was sharp when the rounded belt was up.while the opposite was true when the rounded belt was down.In addition,with the increase of the discharge energy,the quality of the flanging of punching holes first increases and then decreases.When the discharge energy was 12 k J,the flanging quality was the best.There were obvious differences in the quality of the flanging under different sheet thicknesses.There wre dense cracks on the top of the 0.8 mm flanging piece,and the sheet was seriously thinned and even cracked at the bending part.When the thickness of the sheet was 1.2 mm,the flanging piece failed to be moulded.