Optimization Of Extrusion Forming Process For Aluminum Alloy Cartridge

As an important way to realize lightweight of light weapons,the application of aluminium alloy materials can greatly reduce the weight of shell and enhance the combat effectiveness of individual soldiers.The 7 series aluminium alloy which meets the comprehensive requirements of cartridge case has good strength and corrosion resistance,but its low extrusion and elongation make its plastic forming have many engineering problems to be solved.Aiming at the problems of insufficient forming length and low production efficiency in the forming process of aluminium alloy cartridge in the early stage of this project,this paper carries out the optimization design,including material selection,forming scheme optimization,die structure design,numerical simulation of forming process,forming experiment and post-forming heat treatment experiment,and obtains the optimal forming process at the present stage.Firstly,the optimal forming scheme is determined,7050-H112 aluminum alloy is selected as blank material;the difficulties of reverse extrusion forming are analyzed from the plastic deformation principle,and the hot deformation scheme and related parameters to reduce the deformation resistance are put forward;the reverse extrusion-tension combined forming mode of the die is determined;after setting the relevant material parameters,the optimized forming scheme is carried out by using DEFORM finite element method.The distribution and variation of equivalent stress,strain,temperature field,flow rule,residual stress and damage value in extrusion process were obtained by numerical simulation.The influence of temperature,velocity,friction and blank shape on the forming results was analyzed.The simulation results show that the die load of the optimized forming scheme can be reduced by45% effectively,and the deformation of each part in the forming process is not changed.Uniform,recrystallization occurs on the cylinder wall,grain size is reduced by 50%,damage value is controlled below 0.3;combined with extrusion forming experiment,the optimal process of new forming scheme is obtained;secondly,through heat treatment and mechanical properties test of the formed products,the optimal heat treatment process of 410 C/30 min +200 C/4h is established to meet the mechanical properties requirements of subsequent processing.By optimizing the forming process of aluminium alloy cartridge,the forming quality and production efficiency are improved,and the small batch production is realized.