| In order to improve the army’s individual combat capability,it is very important to reduce the weight of ammunition.As an important part of ammunition cartridge,the material has developed from brass,steel and thin-wall steel to the present light alloy.The research on the aluminum alloy cartridge is not mature.Secondly,the cartridge is prone to ablation and cracking during shooting.Finally,aluminum alloy has obvious tendency of corrosion and cracking,and its long storage property is facing great threat.In a production of aluminum alloy powder in the shoot test appear serious ablation burst problems,this paper analyze the causes of cartridge ablation breaking,through comparison and analysis to choose the suitable powder raw materials,optimize the multichannel time forming technology to improve the distribution of stress and organization at the bottom of the cartridge,eliminates the cartridge case the root causes of defects,and through the optimization research on quenching process cartridge corrosion resistance.The specific research content of this paper is as follows:(1)analysis of ablation failure reason of aluminum alloy cartridgeUsing scanning electron microscope,optical microscope to burst cartridge parts for microstructure analysis,found that the failure parts defects of tiny cracks and pores,and broken parts of the coarse grains,organization is not uniform,cracks may be internal defects caused by the matrix,and the analysis of the powder raw material,found that organization is not uniform,loose and holes defects,leads to formation of cracks or in the process of forming microporous gathered themselves together,and makes the generated when the shooting rupture.(2)analysis and selection of raw materials for aluminum alloy cartridgeThe composition analysis of aluminum alloy raw materials provided by different manufacturers and the detection of mechanical properties and microstructure showed that the comprehensive mechanical properties of material c were good,the tensile strength reached 527.02 mpa,the elongation was 12.2345%,and the electrical conductivity was the highest,36.425%IACS.Moreover,the grain size is uniform and the microstructure has no obvious defects.After the shooting test,there was no ablation hole defect in the wall of the cartrig prepared by material c,and ablation cracking at the bottom was significantly reduced.(3)optimization of multi-pass forming process of aluminum alloy cartridgeThrough the simulation analysis of the whole forming process of aluminum alloy cartridge,it is found that the processes of pellet and bottom punching have the greatest influence on the bottom of the cartridge,which is easy to cause the defects of the bottom of the cartridge.Hedge jar mould,process parameters and bottom die is optimized and the mold after optimization under 430 ℃,the speed of 13.3 mm/s,the friction factor of 0.3,uniform deformation,at the bottom of the cartridge case of stress decreases,and organization.After the shooting test,the cracking at the bottom decreased obviously.(4)study on quenching process optimization of aluminum alloy cartridgeStudy found that the quenching process of quenching medium,quenching temperature,concentration of quenching medium,quenching transfer time four influencing factors are mainly by changing the second phase volume fraction and length-width ratios affect the corrosion resistance of grains,experiment of 20 ℃ when using 5% Na Cl solution for quenching,quenching 10 s,transfer time can be on the basis of the comprehensive mechanics performance guarantee improved corrosion resistance. |
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