Study On Forming Of Isothermal Extrusion For Aluminum Alloy Empennage Cylinder

The empennage cylinder is one of the important component parts of empennage on missiles, which has complex shape, high precision size and high performance requirement. It has been manufacture by the way of machine cut with steel as raw materials all the time,but low material utilization rate, high energy consumption and production cost are not suitable for saving energy ,reducing consumption requirements and mass production. Steel products can not meet the needs of future empennage service due to high weight. In view of the above questions, this paper use of 2A12 aluminum alloy as raw materials in instead of steel materials, which with light weight and high strength. 2A12 aluminum alloy cylinder forming technology of isothermal extrusion is studied.This parts with special shape: through-hole in the center of the cylinder, some small convex platform on the wall which use for fixed blades of the empennage .They are evenly distributed on the cylinder wall by vertical distribution of three rows and each row six ,and convex platforms with the same cross-section shape, but height disagreed. Research on this kind of special structure and complex parts for extrusion forming is very meaningful.According to the characteristics of the structure of the parts, the forming process was analyzed and extrusion part drawing was determined. The different simulation results of different forming steps based on the establishment of simplified model was analyzed by the way of three dimensional finite element numerical simulation software DEFORM, and determined the process scheme of forming the whole rib made of convex platforms. The flow law of metal during isothermal extrusion was analyzed based on based on the establishment of simplified model. The influence of upsetting extrusion to top of the extrusion part, The influence of different extrusion temperature and extrusion speed and friction factors on the strain-effective and load of metal variation curve with simulation steps, which promotes the technological parameter reference for the aluminum alloy empennage cylinder forming. Combined with the simulation results and comprehensive other factors to consider: under the condition of the extrusion temperature is about 430℃,the friction factor is 0.25,and the extrusion speed is 15mm/s for forming is more reasonable.On the basis of the research, the mould was designed and optimized,and the experimental research was carried out.The result showed that: formulation process scheme was feasible, designed mould was appropriately applied,metal flow was uniform,and the material utilization rate increased from 34% to 71%,and the economic benefits was high,which laid the foundation for engineering applications of the similar parts.