Research On Necking And Hot Extrusion Thickening Forming Device And Technology Of Thin-walled Aluminum Alloy Tube

In the aircraft control mechanism,the traditional forming method of the rod is mainly made by necking and riveting screw sleeve.This method can not reduce the weight of the body,and it has the disadvantages of low connection strength,complicated process and high manufacturing cost as well.The use of tube necking and thickening forming technology can solve the above problems effectively.Although this new technology has certain advantages,but it still exists many problems in the process of forming,such as the wrinkling of the tube conveying force area,the distortion of the tube body,the surface material falling off and other defects.In this paper,the author has made improvements on the basis of the traditional necking forming,the thin-walled tube forming by hot spinning compression necking and hot extrusion thickening.By analysis on forming theory and influencial factor,finite element numerical simulation,forming device design and assembly,necking and hot extrusion thickening experiment,the author has researched on necking and thickening forming of thin-walled LF2 M aluminum alloy tube with outer diameter D=32mm and wall thickness t=1mm,the specific research contents are the following:Through analysis on principle of the tube necking and thickening forming,the author gets a good theoretical basis for tube necking and thickening of the forming method;and the paper focuses on the analysis of several factors affecting the effect of tube forming,by forming temperature,friction coefficient,die angle and other parameters on the concrete influence the forming quality,and provides a reliable theoretical basis for the finite element numerical simulation and forming experiment.Based on the finite element analysis software DEFORM-3D,the finite element model of necking and thickening forming of thin-walled tube was established,and the forming parameters such as forming temperature,friction coefficient and taper angle of die were simulated by finite element method.The simulation results show that when the temperature is T=400 ?,the friction coefficient is f=0.06,and the taper angle of the die is 2a=20°,the necking coefficient is 0.75 and the necking forming quality is better;In the process of thickening simulation,the thickening rate is 66%.The author has made design and adjustment device of tube necking and hot extrusion thickening forming.The main contents include:designing and manufacturingtwo sets of special forming mould,one cannot be heated and,the other can be heated.The author designs principle diagram of heating circuit,and installs electrical components through debugging and eventually implement the function of temperature can be measured,can be digital displayed and can be adjusted.The actual effect of forming temperature and friction lubrication on the quality of tube necking and thickening forming was investigated by tube necking and hot extrusion thickening forming experiment.The results show that when the forming temperature is above 150? and the lubricant is molybdenum disulfide,the necking forming quality is better.When the thickening forming temperature is 400 ?,the maximum thickening rate reaches 80%.In order to better meet the practical application of the project,it is necessary for the author to further optimize and improve the forming device and process in the follow-up study.