Research On Superplastic Bulging Forming 5083 Aluminium Window Part For High-speed Train

China's railway transportation industry has been developing rapidly in the past decades.Safety,high speed and light weight have become the basic traits of modern railway transportation.Traditional design requires lots of joining parts,resulting in mass of weight.An improved design which merge different parts as much as possible by means of superplastic gas bulging forming can help reduce redundant parts and lose weight.The 5083 aluminium has a fairly good superplasticity compared with most of the other kinds of aluminium.As for the production of domestic superplastic parts,there are two conspicuous problems.One is the problem of domestic materials.The domestic industrial 5083material is usually characterized by more impurity substances and bigger grain size.Even the finely grained 5083 has a grain size of more than10?m,whilst the imported superplastic aluminium has a grain size of less than 10?m.The second problem is the efficiency of production.Since the superplastic forming usually means the material deform at a low strain rate,the efficiency is restricted within a low level.Therefore,how to figure out appropriate forming parameters to ensure the superplastic forming of complex surface parts with domestic industrial state 5083 aluminium and realize mass production is very important.The superplasticity of domestic 5083 aluminium is evaluated by metallographic examination and high temperature tensile test.The result reveals the conclusions below:the domestic industrial state 5083aluminium has a grain size of about 20?m.The thermal stability of grain size is fairly good.No obvious grain growth is found after remaining at the temperature ranging 450?⁵25?for 30 minutes.The elongation rate of 450?⁴75?is generally 99%¹00%,and the grain is obviously elongated during the deformation.The elongation rate of500?⁵50?is generally 120%¹50%,and the grain remains equiaxed.Through the experiments,it is found that the material acquire a better superplasticity at the temperature ranging 500?⁵25?,with the strain rate ranging 1×10^-4s^-11×10^-3s^-1.The fillet of the forming parts cracked in the initial production,because of the poor superplasticity of domestic industrial state 5083aluminium.Superplastic gas forming parameters is reconsidered with reference to the results of experiments in order to solve the problem.The forming temperature is about 500?,which is controlled by heating curve;The forming strain rate is about 6.56×10^-4s^-1,which is controlled by pressure loading curve.The improved forming parameters is introduced into the ABAQUS FEM software to simulate the forming process,which turns out to be well-performed.Adopting the improved forming parameters in the process of practical production,no crack appears in the fillet and the part deforms perfectly.In order to improve the production efficiency,the method of loading and unloading the parts by using auxiliary tool is introduced to realize mass production.The results of this study have a certain significance for the application and popularization of the domestic industrial state 5083 aluminum alloy superplastic forming parts,which lays a foundation for further research on the superplastic forming technology of non ideal materials.