Research On Hydrodynamic Deep Drawing Of A 5A02 Aluminum Alloy Conical Part Utilizing A Combined Floating And Static Die Cavity

With the development of the aerospace and automobile industries,complex curved parts made of lightweight alloys have been widely used.The curved parts are difficult to form by deep drawing method and easy to appear wrinkling and cracking defects,due to the suspended area in the side wall.In this study,the forming process of 5A02 aluminum alloy conical part based on hydrodynamic deep drawing utilizing a combined floating and static die cavity was studied by numerical simulation and experiments.In order to solve the above problems,this study adopts the hydrodynamic deep drawing utilizing a combined floating and static die cavity technology(HDDC).On the basis of the traditional hydrodynamic deep drawing technology,a movable concave die is added to make the combined liquid pool for forming parts.Firstly,finite element analysis was carried out according to the forming principle of the method,and the forming effects were evaluated.Then,the influence of two stage hydraulic loading path and die parameters in the conical forming process was investigated.Finally,the experimental verification is carried out according to the simulation results.(1)The forming principle of hydrodynamic deep drawing utilizing a combined floating and static die cavity and its influence on forming were studied.According to the forming characteristics of the new process,a two-stage hydraulic loading path is proposed.The simulation shows that the HDDC technology can effectively reduce the suspend area of side wall,restrain the instability of sheet metal and improve the forming quality,compared with traditional hydrodynamic deep drawing.(2)The initial hydraulic loading mode,liquid chamber pressure,hydraulic loading speed,blank holder force and other technological parameters under two-stage hydraulic loading path were investigated by simulating the hydrodynamic deep drawing of conical parts based on HDDC.According to the influence of various process parameters on the wall thickness distribution,wrinkling height and forming accuracy,the reasonable pressure loading path of the liquid chamber was obtained.The simulation result shows that the proper hydraulic loading path can significantly improve the wrinkling defects and forming accuracy of parts,and improve the uniformity of wall thickness distribution of parts.(3)The variation law of floating die’s geometrical parameters,friction coefficient,position and fillet radius of static die on surface quality and forming accuracy was studied,and the function of floating die in forming was analyzed.The simulation results show that the floating die reduces the suspend area of the side wall of the sheet and increases the anti-wrinkling ability of the sheet.At the same time,the floating liquid pool increased the friction retention between the punch bottom and the sheet at the initial stage of forming,and the formed part reduced the influence of the static pool pressure on the wall thickness distribution.The simulation results are verified by HDDC experiment;it can be seen that the experimental results are basically consistent with the results of finite element analysis.Under the hydrodynamic deep drawing utilizing a combined floating and static die cavity technology,the forming accuracy and surface quality of parts are improved obviously.