Research On Compound Hydroforming Technology Of Thin-walled Ring Parts

In the factory production of a TA2 titanium alloy ring parts,manual hot spinning is adopted,which has low efficiency,unstable product quality and obvious spinning marks on the surface of the part after hot spinning.In order to facilitate the removal of the core of the hot spinning part,the core is assembled,and the marks of the hot spinning part at the joint of the core are obvious.In view of the above problems,this research plans to adopt the normal temperature compound hydroforming process which combines the hydromechanical deep drawing and the hydraulic bulging process to form the ring parts.In the same die,the sheet metal is drawn into a cylinder shaped preform by using the hydromechanical deep drawing,and then the cylinder shaped preform is hydraulically expanded to form a ring-shaped part that meets the requirements.First of all,the basic formability of TA2 titanium alloy sheet is tested and evaluated,and the basic properties of drawing and bulging are studied;the material model is constructed according to the basic performance parameters of the material,and the complex hydroforming process is studied in detail with DYNAFORM finite element software,and the influence of the forming process parameters on the forming quality of the ring parts is explored;finally,the ring parts is carried out according to the simulation results,and verify that simulation results are qualified.The results show that the thinnest point of the wall thic KNess of the tubular preform and the ring parts is located in the straight wall area,but the two thinnest points are not the same,and there is no interaction in the process of the hydraulic bulging.In order to ensure the forming quality of the ring parts,the biggest hydraulic pressure of the tubular preform in the process of the hydraulic deep drawing should not be too large,it is better to form effective lubrication in the forming process;The punch fillet radius is one of the important factors that affect the wall thic KNess distribution of the final formed ring parts,with the increase of punch fillet radius,the wall thic KNess of the fillet of the preformed tubular parts increases,the wall thic KNess of the thinnest point remains unchanged,and the wall thic KNess of the thinnest point of the ring parts gradually decreases;in order to obtain the ring parts with high forming quality,the hydraulic bulging is used In the process,it is necessary to keep good lubrication conditions between the tubular preform and the die;annealing and hydroforming of the tubular preform are beneficial to further reduce the wall thic KNess reduction rate of the ring parts and improve the formability.The influence of the matching relationship between the internal pressure and the axial force of the hydroforming on the forming limit of the ring parts is studied.The results show that when the axial force is fixed,the maximum bulging diameter of the ring decreases with the increase of the internal pressure,which means that the forming limit of the ring decreases with the increase of the internal pressure alone.The axial force is the key factor affecting the forming limit of the ring.When the internal pressure remains constant,the maximum bulging diameter increases with the increase of the axial force,which means that the increase of the axial force is conducive to the increase of the forming limit of ring parts.According to the simulation results,the compound hydroforming experiment of the ring parts is carried out,and the ring parts that meet the requirements are successfully formed,and the experimental results are basically consistent with the simulation results.In the process of the experiment,because of the unreasonable matching between the internal pressure and the axial force,the ring parts are easy to produce forming defects.