Study On Hot Stretch Bending Process For L-section Section Section Of TC4 Titanium Alloy

Stretch bending technology is a kind of composite technology combining stretching and bending.Stretch bending products are widely used in aerospace,construction,automobile and other fields.With the continuous improvement of product accuracy requirements,the theoretical research of stretch bending process and the improvement of process control methods have never been interrupted.Because of its light weight and high strength,titanium alloy components are more and more used in manufacturing.At room temperature,titanium alloy has high yield strength,narrow range of plastic deformation,easy to crack,and large amount of springback.Therefore,hot forming is generally used to process titanium alloy profiles.The three-dimensional bending of titanium alloy profile is realized by superposition of horizontal and vertical bending deformation.In this paper,the influence of process parameters on the forming quality of TC4 titanium alloy profile in the three-dimensional hot stretch bending process is studied by means of numerical simulation and physical experiment.The details are as follows:The high temperature mechanical property parameters of TC4 titanium alloy were obtained by unidirectional hot tensile test.The simulation model of TC4 titanium alloy profile 3D hot tension bending process was established by ABAQUS software.Based on the simulation results of 3D hot stretch bending of TC4 titanium alloy profiles,the distribution characteristics and laws of temperature field and stress field in the forming process were described.Taking springback as the standard to evaluate the forming accuracy,the influence laws of process parameters,such as profile temperature,die temperature,pre-tension and supplementary tension,on the forming results were analyzed.The influence of each influencing factor on the forming result is as follows: the smaller the temperature difference between the profile and the initial temperature of the die,the more uniform the stress distribution of the profile;The curvature of the profile increases gradually with the increase of temperature,and the optimal temperature range of the profile is between 700??750?.Pre-tension and supplementary tension play an important role in reducing springback.With the increase of pre-tension and supplementary tension,the curvature of the profile after springback shows an increasing trend.The influence of the ratio of height to thickness of L-shaped section was analyzed,and the range of vertical edge height was determined based on the profile shape in this paper.The optimum range of friction coefficient in hot forming process is determined.The influence of each process parameter on the forming quality is obtained,which provides a reference for the subsequent research of 3D hot stretch bending.Finally,the reliability of process parameters was verified by physical experiment..