Simulation Study On Process Of Hot Stretch Bending And Creep Forming Of TC4 Titanium Alloy

Titanium alloy has the advantages of high specific strength and good thermal strength.With the lightweight requirements of the development of aircraft,titanium alloy profile bending parts are increasingly used in aircraft.However,titanium alloys have poor plasticity at room temperature and are difficult to form,so the hot stretch bending process is often used.With the increasing accuracy of aircraft assembly,higher requirements are put forward for the forming accuracy of profile parts.In recent years,the hot-stretch bending creep forming process has become an important technology for achieving high-precision forming of titanium alloy profiles.This paper used finite element software to establish high-temperature bending creep model,hot-stretch bending finite element model and hot-stretch bending creep model for titanium alloy L-sections to provide technical basis and process guidance for titanium alloy hot-stretch bending and creep forming process design.The main research contents and results are as follows:For the TC4 titanium alloy L-section,the stress relaxation behavior and spring back law during the hot-press bending and creep forming process were first studied.A finite element model of high temperature bending creep was established based on the ABAQUS finite element analysis software,and the effects of creep temperature and creep time on the stress relaxation behavior and spring back of the profile were studied,and compared with the results of the hot press bending test,it was verified that the model was valid.The results of the research show that the creep temperature and creep time have an important influence on the stress relaxation behavior of TC4 titanium alloy profiles.With the increase of creep temperature and creep time,the internal residual stress of the profile decreases,and the temperature has a more significant effect on the stress relaxation during the creep process.The finite element model of hot stretch-bending forming was established using ABAQUS software,and the influence of forming temperature,pre-stretching amount and friction conditions on the change of profile thickness and forming accuracy in the stretch-bending process were studied.And on this basis,a finite element model of hot-stretch bending and creep forming was established,and the influence of key process parameters such as creep temperature and creep time on forming accuracy was studied.In the process of hot stretch-bending forming,process parameters such as forming temperature,pre-stretching amount and friction conditions have an important influence on forming quality.The higher the forming temperature,the larger the pre-stretching amount,and the smaller the friction coefficient,the higher the forming accuracy.In addition,the temperature and pre-stretching amount have a more obvious influence on the thickness of the profile,and friction conditions have little effect on it.A finite element model of hot-stretch bending and creep forming was established by using ABAQUS software,and the influence of forming process parameters on hot-stretch bending and creep forming was studied.The research results show that,due to the influence of stress relaxation,the friction coefficient and pre-tension have a low impact on the forming accuracy during the hot-stretch bending and creep forming process.The longer the creep time and the higher the creep temperature,the higher the forming accuracy.