Research On Technology And Mechanism Of Rotary Forging For Components With Cross Ribs And Thin Webs

The component with cross ribs and thin webs has the advantages of light weight,high stiffness and strength,strong bearing capacity and mechanical stability.It is widely used in automobile,weapon equipment,aerospace and other industries.The component with cross ribs and thin webs is a kind of part with different mesh ribs on thin webs.At present,the main machining methods are milling,precision casting,welding,etc.However,these processes will lead to many serious defects such as waste of materials,high processing cost,poor performance and low service life.High-performance component can be manufactured with efficiency and low cost by traditional forging process.However,the component with cross ribs and thin webs will not be directly formed due to the shortage of poor forming load and difficulty of filling.At the same time,the rotary forging is a kind of the local plastic forming process which can greatly reduce the forming load and improve the filling quality of the stiffened plate.Therefore,a rotary forging process for the component with cross ribs and thin webs is presented in this paper.Firstly,the point-to-point correspondence equation of the non-rotating part to the non-rotary die is established by the rotation matrix method.The initial model of the nonrotary die is established according to the corresponding relation of the points.Subsequently by using the motion equation of non-rotary die,the position and the corresponding degree of interference of the non-rotary die on the component with cross ribs and thin webs during the rotary forging process are located.The results showed that the middle part of the inner rib is the most serious.According to the size of the interference on surface,the correction model of the non-rotary die is obtained.Secondly,based on the Deform-3D finite element simulation software,the rotary forging process of the component with cross ribs and thin webs was simulated,the law of metal flow and temperature field in the process of rotary forging is studied.It is determined that the filling discontent of the component occurs in the middle of the inner reinforcement and the corner of the outer wall,and the causes are analyzed.The effects of different process parameters(friction factor,feed per rotation,rotary angle)on filling property and forming load are investigated.The results show that the increase of friction factor can promote the filling of the middle part of the inner reinforcement,and the increase of the feed per rotation and rotary angle is beneficial to the filling at the corner of the outer wall.With the increase of friction factor and feed per rotation,the load of rotary forging increases gradually.With the increase of rotary angle,the forming load decreases gradually.Through the comparison of the experiment and the simulation results,the forming results are in good agreement,and the reliability of the finite element simulation of the component with cross ribs and thin webs by rotary forging process is verified.Finally,a simplified metal flow model of the component with cross ribs and thin webs combined with the principal stress method is used to analyze the plastic instability and piercing defects in the rotary forging process.The criteria of plastic instability and piercing defects are verified by finite element analysis.