Simulation Study On Feeding Parameter Change Of Coreless Rod Rotary Forging Of Hollow Shaft Of Car

The rotary swaging process is a near-net forming process with high production efficiency and good forming quality,and is widely used in the production of shaft tubular parts.However,the change of the feed parameters of the hollow shaft of the hollow shaft of the car is unreasonable,which will lead to poor internal and external roundness.Especially when the geometrical defects of the rotary forging occur,the subsequent swaging will increase the folding phenomenon,the fatigue strength of the rotary swaging shaft and The fatigue life is greatly reduced,and it is difficult to meet the product durability requirements.Therefore,it is of great engineering significance to deeply analyze the change of the feed parameters of the mandrel of the hollow shaft of the car and avoid the occurrence of folding defects during the rotary swaging process.In this paper,the coreless rod swaging of a hollow shaft of a car is taken as the research object.Since the coreless rod is not forged by the core without the core rod,the forming quality is difficult to control.Therefore,as the outer diameter of the coreless forging is reduced and the mechanical properties are changed,the coarse,medium and fine feed passes are divided according to the feed amount at different outer diameters.The main research contents of this paper are as follows:(1)The constraint conditions of the coreless forging feed parameters are proposed as stress constraints and geometric constraints.The stress constraint combines the mechanical properties of the blank with the work hardening characteristics to avoid damage caused by excessive radial feed and affect subsequent processing.Geometric constraints avoid geometrical defects in the inner circle under excessive radial feed and multi-pass radial feed.(2)The radial feed range is determined by stress constraint and geometric constraint.The inner circularity control avoids geometric defects and forging efficiency to determine the radial feed pass;the circumferential feed is determined by the maximum deformation and minimum deformation position of the outer circle to ensure Each part of the billet is subjected to forging and internal and external roundness quality requirements as well as forging efficiency to determine the circumferential feed pass.Radial and circumferential process parameter variation matching was developed at different outer diameters.(3)The whole process simulation of the coreless rods is carried out for the change of the feed parameters,and the foreign process parameters and physical section dimensions are compared.It shows that the feed parameters have been changed reasonably,which can be used for the next trial production and at the same time for China to master the hollow shaft of the car.The change of process parameters of coreless bar forging is important to avoid the problem of rotary forging.