Cause Analysis And Control Research Of Extrusion Forming Defects Of Branch-type Forgings

Branch-type forgings have structural diversity which can connect multiple components,bear large loads,and transmit torque,and have a wide applications in defense industry,automotive industry,energy field,and aerospace field.For adapting to the complex working environment,the requirements of parts mechanical properties are very strict,and most of them are formed by extrusion process.In order to avoid defects during forming process and produce high-quality forgings,it is necessary to study the causes and its control methods of forging defects.The defects in the extrusion forming process of branch-type forgings have been taken as the mainly research object in this dissertation,and the defect forming mechanism and the law of the influence of main process parameters have been explored on the defects of branch-type forgings.Firstly,a numerical simulation model of branch-type forgings is established through the DEFORM-3D software platform.Through the analysis of the metal velocity field,equivalent stress,and folding angle of the forging,the metal flow law and defect formation mechanism during the extrusion deformation of the forging are clarified.Secondly,the finite element numerical simulation is used to study the influence of the distance from the end of the branch to the round surface of the punch,the size of the punch,the cross-section size of branch,the size of the blank,the extrusion speed of the punch and other parameters on the metal mesh streamline and forming defects,and analyze the defects produce critical conditions.Thirdly,through the construction of orthogonal experiment and BP neural network model,the prediction model of the degree of influence of main parameters on defects is obtained.Finally,based on the results of the finite element simulation,the experimental study of branch forgings was carried out to obtain the metal flow law of extrusion forming of branch-type forgings,further clarify the forming mechanism of defects,and verify the accuracy of numerical simulation analysis and network prediction model.After studying the forming defects of branch-type forgings,this paper constructs a prediction model of forging defects,which provides a reliable theoretical reference for manufacturing sophisticated and flawless branch-type forgings.