Research On Forming Force Of Radial Expansion-Closed Control Extrusion

Demand for resources is more urgent with the rapid development of modern society.Extrusion, as a method of materials processing with high-energy,is developing toward more refined and more provincial.Reduce the pressing force can effectively reduce energy consumption during the extrusion.Domestic and foreign scholars have proposed many new extrusion technology to reduce the pressing force.A new technology of radial expansion-closed control extrusion has been presented in this context.To study this new technology of extrusion, theoretical analysis-numerical simulation-Experimental verification method is used.According to finite element theory, the billet and die model of radial expansion-closed control extrusion in each phase was established.Based on the result of finite element simulation, analysis the metal flow and stress and strain state of forming process in the new technology.The forming force of the new process and the traditional process were simulated,found that the radial expansion-closed control extrusion process is 68% less than that of conventional extrusion process.By studying the force state and metal flow during the forming process, the forming force calculation formula is established by using the principal stress method and the upper bound method respectively.And an empirical formula is proposed to calculate the forming force.On the basis the formula of the the principal stress method,the influence of the extrusion parameters on the forming force is analyzed.Using Deform-3D software to simulate the influence of variation of friction coefficient,punch radius,working with height, the inner diameter of the billet, extrusion rate, extrusion temperature on extrusion force.Radial expansion-closed control extrusion processing is used to forming aluminum rim.Experimental result shows:Radial expansion-closed control extrusion process caneffectively reduce the pressing force.The calculation of forming force theory and experimental results were compared, the results show that the error of the numerical simulation value,the principal stress method, the upper bound method the empirical value with the measured value is 3.5%, 8.5%, 13.1%, 18.7%, respectively, the calculation of theoretical formula has a good agreement with forming force by measured forming force.This paper provides some references for extension and application of the radial expansion-closed control extrusion processing.