Based On The Rapid Shear Extrusion Deformation Q345 Steel Constitutive Relation Research

Endless rolling technology is one of the most advanced rolling technology on current international.The key of Endless rolling technology is the connection of the metal,the commonly metal connection method to achieve the purpose of scale casting connection by induction welding,or laser welding at present,which has the disadvantage of high energy consumption,low efficiency,difficult to remove welding etc.,so the popularization and application of the rolling technology is affected to a certain extent.To overcome these problems,a new type of metal joining technology is developed,that is:Intermediate billet solid connection fast shear extrusion connection technology,which compared with the traditional rolling process,make the connection time shorten,and the connection process is simplified,thereby enhancing production efficiency,reduce production costs.The study on stress strain constitutive mode of material at high temperature and rapid shear extruding lay a theoretical foundation for the development and application of intermediate billet solid state fast shear extrusion connection technology of endless rolling.In this paper,the constitutive relation of Q345 steel is established by using Cook and Johnson constitutive model.The tensile and compression tests of Q345 steel were carried out at room temperature?t=25??and high temperature?900?--1100??under different strain rate(10^-3/s-2.5×10³/s)by using Gleeble and Split Hopkinson pressure bar test,and the band gap of quasi static tensile experiment of Q345 steel was carried out by useing the electronic universal test machine?MTS?.Using the least square method fitting Johnson-Cook constitutive model parameters by analyzing the experimental results of the mechanical properties of Q345 steel,which respectively were:yield strength A,strain hardening parameters B,n,strain rate effect parameters C,temperature effect parameter m,and invalid parameters D₁?D₂?D₃?D₄ and D₅.The fitting results will be parameter modification.The intermediate billet solid connection process of headless rolling technology is used to numerically simulate by means of finite element simulation software DEFORM and Q345 Johnson-Cook constitutive equation.The experimental data and the simulation data are approximate,errors are within an acceptable range,which verifies the accuracy of the model parameters.The research results of this paper have a certain reference value for studying the deformation mechanism of metal plate in high temperature and fast shear extrusion,which laid a theoretical foundation for metal materials of solid connection technology.