| In this paper,Q460 E steel is taken as the research object.Through the study of the new creep straightening curve,the expression of the strain rate of the straightening curve is derived,that is,the expression of the deformation rate during the straightening process of the continuous casting billet.Then the creep constitutive relation of Q460 E steel was established,and the creep constitutive equation was established by norton-power.The Q460 E creep rate equation was fitted.The creep rate and the deformation rate of continuous casting billet were compared,and the proportion of creep deformation and plastic deformation in the straightening process of continuous casting billet was determined.By simulating the temperature field of the slab,the temperature distribution during the straightening process is obtained,and the thickness change of the shell is analyzed according to the temperature field.Based on the viscoplastic theory,the theoretical calculation equation for the straightening force of the continuous casting billet is established,and the simulation results of the straightening force of the continuous casting billet are obtained by the finite element simulation method.The theoretical results are compared with the simulation results to verify the correctness of the theoretical deduction.First,the high temperature creep tensile test was carried out by the Gleeble3800 thermal simulation test machine.The high temperature creep characteristics of Q460 E steel were analyzed.The thermal plasticity and the high temperature mechanical properties of Q460 E steel were obtained.The creep and creep rate under different temperatures and different stresses were obtained.The experimental data were processed and the creep rate equation was obtained.Secondly,the two-dimensional finite element model of billet is set up,the cooling process in the casting process is analyzed,the process parameters are determined,the temperature field of the continuous casting billet is simulated,and the change of the shell thickness of the continuous casting billet is obtained according to the temperature field,and the integral interval of calculating the bending moment in the theoretical calculation of the straightening force is determined.According to the expression of creep straightening curve,the expression of strain rate in straightening process of continuous casting billet is derived by means of the limit method.The change of strain rate in straightening process of continuous casting billet is obtained according to the derived creep rate.Finally,by using the elastoplastic constitutive model and the creep model,the formula of straightening force based on the viscoplastic theory is derived,and the analytical solution of the straightening force is calculated based on the selected creep straightening curve.The three-dimensional model of continuous casting machine is established by Marc finite element analysis software.The cooling condition of billet and the smooth friction of the billet are added.The simulation analysis of the bending and straightening process of the continuous casting billet is carried out.The simulation results of the straightening force of the continuous casting billet are obtained.The comparison is made with the analytical solution,and the calculation of the continuous casting billet based on the viscoplastic theory is proved.The accuracy of direct force. |
PDF Full Text Request