The Research On The Model Of Austenitid Transformation And Temperature Coupling For Hot Rolled Strips During Cooling Process

In this paper, the author aims to depict the process of austenitic transformation exactly. The author chooses the model of austenitic transformation and temperature coupling as research subject. On the basic of the transformation kinetics model and latent heat calculation model, a new model of austenitic transformation and temperature coupling is established.The equilibrium composition, total driving forces for transformation and transformation start temperatures in deformed austenite→ferrite transformation of Fe-C-Mn alloys were calculated by using of the regular solution sub-lattice model at orthoequilibrium and paraequilibrium.On the basis of transformation kinetics, the transformation volume fraction has been researched through the theory of nucleation and growth. The idea can embody transformation's essential much better, the final transformation compositions include ferrite,pearlite and bainite.The latent heat is obtained by subtracting the enthalpy contribution of specific heat from the total enthalpy change of the system before and after transformation which were calculated by using of the regular solution sub-lattice model. The calculation results would be testified by the DSC experiment.The volume fraction and the temperature iterative calculated by the two-dim unstable temperature fields to establish a new model of austenite transformation and temperature coupling. By comparing three phases volume fraction are obtained by kinetics model,coupling model and the experiment,the superiority and the accuracy of the coupling model can be testified.