Hot Deformation Characteristic And Processing Maps Of FeMnAlC Light Steel

With the rapid development of economy,automobile has gradually become one of the world’s important energy consumables.Researchers found that fuel consumption could be greatly reduced with the reduction of the body mass and developed FeMnAlC-based light steel so nowadays the main research topic of steel is to reduce the density of steel as much as possible with ensuring its performance.In research of new materials,hot deformation is inevitably involved,but the literatures and documents related to the thermal deformation of steel with low density and high intensity are still to be supplemented.Fe-30Mn-10Al-2.3C light steel is studied in this paper.The true stress-true strain curves under certain deformation conditions are obtained by Gleeble-3500 hot compression simulation machine and analyzed.The thermal deformation constitutive equation of the Arrhenius type exponential function equation for this kind of light steel is established and verified.The microstructure of this kind of light steel under different deformation conditions is analyzed by metallographic microscope（OM）,scanning electron microscope（SEM）and X-ray diffraction（XRD）.According to dynamic material model（DMM）,the processing map of this kind of light steel is established,and the optimal hot working process is determined based on the analyzation of microstructure.The result of experiment shows that the flow stress and peak stress of this kind of light steel all decrease with the increase of deformation temperature or decrease of strain rate and that the material exhibits dynamic recrystallization transformation under all deformation conditions in this experiment.The thermal constitutive equation is （?） which can accurately reflect the flow stress characteristics of this kind of light steel because the error between the calculated and experimental value of peak stress under different deformation conditions is small.The analysis of microstructure shows that both deformation temperature and strain rate have great influence on the optimum grain refining of this kind of light steel,and the best grain refinement effect is obtained under the condition of deformation temperature of 1000°C and strain rate of 1s^-1.At low temperature and low strain rate,there is no significant difference between the ferrite phase and the original microstructure.With the increase of deformation temperature and strain rate,the ferrite phase gradually transforms into austenite phase.The analysis of processing map shows that the optimal hot working conditions of this kind of light steel are deformation temperature T=1 004℃ and strain rate （?）=1s^-1.Under these conditions,the maximum power dissipation rate is 62.6%,and dynamic recrystallization takes place in this area.The grains of dynamic recrystallization are distributed finely and evenly.