Static Recrystallization Mechanism of LZ50 Steel and Cellular Automata Simulation

Abstract：Although LZ50 steel is a classic axle steel, there are many deficiencies in the research of microstructure evolution in the forging process.In order to investigate the influence of process parameters on the evolution of microstructure, the static recrystallization behavior of LZ50 steel is analyzed by double-pass hot compression test on Gleeble-3500 thermal simulation machine.It is found that the static recrystallization volume fraction is higher at high temperature, high strain and high strain rate.Temperature and strain have a great influence on the static recrystallization volume fraction.The static recrystallization kinetics model isconstructed according to the stress-strain curve.The simulation results of cellular automata are consistent with the experimental results, which can predict the static recrystallization behavior of LZ50 steel.It can be seen from the simulation that the higher temperature is, the faster new grain growth rate will be, however, the higher strain or strain rateis, the faster the nucleation will be.The electron backscatter diffraction (EBSD) technique is used to analyze the microstructure orientation of LZ50 steel after deformation.The nuclei of static recrystallization forms by bulging of initial grain boundaries.There is a difference in dislocation density onboth sides of original grain boundary.The grain boundary will migrate to the side with high dislocation density to promote the generation of new nuclei.The obtained evolution law of the organization has guiding significance for production and processing.