Martensite Leaves Steel 403nb The Recrystallization Kinetics

It has become a hotspot on the research in computer simulation of the microstructure evolution during thermal deformation, and the study on the relationship between microstructures and mechanical properties. This paper is a part of Microstructure Evolution and Control Theory of Special Alloy and High Alloy Steel during Hot Continuous Rolling Process, which is the key project of the National Natural Science Foundation of China (No.50634030) undertook together by Northeastern University and China Iron & Steel Research Institute Group. Dynamic recrystallization, meta-dynamic recrystallization, static recrystallization behaviors and the size of recrystallized grains of Rolled Pieces during hot continuous rolling has mainly researched. It is the preliminary preparation for the process route optimization of hot continuous rolling to ensure mechanical properties and surface qualities by real-time simulation, which is also the fundamental work of the microstructures and properties forecast system of high alloy steel hot continuous rolling.The following is the basic research of the preliminary preparation for the microstructures and properties forecast system of high alloy steel hot continuous rolling. Single-pass and double-pass hyperthermia thermo-simulation compression experiment of Martensitic blade 403Nb steel are tested respectively on the Gleeble-3500 thermo-mechanical to calculate and establish the model of dynamic recrystallization, meta-dynamic recrystallization and static recrystallization of 403Nb steel. Then the microstructure evolution rule of compressed sample is analyzed by optical microscope, scanning and transmission electron microscope and X-ray diffraction method.The model of recrystallization has been established, and the conclusions are drawn as follows:The parameter expression of Z, Peak Stress, Activation Energy and Dynamic Equation of403Nb steel under hyperthermia thermo-simulation compression: The parameter expression of Model of static recrystallization, Model of grain size and Activation Energy of recrystallization:The parameter expression of Dynamic Model of meta-dynamic recrystallization and Activation Energy of recrystallization:The growth rate of static recrystallization ratio is the most stable under the strain rate of 1s-1 in403Nb steel. It is not unlimited developed with the prolongation ofpass interval, but the grains grow significantly, and the trend of dynamic recrystallization is reduced when pass interval increased to the certain value. There are two kinds of fine precipitates, M23C6 and NbC in 403Nb steel, which is dispersive distribution to effectively inhibit recrystallization and grain growth.