Modelling of Precipitate and Austenite Evolution during Hot Working of Nb-Microalloyed Steels

摘要

The computer model for prediction of the precipitation behavior duringthermomechanical control processes has been developed, in order to control the precipitation during and after processing. The proposed model is based on the classical nucleation theory and the kinetics of growth controlled by diffusion of Nb. The routine requires input of steel chemistry and a starting grain size after austenitization together with temperature, strain and the contants for precipitate nucleation rate. The precipitation behavior of Nb(C,N) in deformed and undeformed austenite as well as static recrystallization characteristics in the 0.03%Nb-(Ti)-N-microalloyed steels have been determined on the base of systematic experimental investigations. These have been compared with the computer routine calculation of strain induced Nb(C,N) precipitate and austenite (recrystallization) evolution.