Effect of Dislocation Density in an Unrecrystallized Part of Austenite on Growth Rate of Recrystallizing Grain

Abstract

The growth rate of recrystallizing austenite grains of Si-Mn steels and Nb added steels after hot deformation was investigated by measurement of the fraction of recrystallized austenite and recrystallized austenite grain size. The fraction of recrystallized austenite (X_cr) at which the mechanism of recrystallization changed rrom nucleation and growth (NG) to site saturation (SS) was formulated as a function of Nb concentration and deformation conditions. According to the increase in deformation temperature and strain, X_cr increases while the increase in Nb in solution decreases X_cr.
The growth rate of recrystallizing austenite was also formulated as a function of strain energy (F_v) and Nb concentration. The growth rate decreases rapidly after deformation due to the decrease in F_v. The growth rate also decreases Nb addition.