Modelling the kinetics of strain induced precipitation in Nb microalloyed steels

Strain induced precipitation is a key phenomenon that controls the microstructure evolution during the finish rolling stages of microalloyed steels. Extensive research has shown that the precipitation of Nb(CN) delays the onset of recrystallisation. This paper presents a model to describe the precipitation kinetics during isothermal holding following high temperature deformation in Nb-containing steels. The model is based on the assumption that heterogeneous nucleation of precipitates on dislocations and enhanced coarsening due to pipe diffusion are responsible behind the accelerated kinetics observed in strain induced precipitation. Results show a very good agreement between reported experimental observations and predictions of the present model for precipitate size and volume fraction evolution.