Abstract: By using isothermal double hit compression tests and applying the 2% offset method, a new model was developed to predict the microstructural evolution of Nb-bearing steels at temperatures above and below the start temperature of strain-induced precipitation (TP). The TP was developed as a function of true strain, initial austenite grain size and the Nb content. The activation energy of static recrystallization (Qrex) was expressed as a function of the content of different alloy elements. It was found that Nb played the most important role in increasing the value of Qrex. The microstructural observations and measurements confirmed the validity of the model developed in the present investigation.

Key words: Nb-bearing steel, static recrystallization