After the recrystallization process, the growth of newly formed grains starts. Large grains grow at the cost of crystallized fine grains. Higher the steel annealing temperature and higher will be the driving force for the growth process. This driving force is associated with grain boundaries. With an increase in grain boundary area to increased grain size gives lower total energy per unit area.
In the case of strain-free metals, the growth process in normal grains starts earlier as the temperature is inputting large free energy in grain boundaries.
This growth process continues until phase transformation takes place in steel at the A1 line.