Effect of niobium on the recovery and recrystallization behavior of low-carbon micro-alloyed steel

The kinetic processes of recrystallization and precipitation in low carbon steels with different Nb contents were studied by stress-relaxation method. The effects of Nb solute drag and its precipitation on the recovery and recrystallization behavior were analyzed by the experiment and theoretical model. When the Nb content increases, the nose temperature of precipitation kinetic curves (PTT) rises, but the time of precipitation corresponding to the nose temperature changes a little, which is about 20 to 30 s. The precipitation can obviously restrain the recrystallization process, and increasing the Nb content makes the non-recrystallized temperature rise. The Nb solute drag can inhibit the mobility of grain boundaries, lead to the decreasing mobility rate of grain boundaries, and finally cause the process of recrystallization retarded. The recrystallized activation energy is linear with the square root of Nb mass fraction.