Dynamic and Static Recrystallization Behavior of Low Carbon High Niobium Microalloyed Steel

The recrystallization behavior of a low carbon high niobium microalloyed steel was investigated using continuous and interrupted hot compression tests. The results showed that the initiation of dynamic recrystallization (DRX) could be detected from inflection in the plot of the strain hardening rate against stress regardless of the stress peak appearance. According to the Zener-Hollomon parameter equation, the activity energy of DRX (Q(def)) was obtained and a new modified expression calculating Q(def) was proposed in consideration of the chemical composition of experimental steel. Applying the 2% offset method, the static softening fraction was determined. The graphic representation of the softening fraction vs interruption time gave the information about the non-static recrystallization temperature (about 1 000 degrees C) and the relationship of precipitation-time-temperature. Static recrystallization kinetics followed the Avrami's law at high deformation temperature, and different values of the exponent m were given to illustrate the effect of niobium element on static recrystallization at different deformation temperatures.