Kinetic analysis of the austenitic grain growth in HSLA steel with a low carbon content

The austenitic normal grain growth of the 16MnNi4 HSLA steel has been investigated by means of the simplified kinetic model developed by Burke and Turhbull. The equation involved in the model allows the setting of a correlation between the kinetic parameters and the microstructure features of the materials. The grain growth exponent (n) has been studied to interpret the mechanism of grain growth in the samples with different heat treatments. It was noted that the kinetic n exponent value increases when the temperature decreases. The variation in the n values (from 2 until 8) has been associated with the solubility or precipitation of the different microalloyed elements presented in the HSLA steel. Also, the activation energies have been calculated obtaining different values depending on the heat treatment.