Dynamic recrystallization behavior in a low-carbon martensite steel by warm compression

The dynamic recrystallization behavior during warm compression for a low carbon martensite steel was investigated to make clear the effects of initial martensite block size, compression strain and pre-tempering before compression. It is found that the average size of recrystallized ferrite grains is influenced neither by the initial martensite block size (austenitizing temperature) nor by the amount of compression strain. The pre-tempering before compression shows two competitive effects: cementite particles precipitated during pre-tempering at 600 degrees C promotes the occurrence of dynamic recrystallization while the decrease in dislocation density during pre-tempering at a higher temperature delays the dynamic recrystallization. Dispersed cementite particles suppress ferrite grain growth. Hence, there is an optimum tempering condition before warm-compression in order to obtain fine grained microstructure.