Formation of Fine Austenite through Static Recrystallization in Low Carbon Micro-alloyed Steels

摘要

The feasibility of further refinement of recrystallized austenite in a low carbon micro-alloyed steel was investigated through warm deformation of the overcooled austenite followed by reheating to the austenite non-recrystallization region. The results showed that static recrystallization of the deformed austenite happened at a higher degree of overcooling due to the increased driving force by warm deformation. The fraction of recrystallized austenite during reheating increased with increasing degrees of overcooling. After warm deformation at 550℃, the fraction of recrystallized austenite reached about 20.9%, and the average grain size was less than 5 μm. In addition, if a second deformation was imposed to the overcooled austenite at 550℃, considerable recrystallization was activated, resulting in a dramatically higher fraction of recrystallized austenite (94.0%) and a finer austenite grain size of 3.3 μm.