Recrystallization Behavior During Warm Compression of Martensite Steels

Abstract

The application of high strength-toughness-ductility structural steels is beneficial to reduce the body weight of automotives and to improve the usage efficiency of energy without any potential damage of safe and security of human beings. Grain refinement is an important fundamental research field for the development of such low alloy structural steels. The conventional thermo-mechanically controlled process (TMCP) of ferrite or ferrite-pearlite steels including severe deformation at a lower temperature of ferrite transformation and rapid cooling is usually utilized to refine the grain size down to about 5 microns. For ferrite/pearlite steels, the grain refinement through dynamic recrystallization was observed to take place at a true strain of 1.2 at 873K, and the fully recrystallized ferrite/cementite microstructure may be realized at a strain of 2.0 (Torizuka, 2005). The final grain size is dependent on the Zener-Hollomon parameter, Z, which is given by