炭素鋼における動的再結晶オーステナイトの静的軟化

抄録

The static softening processes taking place after dynamic recovery (DRV) and dynamic recrystallization (DRX) were studied by means of interrupted tensile tests for a 0.4%C-1.5%Mn steel at a temperature-compensated strain rate Z. The softening curves associated with DRV matrices (ε=0.1) consist of two stages followed by complete softening, in which (i) classical recovery and (ii) classical recrystallization take place in sequence. By contrast, the softening curves in a full DRX structure (ε=0.26) consist of three distinct stages with each inflection plateau, followed by incomplete softening. These can be controlled mainly by (i) metadynamic recrystallization, (ii) metadynamic recovery and classical recrystallization, and (iii) grain growth. The activation energy for the softening in stage 2 nearly equals that for dynamic recrystaIlization, which is clearly smaller than that for static recrystallization. It is concluded that all stages of softening after DRX can be strongly affected by the existence of growing DRX grains having no potentiality for classical nucleation and the role of metadynamic recovery taking place within them.