1995 Volume 35 Issue 2 Pages 210-216
Effect of carbon content on the static softening taking place in hot deformed austenite was studied by means of interrupted tension and compression tests at a temperature of 1133 K and at a strain rate of 2×10-3s-1 for plain carbon steels. The softening curve after dynamic recovery (DRV) consists of two stages, followed by complete softening. In contrast, the softening curve after dynamic recrystallization (DRX) consists of three distinct stages accompanied with three plateaus, followed by incomplete softening. These can be controlled by metadynamic recovery (MDRV) and recrystallization (MDRX) in addition to classical static recovery (SRV) and recrystallization (SRX). The static softening taking place after DRX sensitively depends on the volume fractions of DRX nuclei, growing DRX grains and fully work heardened DRX grains. The increasing in the fractions of DRX nuclei and growing DRX grains causes the amount of rapid softening in stage I and incomplete softening in stage III to increase, respectively. The static softening rates on DRV and DRX matrices increase with carbon content because of the increased diffusivity of vacancies, which can promote the operation of static restoration mechanisms, i.e. SRV, SRX, MDRV and MDRX.