Using hot torsion tests, the dynamic (DRX), static (SRX) and metadynamic (M
DRX) recrystallization characteristics of a Nb-microalloyed steel were stud
ied. The torsion tests were carried out at temperatures in the range 850 to
1 050 degreesC with strain rates ranging from 0.5 to 5/sec. At the higher
temperatures, the Nb remained in solution, while precipitation was underway
in the lower temperature range. The results indicate that Nh precipitation
has little influence on the value of the critical strain (epsilon (c)) for
dynamic recrystallization. The peak strain/Zener-Hollomon parameter equati
on is derived and the effect of austenite grain size on the peak strain is
considered. The times for 50 % recrystallization for static and metadynamic
recrystallization were established by means of interrupted torsion tests a
nd are compared. The rate of metadynamic recrystallization increases With S
train rate and temperature and is observed to be independent of the pass st
rain; this contrasts sharply with the observations for static recrystalliza
tion. Finally, an example is given of an industrial rolling process in whic
h DRX/MDRX can play important roles. Here, the occurrence of dynamic/metady
namic recrystallization causes the load to drop or else to increase less ra
pidly than in the case of pure strain accumulation in the absence of SRX.