In the present work, to improve the workability of a 0.19C-1.54Si-1.52Mn (mass%) high-strength TRIP type multiphase (TMP) steel used warm forming, the effects of forming rate and forming temperature on mechanical properties in torsion were investigated. The TMP steel for a solid cylindrical specimen which was subjected to a torsional moment at one end was investigated at torsional strain rates between 0.002s^<-1> and 0.8 s^<-1>, and temperatures between 20℃ and 250℃. The shearing strain did not constantly depend on the torsional strain rate though the high strain rate of TMP steel decreased the maximum shearing stress, and raised the shearing yeild stress in the torsion characteristic at the room temperature. Furthermore, the torsional strain was increased by warm forming at about 150℃, at which the strain-induced transformation of retained austenite was suppressed most.
TRIP鋼のねじり特性
