Work hardening, strength and ductility in the hot working of 304 austenitic stainless steel

Abstract

Stress-strain curves, generated through continuous hot torsion tests of as-cast and worked type 304 austenitic stainless steel in the range 1200-:900°C and.0.1-5.0s^-1, were analysed with respect to the characteristics of work harder:mg, dynamic recovery, dynamic recrystallization and ductility. The work-hardemng behavwur was related to the Kocks-Mecking model where the saturatwn stress is due to dynamw recovery Furthermore the associated activation enthalpy ranged from 274 to 392 kJ mole . as the temperature increased. Through sinh analysis, the activation energy was determined to be 393 kJ mole^-1 and was also corrected upwards in consideration of deformatwnal heating. The time-to-fracture criterion was shown to qualitatively represent the hot ductility, which rose with increase in both temperature and stram rate.