The Effect of Temperature and Strain Rate on the Tensile Deformation Behaviour of Austenitic Steel

Tensile deformation behaviour of Fe-Cr-Ni and Fe-Mn-Cr austenitic steels with various combinations of carbon and nitrogen contents was determined by means of tesile testing in the range of temperatures from room temperature to 700°C with various strain rates.Tensile strength and yield strength of low carbon austenitic steel decrease gradually as the temperature increases and austenitic steel with carbon content of more than 0.3wt% shows a rapid increase of work hardening rate in the temperature range from room temperature to 200°C and in this temperaturc range, serration is observed in stress-strain curves. It is assumed that this serration is associated with the interaction of interstitial atoms (such as carbon) and dislocations. When temperature reaches 450°C, another type of serration appears, but this serration gives a smaller work hardening rate compared with the one observed at temperatures from room temperature to 200°C. This observation proves that serration is closely related with tensile deformation behaviour.