Flow behavior and microstructural evolution during hot deformation of AISI Type 316 L(N) austenitic stainless steel

Type 316 L(N) steel was deformed to 10%, 30% and 50% engineering strain under hot compression at strain rates of 0.1 and 1 s−1 in the temperature range 1073–1273 K (at steps of 100 K). This paper mainly deals with two aspects: (a) to describe the flow behavior through a suitable constitutive equation and (b) to evaluate the critical condition for onset of dynamic recrystallization (DRX) through work hardening analysis and to corroborate the same with those obtained from a detailed microstructural study. The steel exhibited a strong dependence of work hardening on temperature as well as strain and the modified Zerilli Armstrong model could predict the flow stress which was reflected by a lower average absolute error (3.22%) and a higher correlation coefficient (R = 0.99) for the entire investigated hot working domain. The critical condition for the initiation of DRX was met only for the specimen deformed to 50% at 1273 K/1 s−1. This specific condition revealed the nucleation of necklace DRX grains and was in agreement with the work hardening analysis which showed that the critical strain is achieved at true plastic strain of 0.45.

► 316 L(N) was compressed to 10%, 30% and 50% at 0.1, 1 s−1 in the range 1073–1273 K.
► Flow behavior and critical condition for the onset of DRX have been evaluated.
► Modified Zerilli Armstrong model could predict flow stress in the entire domain.
► θ–ɛ showed that critical strain for DRX is met at ɛ = 0.45 for 50% at 1273 K/1 s−1.
► This observation was corroborated with the nucleation of necklace DRX grains.