Hot deformation behavior and microstructural evolution of 316 austenitic stainless steel

The tensile behavior of 316 austenitic stainless steel was investigated over a temperature range of 850–1050°C and strain rates from 10⁻3 to 10⁻1 s⁻1 to explore the interplay between dynamic recovery (DRV) and dynamic recrystallization (DRX). Flow stress and strain hardening behavior were characterized and correlated with microstructural evolution using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). At 850–950°C, DRV dominated across all strain rates, although heterogeneous discontinuous DRX nucleated at grain boundaries and triple junctions. Above 950 °C, partial DRX was evidenced by the formation of fine, strain-free grains with high-angle boundaries, which subsequently developed into coarser grains at higher temperatures. A fully recrystallized microstructure with an average grain size of ~ 16 µm was achieved at 1050 °C and a strain rate of 10⁻1 s⁻1. EBSD microtexture analysis revealed a transition from a ⟨111⟩ fiber texture to a ⟨100⟩ fiber texture with increasing temperature for all strain rates. This transition is strongly associated with the growth of strain-free grains during dynamic recrystallization, leading to the formation of cube orientation and texture randomization. At 1050°C, the microhardness decreased to ~ 152 Hv, slightly lower than that of the as-received material in a fully annealed condition (~ 158 Hv). This hardness reduction is consistent with DRX-induced strain softening observed during tensile deformation in the 1000–1050°C temperature range.