Kinetics and Critical Conditions for the Initiation of Dynamic Recrystallization in 304 Stainless Steel

Commercial 304 austenitic stainless steel was deformed in compression at high temperatures (800 to 1 280°C) and at strain rates from 0.001 to 1 s - 1 . The critical and peak strains associated with dynamic recrystallization were determined based on changes in the work hardening rate as a function of the flow stress. The effect of the deformation variables (T, e) on these values is analyzed; it is shown that over a range of temperature corrected strain rate (Z=10 1 4 to 10 1 6 s - 1 , Q d e f =405 kJ/mol), the initiation of dynamic recrystallization is delayed. This retardation is attributed to the segregation of substitutional impurity elements, principally phosphorus, to the sub-boundaries of the newly-forming DRX grains.