Analysis of Strain Hardening Processes of AISI 316 LN Austenitic Stainless Steel

The primary objective of this contribution is to numerically and graphically evaluate engineering stress–strain curves, transform them into true stress–strain curves, and de-scribe the key points of material processed by cold rolling with strains of εRoll = 0%, 10%, 30%, and 50%. The initial and final conditions for uniform plastic deformations have been described. The initial point of uniform deformation lies above the onset yield strength value (σT,S > RP0,2). The necking point, as the final point of uniform deformation, was determined as the intersection point of the curves of the true stress–strain and strain hardening rate. The strain hardening coefficient and the recovery rate, as a function of cold rolling deformations, were derived. Convex polyhedra were derived which describe the dependencies of the development of maximal strain hardening rate values (θMax) and initial strain hardening rates (θ0) as a function of cold rolling deformations and the diameter of grain. The decisive point at which the curves showed a local maximum was a cold rolling deformation εRoll = 30%. The saturation stress required to initiate dynamic recovery of the microstructure is significantly higher than the stress necessary for necking (σT,Sat > σT,Neck). The saturation strain required to initiate dynamic recovery of the microstructure is significantly higher than the strain needed for necking formation (εT,Sat > εT,Neck).