Tensile stress-strain and work hardening behaviour of 316LN austenitic stainless steel

The true stress (sigma)- true plastic strain (epsilon) data of a type 316LN austenitic stainless steel tested at nominal strain rates in the range 3x1 0(-5)-3x10(-3) s(-1) and temperatures of 300-1123 K were analysed in terms of flow relationships proposed by Hollomon, Ludwik, Swift, Voce, and Ludwig son, The applicability of the particular flow relationship is discussed in terms of 'complete' and 'applicable' range fits of the experimental sigma-e psilon data. At all strain rates, in the case of the complete range fit, th e Ludwigson equation followed the stress - strain data most closely at 300 K, while in the temperature range 523-773 K, the flow behaviour was describ ed equally well by both the Ludwigson and Voce equations. In the temperatur e range 823-1023 K, the Voce equation described the flow behaviour most acc urately in the case of the complete range fit of sigma-epsilon data at all strain rates. The analysis of sigma-epsilon data employing the Ludwigson eq uation in the applicable range fit covering low and intermediate strains, a nd the Hollomon equation at high strains provided close simulation of the o bserved flow behaviour in the temperature range 823-1023 K. At high tempera tures of 1073 and 1123 K, the Ludwigson equation reduces to the Hollomon eq uation. The variations in different flow parameters of the Ludwigson and Vo ce equations with temperature and strain rate exhibited anomalous behaviour at intermediate temperatures because of dynamic strain aging.