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

Abstract

The true stress (s) ± true plastic strain (e) data of a type 316LN austenitic stainless steel tested at nominal strain rates in the range 3610 25 ± 3610 23 s 21 and temperatures of 300 ± 1123 K were analysed in terms of ¯ow relationships proposed by Hollomon, Ludwik, Swift, Voce, and Ludwigson. The applicability of the particular ¯ow relationship is discussed in terms of `complete' and `applicable' range ®ts of the experimental s ± e data. At all strain rates, in the case of the complete range ®t, the Ludwigson equation followed the stress ± strain data most closely at 300 K, while in the temperature range 523 ± 773 K, the ¯ow behaviour was described equally well by both the Ludwigson and Voce equations. In the temperature range 823 ± 1023 K, the Voce equation described the ¯ow behaviour most accurately in the case of the complete range ®t of s ± e data at all strain rates. The analysis of s ± e data employing the Ludwigson equation in the applicable range ®t covering low and intermediate strains, and the Hollomon equation at high strains provided close simulation of the observed ¯ow behaviour in the temperature range 823 ± 1023 K. At high temperatures of 1073 and 1123 K, the Ludwigson equation reduces to the Hollomon equation. The variations in different ¯ow parameters of the Ludwigson and Voce equations with temperature and strain rate exhibited anomalous behaviour at intermediate temperatures because of dynamic strain aging.MST/4679

Comparative tensile flow and work hardening behaviour of thin section and forged thick section 9Cr–1Mo ferritic steel in the framework of Voce equation and Kocks–Mecking approach

“…8) and hr-r and in the variations of work hardening parameters associated with Voce equation (Figs. 9-11) and K-M approach with temperature observed for plate and tubeplate forging are in agreement with those reported for ferritic and austenitic steels [11][12][13][14][15]24].…”

“…However, tubeplate forging displayed higher e U values than the plate material as well as the predicted e U,Voce values in the temperature range 300-873 K. Such a correlation observed for ductility values is in agreement with that reported for high strength low alloy steel[11]. The observed equivalence of initial stress, saturation stress and true uniform plastic strain values predicted by Voce relation with the respective experimental values (Figs [13][14][15]. further suggest that the flow and work hardening behaviour of 9Cr-1Mo steel is adequately described by Voce equation.5.4.…”

“…n V describes the rate at which the stress from its initial value tends to reach steady state or saturation stress value [6]. The applicability of Voce relationship for describing stress-strain behaviour useful for engineering applications has been demonstrated for ferritic, pearlitic-ferritic and austenitic stainless steels [11][12][13][14][15]. In the Kocks-Mecking phenomenological approach [7,8], the evolution of dislocation structure with strain at constant strain rate is assumed as a single structural parameter responsible for plastic flow.…”

Applicability of Voce equation for tensile flow and work hardening behaviour of P92 ferritic steel

“…9e12) for P92 steel are in agreement with those reported for 9% Cr ferritic steels [22,23,27]. The observed three temperature regimes in P92 steel also compare favourably with those reported for the flow and work hardening behaviour of austenitic stainless steel [29,30]. The grouping of s-ε and q-s in a narrow band and the occurrence of peaks/plateaus rather than a monotonic decrease in work hardening parameters along with negative strain rate sensitivity on initial and saturation stresses at intermediate temperatures indicate anomalous flow and work hardening behaviour in the steel.…”

Work-Hardening Behavior of the Ni-Fe Based Superalloy IN718

“…Ludwigson and Voce relationships are known to describe the flow behavior of materials, exhibiting similar nonlinear behavior of log r vs log e p , such as Nimonic 263 and austenitic stainless steels. [20][21][22] The Ludwigson equation is simply a best-fit mathematical model based on the deviation of stress at low strain from that resulting from extrapolation of the linear high strain data. The physical interpretation of flow curve parameters has been given earlier.…”