Influence of temperature and post weld heat treatment on tensile stress–strain and work hardening behaviour of modified 9Cr–1Mo steel

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

“…7) and in the variations of work hardening parameters associated with Voce equation (Figs. 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].…”

“…Also, rapid increase in n V,Voce (Fig. 11) [22,23]. A change in controlling mechanism from cross-slip to dislocation climb and subboundary migration at high temperatures leads to high n V,Voce values [22,23] as observed in the present investigation.…”

“…11) [22,23]. A change in controlling mechanism from cross-slip to dislocation climb and subboundary migration at high temperatures leads to high n V,Voce values [22,23] as observed in the present investigation. The dominance of dynamic recovery in terms of climb of dislocations and subboundary migration as controlling deformation mechanism at high temperatures is further demonstrated by correlating applied strain rate dependence of saturation stress [40] or steady state stress with stress dependence of minimum creep rate obtained for the steel.…”

“…One of the important gains from the applicability of Voce equation has been shown by the equivalence between the predicted flow parameters such as initial and saturation stresses with the respective strength values obtained from the tensile test [22,23]. It has been suggested that the use of Voce equation as a single flow relationship to describe the true stressetrue plastic strain behaviour in P9 and P91 steels for the entire temperature range of interest is useful for engineering applications [22,23].…”

“…One of the important gains from the applicability of Voce equation has been shown by the equivalence between the predicted flow parameters such as initial and saturation stresses with the respective strength values obtained from the tensile test [22,23]. It has been suggested that the use of Voce equation as a single flow relationship to describe the true stressetrue plastic strain behaviour in P9 and P91 steels for the entire temperature range of interest is useful for engineering applications [22,23]. In this paper, the applicability of Voce equation [6] for describing the true stress (s)-true plastic strain (ε) behaviour of P92 ferritic steel has been examined for the strain rates ranging from 3.16 Â 10 À5 to 1.26 Â 10 À3 s À1 over a temperature range 300e923 K. The work hardening behaviour has been investigated in terms of the variations of instantaneous work hardening rate (q ¼ ds/dε) with true stress for the range of temperatures and strain rates used in this study.…”