Strain Rate Sensitivity Behaviour of a Chrome-Nickel Austentic-Ferritic Stainless Steel and its Constitutive Modelling

Abstract

In the present investigation, the plastic flow curves and work softening behaviour of a dual phase Fe-Cr-Ni alloy during hot deformation (low to intermediate temperature range, 948 K (675°C) to 1 248 K (975°C)) along with concurrent microstructural development were investigated. The flow stress increased with the increase in strain rate and decreased with the increase in deformation temperature. The single peak characteristic appearing in all the flow curves indicated that dynamic recrystallization (DRX) was the dominant softening mechanism in the later stage of deformation. The critical strain for DRX initiation was ε c = 0.632ε p and the peak strain (ε p ) were expressed through the Zener-Hollomon parameter (Z). For flow stress modelling, an Arrhenius type constitutive model was established to predict the flow stress behaviour during hot deformation. The results showed that the calculated flow curves agreed reasonably well with the experimental results. The microstructural analysis using optical microscopy indicated that all the deformed structures exhibited elongated grains similar to that of parent microstructure and some equiaxed grains (resulting from DRX in the austenite phase). The fraction of equiaxed grains (in austenite) increased with the deformation temperature. At low Z, the ferrite phase accommodates the strain and dynamic recovery was the prominent restoration process. At high Z, austenite controlled the deformation mechanism and DRX was the likely cause for microstructural refinement. The iso-strain rate sensitivity (m) contour map was used to determine the optimum regime of high temperature workability.

Hot Compression Behavior of 18Cr–11Mn–0.06Ni–0.19N High‐Mn Ultralow Nickel Duplex Stainless Steel under Large Deformation

“…The following is the calculation and fitting process of the general Arrhenius constitutive equation, which uses peak stress calculation. [ 35 ] Putting Equation (9) and (10) into Equation (8) and taking the natural logarithm obtains Equation (12) and (13). The relationship curves between for ln …”

Flow Stress of Duplex Stainless Steel by Inverse Analysis with Dynamic Recovery and Recrystallization Model

“…Emami et al 6) investigated the behaviors of the austenite and ferrite phases in SAF2205 duplex stainless steel and reported that dissimilar behaviors occurred owing to the SFE. Kumar et al 7) reported that DRV is the prominent restoration process in ferrite with low values of the Zener-Hollomon parameters, whereas DRX is the prominent process in austenite with high values of the parameters.…”

“…( 5) and ( 6) can be expressed by the strain and strain rates, as shown in Eq. (7). Finally, applying Eqs.…”

Numerical analysis of flow behaviour, grain size prediction and experimental verification of hot rolled ultralow carbon niobium microalloyed steel

“…As an alternative, dual-phase steel can be economically produced by hot deformation method starting with an austenitic microstructure followed by quenching [9]. Compact slab production technology offers an economic way to produce a hot rolled strip with characteristics comparable to those of a cold rolled material [10]. It combines steel making, steel refining, and thin slab caster with direct hot rolling to reduce production cost [11].…”