Hot Deformation and Recrystallization Mechanisms in a Coarse-Grained, Niobium Stabilized Austenitic Stainless Steel (316Nb)

Hermant, Alexandre; Suzon, E.; Petit, Philippe; Bellus, Jacques; Georges, Eric; Cortial, F.; Sennour, Mohamed; Gourgues-Lorenzon, Anne-Françoise

doi:10.1007/s11661-018-05103-x

Cited by 14 publications

(13 citation statements)

References 53 publications

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“…Hermant et al investigated the hot deformation behavior and the associated microstructural evolution of a coarse-grained Nb-bearing austenitic stainless steel (316Nb), which is an FCC alloy. [58] When 316Nb steel was water cooled immediately after hot working (dynamic recrystallization grain freezing), almost no dynamic recrystallization grains were observed, whereas post-dynamic recrystallization grains with DRX growth were observed after slow cooling (0.15 K s À1 ). Then, the correlation between GOS < 2 deg and the fraction of post-dynamic recrystallization grains after cooling was obtained.…”

Section: B Fraction Of Dynamic Recrystallizationmentioning

confidence: 99%

Recovery and Recrystallization Behaviors of Ni–30 Mass Pct Fe Alloy During Uniaxial Cold and Hot Compression

Yamaguchi

Yonemura

2021

Metall Mater Trans A

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The recovery and recrystallization behaviors of the high-temperature γ-phase of carbon steel during deformation strongly affect the mechanical properties of steel. However, it is difficult to evaluate such behaviors at a high temperature. This study proposes the deformation behavior of the high-temperature γ-phase of low-carbon steel based on the quantitative observation of dislocation density and vacancies in the Ni–30 mass pct Fe alloy. This alloy was used because its stacking fault energy (60 to 70 mJ m-2) is similar to that of low-carbon steel. Uniaxial compression tests were conducted at a strain rate of 10−3 s−1 and 1473 K (1200 °C) for dynamic recrystallization and at 293 K (20 °C) for work hardening. The compression process was interrupted at different strain values to systematically investigate microstructural changes. The changes in work hardening, recovery, and recrystallization behaviors were obtained from the true stress–true strain curves of the uniaxial compression tests. Further, the microstructure changes during cold and hot uniaxial compression were investigated from the viewpoint of lattice defects by X-ray diffraction, positron annihilation analysis, transmission electron microscopy, and electron backscatter diffraction to comprehend the work hardening, dynamic recovery (DRV), and dynamic recrystallization (DRX). This study helps understand the DRV, DRX, and work hardening behaviors in the γ-phase of the Ni–30 mass pct Fe alloy during cold and hot compression.

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Section: B Fraction Of Dynamic Recrystallizationmentioning

confidence: 99%

Recovery and Recrystallization Behaviors of Ni–30 Mass Pct Fe Alloy During Uniaxial Cold and Hot Compression

Yamaguchi

Yonemura

2021

Metall Mater Trans A

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“…When it reached a critical value, DRX nuclei would form and grow up near grain boundaries, twin boundaries, and deformation bands. Once recrystallization occurred in the region, the dislocation density of it would reduce by rearrangement and annihilation of dislocation [32]. e peak stress-strain, critical stress-strain, steadystate stress, and saturated stress on the true stress-strain curve are illustrated in Figure 5(a).…”

Section: (B))mentioning

confidence: 99%

Evolution of Dynamic Recrystallization in 5CrNiMoV Steel during Hot Forming

Wang

2020

Advances in Materials Science and Engineering

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The dynamic recrystallization (DRX) behavior of 5CrNiMoV steel was investigated through hot compression at temperatures of 830–1230°C and strain rates of 0.001–10 s−1. From the experimental results, most true stress-strain curves showed the typical nature of DRX that a single peak was reached at low strains followed by a decrease of stress and a steady state finally at relatively high strains. The constitutive behavior of 5CrNiMoV steel was analyzed to deduce the operative deformation mechanisms, and the correlation between flow stress, temperature, and strain rate was expressed as a sine hyperbolic type constitutive equation. Based on the study of characteristic stresses and strains on the true stress-strain curves, a DRX kinetics model was constructed to characterize the influence of true strain, temperature, and strain rate on DRX evolution, which revealed that higher temperatures and lower strain rates had a favorable influence on improving the DRX volume fraction at the same true strain. Microstructure observations indicated that DRX was the main mechanism and austenite grains could be greatly refined by reducing the temperature of hot deformation or increasing the strain rate when complete recrystallization occurred. Furthermore, a DRX grain size model of 5CrNiMoV was obtained to predict the average DRX grain size during hot forming.

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“…Niobium is well known for delaying or hindering recrystallization via different effects: (i) it can form fine precipitates leading to pinning of grain boundaries [11][12][13], (ii) it can dramatically slow down grain boundary migration via the solute drag effect [11][12][13][14], and (iii) it may enhance the recovery process by changing the stacking fault energy in austenite [15]. These different effects were indirectly revealed by Hermant et al [16], who showed that heat treatments prior to high-temperature deformation of 316Nb steel were critical for subsequent recrystallization. More precisely, in contrast to isothermal holding at 1373 K (1100 °C) during 1 h, isothermal treatment at 1473 K (1200 °C) for 1 h hindered further post-dynamic and static recrystallization.…”

Section: Introductionmentioning

confidence: 99%

“…To do so, four-element (Fe-Nb-C-N), seven-element (Fe-Cr-Ni-Mo-Nb-C-N), and nine-element (full composition, Fe-Cr-Ni-Mo-Mn-Si-Nb-C-N) simulations were carried out using Thermo-Calc and DICTRA and the high-temperature evolution of primary Nb(C,N), and austenite was addressed. Isothermal and anisothermal simulations were carried out for transformations occurring in the temperature range between 1373 and 1473 K used for the experimental study in Reference [16]. The role of the thermodynamic database was also studied through the comparison of results obtained using the TCFE7 and TCFE9 databases.…”

Section: Introductionmentioning

confidence: 99%

Thermokinetic Modelling of High-Temperature Evolution of Primary Nb(C,N) in Austenite Applied to Recrystallization of 316Nb Austenitic Stainless Steel

Cliche

Ringeval

Petit³

et al. 2021

Metals

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The size evolution of niobium carbonitrides Nb(C,N) and the evolution of the composition of an austenitic matrix in 316Nb stainless steel were simulated using DICTRA software. For the first time, the complete nine-element composition of steel was taken into account during isothermal and even anisothermal heat treatments. A reduced model was then proposed to optimize the calculation time for complex heat treatments. The change in the mean Nb content in austenite due to Nb(C,N) evolution during different heat treatments was studied. It qualitatively agrees with experimental data as obtained by electron probe microanalysis. Furthermore, the model was successfully applied to explain the effect of heat treatments on the recrystallization behavior of 316Nb steel during hot torsion tests. Moreover, the effect of the thermodynamic database and the number of alloying elements chosen was discussed. We showed that taking into account seven or even nine elements greatly improves the accuracy compared to usual simplified compositions. The proposed method can be useful in designing heat treatments promoting or conversely hindering recrystallization for a wide variety of Nb-bearing steels.

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Hot Deformation and Recrystallization Mechanisms in a Coarse-Grained, Niobium Stabilized Austenitic Stainless Steel (316Nb)

Cited by 14 publications

References 53 publications

Recovery and Recrystallization Behaviors of Ni–30 Mass Pct Fe Alloy During Uniaxial Cold and Hot Compression

Recovery and Recrystallization Behaviors of Ni–30 Mass Pct Fe Alloy During Uniaxial Cold and Hot Compression

Evolution of Dynamic Recrystallization in 5CrNiMoV Steel during Hot Forming

Thermokinetic Modelling of High-Temperature Evolution of Primary Nb(C,N) in Austenite Applied to Recrystallization of 316Nb Austenitic Stainless Steel

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