Work-Hardening Mechanism in High-Nitrogen Austenitic Stainless Steel

Masumura, Takuro; Seto, Yuki; Tsuchiyama, Toshihiro; Kimura, Ken

doi:10.2320/matertrans.h-m2020804

Cited by 27 publications

(9 citation statements)

References 33 publications

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“…Firstly, bibliographic data suggest that nitrogen addition in austenitic stainless steels modifies the behaviour of dislocation by promoting planar slip [16], [44]. Thus, cross-slip is limited, affecting dislocation interactions and, ultimately, increasing work-hardening [47], [48]. Some authors claim that planar slip is promoted because nitrogen decreases the stacking fault energy (SFE).…”

Section: Influence Of Nitrogen On Plastic Deformationmentioning

confidence: 99%

Nitrogen-induced hardening in an austenitic CrFeMnNi high-entropy alloy (HEA)

Traversier

Mestre-Rinn

Peillon

et al. 2021

Materials Science and Engineering: A

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Nitrogen is a well-known gamma-stabiliser in austenitic steels, also responsible for significant solid solution hardening of these materials. Yet, only few papers have studied its impact on austenitic high-entropy alloy (HEA) matrixes. This study focuses on a cobalt-free, non equimolar CrFeMnNi HEA doped with nitrogen. A series of alloys was cast under a nitriding atmosphere to promote nitrogen absorption into the liquid alloy. Study of as-cast alloys has shown nitrogen presence in solid solution up to 0.3 wt. % (1.2 at. %). Over the whole range of compositions, a linear increase of hardness (134 HV/wt. % of N) was measured as well as an expansion of the lattice parameter of a/a= 1.01 / wt. % N due to nitrogen addition in the interstitial sites of the lattice. Tests on forged and annealed samples showed that the increase of hardness with nitrogen addition is higher than in as-cast state (210 HV / wt. % of N) surely due to presence of other strengthening mechanisms. Tensile tests confirmed that the presence of dissolved nitrogen increases yield strength and ultimate strength and enhances strain-hardening, without any modification of ductility.

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Section: Influence Of Nitrogen On Plastic Deformationmentioning

confidence: 99%

Nitrogen-induced hardening in an austenitic CrFeMnNi high-entropy alloy (HEA)

Traversier

Mestre-Rinn

Peillon

et al. 2021

Materials Science and Engineering: A

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“…On the other hand, for 0.2N steel, in which DIMT hardly occurs as with 0.2C steel, its UE rather increased in comparison with that of 0.1N steel because of the high work-hardening rate based on the planar dislocation developed in high-N austenitic steel. [19][20][21][22] Figure 8(d) shows the strength-ductility balance (TS × UE) in each steel. Compared to Base steel, the strength-ductility balance is improved by increasing the UE in C-and N-added steels.…”

Section: Tensile Deformation Behaviormentioning

confidence: 99%

Effect of Carbon and Nitrogen on Work-hardening Behavior in Metastable Austenitic Stainless Steel

Masumura

2021

ISIJ Int.

Self Cite

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The effects of C and N on the work-hardening behaviors were compared in metastable austenitic steels in which varied amounts of C and N were separately added (Fe-18%Cr-8%Ni-(C,N) alloys). Although both C and N suppressed deformation-induced martensitic transformation during tensile deformation due to their austenite-stabilizing effect, they enhanced the work hardening of the steels. Comparison of C-added and N-added steels revealed that C addition more increased the work-hardening rate than N addition. In order to clarify the reason of the more significant effect of C, the individual hardness of deformed austenite and deformation-induced martensite (DIM) were measured in cold-rolled C-added and N-added steels by using a nano-indentation tester. The nanohardness of deformed austenite increased with increasing the thickness reduction and amount of added C and N. However, there is little difference between C-added and N-added steels in the hardening behavior of austenite, meaning that the difference in work-hardening rate of metastable austenitic steel between C-added and N-added steels is not derived from the hardness of deformed austenite but that of DIM. The nanohardness of DIM was significantly higher in the C-added steel than N-added steel, and thus, the main factor affecting the higher work hardening of 0.1C steel should be considered to be the higher hardness of C-containing DIM. In addition, in C-added steels, an excellent strength-ductility balance was achieved compared with N-added steel because the hard DIM is gradually formed until the later stage of deformation, meaning that pronounced TRIP effect was obtained in C-added steels than N-added steels.

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“…Moreover, it is also known that the conventional hardening and tempering treatments that is typically used to improve the mechanical performances of other steel grades (such as ferritic-martensitic [45,46] or maraging steels [47]) are not effective on austenitic stainless steels. On the contrary, cold rolling and subsequent heat treatment is a very effective method for grain size refinement [48], consequentially leading to an increase in the mechanical properties of austenitic stainless steels [49,50]. The work-hardening behavior of steels after the cold rolling process is heavily dependent on the amount of stored energy in the material during the process.…”

Section: Introductionmentioning

confidence: 99%

Recrystallization and Grain Growth of AISI 904L Super-Austenitic Stainless Steel: A Multivariate Regression Approach

Stornelli

Gaggiotti

Mancini

et al. 2022

Metals

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AISI 904L is a super-austenitic stainless steel that is remarkable for its mechanical properties and high corrosion resistance, which strictly depend on its chemical composition and microstructural features. The recrystallization process and grain growth phenomena play key roles in achieving high levels of material quality, as often requested by customers for specific applications. In this paper, the evolution of the microstructure and hardness values after cold rolling and subsequent annealing is reported, with the aim of optimizing the thermomechanical treatment conditions and improving the efficiency of the production process. The investigation was focused on three different cold reduction ratios (50%, 70% and 80%), while combining different annealing temperatures (950, 1050 and 1150 °C) and soaking times (in the range of 20–180 s. The test results were organized using a data analysis and statistical tool, which was able to show the correlation between the different variables and the impacts of these on recrystallization and grain growth processes. For low treatment temperatures, the tested soaking times led to partial recrystallization, making this condition industrially unattractive. Instead, for the higher temperature, full recrystallization was achieved over a short time (20–40 s), depending on the reduction ratio. Regarding the grain growth behavior, it was found to be independent of the reduction ratio; for each treatment temperature, the grain growth showed a linear trend as a function of the soaking time only. Moreover, the static recrystallization kinetics were analyzed using a statistical analysis software program that was able to provide evidence indicating the most and least influential parameters in the process. In particular, taking into consideration the hardness values as output data, the temperature and soaking time were revealed to have major effects as compared with the reduction ratio, which was excluded from the statistical analysis. The prediction approach allowed us to formulate a regression equation in order to correlate the response and terms. Moreover, a response optimizer was used to predict the best solution to get as close as possible to the hardness target required by the market.

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Work-Hardening Mechanism in High-Nitrogen Austenitic Stainless Steel

Cited by 27 publications

References 33 publications

Nitrogen-induced hardening in an austenitic CrFeMnNi high-entropy alloy (HEA)

Nitrogen-induced hardening in an austenitic CrFeMnNi high-entropy alloy (HEA)

Effect of Carbon and Nitrogen on Work-hardening Behavior in Metastable Austenitic Stainless Steel

Recrystallization and Grain Growth of AISI 904L Super-Austenitic Stainless Steel: A Multivariate Regression Approach

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