Sensitization and Self-healing in Austenitic Stainless Steel: Quantitative Prediction Considering Carbide Nucleation and Growth

Kolli, Satish; Ohligschläger, Thomas; Kömi, Jukka; Porter, David

doi:10.2355/isijinternational.isijint-2019-264

Cited by 11 publications

(3 citation statements)

References 29 publications

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“…A good correlation between measured NDOS values and DP was only found when d a was considered to be 1/6 th of the average grain ECD and not if it was taken to be the full average grain ECD or half of the average. This supports the earlier assumptions regarding d a made by Sourmail [29] and Kolli [30]. The approach is based on the idea that grains are taken as cubes with six faces making it appropriate to attribute to each calculation volume a sixth of the grain diameter from which C and Cr can be drawn.…”

Section: Discussionsupporting

confidence: 76%

“…Automatic time step control is chosen for the simulations. In order to take into account the effect of soft-impingement, the width of the austenite from which C can be withdrawn was taken to be one sixth of the grain size as suggested by Sourmail [29] and also employed by Kolli et al [30] but additionally, the effect of taking the whole average equivalent circle diameter (ECD) grain size and half the ECD grain size were also simulated.…”

Section: Methodsmentioning

confidence: 99%

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On the Role of Grain Size and Carbon Content on the Sensitization and Desensitization Behavior of 301 Austenitic Stainless Steel

Kolli

Javaheri

Kömi

et al. 2019

Metals

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The effect of grain size in the range 72 to 190 μm and carbon content in the range 0.105–0.073 wt.% on the intergranular corrosion of the austenitic stainless steel 301 has been investigated. Grain boundary chromium depletion has been studied directly using energy dispersive X-ray spectroscopy combined with scanning transmission electron microscopy and indirectly using double loop electrochemical potentiokinetic reactivation tests. In addition, chromium depletion has been modelled using the CALPHAD Thermo-Calc software TC-DICTRA. It is shown that the degree of sensitization measured using the double loop electrochemical potentiokinetic reactivation tests can be successfully predicted with the aid of a depletion parameter based on the modelled chromium depletion profiles for heat treatment times covering both the sensitization and de-sensitization or self-healing. Additionally, along with intergranular M23C6 carbides, intragranular M23C6 and Cr2N nitrides that affect the available Cr for grain boundary carbide precipitation were also observed.

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Section: Discussionsupporting

confidence: 76%

Section: Methodsmentioning

confidence: 99%

On the Role of Grain Size and Carbon Content on the Sensitization and Desensitization Behavior of 301 Austenitic Stainless Steel

Kolli

Javaheri

Kömi

et al. 2019

Metals

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“…Consequently, the Ir decreases, and the DOS value decreases as well. For DL-EPR testing, this phenomenon is called desensitization or the healing effect [24,34,35].…”

Section: Pitting Potential Measurementmentioning

confidence: 99%

Intergranular Corrosion Analysis of Austenitic Stainless Steels in Molten Nitrate Salt Using Electrochemical Characterization

Kanjanaprayut,

Siripongsakul,

Promdirek

2024

Metals

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This study investigates the influence of molten nitrate salt exposure on the intergranular corrosion (IGC) behavior of three grades of austenitic stainless steel (namely, AISI 304, AISI 304H, and AISI 321H). Two electrochemical techniques, double loop electrochemical potentiokinetic reactivation and potentiodynamic polarization methods, are applied after stainless steel is exposed to 600 °C molten nitrate salt, 60% NaNO3, and 40% KNO3 for varying immersion durations. Corrosion morphology is examined using optical microscopy and scanning electron microscopy images to assess susceptibility to IGC. IGC is prompted by the presence of chromium carbides at grain boundaries, which leads to chromium depletion around these carbides. The findings of the experiments reveal distinct IGC behavior among stainless steel grades. For AISI 304, the degree of sensitization (DOS) increases as exposure time progresses. However, AISI 304H and AISI 321H stainless steel exhibit diminishing DOS after 100 and 10 h of exposure, respectively. This trend is attributed to desensitization or the healing effect when stainless steel is exposed to molten salt for a prolonged time. The depletion and recovery of Cr near grain boundaries are confirmed by the inverse relationship to DOS of pitting potential.

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Sensitization and Desensitization (Healing) in Austenitic Stainless Steel: A Critical Review

Gajjar¹,

Khatri²,

Siddhpura³

et al. 2022

Trans Indian Inst Met

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Sensitization and Self-healing in Austenitic Stainless Steel: Quantitative Prediction Considering Carbide Nucleation and Growth

Cited by 11 publications

References 29 publications

On the Role of Grain Size and Carbon Content on the Sensitization and Desensitization Behavior of 301 Austenitic Stainless Steel

On the Role of Grain Size and Carbon Content on the Sensitization and Desensitization Behavior of 301 Austenitic Stainless Steel

Intergranular Corrosion Analysis of Austenitic Stainless Steels in Molten Nitrate Salt Using Electrochemical Characterization

Sensitization and Desensitization (Healing) in Austenitic Stainless Steel: A Critical Review

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