Influence of Chloride-Containing Media on the Pitting Resistance of AISI 321 Steel

Narivs’kyi, O. E.; Беликов, С. Б.; Субботин, С. А.; Пуліна, Тетяна Веніамінівна

doi:10.1007/s11003-021-00544-z

Cited by 14 publications

(4 citation statements)

References 8 publications

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“…Таке узагальнення також узгоджується з даними аналізу ланцюжка моделі x 1 (pH) ≥ 7,5 (вуз.41, II частина), то КТП сплаву 06ХН28МДТ становить 56,7 °С (вуз.61) та загально відомими літературними даними [11,29,30] [31]. Це узгоджується з даними праць [32,33] для корозійнотривких сталей за таких самих умов випробувань.…”

Section: результати досліджень та їх обговоренняunclassified

Patterns and Mechanisms of Pitting of 06xh28mдt Alloy (Analogue of Aisi 904l Steel) in Model Recycled Water of Enterprises

Dzhus,

Narivskyi,

Snizhnoi

et al. 2024

НМТ

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Purpose. The aim of the study is to establish the patterns and mechanisms of pitting of the 06ХН28МДТ alloy in model recycled waters with a pH of 4-8 and a chloride concentration of 350 up to 600 mg/l, which are most often used in industrial enterprises. Research methods. A mathematical model based on regression trees to establish the relationship between the critical pitting temperatures (CPT) of the 06ХН28МДТ alloy and its chemical composition, structure components, and parameters of model recycled water (pH, chloride concentration) has been developed. Metallographic analysis, energy dispersion analysis, regression analysis. Results. Based on the results of the analysis of the developed mathematical model, chemical composition, structural heterogeneity of the alloy, and known literature data, it was found that in model recycled waters with a pH of 4.5 up to 7.5, the CPT of the 06ХН28МДТ alloy has a constant value of about 48.3 °C, which does not depend on its chemical composition, structural components, and chloride concentration in the model recycled waters. In model recycled waters with a chloride concentration of 350 up to 600 mg/l, the alloy’s CPT increases, on mean, to 59 °C, with an increase in their pH from 7.5 up to 8, but it decreases to 39 °C, with its decrease from 5 to 4. It has been found that the pH of the media has a more significant effect on the CPT of the alloy than the concentration of chlorides in it. It was found that the pH of the media has a more significant effect on the CTE of the alloy than the concentration of chlorides in it. Scientific novelty. Based on the established patterns between the critical pitting temperatures of the 06ХН28МДТ alloy and its chemical composition, structure components, and parameters of recycled water, the mechanisms of its pitting has been determined, in particular, in low acidic media with pH 4.5, its CPT is minimal, which is due to a decrease in the hydrogen ionisation overvoltage on the carbide phase (Cr, Mo, Ti, Si, Mn, C) in the vicinity of titanium nitrides, where pitting occurs, and in close to neutral model recycled waters, the alloy’s CPT is higher in a wide pH range, which is associated with the formation of an oxide film from a monolayer of Cr atoms on its surface due to its solid-phase diffusion under the influence of Mn, but in low alkaline model recycled waters, the alloy’s CPT is the highest, which is due to a decrease in the activity of chlorine ions and their adsorption on the imperfections of the alloy structure. Practical value. The developed mathematical models are proposed to be applied to the selection of the most resistant melts to pitting in recirculating industrial waters of the alloy 06KhN28MDT melts and prediction of its pitting during the operation of heat exchangers.

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Section: результати досліджень та їх обговоренняunclassified

Patterns and Mechanisms of Pitting of 06xh28mдt Alloy (Analogue of Aisi 904l Steel) in Model Recycled Water of Enterprises

Dzhus,

Narivskyi,

Snizhnoi

et al. 2024

НМТ

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“…Тому актуальною проблемою є оцінка пітінготривкості конструкційних матеріалів, з яких виробляють теплообмінники, і прогнозування їх корозійної поведінки при експлуатації. У роботах [9,10] встановлено, що параметри оборотної води і структурна гетерогенність сталей AISI 304, 12Х18Н10Т, 08Х18Н10, AISI 321 суттєво впливають на їх пітінготривкість в оборотних водах, а вплив їх хімічного складу не є значним і визначається тільки кількістю Cr в їх складі.…”

Section: вступunclassified

“…x -0,0014 Дослідження пітінготривкості сталей AISI 304 [10] і AISI 321 [9] показали, що вона, в основному, залежить від параметрів модельних оборотних вод (x i , x 2 ), структурної гетерогенності цих сталей (x 6 , x 7 ) і меншою мірою від вмісту у них Cr у межах стандарту. При цьому результати аналізу (табл.…”

Section: результати досліджень та їх обговоренняunclassified

“…3, п. 13, 14) та математичної моделі (1) узгоджуються з даними праць [9,10,25], тому що встановлено, що y(КТП) сталей, що досліджуються, практично не змінюється при збільшенні в них вмісту Mn від 1,22 до 1,81 мас.% (табл. 1, 2).…”

Section: результати досліджень та їх обговоренняunclassified

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Mathematical Modeling of the Corrosion Behavior of Austenitic Steels in Chloride-Containing Environments During the Operation of Plate Heat Exchangers

Narivs’kyi¹,

Сніжной²,

Subbotin³

et al. 2023

НМТ

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Purpose. It consists in the development of mathematical models that describe the dependence of the critical pitting temperatures of AISI 304, 08X18N10, AISI 321, 12X18N10T steels in model circulating waters with pH 4...8 and chloride concentration from 350 to 600 mg/l. Research methods. The developed mathematical models are based on linear square regression and a neural network of direct signal propagation for a reduced set of features. Results. It was established that the critical pitting temperatures of the studied austenitic chrome-nickel steels increase with an increase in the pH of the circulating water, the number of oxides up to 3.95 μm in size, the average distance between titanium nitrides, the Cr content and a decrease in the concentration of chlorides in the circulating water, the average distance between oxides, and the austenite average grain diameter. Scientific novelty. Based on the established relationships between the critical pitting temperatures of corrosion-resistant steels AISI 304, 08Х18Н10, AISI 321, 12Х18Н10Т, their chemical composition within the standard and structural heterogeneity, the mechanisms of their influence on the pitting resistance of these structural materials in circulating chloride-containing waters have been developed. It was established that metastable pitting is formed in a solid solution of austenite of steels around oxides with a size of 1,98...3,95 microns and repassivates before reaching critical dimensions of about 5 microns, which contributes to the growth of their pitting resistance in reversible chloride-containing environments. Practical value. The developed mathematical models are proposed to be used for the selection of optimal melts of austenitic chrome-nickel steels for the production of heat exchangers and prediction of their pitting resistance during their operation in circulating waters. The processes contributing to the perforation of heat transfer elements of heat exchangers during their operation have been identified.

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Modeling of Pitting of Heat Exchangers Made of 18/10 Type Steel in Circulating Waters

Narivskyi,

Subbotin,

Pulina

et al. 2023

Mater Sci

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Influence of Chloride-Containing Media on the Pitting Resistance of AISI 321 Steel

Cited by 14 publications

References 8 publications

Patterns and Mechanisms of Pitting of 06xh28mдt Alloy (Analogue of Aisi 904l Steel) in Model Recycled Water of Enterprises

Patterns and Mechanisms of Pitting of 06xh28mдt Alloy (Analogue of Aisi 904l Steel) in Model Recycled Water of Enterprises

Mathematical Modeling of the Corrosion Behavior of Austenitic Steels in Chloride-Containing Environments During the Operation of Plate Heat Exchangers

Modeling of Pitting of Heat Exchangers Made of 18/10 Type Steel in Circulating Waters

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