• Journal of Surface Science and Engineering
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• v.54 no.6
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• pp.294-301
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• 2021

As the number of cases of performance degradation owing to corrosion of plant during processing in industries increases, the cost of maintaining industrial factory is increasing year by the year. Most of the materials of the facilities are consist of stainless steel (SS) such as austenite SS, ferrite SS, martensite SS, and duplex SS. Among them austenite SS is cheap and has excellent corrosion resistance and heat resistance. Corrosion is the consumption and change of metals by altering chemical and electrical reactions. The types of SS corrosion include pitting corrosion, crevice corrosion, galvanic corrosion, stress corrosion cracking, and thermal corrosion. The corrosion of SS is not only investigated various environmental factors but also the measurement of the corrosion rate. Therefore, it aims to understand comprehensive corrosion rates in various environments using qualitative, quantitative and electrochemical methods.

• Journal of Surface Science and Engineering
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• v.43 no.1
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• pp.12-16
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• 2010

The morphology of the passivated surface of stainless steel (SS) was quantitatively characterized based on fractal geometry. In particular, the surface irregularities of the passivated 304 and 439 SSs were comparatively analyzed in terms of their self-similar fractal dimensions. The passivated surface of 439 SS in an acid-based electrolyte proved to have a higher fractal dimension, as compared to that of 304 SS, esp. at a scale of several tens of nanometers, strongly indicating the higher irregularity of the passivated surface. It is anticipated that the fractal approach suggested herein might be effectively utilized to analyze the irregularity of the steel surface and/or the compactness of the oxide film.

• Corrosion Science and Technology
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• v.18 no.3
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• pp.73-77
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• 2019

Hot-dip aluminized coating has been widely used to protect steel substrate against corrosion. In this study, the corrosion behavior of hot-dip aluminized type 409L (11% Cr) stainless steel (SS) was investigated using macro- and micro-scale polarization tests. An Al-Fe-Si alloy layer that was formed due to inter-diffusion of alloying elements between Al coating and SS substrate was observed between Al coating and 409L SS substrate. In both macro- and micro-scale polarization tests, the corrosion potential ($E_{corr}$) of the 409L SS substrate was much nobler than that of the Al coating and alloy layer. $E_{corr}$ of the alloy layer was between that of Al coating and 409L SS substrate. This indicates that the alloy layer can act as a buffer between the more active Al coating and the nobler SS substrate for pit growth in aluminized SS. The presence of the alloy layer appears to be helpful in hindering pitting corrosion of aluminized SS.

• Progress in Superconductivity
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• v.1 no.1
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• pp.51-55
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• 1999

A Ni/Ag/Stainless steel 310S(SS310S) multi-layer sheet has been fabricated by a combination of vacuum brazing, cold rolling and texture annealing processes. After heat-treating the thin Ni/Ag/SS310S multi-layer sheet at $900^{\circ}C$ for 2h, development of (100)<001>cube texture on Ni surface was revealed by (111) pole figure. Quantitative chemical analysis was made by EPMA for the cross-section of the Ni/Ag/SS310S multi-layer sheet. EPMA results showed that Ag diffusion into the Ni layer, which may suppress the cube texture development, was negligible. A small amount of Cr atoms were detected in the Ni layer. It showed that Ag can be used as a chemical barrier of alloying element atoms in Ni layer for the Ni/Ag/SS310S multi-layer sheet and a strong cube texture was developed for the Ni layer in the Ni/Ag/SS310S multi-layer sheet.

• Nuclear Engineering and Technology
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• v.44 no.7
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• pp.773-780
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• 2012

The article presented is concerned with an evaluation of the corrosion behavior of SA-508 low alloy steel (LAS) and Type 309L stainless steel (SS) cladding of a reactor pressure vessel under the simulated primary water chemistry of a pressurized water reactor (PWR). The uniform corrosion and galvanic corrosion rates of SA-508 LAS and Type 309L SS were measured in three different control conditions: power operation, shutdown, and power operation followed by shutdown. In all conditions, the dissimilar metal coupling of SA-508 LAS and Type 309L SS exhibited higher corrosion rates than the SA-508 base metal itself due to severe galvanic corrosion near the cladding interface, while the corrosion of Type 309L in the primary water environment was minimal. The galvanic corrosion rate of the SA-508 LAS and Type 309L SS couple measured under the simulated power operation condition was much lower than that measured in the simulated shutdown condition due to the formation of magnetite on the metal surface in a reducing environment. Based on the experimental results, the corrosion rate of SA-508 LAS clad with Type 309L SS was estimated as a function of operating cycle simulated for a typical PWR.

• Nuclear Engineering and Technology
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• v.51 no.3
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• pp.784-791
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• 2019

In the present study, a series of tungsten austenitic stainless steel alloys have been developed by interchanging the molybdenum in standard SS316 by tungsten. This was done to minimize the long-life residual activation occurred in molybdenum and nickel after decommissioning of the power plant. The microstructure and mechanical properties of the prepared alloys are determined. For the sake of increasing multifunction property of such series of tungsten-based austenitic stainless steel alloys, gamma shielding properties were studied experimentally by means of NaI(Tl) detector and theoretically calculated by using the XCOM program. Moreover, fast neutrons macroscopic removal cross-section been calculated. The obtained combined mechanical, structural and shielding properties indicated that the modified austenitic stainless steel sample containing 1.79% tungsten and 0.64% molybdenum has preferable properties among all other investigated samples in comparison with the standard SS316. These properties nominate this new composition in several nuclear application domains such as, nuclear shielding domain.

• Nuclear Engineering and Technology
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• v.55 no.3
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• pp.902-907
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• 2023

To understand the eutectic reaction mechanism and the relocation behavior of the core debris is indispensable for the safety assessment of core disruptive accidents (CDAs) in sodium-cooled fast reactors (SFRs). This paper addresses reaction products and their distribution of the eutectic melting/solidifying reaction of boron carbide (B₄C) and stainless-steel (SS). The influence of the existence of carbon on the B₄C-SS eutectic reaction was investigated by comparing the iron boride (FeB)-SS reaction by Raman spectroscopy with Multivariate Curve Resolution (MCR) analysis. The scanning electron microscopy with dispersive X-ray spectrometer was also used to investigate the elemental information of the pure metals such as Cr, Ni, and Fe. In the B₄C-SS samples, a new layer was formed between B₄C/SS interface, and the layer was confirmed that the formed layer corresponded to amorphous carbon (graphite) or FeB or Fe₂B. In contrast, a new layer was not clearly formed between FeB and SS interface in the FeB-SS samples. All samples observed the Cr-rich domain and Fe and Ni-rich domain after the reaction. These domains might be formed during the solidifying process.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2131-2140
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• 2024

The chloride-induced stress corrosion cracking (CISCC) is one of the major integrity concerns in dry storage canisters made of austenitic stainless steels (ASSs). In this study, an advanced duplex stainless steel (DSS) with a composition of Fe-19Cr-4Ni-2.5Mo-4.5Mn (ADCS) was developed and its performance was compared with that of commercial ASS and DSS alloys. The chemical composition of ADCS was determined to obtain greater pitting and CISCC resistance as well as a proper combination of strength and ductility. Then, the thermomechanical processing (TMP) condition was applied, which resulted in higher strength than ASSs (304L SS and 316L SS) and better ductility than DSSs (2101 LDSS and 2205 DSS). The potentiodynamic polarization and electrochemical impedance spectra (EIS) results represented the better pitting corrosion resistance of ADCS compared to 304L SS and 316L SS by forming a better passive layer. The CISCC tests using four-point loaded specimens showed that cracks were initiated at 24 h for 304L SS and 144 h for 316L SS, while crack was not found until 1008 h for ADCS. Overall, the developed alloy, ADCS, showed better combination of CISCC resistance and mechanical properties as dry storage canister materials than commercial alloys.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.4
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• pp.207-212
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• 2013

It is well known that fatigue failure occur on welded structures in industrial application due to the repetitive load force. In order to decrease the fatigue failure, we analysed the mechanical properties based on their structural aspect, roll steel (SS 400) welded onto stainless steels (STS 304) by $CO_2$ gas as well as structure roll steel welded onto itself. We compared the hardness, tensile and fatigue properties with two kinds of samples which had no defects on the welding part observed by X-ray topographic analysis. It was recognized that the tensile and fatigue strength of SS 400 welded onto itself by $CO_2$ gas was higher than that of SS 400 welded onto STS 304.

• Journal of Electrochemical Science and Technology
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• v.6 no.1
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• pp.7-15
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• 2015

3-(4-Iodophenyl)-2-imino-2,3-dihydrobenzo[d]oxazol-5-yl 4-methylbenzenesulfonate (4-IPhOXTs) was synthesized and its inhibiting action on the corrosion of stainless steel 316L (SS) in sulfuric acid was investigated by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The results of the investigation show that this compound has excellent inhibiting properties for SS corrosion in sulfuric acid. Inhibition efficiency increases with increase in the concentration of the inhibitor. The adsorption of 4-IPhOXTs onto the SS surface followed the Langmuir adsorption model with the free energy of adsorption ΔG⁰_ads of −8.45 kJ mol⁻¹ . Quantum chemical calculations were employed to give further insight into the mechanism of inhibition action of 4-IPhOXTs.