Research

Jump to: Review

17 pages, 5148 KiB

Open AccessEditor’s ChoiceArticle

Stress Corrosion Cracking Mechanisms of UNS S32205 Duplex Stainless Steel in Carbonated Solution Induced by Chlorides

by Ulises Martin and David M. Bastidas

Metals 2023, 13(3), 567; https://0-doi-org.brum.beds.ac.uk/10.3390/met13030567 - 11 Mar 2023

Cited by 4 | Viewed by 3426

Herein, the chloride-induced stress corrosion cracking (SCC) mechanisms of UNS S32205 duplex stainless steel (DSS) reinforcing bars in alkaline and carbonated solutions are studied. Electrochemical monitoring and mechanical properties were tested using linear polarization resistance and electrochemical impedance spectroscopy, coupled with the slow [...] Read more.

Herein, the chloride-induced stress corrosion cracking (SCC) mechanisms of UNS S32205 duplex stainless steel (DSS) reinforcing bars in alkaline and carbonated solutions are studied. Electrochemical monitoring and mechanical properties were tested using linear polarization resistance and electrochemical impedance spectroscopy, coupled with the slow strain rate tensile test (SSRT) to evaluate the SCC behavior and unravel the pit-to-crack mechanisms. Pit initiation and crack morphology were identified by fractographic analysis, which revealed the transgranular (TG) SCC mechanism. HCO₃⁻ acidification enhanced the anodic dissolution kinetics, thus promoting a premature pit-to-crack transition, seen by the decrease in the maximum phase angle in the Bode plot at low frequencies (≈ 1 Hz) for the carbonated solution. The crack propagation rate for the carbonated solution increased by over 100% compared to the alkaline solution, coinciding with the lower phase angle from the Bode plots, as well as with the lower charge transfer resistance. Pit initiation was found at the TiN nonmetallic inclusion inside the ferrite phase cleavage facet, which developed TG-SCC. Full article

(This article belongs to the Special Issue Corrosion and Protection of Stainless Steels)

► Show Figures

Figure 1

12 pages, 1800 KiB

Open AccessArticle

Pitting Potential Improvement of 304 Stainless Steel in Hydrochloric Acid Solution by Terminalia bellirica Fruit Extract

by Sutha Sutthiruangwong, Chutikan Wongpaiboon, Nathatida Sritha and Nattha Anukulkich

Metals 2023, 13(2), 262; https://0-doi-org.brum.beds.ac.uk/10.3390/met13020262 - 29 Jan 2023

Cited by 3 | Viewed by 1548

Abstract

Pitting is a form of localized corrosion. One way to increase pitting resistance is, therefore, to cover surfaces with inhibitor molecules. Many plant extracts have been reported to be able to adsorb onto metal surfaces. According to uniform corrosion, the corrosion rate is [...] Read more.

Pitting is a form of localized corrosion. One way to increase pitting resistance is, therefore, to cover surfaces with inhibitor molecules. Many plant extracts have been reported to be able to adsorb onto metal surfaces. According to uniform corrosion, the corrosion rate is reported to be decreased due to adsorption. Terminalia bellirica fruit contains organic chemicals which can adsorb onto metal surfaces. The extract of Terminalia bellirica fruit was used in this work as a corrosion inhibitor for 304 stainless steel in an acidic solution. The results showed a decrease in the corrosion current density of 304 stainless steel when the extract was added. A very high corrosion inhibition efficiency (%IE) of 95% was obtained with an extract addition of 300 mg L^–1. Moreover, Terminalia bellirica fruit extract clearly showed an increase in the pitting potential of 304 stainless steel in potentiodynamic polarization curves, which was caused by the physical adsorption. The Langmuir adsorption isotherm model can be used to describe the adsorption of the extract molecule on 304 stainless steel surfaces. Besides the conventional pitting potential (E_pit), the parameter called pitting potential improvement in percentage (%PPI) was shown in this work. Additionally, it was calculated based on two boundaries. It can be used to quantify the pitting potential in a percentage. Pitting resistance both in terms of pitting potential and in terms of pitting potential improvement was found to be increased with increasing concentrations of the extract. The highest pitting potential improvement of 29% was achieved at 300 mg L^–1 of extraction addition. Full article

(This article belongs to the Special Issue Corrosion and Protection of Stainless Steels)

► Show Figures

Figure 1

12 pages, 5911 KiB

Open AccessArticle

Effect of Boron Addition on the Oxide Scales Formed on 254SMO Super Austenitic Stainless Steels in High-Temperature Air

by Junyu Ren, Yi Zhang, Song Yang, Jinyao Ma, Caili Zhang, Zhouhua Jiang, Huabing Li and Peide Han

Metals 2023, 13(2), 258; https://0-doi-org.brum.beds.ac.uk/10.3390/met13020258 - 28 Jan 2023

Cited by 3 | Viewed by 1216

Abstract

Focusing on the serious volatilization of MoO₃ in super austenitic stainless steel with a high Mo content, the influence of B on the formation of oxide film and the distribution of Cr and Mo was investigated at 900 °C and 1000 °C. [...] Read more.

Focusing on the serious volatilization of MoO₃ in super austenitic stainless steel with a high Mo content, the influence of B on the formation of oxide film and the distribution of Cr and Mo was investigated at 900 °C and 1000 °C. Without the addition of B, Mo tends to diffuse to the surface, forming porous Cr/Mo-rich oxides, causing the volatilization of Mo. The addition of B can inhibit the diffusion of Mo to the surface, facilitate the diffusion of Cr to the surface and combines with O, providing conditions for the nucleation of Cr₂O₃. A large amount of Cr₂O₃ accumulated on the surface to form a dense passive film, which inhibited the diffusion of Mo to the surface, reduced the loss of Mo, and formed Mo/Cr-rich precipitates at grain boundaries that are close to the surface. However, it was difficult to form Mo-rich precipitates at the grain boundaries of a sample without B, which aggravated the volatilization of Mo from grain boundary to surface. Therefore, the addition of B can improve the oxidation resistance of 254SMO and inhibit the volatilization of Mo. Full article

(This article belongs to the Special Issue Corrosion and Protection of Stainless Steels)

► Show Figures

Figure 1

15 pages, 1251 KiB

Open AccessArticle

A Comprehensive Investigation on the Effects of Surface Finishing on the Resistance of Stainless Steel to Localized Corrosion

by Elena Messinese, Luca Casanova, Luca Paterlini, Fausto Capelli, Fabio Bolzoni, Marco Ormellese and Andrea Brenna

Metals 2022, 12(10), 1751; https://0-doi-org.brum.beds.ac.uk/10.3390/met12101751 - 18 Oct 2022

Cited by 16 | Viewed by 2306

Abstract

The present research investigates the influence of surface roughness imparted by cold surface finishing processes on the localized corrosion resistance of stainless steel. Five different alloys were studied: ferritic AISI 430, martensitic AISI 430F, austenitic AISI 303, AISI 304L, and AISI 316L. It [...] Read more.

The present research investigates the influence of surface roughness imparted by cold surface finishing processes on the localized corrosion resistance of stainless steel. Five different alloys were studied: ferritic AISI 430, martensitic AISI 430F, austenitic AISI 303, AISI 304L, and AISI 316L. It was demonstrated that the grinding process, executed on previously cold drawn bars, leads to an improvement in corrosion resistance according to the results obtained with electrochemical tests, namely, potentiostatic and potentiodynamic tests in chloride-rich environments, the salt spray test, and long-term exposure in urban and marine atmospheres. This allowed us to establish a trend among the different alloys regarding the resistance to pitting corrosion, which was assessed according to pitting potentials, critical chloride contents, and pitting initiation time. All the tests confirmed that surface finishing, as well as alloy chemical composition, is an important factor in controlling the corrosion resistance of stainless steel. Full article

(This article belongs to the Special Issue Corrosion and Protection of Stainless Steels)

► Show Figures

Figure 1

13 pages, 5018 KiB

Open AccessEditor’s ChoiceArticle

Investigation on Corrosion Resistance Properties of 17-4 PH Bound Metal Deposition As-Sintered Specimens with Different Build-Up Orientations

by Pietro Forcellese, Tommaso Mancia, Michela Simoncini and Tiziano Bellezze

Metals 2022, 12(4), 588; https://0-doi-org.brum.beds.ac.uk/10.3390/met12040588 - 30 Mar 2022

Cited by 6 | Viewed by 3156

Abstract

Additive manufacturing is a promising and emerging technology that can transform the global manufacturing and logistics by cutting costs and times of production. Localized corrosion resistance properties of 0°, 45°, and 90° build-up orientations of 17-4 PH as-sintered samples, manufactured by means of [...] Read more.

Additive manufacturing is a promising and emerging technology that can transform the global manufacturing and logistics by cutting costs and times of production. Localized corrosion resistance properties of 0°, 45°, and 90° build-up orientations of 17-4 PH as-sintered samples, manufactured by means of Bound Metal Deposition (BMD), have been investigated by electrochemical and morphological investigations. The cyclic potentiodynamic polarization curves and the open circuit potential monitoring, together with potential drop analysis, revealed that the BMD localized corrosion resistance properties were lowered if compared to a wrought 17-4 PH: a characteristic anodic behavior and many drops in potential were recorded for BMD, whilst the wrought specimens presented a typical passive behavior with pitting corrosion. Morphological investigations by scanning electron microscopy and energy-dispersive X-ray analysis revealed the presence of porosities and defects, especially for the 90° build-up orientation, and inclusions of SiO₂. The 45° build-up orientation showed the best corrosion resistance properties among all the BMD specimens, even though defects and porosities were observed, suggesting that their morphology and geometry influenced the overall corrosion behavior. Full article

(This article belongs to the Special Issue Corrosion and Protection of Stainless Steels)

► Show Figures

Figure 1

11 pages, 8506 KiB

Open AccessEditor’s ChoiceArticle

Transmission Electron Microscopy Study on the Precipitation Behaviors of Laser-Welded Ferritic Stainless Steels and Their Implications on Intergranular Corrosion Resistance

by Niklas Sommer, Clementine Warres, Tarek Lutz, Martin Kahlmeyer and Stefan Böhm

Metals 2022, 12(1), 86; https://0-doi-org.brum.beds.ac.uk/10.3390/met12010086 - 04 Jan 2022

Cited by 6 | Viewed by 1821

Abstract

The intergranular corrosion susceptibility of ferritic stainless-steel weldments is strongly dependent on chromium carbide precipitation phenomena. Hence, stabilization is widely used to mitigate the aforementioned precipitation. In contrast, stabilization has proved ineffective to fully prevent intergranular corrosion due to segregation of unreacted chromium [...] Read more.

The intergranular corrosion susceptibility of ferritic stainless-steel weldments is strongly dependent on chromium carbide precipitation phenomena. Hence, stabilization is widely used to mitigate the aforementioned precipitation. In contrast, stabilization has proved ineffective to fully prevent intergranular corrosion due to segregation of unreacted chromium during solid-state heat-treatments. To analyze the precipitation behavior of 17 wt.-% chromium ferritic stainless steels during laser welding, sheets of unstabilized and titanium-stabilized ferritic stainless steels were welded in a butt joint configuration and characterized with special consideration of precipitation behavior by means of transmission electron microscopy. While unstabilized ferritic stainless steels exhibit pronounced chromium precipitate formation at grain boundaries, titanium-stabilization leads to titanium precipitates without adjacent chromium segregation. However, corrosion tests reveal three distinctive corrosion mechanisms within the investigated ferritic stainless steels based on their inherent precipitation behaviors. In light of the precipitation formation, it is evident that immersion in sulfuric acid media leads to the dissolution of either grain boundaries or the grain boundary vicinity. As a result, the residual mechanical strength of the joint is substantially degraded. Full article

(This article belongs to the Special Issue Corrosion and Protection of Stainless Steels)

► Show Figures

Figure 1

8 pages, 2909 KiB

Open AccessFeature PaperArticle

One-Step Electrodeposition of Superhydrophobic Coating on 316L Stainless Steel

by Andrea Zaffora, Francesco Di Franco, Bartolomeo Megna and Monica Santamaria

Metals 2021, 11(11), 1867; https://0-doi-org.brum.beds.ac.uk/10.3390/met11111867 - 20 Nov 2021

Cited by 10 | Viewed by 1924

Abstract

Superhydrophobic coatings were fabricated through a one-step electrochemical process onto the surface of 316L stainless steel samples. The presence of hierarchical structures at micro/nanoscale and manganese stearate into the coatings gave superhydrophobicity to the coating, with contact angle of ~160°, and self-cleaning ability. [...] Read more.

Superhydrophobic coatings were fabricated through a one-step electrochemical process onto the surface of 316L stainless steel samples. The presence of hierarchical structures at micro/nanoscale and manganese stearate into the coatings gave superhydrophobicity to the coating, with contact angle of ~160°, and self-cleaning ability. Corrosion resistance of 316L samples was also assessed also after the electrodeposition process through Electrochemical Impedance Spectra recorded in an aqueous solution mimicking seawater condition. Full article

(This article belongs to the Special Issue Corrosion and Protection of Stainless Steels)

► Show Figures

Figure 1

15 pages, 11082 KiB

Open AccessArticle

Enhancement of Corrosion Properties of Fe-18Cr-9Mn-5.5Ni-0.3(C + N) Austenitic Stainless Steels by Carbon Alloying

by Daun Byeon, Heon-Young Ha, Sung-Dae Kim, Hyo-Haeng Jo, JinJong Lee, Jae Hoon Jang, Tae-Ho Lee, Jong-Ho Shin and Namhyun Kang

Metals 2021, 11(7), 1124; https://doi.org/10.3390/met11071124 - 15 Jul 2021

Cited by 2 | Viewed by 1782

Abstract

In this study, the resistance to pitting corrosion of Fe-18Cr-9Mn-5.5Ni-0.3(C + N) austenitic stainless steel γ-SSs (in wt%) with different C/(C + N) ratios (0.02, 0.29, and 0.60) was evaluated. It was found to be difficult to form a γ-matrix without precipitation, because [...] Read more.

In this study, the resistance to pitting corrosion of Fe-18Cr-9Mn-5.5Ni-0.3(C + N) austenitic stainless steel γ-SSs (in wt%) with different C/(C + N) ratios (0.02, 0.29, and 0.60) was evaluated. It was found to be difficult to form a γ-matrix without precipitation, because the Cr₂₃C₆ precipitation rate in the γ-SSs with the C/(C + N) value of 0.60 was too fast. Thus, it was recommended to maintain the C/(C + N) ratio below 0.6 in Fe-18Cr-9Mn-5.5Ni-0.3(C + N) γ-SSs. As a result of the potentiodynamic polarization tests, the γ-SS with a C/(C + N) ratio of 0.29 showed the highest resistance to pitting corrosion, and the resistance level of this alloy was superior to that of the AISI 304 γ-SS. Analysis of the passive film and matrix dissolution rates revealed that a higher C/(C + N) ratio of γ-SS increased the protective ability of the passive film and decreased the growth rate of the pits. Therefore, it could be concluded that partial substitution of C for N was advantageous for improving the pitting corrosion resistance of Fe-18Cr-9Mn-5.5Ni-0.3(C + N) γ-SSs, as long as C and N existed in a solid solution state. Full article

(This article belongs to the Special Issue Corrosion and Protection of Stainless Steels)

► Show Figures

Figure 1

Review

Jump to: Research

23 pages, 9095 KiB

Open AccessReview

Duplex Stainless Steels—Alloys for the 21st Century

by Roger Francis and Glenn Byrne

Metals 2021, 11(5), 836; https://0-doi-org.brum.beds.ac.uk/10.3390/met11050836 - 19 May 2021

Cited by 57 | Viewed by 10238

Abstract

Duplex stainless steels were first manufactured early in the 20th century, but it was the introduction in the 1970s of the argon-oxygen decarburisation (AOD) steel making process and the addition of nitrogen to these steels, that made the alloys stronger, more weldable and [...] Read more.

Duplex stainless steels were first manufactured early in the 20th century, but it was the introduction in the 1970s of the argon-oxygen decarburisation (AOD) steel making process and the addition of nitrogen to these steels, that made the alloys stronger, more weldable and more corrosion resistant. Today, duplex stainless steels can be categorised into four main groups, i.e., “lean”, “standard”, “super”, and “hyper” duplex types. These groups cover a range of compositions and properties, but they all have in common a microstructure consisting of roughly equal proportions of austenite and ferrite, high strength, good toughness and good corrosion resistance, especially to stress corrosion cracking (SCC) compared with similar austenitic stainless steels. Moreover, the development of a duplex stainless-steel microstructure requires lower levels of nickel in the composition than for a corresponding austenitic stainless steel with comparable pitting and crevice corrosion resistance, hence they cost less. This makes duplex stainless steels a very versatile and attractive group of alloys both commercially and technically. There are applications where duplex grades can be used as lower cost through-life options, in preference to coated carbon steels, a range of other stainless steels, and in some cases nickel alloys. This cost benefit is further emphasised if the design engineer can use the higher strength of duplex grades to construct vessels and pipework of lower wall thickness than would be the case if an austenitic grade or nickel alloy was being used. Hence, we find duplex stainless steels are widely used in many industries. In this paper their use in three industrial applications is reviewed, namely marine, heat exchangers, and the chemical and process industries. The corrosion resistance in the relevant fluids is discussed and some case histories highlight both successes and potential problems with duplex alloys in these industries. The paper shows how duplex stainless steels can provide cost-effective solutions in corrosive environments, and why they will be a standard corrosion resistant alloy (CRA) for many industries through the 21st century. Full article

(This article belongs to the Special Issue Corrosion and Protection of Stainless Steels)

► Show Figures

Figure 1

Journal Menu

Journal Browser

Corrosion and Protection of Stainless Steels

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Published Papers (9 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI