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3 pages, 204 KiB

Open AccessEditorial

Special Issue: Corrosion Properties and Mechanism of Steels

by Vít Křivý

Materials 2022, 15(19), 6796; https://doi.org/10.3390/ma15196796 - 30 Sep 2022

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Abstract

The economic losses caused by corrosion are estimated to be 3–5% of gross domestic product in developed countries [...] Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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14 pages, 4540 KiB

Open AccessArticle

Effect of Sulfate Ions on Galvanized Post-Tensioned Steel Corrosion in Alkaline Solutions and the Interaction with Other Ions

by Andrés Bonilla, Cristina Argiz, Amparo Moragues and Jaime C. Gálvez

Materials 2022, 15(11), 3950; https://doi.org/10.3390/ma15113950 - 1 Jun 2022

Cited by 3 | Viewed by 1650

Abstract

Zinc protection of galvanized steel is initially dissolved in alkaline solutions. However, a passive layer is formed over time which protects the steel from corrosion. The behavior of galvanized steel exposed to strong alkaline solutions (pH values of 12.7) with a fixed concentration [...] Read more.

Zinc protection of galvanized steel is initially dissolved in alkaline solutions. However, a passive layer is formed over time which protects the steel from corrosion. The behavior of galvanized steel exposed to strong alkaline solutions (pH values of 12.7) with a fixed concentration of sulfate ions of 0.04 M is studied here. Electrochemical measurement techniques such as corrosion potential, linear polarization resistance and electrochemical impedance spectroscopy are used. Synergistic effects of sulfate ions are also studied together with other anions such as chloride Cl⁻ or bicarbonate ion HCO₃⁻ and with other cations such as calcium Ca²⁺, ammonium NH₄⁺ and magnesium Mg²⁺. The presence of sulfate ions can also depassivate the steel, leading to a corrosion current density of 0.3 µA/cm² at the end of the test. The presence of other ions in the solution increases this effect. The increase in corrosion current density caused by cations and anions corresponds to the following orders (greater to lesser influence): NH₄⁺ > Ca²⁺ > Mg²⁺ and HCO₃⁻ > Cl⁻ > SO₄²⁻. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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26 pages, 26017 KiB

Open AccessArticle

Corrosion Damage to Joints of Lattice Towers Designed from Weathering Steels

by Vít Křivý, Zdeněk Vašek, Miroslav Vacek and Lucie Mynarzová

Materials 2022, 15(9), 3397; https://doi.org/10.3390/ma15093397 - 9 May 2022

Cited by 3 | Viewed by 2584

Abstract

The article dealt with the load-bearing capacity and durability of power line lattice towers designed from weathering steel. Attention was paid in particular to the bolted lap joints. The article evaluates the static and corrosion performance of bolted lap joints in long-term operating [...] Read more.

The article dealt with the load-bearing capacity and durability of power line lattice towers designed from weathering steel. Attention was paid in particular to the bolted lap joints. The article evaluates the static and corrosion performance of bolted lap joints in long-term operating towers, and also presents and evaluates design measures that can be applied in the design of new lattice towers, or in the reconstruction of already operating structures. Power line lattice towers are the most extensive realization of weathering steel in the Czech Republic. On the basis of the inspections carried out to evaluate the working life of the transmission towers in operation, it can be stated that a sufficiently protective layer of corrosion products generally developed on the bearing elements of the transmission towers. However, the development of crevice corrosion at the bolted joints of the leg members is a significant problem. In this paper, the corrosion damage of bolted joints was evaluated considering two basic aspects: (1) the influence of crevice corrosion on the bearing capacity of the bolted joint was evaluated, using experimental testing and based on analytical and numerical calculations; (2) appropriate design measures applicable to the rehabilitation of developed crevice corrosion of in-service structures, or the elimination of crevice corrosion in newly designed lattice towers, was evaluated. Calculation analyses and destructive tests of bolted joints show that the development of corrosion products in the crevice does not have a significant effect on the bearing capacity of the joint, provided that there is no significant corrosion weakening of the structural elements, and bolts of class 8.8 or 10.9 are used. The results of the long-term experimental programme, and the experience from the rehabilitations carried out, show that, thanks to appropriate structural measures, specified in detail in the paper, the long-term reliable behaviour of the lattice towers structures is ensured. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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14 pages, 3322 KiB

Open AccessArticle

Localized Corrosion Occurrence in Low-Carbon Steel Pipe Caused by Microstructural Inhomogeneity

by Yun-Ho Lee, Geon-Il Kim, Kyung-Min Kim, Sang-Jin Ko, Woo-Cheol Kim and Jung-Gu Kim

Materials 2022, 15(5), 1870; https://doi.org/10.3390/ma15051870 - 2 Mar 2022

Cited by 6 | Viewed by 2765

Abstract

In this study, the cause of failure of a low-carbon steel pipe meeting standard KS D 3562 (ASTM A135), in a district heating system was investigated. After 6 years of operation, the pipe failed prematurely due to pitting corrosion, which occurred both inside [...] Read more.

In this study, the cause of failure of a low-carbon steel pipe meeting standard KS D 3562 (ASTM A135), in a district heating system was investigated. After 6 years of operation, the pipe failed prematurely due to pitting corrosion, which occurred both inside and outside of the pipe. Pitting corrosion occurred more prominently outside the pipe than inside, where water quality is controlled. The analysis indicated that the pipe failure occurred due to aluminum inclusions and the presence of a pearlite inhomogeneous phase fraction. Crevice corrosion occurred in the vicinity around the aluminum inclusions, causing localized corrosion. In the large pearlite fraction region, cementite in the pearlite acted as a cathode to promote dissolution of surrounding ferrite. Therefore, in the groundwater environment outside of the pipe, localized corrosion occurred due to crevice corrosion by aluminum inclusions, and localized corrosion was accelerated by the large fraction of pearlite around the aluminum inclusions, leading to pipe failure. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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11 pages, 28366 KiB

Open AccessArticle

Method for Mitigating Stray Current Corrosion in Buried Pipelines Using Calcareous Deposits

by Sin-Jae Kang, Min-Sung Hong and Jung-Gu Kim

Materials 2021, 14(24), 7905; https://doi.org/10.3390/ma14247905 - 20 Dec 2021

Cited by 3 | Viewed by 1747

Abstract

Stray current corrosion in buried pipelines can cause serious material damage in a short period of time. However, the available methods for mitigating stray current corrosion are still insufficient. In this study, as a countermeasure against stray current corrosion, calcareous depositions were applied [...] Read more.

Stray current corrosion in buried pipelines can cause serious material damage in a short period of time. However, the available methods for mitigating stray current corrosion are still insufficient. In this study, as a countermeasure against stray current corrosion, calcareous depositions were applied to reduce the total amount of current flowing into pipelines and to prevent corrosion. This study examined the reduction of stray current corrosion via the formation of calcareous deposit layers, composed of Ca, Mg, and mixed Ca and Mg, at the current inflow area. To verify the deposited layers, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were performed. The electrochemical tests revealed that all three types of calcareous deposits were able to effectively act as current barriers, and that they decreased the inflow current at the cathodic site. Among the deposits, the CaCO₃ layer mitigated the stray current most effectively, as it was not affected by Mg(OH)₂, which interferes with the growth of CaCO₃. The calcium-based layer was very thick and dense, and it effectively blocked the inflowing stray current, compared with the other layers. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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13 pages, 3451 KiB

Open AccessArticle

Evaluation of the Influence of the Combination of pH, Chloride, and Sulfate on the Corrosion Behavior of Pipeline Steel in Soil Using Response Surface Methodology

by Nguyen Thuy Chung, Yoon-Sik So, Woo-Cheol Kim and Jung-Gu Kim

Materials 2021, 14(21), 6596; https://doi.org/10.3390/ma14216596 - 2 Nov 2021

Cited by 18 | Viewed by 2318

Abstract

External damage to buried pipelines is mainly caused by corrosive components in soil solution. The reality that numerous agents are present in the corrosive environment simultaneously makes it troublesome to study. To solve that issue, this study aims to determine the influence of [...] Read more.

External damage to buried pipelines is mainly caused by corrosive components in soil solution. The reality that numerous agents are present in the corrosive environment simultaneously makes it troublesome to study. To solve that issue, this study aims to determine the influence of the combination of pH, chloride, and sulfate by using a statistical method according to the design of experiment (DOE). Response surface methodology (RSM) using the Box–Behnken design (BBD) was selected and applied to the design matrix for those three factors. The input corrosion current density was evaluated by electrochemical tests under variable conditions given in the design matrix. The output of this method is an equation that calculates the corrosion current density as a function of pH, chloride, and sulfate concentration. The level of influence of each factor on the corrosion current density was investigated and response surface plots, contour plots of each factor were created in this study. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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16 pages, 60590 KiB

Open AccessArticle

The Influence of the Type of Electrolyte in the Modifying Solution on the Protective Properties of Vinyltrimethoysilane/Ethanol-Based Coatings Formed on Stainless Steel X20Cr13

by Aleksandra Kucharczyk, Lidia Adamczyk and Krzysztof Miecznikowski

Materials 2021, 14(20), 6209; https://doi.org/10.3390/ma14206209 - 19 Oct 2021

Cited by 8 | Viewed by 1888

Abstract

The paper reports the results of the examination of the protective properties of silane coatings based on vinyltrimethoxysilane (VTMS) and ethanol (EtOH), doped with the following electrolytes: acetic acid (AcOH), lithium perchlorate LiClO₄, sulphuric acid (VI) H₂SO₄ and [...] Read more.

The paper reports the results of the examination of the protective properties of silane coatings based on vinyltrimethoxysilane (VTMS) and ethanol (EtOH), doped with the following electrolytes: acetic acid (AcOH), lithium perchlorate LiClO₄, sulphuric acid (VI) H₂SO₄ and ammonia NH₃. The coatings were deposited on stainless steel X20Cr13 by the sol–gel dip-coating method. The obtained VTMS/EtOH/Electrolyte coatings were characterized in terms of corrosion resistance, surface morphology and adhesion to the steel substrate. Corrosion tests were conducted in sulphate media acidified up to pH = 2 with and without chloride ions Cl⁻, respectively. The effectiveness of corrosion protection was determined using potentiometric curves. It has been demonstrated that the coatings under study slow down the processes of corrosion of the steel substrate, thus effectively protecting it against corrosion. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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9 pages, 881 KiB

Open AccessCommunication

Hydrogen-Induced Cracking Caused by Galvanic Corrosion of Steel Weld in a Sour Environment

by Jin Sung Park, Jin Woo Lee and Sung Jin Kim

Materials 2021, 14(18), 5282; https://doi.org/10.3390/ma14185282 - 14 Sep 2021

Cited by 3 | Viewed by 2078

Abstract

This study examined the hydrogen-induced cracking (HIC) caused by galvanic corrosion of an ASTM A516-65 steel weld in a wet sour environment using a combination of standard immersion corrosion test, electrochemical analyses, and morphological observation of corrosion damage. This study showed that the [...] Read more.

This study examined the hydrogen-induced cracking (HIC) caused by galvanic corrosion of an ASTM A516-65 steel weld in a wet sour environment using a combination of standard immersion corrosion test, electrochemical analyses, and morphological observation of corrosion damage. This study showed that the weld metal has lower open circuit potential, and higher anodic and cathodic reaction rates than the base metal. The preferential dissolution and much higher density of localized corrosion damage were observed in the weld metal of the welded steel. On the other hand, the presence of weldment can make steel more susceptible to HIC, specifically, in areas of the base metal but not in the weld metal or heat affected zone, which is in contrast to typical expectations based on metallurgical knowledge. This can be explained by galvanic corrosion interactions between the weldment and the base metal, acting as a small anode and a large cathode, respectively. This type of galvanic couple can provide large surface areas for infusing cathodically-reduced hydrogen on the base metal in wet sour environments, increasing the susceptibility of welded steel to HIC. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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11 pages, 14220 KiB

Open AccessArticle

Calibrating the Impressed Anodic Current Density for Accelerated Galvanostatic Testing to Simulate the Long-Term Corrosion Behavior of Buried Pipeline

by Yoon-Sik So, Min-Sung Hong, Jeong-Min Lim, Woo-Cheol Kim and Jung-Gu Kim

Materials 2021, 14(9), 2100; https://doi.org/10.3390/ma14092100 - 21 Apr 2021

Cited by 3 | Viewed by 1603

Abstract

Various studies have been conducted to better understand the long-term corrosion mechanism for steels in a soil environment. Here, electrochemical acceleration methods present the most efficient way to simulate long-term corrosion. Among the various methods, galvanostatic testing allows for accelerating the surface corrosion [...] Read more.

Various studies have been conducted to better understand the long-term corrosion mechanism for steels in a soil environment. Here, electrochemical acceleration methods present the most efficient way to simulate long-term corrosion. Among the various methods, galvanostatic testing allows for accelerating the surface corrosion reactions through controlling the impressed anodic current density. However, a large deviation from the equilibrium state can induce different corrosion mechanisms to those in actual service. Therefore, applying a suitable anodic current density is important for shortening the test times and maintaining the stable dissolution of steel. In this paper, to calibrate the anodic current density, galvanostatic tests were performed at four different levels of anodic current density and time to accelerate a one-year corrosion reaction of pipeline steel. To validate the appropriate anodic current density, analysis of the potential vs. time curves, thermodynamic analysis, and analysis of the specimen’s cross-sections and products were conducted using a validation algorithm. The results indicated that 0.96 mA/cm² was the optimal impressed anodic current density in terms of a suitable polarized potential, uniform corrosion, and a valid corrosion product among the evaluated conditions. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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14 pages, 2637 KiB

Open AccessArticle

Structural Integrity of Steel Pipeline with Clusters of Corrosion Defects

by Maciej Witek

Materials 2021, 14(4), 852; https://doi.org/10.3390/ma14040852 - 10 Feb 2021

Cited by 20 | Viewed by 2435

Abstract

The main goal of this paper is to evaluate the burst pressure and structural integrity of a steel pipeline based on in-line inspection results, in respect to the grouping criteria of closely spaced volumetric surface features. In the study, special attention is paid [...] Read more.

The main goal of this paper is to evaluate the burst pressure and structural integrity of a steel pipeline based on in-line inspection results, in respect to the grouping criteria of closely spaced volumetric surface features. In the study, special attention is paid to evaluation of data provided from the diagnostics using an axial excitation magnetic flux leakage technology in respect to multiple defects grouping. Standardized clustering rules were applied to the corrosion pits taken from an in-line inspection of the gas transmission pipeline. Basic rules of interaction of pipe wall metal losses are expressed in terms of longitudinal and circumferential spacing of the features in the colony. The effect of interactions of the detected anomalies on the tube residual strength evaluated according to the Det Norske Veritas Recommended practice was investigated in the current study. In the presented case, groups of closely-spaced defects behaved similarly as individual flaws with regard to their influence on burst pressure and pipeline failure probability. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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16 pages, 7606 KiB

Open AccessEditor’s ChoiceArticle

Effects of Ti and Cu Addition on Inclusion Modification and Corrosion Behavior in Simulated Coarse-Grained Heat-Affected Zone of Low-Alloy Steels

by Yuhang Wang, Xian Zhang, Wenzhui Wei, Xiangliang Wan, Jing Liu and Kaiming Wu

Materials 2021, 14(4), 791; https://doi.org/10.3390/ma14040791 - 7 Feb 2021

Cited by 7 | Viewed by 2128

Abstract

In this paper, the effects of Ti and Cu addition on inclusion modification and corrosion behavior in the simulated coarse-grained heat-affected zone (CGHAZ) of low-alloy steels were investigated by using in-situ scanning vibration electrode technique (SVET), scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDS), and [...] Read more.

In this paper, the effects of Ti and Cu addition on inclusion modification and corrosion behavior in the simulated coarse-grained heat-affected zone (CGHAZ) of low-alloy steels were investigated by using in-situ scanning vibration electrode technique (SVET), scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDS), and electrochemical workstation. The results demonstrated that the complex inclusions formed in Cu-bearing steel were (Ti, Al, Mn)-O_x-MnS, which was similar to that in base steel. Hence, localized corrosion was initiated by the dissolution of MnS. However, the main inclusions in Ti-bearing steels were modified into TiN-Al₂O₃/TiN, and the localized corrosion was initiated by the dissolution of high deformation region at inclusion/matrix interface. With increased interface density of inclusions in steels, the corrosion rate increased in the following order: Base steel ≈ Cu-bearing steel < Ti-bearing steel. Owing to the existence of Cu-enriched rust layer, the Cu-bearing steel shows a similar corrosion resistance with base steel. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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13 pages, 2845 KiB

Open AccessArticle

Optimizing the Required Cathodic Protection Current for Pre-Buried Pipelines Using Electrochemical Acceleration Methods

by Nguyen-Thuy Chung, Min-Sung Hong and Jung-Gu Kim

Materials 2021, 14(3), 579; https://doi.org/10.3390/ma14030579 - 26 Jan 2021

Cited by 10 | Viewed by 2912

Abstract

Several corrosion mitigation methods are generally applied to pipelines exposed to corrosive environments. However, in the case of pre-buried pipelines, the only option for corrosion inhibition is cathodic protection (CP). To apply CP, the required current should be defined even though the pipeline [...] Read more.

Several corrosion mitigation methods are generally applied to pipelines exposed to corrosive environments. However, in the case of pre-buried pipelines, the only option for corrosion inhibition is cathodic protection (CP). To apply CP, the required current should be defined even though the pipeline is covered with various oxide layers. In this study, an electrochemical acceleration test was used to investigate the synthetic soil corrosion of a pre-buried pipeline. Potentiodynamic polarization experiments were first conducted to ascertain the corrosion current density in the environment, and galvanostatic measurements were performed to accelerate corrosion according to the operating time. In addition, corrosion current density and the properties of the rust layer were investigated via potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) tests. The variation in surface corrosion was subsequently analyzed via optical microscopy (OM) and X-ray diffraction (XRD) measurements. Finally, an empirical equation for the optimized CP current requirement, according to the pipeline service time, was derived. This equation can be applied to any corroded pipeline. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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16 pages, 5593 KiB

Open AccessArticle

A Novel Testing Method for Examining Corrosion Behavior of Reinforcing Steel in Simulated Concrete Pore Solutions

by Yanru Li, Jiazhao Liu, Zhijun Dong, Shaobang Xing, Yajun Lv and Dawang Li

Materials 2020, 13(23), 5327; https://doi.org/10.3390/ma13235327 - 24 Nov 2020

Cited by 3 | Viewed by 1809

Abstract

In this paper, a new mechanical-based experimental method is proposed to determine the corrosion initiation and subsequent corrosion behavior of steel in simulated concrete pore solutions. The proposed experiment is used to investigate the corrosion of the steel wire under various different conditions [...] Read more.

In this paper, a new mechanical-based experimental method is proposed to determine the corrosion initiation and subsequent corrosion behavior of steel in simulated concrete pore solutions. The proposed experiment is used to investigate the corrosion of the steel wire under various different conditions and to examine the effects of pre-stress level in steel wire, passivation time of steel wire, composition and concentration of simulated concrete pore solution on the corrosion initiation, and subsequent corrosion development in the steel wire. The experimental results show that the reduction rate of the cross-section area of the steel wire increases with the increase of chloride concentration or decrease of pH value in the solution. However, for the case where the chloride concentration is high and the pH value is low, there is a slight decrease in the corrosion rate due to the coating function of the corrosion products surrounding the wire. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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16 pages, 9312 KiB

Open AccessArticle

Experimental Study on Corrosion Performance of Oil Tubing Steel in HPHT Flowing Media Containing O₂ and CO₂

by Yihua Dou, Zhen Li, Jiarui Cheng and Yafei Zhang

Materials 2020, 13(22), 5214; https://doi.org/10.3390/ma13225214 - 18 Nov 2020

Cited by 2 | Viewed by 1953

Abstract

The high pressure and high temperature (HPHT) flow solution containing various gases and Cl⁻ ions is one of the corrosive environments in the use of oilfield tubing and casing. The changing external environment and complex reaction processes are the main factors restricting [...] Read more.

The high pressure and high temperature (HPHT) flow solution containing various gases and Cl⁻ ions is one of the corrosive environments in the use of oilfield tubing and casing. The changing external environment and complex reaction processes are the main factors restricting research into this type of corrosion. To study the corrosion mechanism in the coexistence of O₂ and CO₂ in a flowing medium, a HPHT flow experiment was used to simulate the corrosion process of N80 steel in a complex downhole environment. After the test, the material corrosion rate, surface morphology, micromorphology, and corrosion product composition were tested. Results showed that corrosion of tubing material in a coexisting environment was significantly affected by temperature and gas concentration. The addition of O₂ changes the structure of the original CO₂ corrosion product and the corrosion process, thereby affecting the corrosion law, especially at high temperatures. Meanwhile, the flowing boundary layer and temperature changed the gas concentration near the wall, which changed the corrosion priority and intermediate products on the metal surface. These high temperature corrosion conclusions can provide references for the anticorrosion construction work of downhole pipe strings. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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12 pages, 2315 KiB

Open AccessArticle

The Corrosion Features of Q235B Steel under Immersion Test and Electrochemical Measurements in Desulfurization Solution

by Peng Gong, Guangxu Zhang and Jian Chen

Materials 2020, 13(17), 3783; https://doi.org/10.3390/ma13173783 - 27 Aug 2020

Cited by 5 | Viewed by 2377

Abstract

With the continuous tightening marine diesel engines emission standards, removing sulfur oxides (SO_X) by sodium hydroxide solution absorption is a highly efficiency and economic method, which has been a hot area of research. The ensuing desulfurization solution is a new corrosive [...] Read more.

With the continuous tightening marine diesel engines emission standards, removing sulfur oxides (SO_X) by sodium hydroxide solution absorption is a highly efficiency and economic method, which has been a hot area of research. The ensuing desulfurization solution is a new corrosive system, the aim of this paper is to ascertain the corrosion feature of Q235B steel in desulfurization solution, which lays a theoretical foundation for industrialization. For this purpose, mass loss, electrochemical techniques and surface analyses were applied. The results of mass loss highlight a reduction in the corrosion rate with 35 days of immersion. Higher exposure time increased the compactness of the corrosion product layer and changed phase composition. These conclusions are supported by surface analyses, such as X-ray diffraction and scanning electron microscope. However, electrochemical results showed that the polarization resistance R_p was fluctuant. Both of R_p and charge transfer resistance R_t reach a maximum after immersing 21 days. In addition, although the sediments attached to the steel surface could inhibit corrosion, pitting corrosion aggravated by hydrolyzation of FeSO₄ should be given more attention. Full article

(This article belongs to the Special Issue Corrosion Properties and Mechanism of Steels)

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