Corroded Steel Samples Research Articles

Investigations of corrosion inhibition of ethanolic extract of Dillenia suffruticosa leaves as a green corrosion inhibitor of mild steel in hydrochloric acid medium

The utilization of plant extracts as environmentally friendly corrosion inhibitors has garnered considerable interest in the field of metallic corrosion protection. The primary objective of this study was to explore a new approach for utilizing Dillenia suffruticosa leaves extract (DSLE) to provide corrosion protection for mild steel (MS) in a molar hydrochloric acid solution. The phytocompounds responsible for corrosion prevention were extracted using ethanol with Soxhlet apparatus. The effectiveness of the extract as a corrosion inhibitor was evaluated through gravimetric and electrochemical methods, along with surface analysis of the corroded steel samples. This analysis involved the use of scanning electron microscopy (SEM) and Fourier-transformed infrared spectroscopy (FTIR) to examine the specimens with and without addition of the extract as inhibitor. The findings demonstrate that DSLE exhibits notable efficacy as a corrosion inhibitor for MS in an acidic environment. The inhibition efficiency (IE) demonstrates a positive correlation with the concentration of the extract, ultimately reaching a maximum value of 81.4 % at the optimum concentration of 1000 mg/L of the extract investigated. Potentiodynamic polarization data revealed that the DSLE functions as a mixed-type inhibitor.

Classification of pitting corrosion damage in process facilities using supervised machine learning

AbstractCorrosion is widely known to be a major cause of the failures in process facilities. Prediction of corrosion damage is therefore essential for industries to manage the availability of their assets. This research aims to investigate the application of supervised machine learning methods for the classification of pitting corrosion damage. Several machine learning classifiers, namely ensemble methods, support vector machine (SVM), K‐nearest neighbours, and the decision tree are used to classify the extent of pitting corrosion damage in corroded steel samples. To simulate the corrosion of the steel samples, a series of laboratory experiments were conducted. After processing the results using appropriate statistical methods, the corrosion data was used to train the machine learning models. The trained models can predict the class of corrosion damage with acceptable accuracy using the material and environmental specifications of the samples. Additionally, a discussion on the selection of machine learning techniques which classify corrosion damage using a risk‐based approach is provided. With their optimal accuracy and lower risk of misclassification, the SVM and AdaBoost models perform better than the other studied models.

Characterizing steel corrosional features in atomic force microscopy: A Sobel edge detection approach

One of the fundamental characterizations in assessing a material’s surface its surface roughness. Here, we introduce a computational method using measured atomic force microscopy surface roughness data to perform Sobel edge detection of heterogeneity on corroded steel samples. This method enables the spatial mapping of corrosion-induced features and general inconsistencies on a sample’s surface using a freely available algorithm written in the Python computing language. The non-optical method has been tested on three different grades of steel, and results indicate reasonable accuracy when compared to visual observations made from grayscale optical data.

Corrosion Behavior of 20G Steel in Saline (Na2SO4) Circumstances at High Temperature/Pressure

Abstract To study the corrosion characteristic of 20G steel in saline circumstances with sodium sulfate (Na2SO4), a series of corrosion experiments are implemented on a novel setup. The corroded steel samples are analyzed by X-ray photoelectron spectroscopy and X-ray diffraction. The results indicate that the effect of salinity on corrosion products in the gas phase is greater than that in the liquid phase. FeOOH is easier to form in the liquid phase than in the gas phase. The salinity of steam could promote the generation of Fe2O3. The relative content of Fe2O3 within the corrosion products that contained Fe in the gas/liquid phase increases from 49.68%/36.30% (Na2SO4 concentration in solution, c = 0) to 95.70%/74.55%, separately (c = 4 g L−1). The salinity has an inhibiting effect on the generation of FeOOH. In deionized water, the relative contents of FeOOH within the corrosion products that contained Fe are 36.01% (gas phase) and 56.43% (liquid phase), respectively. FeOOH hardly occurs as c = 4 g L−1. For corroded surfaces in Na2SO4 deposit, the main compositions detected are iron oxides (Fe2O3 and Fe3O4) and iron (Fe).

Inhibition of Steel Corrosion Rate in Sulfuric Acid Solution with Various Concentrations Using Soursop (Annona muricata L.) Leaf Extract Inhibitor

Exploration of soursop leaf extract (Annona muricata L.) as one of the natural inhibitors against the corrosion process. The objective of this research is to determine the effect of the extract on inhibiting the corrosion rate of steel. The corrosion rate is determined by the decrease in the mass of the steel during immersion in various concentrations of sulfuric acid solutions, namely 0.01, 0.05, and 0.1 M, and optical microscopy will be used to analyze the corroded steel samples. This study consists of several stages: soursop leaf extraction, steel sample preparation, inhibitor solution and corrosive media preparation, immersion, and characterization. The extraction method is performed by maceration for 168 hours to obtain the extract. The highest corrosion inhibition efficiency obtained is 63.1% with the presence of 600 ppm inhibitor in 0.01 M sulfuric acid solution, while the lowest corrosion inhibition efficiency obtained is 14.8% with the use of 200 ppm inhibitor in 0.1 M sulfuric acid solution. The types of corrosion that occur on the steel surface are uniform corrosion and pitting corrosion.

Corrosion of 1.4016 Ferritic Steel by Urea at High Temperature

The corrosion behavior of a ferritic unstabilized stainless steel 1.4016 during decomposition of aqueous urea solution at high temperature has been investigated. Corrosion was obtained from 100 h of cyclic heating (from room temperature up to 600 °C) and injection of aqueous urea solution on the steel plate in a laboratory-scale test bench. The evaluation procedure covered the metallographic analysis of corroded steel samples by high-resolution scanning electron microscopy (HR-SEM) and transmission electron microscopy (TEM). Uniform corrosion underneath deposits was found as one of the drivers for degradation of the steel. Damage happened by high-temperature depassivation of stainless steel due to the excess of the aggressive medium. Besides uniform corrosion, a nitridation layer underneath surface oxides together with chromium carbonitride particles precipitated through the whole depth of the sample was identified resulting in intergranular attack.

Effect of corrosion on soil-structure interfacial shearing property and bearing capacity of steel foundation in submarine soil environment

As a common type of foundation in ocean engineering, steel foundation encounters great corrosion risk and serious safety hazards throughout its lifecycle. Besides reducing the thickness of steel members, corrosion also has a significant impact on the soil-structure interfacial shearing property by changing the roughness characteristics of steel surface, and eventually affects the bearing capacity of steel foundation in submarine soil environment. In this study, electrolytic accelerated corrosion experiments are conducted first to prepare corroded steel samples suffered different degrees of corrosion. Then, the effect of corrosion on the soil-steel foundation interfacial shearing property is investigated by interfacial shearing experiment and discrete element numerical simulation. The analysis results show that the interface shearing strength under different corrosion degrees can be regarded as following Mohr-Coulomb strength theory. The shearing strength parameters, i.e. the interfacial cohesion and interfacial friction coefficient, increase with the corrosion degree. Finally, the influences of corrosion on the bearing capacity of a steel pipe pile foundation are studied by finite element simulation, with considering the steel thickness reduction and the variation of soil-steel interfacial shearing strength. The numerical results demonstrate the necessity of considering the variation of the interfacial shearing property induced by corrosion.

Mathematical Model of Surface Topography of Corroded Steel Foundation in Submarine Soil Environment

For the corrosion risk of steel structures in the marine environment, the topography characteristics of corroded steel surfaces were paid little attention to, which has a significant effect on the mechanical properties of the interface between steel foundation and soil medium. An effective mathematical model for reconstructing the topography of corroded steel surface is very helpful for numerically or experimentally studying the soil-corroded steel interaction properties. In this study, an electrolytic accelerated corrosion experiment is conducted first to obtain corroded steel samples, which are exposed to submarine soil and suffer different corrosion degrees. Then, the surface height data of these corroded steel samples are scanned and analyzed. It is found that the height of surface two-dimensional contour curves under different corrosion degrees obeys the Gaussian distribution. Based on the spectral representation method, a mathematical model is developed for the profile height of the corroded steel surface. By comparing the standard deviation, arithmetic mean height and maximum height of reconstructed samples with those of experimental samples, the reliability of the developed mathematical model is proved. The proposed mathematical model can be adapted to reconstruct the surface topography of steel with different corrosion degrees for the following research on the shearing behavior of soil-corroded steel interface.

Corrosion of Stainless Steel by Urea at High Temperature

The corrosion mechanism of stainless steel caused by high temperature decomposition of aqueous urea solution has been investigated. The relationship between aqueous urea solution, its thermal decomposition products and the corrosion mechanism of stainless steel is studied by FTIR spectroscopy, SEM and stereo microscopy. The corroded steel samples, together with deposits, were obtained from the injection of aqueous urea solution on the steel plate at high temperatures. Uniform corrosion underneath the deposits was proposed as the main driver for corrosion of the steel samples. At the crevices, corrosion due to the used geometry and due to high temperature cycling could play an acceleration role as well.

Re-analyzing the mechanical properties of corroded steel bar based on similarity measure

In this paper, the records of steel bar mechanical behavior that are similar to condition-specific data are sifted from the corroded steel bar database based on a similarity measure method. The similarity of mechanical behavior between the corroded steel bar database and the corroded steel samples under certain conditions are analyzed by the similarity measure S. The sifted records can be used for linear regression analysis and combined with limited condition-specific data to obtain a larger coefficient of determination \(R^{2}\) as there are more similar steel bar corrosion characteristics that are relevant to the condition-specific data. It is found that nearly all of the sifted records in the database share the same certain conditions which are similar to the condition-specific data.

Study of Microbially Influenced Corrosion in the Presence of Iron-Oxidizing Bacteria (Strain DASEWM2)

The present study deals with the investigation of microbially influenced corrosion of mild steel by the iron-oxidizing bacterium (IOB), Pseudomonas sp. strain DASEWM2, using electrochemical tests, immersion tests, and surface analysis. The corrosion rate obtained by Tafel plots was higher after exposure of ~ 24 h to 72 h when the concentration of sessile cells and constituents of extracellular polymeric substances were high. In inoculated media, cyclic polarization curves show lower pitting potential, repassivation potential, and large area under the hysteresis loop, indicating higher susceptibility of steel to localized corrosion. Immersion tests show higher corrosion rate (0.252 ± 0.05 mpy) and large deep pits in the open area (maximum pit depth 140 ± 8 µm) and under crevice (maximum pit depth 95 ± 4 µm) indicating a higher degree of corrosion in inoculated media. Corrosion products formed on corroded steel samples were analyzed using EDAX, XRD, and FTIR techniques. Goethite and lepidocrocite are the main corrosion products in the case of inoculated media. In contrast, lepidocrocite and iron hydrogen phosphate are the main corrosion products in the case of control media. The absence of iron hydrogen phosphate, a protective type of corrosion product, on steel exposed to inoculated media may be responsible for observing a higher degree of corrosion due to bacteria.

Pomelo Peel Extract as Corrosion Inhibitor for Steel in Simulated Seawater and Acidic Mediums

This study was aimed to establish the possibility of using an eco-friendly plant-based pomelo peel with different concentrations to formulate a novel corrosion green inhibitor for steel applications in 3.5% NaCl and 0.1 M HCl solutions at 30 °C. The corrosion rate and inhibition efficiency were evaluated using weight loss, potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) techniques corresponded with surface morphology characterization of the corroded steel samples without and with inhibitors using a scanning electron microscope (SEM) and energy-dispersive x-ray analysis (EDS). Based on the Fourier-transform infrared spectroscopy (FTIR) results, it was found that the pomelo peels extract is a mixture of the chemical compounds of naringin (C27H32O14), auraptene (C19H22O3) and naringenin-4′-O-glucoside (C21H22O10). The results were also indicated that there is a remarkable improvement in the inhibition efficiency and corrosion rate of low-carbon steel after the addition of inhibitor, and as well as the immersion time was profound to have a significant effect on the corrosion behavior of the different concentrations of inhibitor. The pomelo peels extract of 8000 ppm concentration gave the best inhibition efficiency of 74.64 and 71.15% in 0.1 M HCl and 3.5% NaCl, respectively. The adsorption isotherm of pomelo peels within different concentrations on the steel surface conforms Langmuir’s isotherm, and the thermodynamic parameters of Kads and ΔG have also been calculated and discussed.

Experimental study of the corrosion effect on the elastic properties of steel plates by ultrasonic method

The corrosion effect on the acoustics and elastics parameters of steel plates corroded are studied by ultrasonic techniques. A new method is developed to measure these parameters as a function of the immersion time in the acid solution HCl (corrosion). Lamb waves (plate driven mechanical waves) were selected to perform the different types of inspection required. Their high level of sensitivity to variations in thickness made it a logical choice to achieve the objectives of this work as well as a relevant and interesting research topic. They also offer the advantage of allowing the inspection of a part faster than conventional volume wave methods (point - by - point inspection). The dispersion of the Lamb modes generally causes problems of interpretation of the signals but offers, however, certain advantages as regards the measurement of thickness via certain measurements of the speed of these modes. The Ultrasonic testing is based on the measurement of ultrasonic parameters ie longitudinal and transversal velocities in the corroded steel samples. The corrosion resulting from corroded steel is analyzed by monitoring changes in ultrasonic parameters. The obtained results show that the proposed method is very efficient to characterize the corrosion effect on the elastic properties of steel plates, for acoustic characterization purposes.

Identifying corrosion of carbon steel buried in iron ore and coal cargoes based on recurrence quantification analysis of electrochemical noise

The effect of bulk cargo materials - iron ore and coal – on the corrosion of cargo hulls in carriers was investigated using electrochemical noise. Two reference corrosion systems were set up with the steel samples in contact with moist silica sand and immersed in NaCl solution, which generated localised corrosion and general corrosion, respectively. The electrochemical noise was measured and recurrence quantification analysis was used to extract feature variables. A random forest model using these feature variables as predictors was able to discriminate between the two reference corrosion systems. This model was successfully applied to the assessment of carbon steel corrosion in iron ore and coal. The results predicted by the model were in agreement with visual and microscopic observations of the relevant corroded steel samples. This work provides a novel analytical approach to future on-line monitoring of carrier structures in contact with bulk cargoes.

Evaluation of chitosan and carboxymethyl cellulose as ecofriendly corrosion inhibitors for steel

The study was aimed at establishing the possibility of using eco-friendly natural polymers to formulate corrosion inhibitors for sweet oil field environment. Against this background, the performance of two natural polymers; chitosan and carboxymethyl cellulose (CMC) as single component corrosion inhibitors in comparison with a commercial inhibitor formulations, on API 5L X60 pipeline steel in CO2 saturated 3.5% NaCl solution were investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) techniques; complemented with surface morphology characterization of the corroded steel samples without and with inhibitors using scanning electron microscope (SEM). The results indicate that there is a remarkable difference in inhibition efficiency of each inhibitor on the API 5L X60 steel and the commercial inhibitor formulations. Inhibition efficiency increased with the increase of inhibitors' concentrations. Immersion time was found to have a profound effect on the corrosion inhibition performance of all the inhibitors. Also the inhibition efficiency was found to decrease with the increase in temperature. Potentiodynamic polarization results reveal a mixed-type inhibition for all inhibitors. The adsorption of each inhibitor on the steel surface obeys Langmuir's isotherm.

Effect of temperature and fluid speed on the corrosion behavior of carbon steel pipeline in Qatari oilfield produced water

Metals integrity, such as carbon steel used in pipeline network can be seriously damaged by produced water causing serious corrosion problems. This can result in significant threats to safe operation of the oilfield facilities and leads to considerable economic losses. In this study, the effect of produced water from the North oilfield of Ras Laffan in Qatar on corrosion and scaling of carbon steel is investigated using electrochemical methods. The specimen rotation speed ranged from 0 to 2m/s and temperature between 20 and 60°C were used as test parameters for the study. X-ray power diffractometer (XRD) and scanning electron microscopy (SEM) techniques were employed in the analysis of the corroded steel samples. It was found that the corrosion rate increased with increasing temperature and specimen rotation speed. These results also showed that the steel reacted with the corrosive ions at the early stage of its exposure to the produced water leading to the formation of corrosion products on the steel surface in which CaCO3 scale layer were deposited on the surface of the specimen as loose products due to the presence of large amounts of Ca2+ and HCO3− ions contained in the Rass Lafan oilfield produced water. More so, pitting and cracks were observed on the steel surface which increased as the temperature and specimen rotation speeds were increased, suggesting localized corrosion mechanism.

Synthesis of phosphorylated rust metamorphoses and its comparative corrosion study on steel samples simulated in different atmospheres

Purpose The aim of this study was to evaluate the corrosion inhibition efficiency of steel samples in different environments before and after the treatment with rust metamorphose (RM), which is formulated in this research study and shows excellent adherence over the rusted surface of substrate because of the presence of the P-O-Fe bond. Design/methodology/approach An RM solution (phosphorylated polyphenol) was synthesised and characterised using Fourier transform infrared spectroscopy (FT-IR), and then the degree of protection offered by it to steel surfaces with and without the treatment with the RM solution in different atmospheres was evaluated;. Before and after treating with the RM solution, the corroded steel samples were characterised using X-ray diffraction (XRD), FT-IR, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The study of the passive behaviours of the corroded steel samples and RM-treated steel samples was done in different simulated atmospheres. Findings This RM solution is phosphorylated polyphenol solution (proved by FT-IR), which acts as a corrosion inhibitor on corroded steel surfaces because of the formation of a passive and symmetric adherent layer of phosphorylated polyphenol–iron complex (confirmed by FT-IR, XRD, EDS, SEM and adhesion X test). The significant improvement in corrosion resistance in splash conditions of 3.5 per cent NaCl, tap water and 1.5 per cent Na2SO4 was found with the treatment of phosphorylated polyphenol-based RM. Originality/value The development of RM and its characterisation with performance evaluation in different atmospheres is a novel approach in this research.

Corrosion process of D32 steel used for offshore oil platform in splash zone

Purpose – This paper aims to study the corrosion behavior of D32 steel suffered to marine splash zone. Type D32 structural steel has good mechanical properties and is commonly used for offshore oil platform construction in China. To ensure the safety of marine steel structure, it is important to study the corrosion process of D32 steel in the splash zone. Design/methodology/approach – The corrosion behavior of D32 steel in splash zone environments was studied using polarization curves and electrochemical impedance spectroscopy. The electrochemical results were obtained from the corroded steel samples exposed in the splash zone of a bespoke simulate device, while corrosion morphologies and corrosion products of the steel samples were characterized using scanning electron microscopy and X-ray diffraction. Findings – In wet–dry cyclic exposure, the reaction was a self-perpetuating process of chemical oxidation and electrochemical reduction. The rust itself took part in the reduction processes and, hence, increased the corrosion rate of the steel samples. Originality/value – Finally, the corrosion process of D32 steel in splash zone is considered.

Sulfate-reducing bacteria of the genus Desulfovibrio from south vietnam seacoast

Nine strains of sulfate-reducing bacteria were isolated from a biofouling of corroded steel samples incubated in a marine environment near Nha Trang, South Vietnam. Sulfate-reducing bacteria were obtained from all samples with black corrosion products (in rust-filled metal cavities, beneath the Balanus and oyster booths, and beneath Bryozoa or algal colonies). Analysis of the 16S rRNA gene sequences of these strains showed that they belonged to the genus Desulfovibrio, with D. salexigens, D. marinisediminis, D. alaskensis, D. bizertensis D. indonesiensis, and D. dechloracetivorans as the closest phylogenetic relatives (98–99% similarity). According to the 16S rRNA gene sequencing, one Desulfovibrio isolate was related to “D. caledoniensis”, although the similarity did not exceed 97.0%. All strains utilized hydrogen (in the presence of acetate and CO2), lactate, pyruvate, formate, and fumarate, but not acetate. Utilization of other substrates varied from strain to strain. Some isolates were capable of slow autotrophic growth with H2 as the sole electron donor. D. indonesiensis and D. alaskensis strains were tolerant to long-term exposure to atmospheric oxygen exposure and could grow in the presence of 0.1% O2 in the gas phase.

Adsorption and Corrosion Inhibition Behavior of L-Cystine and Synergistic Surfactants Additives on Mild Steel in 0.1 M H2SO4

The adsorption and corrosion inhibition behavior of mild steel in 0.1 M H2SO4 in presence of L-cystine and L-cystine in combination with surfactants sodium dodecyl sulfate and cetyltrimethyl ammonium bromide at 30–60°C was investigated using weight loss and potentiodynamic polarization measurements. Inhibition efficiency of L-cystine is synergistically enhanced on addition of surfactants. Surface morphology of corroded steel samples was evaluated using scanning electron microscopy and atomic force microscopy, which further confirmed the existence of an adsorbed protective film on the mild steel surface. Calculated thermodynamic parameters reveal that adsorption process is spontaneous and obey Langmuir adsorption isotherm.