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This article aims to investigate the atmospheric corrosion of carbon steel in a marine environment abundant in hydrogen sulfide (H2S) resulting from the decomposition of Sargassum seaweed. To accomplish this, four sites with varying degrees of impact were chosen along the coast of Martinique. The corrosion rates of steel were evaluated through mass loss measurements. After one year of exposure, the corrosion rates were notably high, particularly in atmospheres rich in Cl− ions and H2S, ranging from 107 µm to 983 µm. Complementing these findings, surface and product morphologies were characterized using scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). These analyses revealed a significant degradation of the corrosion surface in the most affected atmospheres compared to those unaffected by Sargassum seaweed strandings. Lepidocrocite (γFeOOH) was identified as the predominant product regardless of the exposure atmosphere. However, goethite (αFeOOH) was found to be present in atmospheres most impacted by H2S. [ABSTRACT FROM AUTHOR]

The laser drilling of carbon steel is always suffered from the formation of slag, the presence of cutting burrs, the generation of a significant quantity of spatter, and the incomplete penetration of the substrate. In order to avoid these defects formed during the laser drilling of carbon steel, the COMSOL multi-physics simulation method was used to model and optimize the laser drilling process. Considering the splash evolution of the material during the complex drilling process, the transient evolution of the temperature field, the flow of the molten fluid, the geometrical changes, and the absorption of the laser energy during the laser drilling process were investigated. The simulated borehole dimensions are consistent with the experimental results. The process parameters have a great influence on the fluid flow pattern and material slag splashing. The laser power has a significant effect on the laser processing compared with the process parameters. With the increase in laser power and the decrease in laser heat source radius, the time required for perforation is reduced, the flow of melt is accelerated, the perforation efficiency is increased, and the hole wall is smoother, but the degree of spattering is greater. The optimized process parameters were obtained: laser heat source radius of 0.3 mm, laser power of 3000 W. These findings can help reduce the machining defects in carbon steel with excellent mechanical properties by optimizing the laser drilling processing parameters. [ABSTRACT FROM AUTHOR]

Urgent action is required to mitigate the severe corrosion of carbon steel in low-latitude regions. The combination of high humidity, temperature, and salinity in these areas significantly accelerates steel corrosion, posing a substantial threat to the service safety of offshore engineering equipment. This study aims to elucidate the atmospheric corrosion mechanisms of 45# steel in low-latitude coastal areas. Samples of 45# steel were exposed to atmospheric conditions over various durations in the following three geographically distinct regions: Guangzhou, Wanning, and the South China Sea. The corrosion rates were calculated using weight loss tracking and potentiodynamic polarization measurements, while surface corrosion products were examined using X-ray diffraction (XRD) tests. The findings indicate a clear correlation between the corrosion rate of 45# steel and the latitude and specific location of the test area, with the highest to lowest rates observed in the South China Sea, Wanning, and Guangzhou, respectively. Similarly, the extent of corrosion rust penetration in defective coatings followed the same order. Moreover, the protection ability index (PAI) calculations revealed that none of the tested samples formed a protective corrosion film. [ABSTRACT FROM AUTHOR]

The structural design of steel–titanium composite plates significantly affects their corrosion resistance. To investigate the impact of defects of different shapes and sizes on the corrosion behavior of steel–titanium composite plates, this study designed six types of defects and conducted a series of characterization tests. The results showed that due to the galvanic interaction between carbon steel and titanium alloy, small defects initially accelerate corrosion, resulting in 50% to 200% more corrosion weight loss compared to large defects. However, in the later stages of immersion, the corrosion rate of small defects decreased by up to 35%, which was attributed to the accumulation of protective corrosion products. Additionally, there is an inverse relationship between the corrosion rate and the thickness ratio of the composite plate. The reduction in the area of Q345B also results in additional corrosion loss of up to 32%. [ABSTRACT FROM AUTHOR]

Flat-rolled steel sheets are one of the major products of the metal industry. Strip steel's production quality is crucial for the economic and safety aspects of humanity. Addressing the challenges of identifying the surface defects of strip steel in real production environments and low detection efficiency, this study presents an approach for strip defect detection based on YOLOv5s, termed SDD-YOLO. Initially, this study designs the Convolution-GhostNet Hybrid module (CGH) and Multi-Convolution Feature Fusion block (MCFF), effectively reducing computational complexity and enhancing feature extraction efficiency. Subsequently, CARAFE is employed to replace bilinear interpolation upsampling to improve image feature utilization; finally, the Bidirectional Feature Pyramid Network (BiFPN) is introduced to enhance the model's adaptability to targets of different scales. Experimental results demonstrate that, compared to the baseline YOLOv5s, this method achieves a 6.3% increase in mAP50, reaching 76.1% on the Northeastern University Surface Defect Database for Detection (NEU-DET), with parameters and FLOPs of only 3.4MB and 6.4G, respectively, and FPS reaching 121, effectively identifying six types of defects such as Crazing and Inclusion. Furthermore, under the conditions of strong exposure, insufficient brightness, and the addition of Gaussian noise, the model's mAP50 still exceeds 70%, demonstrating the model's strong robustness. In conclusion, the proposed SDD-YOLO in this study features high accuracy, efficiency, and lightweight characteristics, making it applicable in actual production to enhance strip steel production quality and efficiency. [ABSTRACT FROM AUTHOR]

In this study, the corrosion properties of plasma-sprayed Al2O3 coating (APSS) with a topcoat of zirconium-based conversion coating (ZrCC) and organofunctional silane coating (3-glycidyloxypropyltrimethoxysilane; GPTMS) on carbon steel are investigated in detail. Additionally, the bond strength of plain steel bars coated with this system in normal strength concrete are newly tested. The APSS coating exhibits significant porosity, with unfavourable open pores limiting the barrier protection effect. In contrast, the surface roughness (Ra) significantly increases, improving the bond strength between steel bars and concrete. Such increase in carbon steel roughness improves bond strength in concrete. The synergic application of ZrCC and GPTMS topcoats significantly enhances the corrosion resistance of the base coat (inhibition effect). The character of the GPTMS coating increases the wettability of the APSS coating, which further positively contributes to bond strength between plain bars and concrete. It is demonstrated that when the ZrCC topcoat is applied without GPTMS, the corrosion resistance increases insignificantly and the surface wettability decreases, negatively affecting bond strength in comparison with carbon steel coated using an APSS base coat only. [ABSTRACT FROM AUTHOR]

Conventionally bisphenol A epichlorohydrin (BPA-EC) is used as epoxy resin and cycloaliphatic amine is used as a curing agent for industrial corrosion mitigation. However, due to their noticeable toxicity, alternative curing agents and decreasing the conventional compounds in the coating is a demanding task. Aminopropyltriethoxysilane can be an alternative curing agent and lignin can partially replace BPA-EC , as the preliminary adhesion study of the developed coating suggested. However, other characteristics of the coating need to be examined to evaluate the coating holistically. Hydrophobicity is such a characteristic, which plays a leading role in enhancing the anti-corrosivity of the coating, especially for coating, implemented on submerged metallic bodies. The current study attempted to find the justification of BPA-EC in terms of hydrophobicity. The response surface methodology has been followed using the Box–Behnken design model to investigate the respective and cumulative effect of each element. Initially, the model has a P value of 0.0198, with some of the terms not significant. Thus, a modified model has been introduced keeping only the terms, close to the significant p-value of 0.05. Finally, a P-value of 0.0001 has been achieved. Experimental verification of the response values exhibited an average error of 9.84%. The result showed a non-linear association between the respective constituents. Statistics showed that BPA-EC positively impacts hydrophobicity. Thus, to maintain the hydrophobicity rather than 100% replacement by lignin, a minimum level of bisphenol epichlorohydrin is obligatory; ensuring the legitimacy of the constituents in the coating. [ABSTRACT FROM AUTHOR]

Repassivation characteristics of carbon steel experienced thermal cycles in tropical marine environments were investigated in a simulated concrete pore solution (SCPS). The results suggested that the damage of passive films on the carbon steel mainly occurred during the cooling process in thermal cycles. The damaged passive films gradually recovered in the SCPS, and the duration of repassivation extended with the amplitude of thermal cycles and cyclic number in the high-amplitude thermal cycles (20–60 °C and 20–70 °C), while it was not significantly affected by the cyclic number in the low-amplitude thermal cycles (20–40 °C and 20–50 °C). [ABSTRACT FROM AUTHOR]

The use of solenoid magnets in welding processes has attracted attention due to their potential to influence the properties of welded joints. This research investigates the effect of the size of the magnetic induction solenoid on the tensile strength and impact toughness of welds between mild steel and medium carbon steel. Welding experiments were carried out using various sizes of solenoid magnets (0; 1.71mT; 2.11mT; 2.31mT; 2.60mT), and the welding results were tested for tensile strength and impact toughness. The findings show that the size of the magnetic induction solenoid has a significant effect on the mechanical properties of the weld. The larger induction size in this study increased the tensile strength of the welded joint, namely 431.576 N/mm2 without induction and 533.33 N/mm2 with induction. Meanwhile, the impact toughness of welded joints also increases, namely 95.92N.m without treatment and 217.35N.m with induction. [ABSTRACT FROM AUTHOR]

Due to issues with the corrosion problem in the petroleum industry and the use of less ecologically acceptable corrosion inhibitors, great emphasis, within research on corrosion inhibitors, is now being put on green corrosion inhibitors (GCIs). In this study, Lady's mantle flower extract (LMFE) has been observed as a plant-based GCI for carbon steel in a simulated CO2-saturated brine solution. The effectiveness of the inhibitor in static and flow conditions has been determined using potentiodynamic polarization with Tafel extrapolation and electrochemical impedance spectroscopy (EIS). In static conditions, the inhibitor has been tested at concentrations from 1 g/L to 5 g/L with an increment of 1 g/L per measurement, while, in dynamic (flow) conditions, the inhibitor has been tested at concentrations from 3 g/L to 6 g/L with an increment of 1 g/L per measurement. All measurements were performed at room temperature. EIS and potentiodynamic polarization methods showed that LMFE achieves maximum effectiveness in protecting carbon steel from corrosion when added at a concentration of 4 g/L in static conditions and at a concentration of 5 g/L in flow conditions. The test methods proved that the inhibitory effectiveness of LMFE is greater than 90% in both test conditions (static and flow). The inhibitor efficiency was attributed to the adsorption of LMFE on the carbon steel surface, which was demonstrated by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). A biodegradability of 0.96 and a toxicity of 19.34% for LMFE were determined. The conducted laboratory tests indicate that LMFE could be used as an effective corrosion inhibitor for CO2 carbon steel corrosion. [ABSTRACT FROM AUTHOR]

The explanation of the broadening of the x-ray diffraction lines of martensite and appearance of the doublets of the diffraction lines is proposed and is based on the representation of the crystal structure of martensite in carbon steels as a system of the lattice blocks with the C atoms on the axes of the blocks. [ABSTRACT FROM AUTHOR]

The global prevalence of metal corrosion is a significant challenge due to its detrimental effect. Environmentally friendly and non-hazardous alternatives for harmful and poisonous synthetic corrosion inhibitors are urgently necessary due to increasing environmental concerns and regulations prohibiting their application. In this study, indole molecules were employed as carbon steel corrosion inhibitors in acidic conditions. Gravimetrical and scanning electronic microscope (SEM) analysis was used in a preliminary investigation of indole as an organic inhibitor. The results revealed that adding indole to carbon steel before exposing it to sulfuric acid slowed and induced resistance to corrosion. The indole affixed themselves to the steel carbon surfaces, producing a barrier/protection for carbon steel. The efficacy of the indole in preventing corrosion was determined through the weight loss method. Temperature and inhibitory concentration effects on inhibition effectiveness under varying parameters were also reported. The temperatures employed were between 298 K and 328 K, while the inhibitor concentrations ranged from 1.2 × 10−3 M to 7.6 × 10−3 M, and both parameters significantly influenced corrosion inhibition effectiveness. The inhibitory mixture attained optimum efficacy in inhibiting corrosion, at 81 %, when the lowest and highest respective temperature and concentration were applied. The kinetic analysis was conducted under a range of temperatures to determine the reaction mechanisms of the inhibitor. The thermal adsorption isotherm of the inhibitor indicated that the surface adhered to Langmuir's adsorption isotherm. Additionally, investigations on corrosion and inhibition using the electrochemical impedance spectroscopy method (EIS) were conducted. This study can provide in-depth knowledge for advancing inhibitory science and engineering to enhance corrosion resistance in acidic media.

Cathodic protection (CP) in combination with organic coating is applied as a secondary technique to mitigate corrosion of buried steel in an effort to prolong the lifespan of the buried steel pipeline. This study was aimed at developing and applying an adequate technique for monitoring the electrochemical behaviour of buried steel in the presence of CP. A modified voltammetry procedure was applied on carbon steel immersed in simulated soil solution for four days under open circuit potential (OCP) before applying CP for further ten days. Electrochemical impedance spectroscopy (EIS) was also applied at various time intervals to investigate the electrochemistry at the steel/solution interface. The voltammetry experiments revealed that the corrosion rate peaked at 680 µm/yr after three days of being subjected to OCP and then decreased to 411 µm/yr on day four as a result of a passive layer development on the steel surface. The corrosion rate was reduced from 411 µm/yr to 8 µm/yr as result of CP application before fluctuating between 21 and 40 µm/yr. The examination of steel surface via x-ray diffraction revealed the presence of calcareous deposit which resulted due to the application of cathodic protection.

Corrosion is a huge challenge in the manufacturing industry during sticky oxides, grease, and rust removal from metal surfaces. It is often managed by the use of inhibitors and current interest is on sustainable inhibitors with less to zero harmful effects. This study explores the efficacy of Heliotropium curassavicum leaves extracts (HCLEs) in retarding the deterioration of API X60 grade steel in 5 wt% HCl solution and the influence of extracting solvent namely acetone (ACE), ethanol (ETH), water (WAT), butanol (BUT), methanol (MET), isopropanol (ISO), and ethyl acetate (ETA) on performance. The characterization of the HCLEs was achieved by Fourier-transform infrared (FTIR) and ultraviolet–visible (UV–vis) spectroscopies while the weight loss, electrochemical, and surface examination approaches were used for anticorrosion property evaluation. The results disclose that irrespective of extracting solvent, the extracts could suppress the dissolution of the substrate under the studied conditions. The best performance is, however, noted for ethanolic HCLE where 300 mg/L protected the substrate surface by 51.46% at 25 °C. Hence, ethanolic HCLE was selected for detailed studies and results indicate that the steel surface can be protected by 78.42% if 1000 mg/L of extract is used. Furthermore, the performance of the extract improves upon an increase in the temperature of the corrodent. The findings suggest that ethanolic HCLE could be considered for material protection during HCl pickling.

The purpose of this study was to determine the effect of variations in the angle and distance of sandblasting on paint coating quality and corrosion properties of low carbon steel. The success of a coating is highly dependent on surface roughness, so sandblasting is needed to clean and create a surface roughness profile with the aim that the paint can coat the surface perfectly. The test method used in this research is the pull off test method for testing the adhesive strength of paint and open circuit potential (OCP) for testing the corrosion potential. The sandblasting variations used are angles of 45⁰, 60⁰, 75⁰ and nozzle distances of 15 cm, 35 and 50 cm. The tests carried out were roughness, paint thickness, paint adhesive strength and corrosion potential. From the test results it can be concluded that the greater the angle and the closer the sandblasting nozzle distance, the greater the surface roughness. The greater surface roughness affects the paint layer to be thicker and has a high paint adhesion strength, resulting in a smaller corrosion potential. In this study, the highest test results were obtained at an angle of 75⁰ and a distance of 15 cm with a surface roughness value of 5.981 µm, a paint thickness of 115 µm, a paint adhesive strength of 7.28 MPa and an initial corrosion potential position of -0.101 V then a final position of -0.063 V.

Abstract In this work, we study the efficiency of N 1, N 3-dibenzyl-N 1, N1, N 3, N 3-tetramethylpropane-1,3-diaminium chloride, as anticorrosion. This compound exhibits potential as a prospective remedy to stop the deterioration of carbon steel caused by corrosion in 1.0 M HCl. The synthesis of this compound is described in a comprehensive manner, and its composition is supported by a range of precise analytical approaches such as elemental analysis, and mass spectroscopy. Based on the findings of the investigation, the synthesized Gemini ionic liquid demonstrates a robust capacity to slow down the rate at which the metal corrodes. The Prepared compound was evaluation by electrochemical and morphology study. Our results revealed that elevating the inhibitor concentration led to an augmentation in inhibition effectiveness, reaching up to 94.8% at 200 ppm of the synthesized compound at 298 K. It is crucial to emphasize that the recently prepared Gemini ionic liquid is consistent with the Langmuir adsorption model and function as a mixed inhibitor, participating in the physio-chemisorption process of adsorption.

For the corrosion problem within the reclaimed water transport pipelines of a steel company in Hunan, water samples from typical reclaimed water sources were collected for water quality analysis. The corrosion behavior of the reclaimed water transport pipelines was systematically investigated through hanging plate tests, microbial culture counting, electrochemical testing, scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray diffraction(XRD). Moreover, the corrosion inhibitory effects of hydroxyethylidene diphosphonic acid(HEDP), 2-Phosphonobutane-1,2,4-Tricarboxylic Acid(PBTCA) and polyaspartic acid(PASP) were examined. Results showed that the quality of reclaimed water was significantly impacted by biological dephenolization wastewater, blast furnace drainage, total drainage in the direction of five meters and drainage from three water stations. The passivation film on the surface of reclaimed water pipelines was destroyed by the action of Cl- and SO42- in the water, while iron bacteria and sulfate-reducing bacteria promoted corrosion, resulting in the formation of Fe(OH)3 and FeS. After the addition of HEDP and PBTCA corrosion inhibitors, a decrease in the thickness of the corrosion layer was observed, and the corrosion rate fell below the national standard. Following the addition of PASP, the corrosion products on the surface of the hanging plate were loose and porous siderite. In the low-frequency impedance region, Warburg impedance characteristics were displayed, and the corrosion inhibition rate was only 3.9%.

Abstract Furosemide (4-chloro-2-furan-2-ylmethylamino-5-sulfamoylbenzoic acid) was examined as an inhibitor for the corrosion of carbon steel (CS) in 1.0 M HCl. The investigation included mass loss (ML) and electrochemical techniques: potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), and electrochemical frequency modulation (EFM). The efficiency of inhibition rises with increasing Furosemide concentration and temperature. This compound follows the Temkin isotherm with good fit. The presence of varying quantities influences both anodic metal dissolution and cathodic hydrogen evolution. Scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) were used to detect the effect of the compound on the CS surface. The molecular inhibitory effect of Furosemide was demonstrated using quantum chemical calculations, and the molecular simulation results demonstrated the adsorption on the carbon steel surface.

This study involves the synthesis of some porphyrins derivatives, these are termed as 4,4',4'',4'''-(porphyrin-5,10,15,20-tetrayl)tetrakis(N-(6-aminoacridin-3-yl)benzamide) (3a), 4,4',4'',4'''-(porphyrin-5,10,15,20-tetrayl)tetrakis(N-(5-methoxybenzo[d]thiazol-2-yl)benzamide) (3b), 4,4'-(10,20-bis(3-hydroxyphenyl)porphyrin-5,15-diyl)bis(N-(6-aminoacridin-3yl)benzamide) (5a), and 4,4'-(10,20-bis(3-hydroxyphenyl)porphyrin-5,15-diyl)bis(N-(benzo[d]thiazol-2-yl)benzamide) (5b). These derivatives were synthesized using open circuit potential (OCP) and potentiodynamic polarization (PDP) in 0.1 M HCl solution methods. These derivatives were characterized using nuclear magnetic resonance (1H- and 13C-NMR) spectroscopy, mass spectra (ESI), and micro elemental analysis (CHN). The activity of these synthesized materials was investigated as a corrosion inhibitor using carbon steel (CS) as a model for corroded materials. The obtained results showed that the synthesized porphyrins derivatives were effective corrosion inhibitors to 0.1 M HCl solution for CS. In the case of the derivative 3a, a maximum inhibition efficiency (IE%) was recorded and it was around 74%. The derivative 3b showed an IE% of around 68.11%, while the %IE of 5a and 5b were around 18.98% and 45.16%, respectively. The best IE% value that was recorded for the derivative 3a has the potential to be effective anticorrosive coatings for industrial applications and act as mixture inhibitor because their ΔEcorr values are less than 85 mV. On the CS surface following treatment with compound 3a, the inhibitor mechanism for acidic medium (HCl) was investigated.

In the electric discharge machining process, the material is separated from the surface of the work piece by an electric spark, and in the presence of the dielectric material and tool electrode, changes are made on the surface of the work piece. In this project, we investigated the effect of dielectric material and brass tool electrode diffusion on the surface of carbon steel workpiece by means of quantmetric analysis, X-ray diffraction and electrochemical impedance spectroscopy. The effect of the parameters such as electric current intensity (I), pulse on time (ton), pulse off time (toff) and machining time (τ) on the composition of work peace, microstructure and electrochemical corrosion of machined work peace, were investigated. The results of quantmetric analysis showed that with the increase of machining parameters, the amount of diffused copper (from brass tool electrode) and carbon (from pyrolysis of flashing dielectric material) on the surface of machined carbon steel was increased. X-ray diffraction results confirmed that the formation of different phases such as Fe1.92C0.08, Cu4, Cu2 and Fe2 on the surface of workpiece, which was accordance with the quantmetric results. Electrochemical studies showed that during the EDM process, the electrochemical corrosion resistance was increased.

The corrosion of solid boric acid (s-BA) has so far remained unnoticed, which could pose a potential hazard to the safety of boron-containing equipment. In this work, a morphology-dependent corrosion behavior of s-BA was found on Q235 carbon steel encompassing temperatures from 160 °C to 240 °C. Concurrent with the corrosion process, s-BA underwent a heat-induced morphology-transition from block-like into sheet-like/flake-like under the delayed decomposition condition, which emerged as a key contributor to the heightened corrosion rates after reducing the volume of the corrosion system. Through integration with the ex-situ pretreatment experiment, our analysis concludes that this morphology-transition accelerated corrosion by facilitating the generation of more Fe5O5[B6O10(OH)3] ·nH2O and filamentous amorphous corrosion products than FeB12O19·5H2O. The crucial relationship between s-BA with distinct morphologies and different types of borate products was also further expounded.