Steel In Corrosive Environment Research Articles

Enhancing adhesion and durability: A biomimetic approach with dopamine-modified lignin-polydimethylsiloxane coatings

Corrosion causes significant challenges in industrial settings, leading to economic losses and safety concerns. Previously, we developed a lignin-polydimethylsiloxane (lignin-PDMS) coating that exhibited high corrosion resistance. However, the adhesion of the developed lignin-PDMS coating to carbon steel was limited, affecting its overall performance. To address this, we incorporated dopamine (DOPA), known for its strong adhesive properties, as a pre-treatment before applying the coating. It was found that the adhesion and corrosion resistance of lignin-PDMS coated steel could be improved by adjusting the pH value of the DOPA solution. The steel treated with pH 4.5 DOPA solution showed two times higher adhesion strength to the coating than non-treated steel. After the DOPA treatment, the coating can maintain high barrier property for at least 3 months in 1 M NaCl solution, which is even better than commercial gelcoat, demonstrating super corrosion protection. Quartz Crystal Microbalance with Dissipation (QCM-D) and X-ray Photoelectron Spectroscopy (XPS) analyses confirmed the DOPA deposition on the steel surface. Our findings show that the DOPA-lignin-PDMS system is an environmentally friendly and efficient solution for enhancing the durability of steels in corrosive environments.

Evaluation of Corrosion Inhibition of Low-Carbon Steel Using Chamomile Plant Extract

The investigation focused on elucidating the corrosion inhibition mechanism of chamomile extract, serving as an environmentally sustainable inhibitor, across various concentrations (0.2, 0.4, 0.6, 0.8, 1.0 w/v %) applied to carbon steel immersed in a 0.6 M NaCl variations in temperature affect the solution. (303, 313, 323, 333 K). The analytical approach involved Assessment of weight reduction metrics complemented by sophisticated techniques, Scanning Electron Microscopy (SEM), Gas Chromatography-Mass Spectrometry (GC-MS), and Energy Dispersive X-ray Spectroscopy (EDS) were used to analyze the carbon steel surface with and without the extract. The principal aim was to conduct a detailed examination of the development of a layer of adsorption layer. The obtained results consistently validated a positive correlation between inhibition efficiency and extract concentration. SEM imaging visually substantiated a more extensive protective film at higher inhibitor concentrations, and EDS analysis corroborated these findings by detailing the elemental composition of the adsorbed layer. The observed reduction in inhibition efficiency with elevated temperatures suggests a thermodynamic effect, where increased temperatures diminish the adsorption of the inhibitor onto the metal surface. This comprehensive investigation establishes the potential of chamomile extract as an eco-friendly inhibitor for effectively mitigating corrosion on carbon steel in corrosive environments. The pinnacle of inhibition efficiency, reaching 96.55%, was achieved at the concentration of the inhibitor.

Enhancing Corrosion Resistance of Mild Steel in 1M HCl: Investigation of New Benzoxazepine Derivatives Through Synthesis, Electrochemical Analysis, Surface Analysis, XPS, DFT, and Molecular Dynamics Simulation

AbstractThis research delineates the corrosion inhibitory efficiency of two newly synthesized benzoxazepine derivatives – [3,3‐dimethyl‐11‐phenyl‐3,4,5,11‐tetrahydrodibenzo[b,e] [1,4]oxazepine‐1(2 H)‐one (S1)] and [11‐(4‐chlorophenyl)‐3,3‐dimethyl‐3,4,5,11‐tetrahydrodibenzo[b,e][1,4]oxazepine‐1(2 H)‐one (S2)] – on mild steel in 1M HCl milieu. These derivatives were characterized by proton (1H NMR) and carbon (13C NMR) nuclear magnetic resonance spectroscopy. The experimental approach encompassed potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) techniques. The corrosion inhibition efficacy of S1 and S2 was concentration‐dependent, with their efficiencies peaking at 92.0 % and 92.1 %, respectively, at a 10−3 M concentration. Surface characterization, conducted using scanning electron microscopy (SEM), energy‐dispersive X‐ray analysis (EDS), X‐ray diffraction (XRD), contact angle measurements, and X‐ray photoelectron spectroscopy (XPS), corroborated the formation of a protective barrier layer on the mild steel surface. Additionally, using an inductive approach, UV‐visible spectrometry was employed to elucidate the adsorption behaviors of these inhibitors on the steel surface. Density functional theory (DFT) and molecular dynamics (MD) simulations were utilized to decipher the interaction mechanisms and adsorption modalities, unveiling critical insights into the interactions of S1 and S2 with the mild steel surface. This comprehensive analysis highlights the robust corrosion inhibition potential of the newly synthesized benzoxazepine derivatives and illuminates their prospective utility as effective inhibitors for mild steel in corrosive environments.

Unraveling the influence of Mo on the corrosion mechanism of Ni-advanced weathering steel in harsh marine atmospheric environments

Ni-advanced weathering steel holds paramount importance in marine atmospheric environments, especially those with heightened Cl− concentrations. The meticulous compositional design plays a crucial role in establishing a rust layer capable of withstanding intrusion by Cl−, making it imperative for the viability of coating-free weathering steel in marine atmospheric environments. This study explores the corrosion evolution and corrosion-resistant mechanisms within a steady-state rust layer in 3Ni weathering steel, with a particular focus on the role of Mo in challenging marine atmospheric conditions. The findings unequivocally demonstrate that the augmentation of the protective properties of the rust layer is directly correlated with an increase in Mo content, transitioning from 0.5 to 1.5 wt.%. This transition is most evident in the reduction of the corrosion rate for the 3Ni-Mo steel, dropping from an initial 1.74 mm a−1 to a robust 1.31 mm a−1 after 768 h of corrosion exposure. The heightened Mo content expedites the formation of a stable and durable rust layer, significantly enriching the proportion of α-FeOOH within this protective layer. The stabilized rust layer of 3Ni-Mo weathering steel exhibits a distinct three-layer structure, comprising an outer layer primarily of γ-FeOOH, an intermediate layer mainly composed of Fe2O3/Fe3O4, and an inner layer predominantly composed of α-FeOOH and β-FeOOH. Additionally, an alkaline interface enriched with NiFe2O4 and CuFe2O4 develops between the inner layer and the substrate. Firstly, Mo promotes the deposition of MoO2, MoO3, and molybdate on both the inner layer and alkaline steel-rust interface to repair corrosion pits and fill cracks. Secondly, Mo facilitates the generation of compounds such as NiFe2O4 and CuFe2O4, which heightens the electronegativity of the intermediate rust layer and the steel-rust interface, preventing Cl−-induced interface acidification and pitting corrosion. The higher Mo content expedites the formation of this alkaline interface and promotes inner layer densification. Most significantly, Mo creates additional nucleation sites for hydroxide oxides through oxide formation, leading to the formation of nano-sized α-FeOOH and β-FeOOH within the inner layer thereby enhancing the stability and compactness of the inner layer. These synergistic effects fortify the resilience of 3Ni-Mo advanced weathering steel in corrosive environments, ultimately strengthening its capacity to withstand environmental challenges.

Electrochemical and computational investigations of the Thysanolaena latifolia leaves extract: An eco-benign solution for the corrosion mitigation of mild steel

The development of eco-benign corrosion inhibitors is gaining increased attention due to the non-biodegradability and toxic effects of conventional inhibitors. In this study, the anti-corrosive efficacy of Thysanolaena latifolia leaves extract (TLLE) has been evaluated on mild steel in an acidic solution (0.5 M HCl) by employing various approaches including gravimetric assessment, electrochemical measurements, scanning electron microscopy and energy dispersive X-ray spectroscopy. The outcomes demonstrated that with the increased concentration of TLLE from 50 ppm to 1000 ppm, the inhibition efficiency (IE%) elevated up to 93.90 % and the corrosion rate decreased significantly from 2.513 mm/yr to 0.203 mm/yr at 298 K. Moreover, it was revealed that at a higher concentration (1000 ppm), the Rp values increased from 30.784 Ω to 157.83 Ω with an Rct in value of 159.627 Ω cm2 suggesting the defensive film formation by TLLE molecules over the metallic surface. The quantum chemical analytics further underpinned the empirical findings, showing a high ΔE(eV) value of 0.239 and interaction and binding energies of −995.45 and 995.45 for TLLE molecules upon Fe (110) substrate. The findings indicate that TLLE has a promising prospect as an eco-benign and efficient inhibitor for preventing the corrosion of mild steel in corrosive environments.

Understanding the passive behaviour of low-chromium high-strength Hybrid steel in corrosive environments

We investigated the unique passive behaviour of Hybrid steel in de-aerated sulfuric acid and aqueous sodium chloride solutions through corrosion tests, surface analysis, and thermochemical modelling. Electrochemical measurements confirmed that Hybrid steel possesses stainless steel characteristics, including passivity, breakdown, and pitting, akin to low-alloyed stainless steel. Synchrotron hard X-ray photoelectron spectroscopy revealed a dynamically protective nanoscale passive film composed of Fe, Cr, Ni, and Al oxides, contributing to its stainless nature. The presence of Al and Ni enhances Cr’s role in forming a spontaneously passive and protective surface, resulting in exceptional corrosion resistance in acidic and chloride-containing solutions. Hybrid steel’s surface oxides remain robust even beyond the Cr(III)-to-Cr(VI) redox potential, distinguishing it from other stainless steels. This work demonstrates the potential for designing sustainable stainless steel with high-strength properties without requiring the conventional Cr threshold concentration of 10.5 per cent.

Effect of continuous wave laser treatment on the adhesion and durability of Heavy-Duty Paint coated carbon steel

This study explored the feasibility of direct coating of steel surfaces treated with a continuous-wave laser (CWL). The adhesion and corrosion resistance of Heavy-Duty Paint coatings were evaluated on CWL-treated surfaces and compared with those of surfaces treated with molten alumina blasting. The results showed that the surface texture created by CWL provided greater adhesion of the Rc-I coating than its cohesive strength. However, the presence of oxides on the CWL-treated surfaces caused a high cathodic disbondment (CD), which reduced the corrosion resistance of the coated steel in corrosive environments. Decreasing the laser head sweep speed can improve the surface roughness and area but does not address the issues of CD and corrosion creep (CC). This study concludes that, given the limitations of current commercial CWL systems, it is recommended to blast CWL-treated surfaces before coating to improve durability and corrosion resistance in corrosive environments.

Data analysis of the corrosion protection behavior of ginger, tea tree and grapefruit essential oil extracts on low carbon steel in H2SO4 solution

Application of corrosion inhibitors are the most versatile corrosion prevention methods of carbon steels in corrosive environments. Research on non-toxic chemical compounds are ongoing and results from previous study have proven the effectiveness of the compounds. Data on corrosion inhibition of ginger (GG), tea tree (TR) and grapefruit (GF) oil extracts on low carbon steel in 0.5 M H2SO4 are presented. The extracts performed effectively with optimal values of 99.56 %, 98.17 % and 98.32 % at 2.5 % GG, 3.5 % TR and 3 % GF concentrations. Corresponding corrosion rate values are 0.28 mm/y, 1.16 mm/y and 1.49 mm/y. Corrosion rate at 0 % extract concentration is 63.33 mm/y. Performance of TR extract significantly varies with time and concentration with statistical value of 48.21 % and 23.02 %. GG and GF concentration where the only statistically relevant factors for GG and GF performance with statistical values of 68.42 % and 73.20 %. Standard deviation data for GG extracts varied minimally from mean values compared to TR and GF extracts. Results shows 92 %, 18 % and 63 % of GG, TR and GF extracts inhibition data are above 95 % inhibition value at margin of error of 6.99 %, 10 % and 12.19 %.

Experimental investigation of new compound adsorption on carbon steel in 1M HCl

The effect of new compounds named, 6,6'-(((2,2-dimethylpropane-1,3-diyl)bis(azanediyl))bis(methylene))bis(2- methoxyphenol) (RSH) on the corrosion inhibiting of ST- 37 low carbon steel in 1.0 M HCl has been studied. The inhibitor effects on the corrosion behaviour of the samples have been determined at three different concentrations, 0.5, 1.0, 1.5 and 2.0 mg/L. Weight loss, polarization curves, AC impedance measurements and Atomic Force Microscopy (AFM) have been utilized to study the corrosion behaviour of carbon steel in corrosive environment in the presence and absence of new ligand. Results show that the inhibition occurs through adsorption of the inhibitors molecules on the metal surface. The inhibition efficiency was found to increase with increasing inhibitor’s concentration. Polarization data indicated that this compounds act as mixed-type inhibitors. The corrosion efficiency of RSH at an optimal concentration of 2mg/L is 86. The adsorption of inhibitors follows the Langmuir isotherm. The values of free energy of adsorption in the presence of the corrosion inhibitor are around -32 KJmol-1, which indicate chemiosorption of the molecules. Powerful Atomic Force microscopy is used for the surface morphology studies.

Inhibition Reaction Behaviour of Combined Grapefruit and Lemongrass Plant Distillates on Plain Carbon Steel Degradation

Applications of harmless fluid derivative for the sustenance of carbon steel in corrosive environments are more appropriate for environmental sustainability and safety of personnel. Admixture of grapefruit and lemongrass distillates was assessed for their protective performance on plain carbon steel within 0.5 M of H2SO4 and HCl solution through weight loss analysis and optical macroscopy studies. Results shows the plant extracts effectively stifled corrosion in both acids with inhibition value range (lowest to highest) of 98.65%-99.5% in H2SO4 solution and 96.31%- 98.39% in HCl. PCS in H2SO4 and HCl electrolyte at 0% extract concentrate were 5.330 mm/y and 2.701 mm/y. Inclusion of the distillate to the electrolyte significantly reduced the corrosion rates in both acids to midpoint values of 0.0448 mm/y and 0.072 mm/y at 240 h of test. The oil extract strongly adsorbed unto the steel surface by means of chemisorption with midpoint Gibbs free energy value above -44 Kjmol-1 signifying strong covalent bonding. The extract adsorption aligned with Langmuir and Frumkin adsorption isotherms with interaction coefficient above 0.9. Optical images of steel surface without inhibitor showed a severely corroded morphology and significant reduction in thickness. The protected steel substantially differs the earlier observation due to the presence of the oil extract which passivated the steel exterior.

Synergistic effect of Black cumin extract and zinc cations on the mild steel corrosion resistance improvement in NaCl solution; Surface and electrochemical explorations

Corrosion inhibitors are used to enhance the anti-corrosion properties of mild steel in corrosive environments. In this study, for the first time, a hybrid corrosion inhibitor based on Black cumin extract (BCE) and zinc cations was employed to mitigate the mild steel dissolution rate in NaCl media. The inhibitive film fabricated on the metal surface in the presence of BCE was characterized by scanning electron microscopy equipped with energy dispersive spectroscopy (SEM/EDS), Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, Grazing Incidence X-ray Diffraction (GIXRD), and UV–vis tests. Also, the electrochemical impedance spectroscopy (EIS) and Potentiodynamic polarization tests were engaged in 3.5 wt%. NaCl solution to study the protection performance of the metal in the presence of inhibitors. Due to the fabrication of inhibitive film, the anti-corrosion properties of the mild steel are significantly enhanced in the presence of organic/inorganic corrosion inhibitors. The creation of the inhibitive film in the presence of hybrid corrosion inhibitors was proved through SEM analysis and electrochemical testing. Electrochemical tests proved a synergistic effect between the selected inhibitors. The inhibitor efficiency for hybrid corrosion inhibitor was calculated at about 95 %, and 90 % in EIS and polarization tests, respectively. FT-IR, Raman, and XRD tests' outcomes proved the complex inhibitors' film formation over the metal substrate.

Corrosion behaviour OF HVOF deposited Zn–Ni–Cu and Zn–Ni–Cu–TiB2 coatings on mild steel

Abstract In this study, Zn–Ni–Cu and Zn–Ni–Cu–TiB2 coatings were deposited using high-velocity oxy-fuel (HVOF) thermal spray technique on a mild steel substrate. Corrosion tests like neutral salt spray (NSS) following (ASTM B-117) standard and immersion cycle test following ASTM G-31, ASTM G1-03, standards were carried out for Zn–Ni–Cu and Zn–Ni–Cu–TiB2 coated mild steel along with uncoated mild steel acting as a control. Both Zn–Ni–Cu and Zn–Ni–Cu–TiB2 coated mild steel were corrosion resistant as compared to uncoated mild steel. Raman analysis following the immersion cycle test inferred that uncoated mild steel had all forms of rust. While Zn–Ni–Cu and Zn–Ni–Cu–TiB2 coated mild steel developed very little rust. The characterization helped to understand the changes in the surface before and after tests. It was observed that both Zn–Ni–Cu and Zn–Ni–Cu–TiB2 coated mild steel had little corrosion degradation of surface as compared to uncoated mild steel. Suggesting that both coatings performed significantly better compared to uncoated mild steel in corrosive environments. Polarization and EIS tests of both coated and uncoated mild steel in a 3.5% NaCl medium helped to understand the behaviour of coatings over a range of frequencies. Both coated samples had high polarization potential E corr values and lower polarization current I corr values as compared to uncoated mild steel. Inferring better performance of coatings in corrosive environments as compared to uncoated mild steel.

Degradation behavior of mechanical properties of galvanized steel exposed to the wind and sand environment

AbstractIn this work, the degradation of mechanical properties of galvanized steel under wind and sand erosion environment was studied. The law of weight loss of galvanized steel in corrosive environment was studied by accelerated corrosion experiment. The micro‐morphology and formation mechanism of corrosion products were investigated in detail by scanning electron microscopy and x‐ray diffraction, respectively. In addition, the mechanical properties of galvanized steel such as elastic modulus, yield strength, ultimate strength and elongation were investigated in detail. The results show that the weight loss rate of the zinc layer on the surface of galvanized steel follows an exponential function. Without the protection of the zinc layer, the mechanical properties of the steel will decrease quickly. Therefore, a zinc layer on the steel is necessary. Besides, it is necessary to strengthen the hot‐dip galvanizing treatment on galvanized steel. This work provides a valuable reference for the corrosion behavior and protection measures of galvanized steel in the wind and sand environment.

Highly stretchable polyurethane coating based on functionalized cerium oxide nanoparticles for anti‐corrosive/UV protection

AbstractTo prolong the active life of carbon steel in corrosive environment, it is an effective way to use inorganic nano‐pigments in polyurethane (PU) coatings. In this work, the CeO2 nanoparticles are modified by APTMS (labeled as mCeNPs), and the organic–inorganic nanocomposite coating is prepared. The morphology and structure of PU/mCeNPs composites are characterized by field emission scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. The mechanical and UV resistance properties of compound material are studied by ultraviolet spectroscopy and universal tensile testing machine. The corrosion resistance of PU/mCeNPs coatings are investigated by Tafel polarization technique and electrochemical impedance spectroscopy. The results show that the PU composite coating with mCeNPs additive had high long‐term corrosion resistance. Under the optimum conditions, when mCeNPs accounted for 5% of PU, the nanocomposite coatings show excellent UV resistance, excellent mechanical properties, and long‐term corrosion resistance due to the characteristics of ceria and its good dispersion in PU.

Visualization of pH Distributions inside the Crevice of Stainless Steel in Corrosive Environments

Stainless steels are known for its excellent corrosion resistance. However, stainless steels sometime suffer from crevice corrosion in chloride environments. The distribution of pH inside the crevice is recognized to be the important factor in crevice corrosion of stainless steels [1, 2]. This study focused on visualization of pH inside the crevice in corrosive environments.An imaging plate was prepared by a sol-gel method. Ethyl violet was used to assess the pH values. The fabricated imaging plates were calibrated by 0.01 M NaCl solution at pH 0.0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0. The imaging plate was immersed in the 0.01 M NaCl solutions, and the color change was observed by an optical microscope. Type 304 stainless steel (Fe-18mass%Cr-8mass%Ni) was used as the specimens. The size of the specimen for the crevice corrosion test is 3 mm × 3 mm×17 mm. The specimen surfaces were polished with a 1 µm diamond paste. The scan rate of potentiodynamic polarization measurements was set to 23mV min- 1. The specimen for the polarization measurements is 17 mm × 25 mm × 3 mm in size. The electrode area was 1 cm2. The electrolyte used for the potentiodynamic polarization was 0.01 M NaCl (pH 3.0). The electrolyte was deaerated before the polarization measurements. The reference electrode was Ag/AgCl (3.33 M KCl). The counter electrode was Pt. The crevice corrosion tests were performed under a potentiostatic polarization. The applied potential was 0.3 V. The crevice was made between the steel surface (3 mm × 3 mm) and the imaging plate. Optical microscope images of the surface were taken every 30 seconds. The pH values inside the crevice were calculated from the R (red), G (green), and B (blue) values of each pixel in the images.In calibration, the color of the imaging plate changed from violet to yellow, suggesting that G values of imaging plate mainly responded to pH. The pitting potential of the specimens was 0.4 V. Therefore, 0.3 V was suitable for the crevice corrosion test. Because 0.3 V (Ag/AgCl (3.33 M KCl)) was lower than the pitting potential. The visualization of pH in the crevice corrosion was conducted. The pH decreased during the incubation, initiation, and growth of crevice corrosion. The pH was the important factor in the initiation and growth of crevice corrosion.[1] T. Kaji, T. Sekiai, I. Muto, Y. Sugawara, N. Hara, Visualization of pH and pCl Distributions: Initiation and Propagation Criteria for Crevice Corrosion of Stainless Steel, J. Electrochem. Soc., 159 (2012), C289-C297.[2] M. Nishimoto, J. Ogawa, I. Muto, Y. Sugawara, N. Hara, Simultaneous visualization of pH and Cl- distributions inside the crevice of stainless steel, Corros. Sci., 106 (2016), 298-302.

Experimental Analysis of Hot Corrosion Behaviour of some Composite Coatings on Boiler Steel at Elevated Temperature

Hot corrosion is the main reason of failure of boiler tubes used at high temperature in thermal power plants. This paper is an attempt to investigate the effect of different composite coatings on boiler tube steel in corrosive environment of Na2SO4 – 60%V2O5 at 900°C for 50 cycles. The coatings have been deposited with high velocity oxy fuel process. The samples were exposed to hot corrosion in a Silicon tube furnace at 900°C for 50 cycles. The kinetics of corrosion behaviour were analysed by the weight gain measurements after each cycle. Corrosion products were analysed with weight change statistics, X-ray diffraction, and scanning electron microscopy. It is found that 100Cr3C2 composite coatings provided the higher resistance to corrosion as compared to other types of coatings. Cr carbide layer was formed on the surface and these layers provided the protection from hot corrosion.

316L Stainless Steel Microstructural, Mechanical, and Corrosion Behavior: A Comparison Between Spark Plasma Sintering, Laser Metal Deposition, and Cold Spray

Herein, Austenitic 316 low carbon stainless steel, a widely used grade for various applications, was studied to understand the effect of processing methods on the material properties. Steel samples were processed using spark plasma sintering (SPS), laser metal deposition (LMD), and cold spray (CS) techniques. Significant difference in hardness and yield strength was observed among the processed samples. The CS sample showed highest hardness (~ 378 Hv) and yield strength (~ 1390 MPa) compared to other samples. In addition to the desirable mechanical properties, corrosion resistance has a significant role in determining the service life of steel in corrosive environments. All the processed samples showed lower corrosion rate than the commercial steel. Results obtained from various characterization tools will be presented in-detail.

Corrosion Inhibition of Mild Steel with Tolyltriazole

Tolyltriazole (TTA) is a well-defined corrosion inhibitor for copper and copper alloys. However, there is little literature about its corrosion inhibition performance for mild steels in corrosive environments. This paper studied the electrochemical behavior of TTA in 0.5 M HCl solutions. Also, the morphology and nature of TTA layers on the steel surface were investigated. Electrochemical results showed that TTA is an excellent corrosion inhibitor for mild steel in acidic media with an efficiency of 91% for 0.07 M concentration. The results also indicated that TTA is a mixed-type inhibitor. XRD analysis revealed that the inhibition mechanism of TTA is based on the formation of an organic film due to the physically adsorbed molecules of TTA. AFM and EDS results showed that the formed layers decrease the adsorptivity of corrosive elements (Cl-) on the steel surface. Density Functional Theory (DFT) study confirmed the experimental results.

Structural capacity and fatigue performance of ASTM A709 Grade 50CR steel

ASTM A709 Grade 50CR steel includes a range of 10.5% to 12.5% chromium, which greatly enhances the corrosion resistance of this type of steel in comparison to conventional steels widely used for structural applications. Despite the wealth of information on the durability of ASTM A709 Grade 50CR steel in corrosive environments, there was a gap in the literature concerning how this type of steel responds to the loads that the structures experience during their service life. To investigate this critical aspect and facilitate the future use of corrosion-resistant steel, the current study devised a holistic structural testing program with a focus on bridge applications. For this purpose, a full-scale girder was designed, fabricated, and tested under a four-point bending setup. The girder’s ability to meet the design expectations was assessed by comparing the results to the requirements of AASHTO Bridge Design Specifications. In addition, several tensile and fatigue tests were carried out to obtain an in-depth understanding of the performance of ASTM A709 Grade 50CR steel under both monotonic and cyclic loading scenarios. This led to the development of load–displacement, stress–strain, and S-N curves. The investigations were then expanded to quantify the remaining capacity of three different types of steel, i.e., corrosion-resistant steel, weathering steel, and carbon steel. For this purpose, a set of simulations were performed to estimate the corrosion rate and section loss of the girders under consideration over time. The outcome of this holistic study contributed to providing the insight necessary for the safe and efficient design of structural members made with corrosion-resistant steel.

Optimized Corrosion Performance of AISI 1345 Steel in Hydrochloric Acid Through Thermo-Mechanical Cyclic Annealing Processes

The thermo-mechanical treatments and cyclic annealing processes have the potential of optimizing the corrosion performance of carbon steels in corrosive environments. Herein, an attempt has been made to optimize the corrosion performance of AISI 1345 steel in hydrochloric acid by thermo-mechanical cyclic annealing treatments. AISI 1345 steel was produced and cast in the laboratory and subjected to three types of thermo-mechanical cyclic annealing treatments (TMCA). The first TMCA treatment comprised hot rolling at 1050 °C followed by oil quenching and single austenitizing at 900 °C followed by furnace cooling (TMSA). The second and the third TMCA treatments involved similar hot rolling processes with double austenitizing and furnace cooling (TMDA) and triple austenitizing and furnace cooling (TMTA) processes. Microstructure analysis showed that dual-phase (retained austenite + pearlite) microstructure was achieved after all TMCA treatments with an exception of secondary phase particles precipitation after TMSA treatment. Maximum fractions of retained austenite and minimum fractions of pearlite were achieved after TMTA treatment. Highly refined microstructure of size 26.7 µm was achieved after TMDA treatment whereas; TMSA treatment offered coarse grained microstructure of size 254 µm. Electrochemical analysis was performed in 5 vol% HCl solution using Tafel scan technique. Results revealed that both TMDA and TMTA treatments caused three-fold reduction in corrosion rates (3.025, 2.771 mpy) compared to non-treated steel sample. After 168 h of immersion corrosion analysis in 5 vol% HCl solution, the surface of TMTA treated sample was observed to be partially covered with a very thin, crack-free oxide layer exhibiting minimum oxygen (8.16%) percentage. These features indicated that the TMTA treated sample underwent a very low-intensity minor corrosion attack of HCl solution and exhibited the best immersion corrosion performance among all samples. Electrochemical and immersion corrosion analysis results were in good agreement.