Corrosion Behavior Of Steel Research Articles

Determination of Optimum Ratio of Selected Carbonaceous Materials on Mechanical and Corrosion Behavior of Carburized Mild Steel

This work is centred on the determination of optimum ratio of selected carbonaceous materials of A(40% Snail shell + 40% Animal bone), B(60% Snail shell + 20% Animal Bone), C(20% Snail shell + 60% Animal bone), D(50 Snail shell + 30 Animal bone) and E(30 Snail shell + 50% Animal bone), the mechanical properties and corrosion behaviour of carburized mild steel. Which were carburized at single austenitic temperatures of 1000°C, soaked at single carburizing time of 5hr, at the treatment temperature and samples were then quenched in water. Before the carburization process, standard test specimens were prepared from the received sample for testing hardness, tensile strength, wear, and microstructure analysis. After the carburization process, the test samples are subjected to standard testing to generate data on the ultimate tensile strength and wear rate of the carburized samples. Research shows that the mechanical properties of mild steel are strongly influenced by each of the mixed ratios of the carbonaceous material (Such as Snail shell and Animal Bone). An improved hardness values in all the samples were observed, with sample A having the highest hardness value of 59.05 RHC while sample B and sample C have the highest wear resistance value of 0.090. The samples were immersed in 0.3M H2SO4 solution for potentiodynamic studies. There results show that sample E had the least corrosion rate of 8.1809 mpy hence is less prone to corrosion attack in acidic environment than others. These samples are found to be useful in automobile industry.

Influence of chromium of low content on the corrosion behavior of SA106B carbon steels in high-temperature pressurized LiOH medium

The corrosion of carbon steel (CS) pipelines widely troubles the primary circuit system of pressurized heavy water reactors. The element chromium (Cr) plays a crucial role in resisting corrosion. However, the mechanism of oxide film formation and dissolution on low Cr-content CS remains unclear. A comparison study in corrosion behavior between SA106B with 0.02 wt% and 0.36 wt% Cr was carried out with weight loss tests, electrochemical measurements, and morphology observations. Immersion tests were performed in deaerated lithium hydroxide solution at 553 K and 6.3 MPa for 30 days. The results showed that although the content of Cr was as low as 0.36 wt%, it exhibited relatively high corrosion resistance to the SA106B with 0.02 wt% Cr. Two layers of oxide film were formed on both the two CSs and chromium oxide was present in the inner oxide layer of 0.36Cr CS. The possible formation mechanism of oxidation film with low content of Cr in high-temperature water was discussed.

Gravimetric and electrochemical investigation of the impact of various factors on XC48 carbon steel corrosion in different environments

ur main motivation in this study was to review the effects of acid concentration and solution temperature on the corrosion behavior of XC48 carbon steel in acidic and saline environments. We conducted both gravimetric and electrochemical analyses to evaluate the extent of corrosion. The gravimetric study revealed interesting findings regarding the influence of acid concentration on the corrosion rate. Initially, as the acid concentration increased, the corrosion rate showed an upward trend, reaching a peak at approximately 6M (44.1%) of sulfuric acid. However, at higher concentrations, such as 10.3M (65.15%) the corrosion rate decreased to a lower value at different immersion times. A similar trend was observed with phosphoric acid, where the maximum corrosion rate occurred at around 10M (66.6%), but decreased at 14.5M (84.68%) over different immersion times. Notably, in the case of hydrochloric acid, the corrosion rate exhibited a logarithmic behavior at higher concentrations (6M, 7M, 10M), which can be attributed to the formation of passive layers. The decrease in corrosion rate at higher concentrations indicates the protective effect of these passive layers. During the electrochemical analysis, we investigated the effect of temperature and NaCl concentration on the corrosion rate. Our results indicated that the corrosion rate increased with an elevation in temperature and NaCl concentration. The maximum corrosion rate was observed within the range of 3 to 4% of NaCl. Overall, this study provides valuable insights into the corrosion behavior of XC48 carbon steel in acidic and saline environments. The gravimetric analysis highlighted the influence of acid concentration on corrosion rate, including the formation of passive layers at high concentrations. The electrochemical study demonstrated the impact of temperature and NaCl concentration on corrosion rate, with higher values observed at elevated temperatures and increased NaCl concentrations. These findings contribute to a better understanding of the corrosion mechanisms and can aid in the development of effective corrosion prevention strategies for carbon steel in similar environments

Effect of some organic surfactants on the corrosion behavior of low-carbon steel in hydrochloric acid solution

Effect of some organic surfactants on the corrosion behavior of low-carbon steel in hydrochloric acid solution

INCIDENCE OF HEAT TREATMENT ON THE CORROSIVE BEHAVIOR OF AISI 316L AUSTENITIC STAINLESS STEEL

Heat treatments of AISI 316L samples were conducted at 900°C with slow cooling in air to induce varied precipitation of chromium-rich carbide particles at grain boundaries, resulting in a microstructure susceptible to intergranular corrosion. The corrosion behavior of the material in this state was investigated in a salt spray chamber containing 5% NaCl. The temperature inside the chamber was set at 35°C, while the saturated air temperature was recorded at 47°C. Samples were periodically extracted for observation and analysis using a stereoscopic magnifying glass, optical microscope, and scanning electron microscope. The results revealed the detrimental effect of chloride ions on the corrosion behavior of these stainless steels. Metallographic examination of corroded specimens after the salt spray test confirmed that the passive layer's breakdown was responsible for the intergranular corrosion occurring along preferential paths of chromium carbides.

Study on the role of solution treatment on corrosion behavior of duplex lightweight steel in different environments

Diverse microstructure and complex application environments increases the uncertainty of the corrosion resistance of lightweight steels. The effect of solution treatment on the corrosion behavior of Fe–16Mn–10Al–1.5C–0.1Ti lightweight steel in Cl−, HSO3− and Cl−–HSO3− environments was investigated using electrochemical measurement, scanning electron microscope (SEM) and X–ray photoelectron spectroscopy (XPS). The lightweight steels are dominated by austenite and contain a small amount of ferrite. The increase in solution treatment temperature leads to more ferrite formation, but it has less effect on grain size. The decrease in austenite content results in more corrosion microcells and a porous oxide film; therefore, the corrosion resistance of the steel deteriorates with increasing temperature. In addition, in the Cl−–HSO3− environment, the synergistic effect of Cl− and HSO3− leads to the formation of a weak protective oxide film, resulting in a significant increase in corrosion rate compared to the Cl−and HSO3− environment.

Corrosion behavior of carbon steel covered with a coating film containing metallic compounds under a sulfuric acid mist environment containing chloride

AbstractThe corrosion behavior of carbon steel covered with coating films containing Al2(SO4)3, CaO, and BaO was examined under a sulfuric acid mist environment containing chloride. CaSO4･2H2O and BaSO4 were formed as the corrosion products in the coating film and prevented the penetration of corrosives, in particular BaSO4 was highly effective. Furthermore, the rust layer containing CaCO3 adhered to the carbon steel substrate suppressed the penetration of chloride. The formation of these corrosion products suppressed the anodic reaction, resulting in higher corrosion resistance of the carbon steel in the chloride‐containing acid environment.

Effect of nitrogen content on corrosion behavior of high-nitrogen austenitic stainless steel

A series of electrochemical tests combined with the techniques of scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and X-ray photoelectron spectroscopy (XPS) were used to study the effect of nitrogen content on the composition, structure and protectiveness of passive films, which were formed on the surfaces of high-nitrogen austenitic stainless steels (HNSS) in 0.5 mol/L NaCl solution. The results showed that the HNSS with higher nitrogen content had a larger proportion of low-angle grain boundaries, and it also had a lower corrosion current density in 0.5 mol/L NaCl solution and thus a lower corrosion rate. The existence of a larger proportion of stable oxides (e.g., Cr2O3) in the passive films facilitates the passivation/repassivation process and contributes to the high corrosion resistance of HNSS.

Mechano-electrochemical interaction of high-strength pipeline steels with Al-Ti deoxidization and Mg-Ca compound treatment

The micro-zone interface of inclusions with the steel matrix of X70 high-strength pipeline steel with Al-Ti deoxidization and Mg-Ca compound treatment in the tropical marine environment was investigated. Results revealed that the Volta potential difference increased in proportion to the residual stress at the interface of inclusions with the steel matrix. The early corrosion behavior of pipeline steel was investigated by immersion testing and corrosion morphology assessment. Three stages of the early corrosion process of pipeline steel were elucidated based on micro mechano-electrochemical (M-E) interaction. Thermodynamic and kinetic models of M-E interactions at the micro-scale were proposed.

Influence of Anions on the Corrosion Behavior of 9Cr-1Mo Ferritic Steel in Aqueous Media

Modified 9Cr-1Mo steel is used as steam generator material in prototype fast breeder reactors, owing to its good corrosion resistance, creep, and thermal conductivity characteristics. In the present study, the corrosion behavior of modified 9Cr-1Mo steel in aqueous environments containing various corrosive ions at potentiodynamic polarization conditions is reported. In chloride-exposed samples, randomly distributed dense shallow pits were seen, whereas mixed anions (, Cl−, and ) in fresh water resulted in deeper pits uniformly distributed on the entire surface. Laser Raman spectroscopy studies revealed the formation of Fe-oxides/hydroxides and Cr(VI) species, except in alkaline solution. A very thin film of only Fe-oxides (Fe3O4, γ-Fe2O3, and α-Fe2O3) was identified in an OH– ion-dominated solution. X-ray photoelectron spectroscopy results confirm the corroded surfaces comprised of Fe, Cr, and Mo-oxides of varying composition and enrichment of Mo-oxides in alkaline solution. Chloride ions present in the corroded layer influenced the pitting corrosion in neutral chloride and fresh water solutions. Field emission scanning electron microscopy images revealed abundant crystalline lepidocrocite with laminar morphology and doughnut-type magnetite together with pits on the samples exposed in neutral chloride and fresh water media.

Technical Note: Study on Accelerated Corrosion Behavior and Mechanism of X80 Pipeline Steel Welded Joint Under Cyclic Salt Spray Test

The corrosion behavior of X80 pipeline steel double-sided submerged arc welded joints in a marine atmospheric environment was simulated by cyclic salt spray accelerated corrosion test. The corrosion behavior and mechanism of X80 pipeline steel welded joints were studied by means of scanning electron microscopy, x-ray diffraction, and electrochemical test, and the current effect of welded joints was evaluated by means of macroscopic and microscopic morphology, corrosion weight loss, corrosion product composition, polarization curve, and impedance spectrum of samples with different cycles. The results show that with the extension of corrosion time, the corrosion morphology of each region of the welded joint changes from the initial uniform corrosion to a large difference. During the whole process, the surface fluctuation of the base-metal area is small, and no obvious pitting pits are observed. Cracks are gradually generated in the heat-affected zone and the weld metal, and as the cracks expand, the surface pits deepen. The corrosion rate of the three regions of the welded joint showed a trend of rapid increase-slow decrease-slow increase-slow decrease. It provides conditions for further research on the simulation and correlation of accelerated corrosion tests.

Interaction between silty sand and temperature towards corrosion behavior of carbon steel in CO2 environment

The interaction between silty sand and temperature towards corrosion of carbon steel in CO2 environment is investigated. The effect of silty sand is more complicated, while the effect of temperature is more remarkable. High temperature causes a more protective corrosion products layer. Silty sand physically adsorbs on the surface and embeds in the porous Fe3C layer at 40 ℃ to slightly reduce corrosion. At 80 ℃, silty sand delays FeCO3 precipitation and significantly increases the porosity of corrosion products layer, thus promoting corrosion. At 120 ℃, silty sand increases the porosity and hinders the formation of Fe3O4 to accelerate corrosion.

Effect of alloying (Cr, Mo, and V) on corrosion behaviors of API-grade steel in CO2-saturated aqueous solutions with different pH

The corrosion behaviors of steels alloyed with Cr, Mo, and V were examined in two different solution chemistries: near-neutral (pH 6) and weakly acidic (pH 4.5) solutions saturated with CO2. In near-neutral solutions, Cr alloying hindered the formation of a stable corrosion scale on the surface, reducing the corrosion resistance compared to conventional low-carbon steel. On the other hand, the alloyed steel exhibited higher corrosion resistance in acidic solutions. In contrast to the conventional carbon steel, which had a single scale of crystalline FeCO3 scale on its surface, a more stable bi-layer of corrosion scale consisting of an inner layer of amorphous Cr(OH)3 and an outer layer of crystalline FeCO3 was developed on the alloyed steel. This was attributed primarily to the increased thermodynamic stability of Cr(OH)3 with an increase in Cr contents at this solution pH. Moreover, the increase in Cr with Mo addition resulted in a refinement of FeCO3 on the outer surface through increased hydrolysis reactions leading to a decrease in the local pH on the steel surface. Furthermore, adding V, even in minute quantities contributed to an increase in Cr-enrichment in the inner scale by suppressing M7C3 precipitation and leaving more Cr in the solid solution.

Investigation into main controlling factors and prediction model of L245NS steel corrosion rate in CO2–O2–SO2–H2S–H2O environment

Multi-component thermal fluid flooding is an increasingly mature technology for heavy oil recovery. However, the production of associated gas containing highly corrosive CO2/O2/SO2/H2S/H2O impurities can lead to corrosion and perforation failure in gathering pipelines. This study systematically investigated the effects of temperature/CO2/O2/SO2/H2S on L245NS steel corrosion in a CO2–O2–SO2–H2S–H2O environment and analyzed the correlation between these factors and corrosion rate. The corrosion behavior of L245NS steel in a CO2–O2–SO2–H2S–H2O environment was investigated through weight-loss experiments and surface characterization techniques. An empirical model for predicting the corrosion rate in this environment was established based on the obtained results. The results indicated that the sequence of importance for corrosion rate was as follows: O2 (0.8181) > H2S (0.7511) > Temperature (0.7491) > CO2 (0.7312) > SO2 (0.7017). Surface characterization revealed that the predominant corrosion products were FeCO3, FeS2, FeS, Fe(OH)3, FeOOH, Fe3O4, Fe2O3, elemental sulfur and FeSO4·4H2O. The corrosion reaction involved CO2/O2/SO2/H2S while synergistic reactions between SO2–O2 and SO2–H2S further promoted corrosion. Finally, an empirical model for the corrosion rate of L245NS steel in a CO2–O2–SO2–H2S–H2O environment was established. The fitting error ranged from 0.03% to 8.99%, and the verification error ranged from 2.62% to 14.83%. This model can provide a valuable reference for preventing and controlling pipeline corrosion.

Microstructure and corrosion behavior of 10CrNi3MoV high-strength low-alloy steel coating via underwater wire-feed laser cladding

The underwater local dry wire-feed laser cladding was successfully used to prepare 10CrNi3MoV high-strength low-alloy steel coating for the first time and the influences of water environment on the surface morphology, cross section, microstructure and corrosion behavior of cladding layer were studied. Compared with the in-air cladding layer, the surface flatness of the underwater cladding layer was poor. There were no defects such as lack of fusion and cracks between the cladding layers and substrate. Besides, the heights of cladding zone and heat affected zone in underwater cladding layer were 94.8 % and 88.5 % that of in-air cladding layer, respectively. Due to the presence of more lath martensite, smaller grain size, higher kernel average misorientation and lower texture strength of (100) lattice plane, the electrochemical corrosion performance of underwater cladding layer was poor. The corrosion mechanisms of both underwater and in-air cladding layers were pitting corrosion, but corrosion degree of underwater cladding layer was more serious and corrosion rate was faster. There were less α-FeOOH, Cr2O3 and NiFe2O4 in underwater cladding layer, which reduced the compactness of corrosion products film. Therefore, the protection ability of the corrosion products film of the underwater cladding layer became weak.

Pitting corrosion behavior and mechanism of 316L stainless steel induced by marine fungal extracellular polymeric substances

In this study, effect of extracellular polymeric substances (EPS) secreted by fungus Aspergillus terreus on the pitting corrosion of 316L stainless steels (SS) was deeply investigated by electrochemical measurements and surface analysis. Results demonstrated that adsorption of EPS can change surface wettability of 316L SS leading to a much more hydrophilic steel–water interface. EPS not only accelerates uniform corrosion but enhances pitting corrosion of 316L SS. EPS can promote the formation of metastable pitting corrosion and the subsequent growth of corrosion pits. The density of corrosion pits (>2 µm) reach (5.6 ± 0.5)× 103 pits/cm2 when EPS is 400 mg/L.

Enhancement of corrosion resistance of CrMoV low alloy steels using cryogenic treatment

The current investigation explores the effect of cryogenic treatment on the microstructural and corrosion behavior of CrMoV low-alloy steels. The casted samples in the required dimensions were treated by annealing followed by deep cryogenic treatment (DCT). Initially, the microstructural modification brought by combined treatments was studied using an optical microscope (OM), scanning electron microscope (SEM), and x-ray diffraction (XRD) technique. After DCT, a refined and uniform grain structure was identified. The DCT resulted in the development of a fine-grained structure and reduced the mean grain size of the alloy, and this refinement of the grain structure is due to the reduction of lattice defects during the cooling process. The corrosion behavior was studied using the weight loss and Tafel polarization tests. The corrosion findings indicated a significant enhancement in the corrosion resistance of the specimens after DCT. The DCT specimens exhibited higher corrosion potentials compared to the base material. The DCT can promote the development of a more protective passive layer on the sample’s surface. This passive layer serves as an obstacle, preventing the diffusion of corrosive products and increasing corrosion resistance. Finally, it suggests that DCT positively impacts the CrMoV steels’ resistance to corrosion.

Understanding the interaction mechanism of chloride ions and carbon dioxide towards corrosion of 3Cr steel

The investigation focused on elucidating the corrosion mechanism and evolution of corrosion products for 3Cr steel after an exposure to CO2-saturated solutions containing different concentrations of Cl− at 80 and 150 °C. The results show an interaction between dissolved CO2 and Cl− toward corrosion behavior of 3Cr steel. Apart from a competitive relationship between the concentrations of two corrosive species, the evolution of inner and outer films at different temperatures under the interaction between dissolved CO2 and Cl− is a decisive factor in the whole corrosion process, causing a trend of a first increase and then a decrease with increasing Cl− concentration. In addition, the destruction of inner Cr-enriched films after the addition of excessive Cl− conversely reduces the corrosion rates of 3Cr steel, which is mainly due to the formation of FeCO3 crystals instead of Cr(OH)3 in an initial stage of corrosion.

Influence of UV Illumination on the Corrosion Behavior of New 3Ni Weathering Steel in Marine Atmospheric Environments

We investigate the effect of pure darkness and UV illumination on the corrosion process of 3Ni weathering steels involved in both marine atmospheric environments. The corrosion behavior of 3Ni steel in both environments was assessed by cyclic acceleration experiments, electrochemical measurements, morphological analysis and physical phase analysis. The results show that UV illumination affects the corrosion process through the photovoltaic effect of the corrosion products, with photoelectrons and photo-vacancies participating in the redox reaction between the substrate and the atmospheric environment, thereby affecting the corrosion rate of 3Ni steel, the physical composition of the corrosion products and the denseness of the rust layer.

Insights into the effect of H2S on the corrosion behavior of N80 steel in supercritical CO2 environment

In this study, the corrosion behavior of N80 steel exposed to 80 bar supercritical CO2 and 0–15 bar H2S environments was investigated by weight loss test, surface analysis, water chemistry simulation, corrosion thermodynamic and kinetic calculations. The results show that a very low H2S pressure of 0.004 bar in supercritical CO2 environment boosts the corrosion rate of N80 steel, whereas the rate is considerably reduced with further increasing the H2S pressure. The variation of corrosion rate with H2S pressure largely depends on the changes in cathode process and overall protectiveness of corrosion product film caused by H2S. As the H2S pressure rises, the evolution of corrosion product film on the steel is as follows: FeCO3 dominated film below 0.16 bar H2S, FeCO3 and FeS mixed film within 0.16–4 bar H2S, and FeS dominated film over 4 bar H2S. Benefiting from the integrity of film structure and the uniformity of film composition, N80 steel experiences uniform corrosion in the formation environment of FeCO3 or FeS dominated film. However, the localized corrosion easily occurs in the formation environment of FeCO3 and FeS mixed film owing to the loss of film integrity induced by uneven precipitation of FeCO3 inside the corrosion product film.