Corrosion Resistance Of Steel Research Articles

Calculation of the elastic modulus of steel during tensile

The rational use of resources in the design of vessels and devices and ensuring their growing needs requires the performance of strength and stability calculations, which require the use of appropriate values of the modulus of elasticity during tension E. The purpose of the article is to improve the definition of the modulus of elasticity of steels during tension, the value of which is normalized by the current in Ukraine by regulatory documents. On the basis of standard tables, dot graphs of changes in modulus of elasticity of carbon, low-alloy, heat-resistant, corrosion-resistant chromium, heat-resistant and heat-resistant austenitic steels and iron-nickel-based alloys during tension E depending on temperature t were constructed and analyzed. It is proposed to approximate these dependencies with simple mathematical equations. As a result, it was determined that the dependence E = f (t) for carbon and low-alloy steels in the range of changing t from 20 oС to 300 oС is described by a simple linear equation E = – 100t + 2.01.105. When changing t from 300 oС to 450 oС inclusive, it is proposed to apply cubic regression E = – 5.33.10–3t3 + 5.2t2 – 1.827.103t + 3.95.105. In the above and further proposed formulas, the temperature t is substituted in °C, and the result is obtained in MPa. Heat-resistant and corrosion-resistant chromium steels in the temperature range t from 20 oС to 100 oС inclusive are characterized by the same modulus of elasticity during tension E = 2.15.105 MPa. The dependence of E = f (t) in the range of changing t from 100 oС to 250 oС inclusive can be described by the cubic regression E = 1.33.10–3t3 – 2.63.102t + 2.4.105, and when changing t from 250 oС to 600 oС inclusive – by cubic regression E = – 7.5.10–4t3 + 0.722t2 – 3.426.102t + 2.4748.105. The value of the modulus of elasticity during tension for heat-resistant and heat-resistant austenitic steels and iron-nickel-based alloys E = 2.15.105 MPa in the temperature range t from 20 oС to 100 oС. The dependence of E = f (t) in the range of changing t from 100 oС to 700 oС inclusive is described by the quadratic regression E = – 0.152t2 + 9.101t + 2.009.105. The obtained formulas make it possible to abandon the use of standard tables and additional interpolation of intermediate values of the modulus of elasticity of steels during tension when performing calculations, which in turn simplifies both the calculation itself and the development of appropriate computer programs. The average error value of the performed approximations is in the range from 0 % to 0.218 %, which indicates a high level of coincidence of the regression equations with the actual values. The use of the proposed formulas for calculating the modulus of elasticity of steels during tension makes it possible to simplify the calculation of vessels and devices for strength and stability.

Enhancing steel corrosion resistance in 1.0 M HCl medium through the synthesized and characterized mixed pyrophosphates BMnP2O7 (B = Ni, Co, and Cd)

In this study, we synthesized three diphosphate materials NiMnP2O7, CoMnP2O7, and CdMnP2O7 intended for use as corrosion inhibitors for carbon steel. The crystallinity of the obtained compounds was analyzed using X-ray diffraction (XRD), and a vibrational analysis was carried out by infrared (IR) and Raman (Ra). The corrosion inhibition properties of steel with these materials in 1.0 M HCl solution were investigated using three important techniques. The electrochemical parameters were obtained via electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curves (PDP) and the surface of the substrate was analyzed, using the scanning electron microscopy (SEM). Our findings indicate that the optimal concentration for NiMnP2O7, CoMnP2O7, and CdMnP2O7 was 10−3 mol/L, with inhibition efficiencies reaching to 87.5 %, 91.04 %, and 92.22 %, respectively. These phosphates also act as a mixed-type inhibitors, imparting high resistance to corrosion, and their inhibition efficiency (η%) increased with the augmentation of the inhibitor concentration. The scanning electron microcopy (SEM) images revealed that the inhibitors form a protective layer against acid attack, preventing carbon steel from being destroyed.

Enhanced the SRB corrosion resistance of 316L stainless steel via adjusting the addition of Cu and Ce elements

316L stainless steel (SS) is the key raw material for the preparation of high-performance oil and gas pipelines, but even 316L with excellent properties will be attacked by sulfate-reducing bacteria (SRB) corrosion. Excellent antibacterial effects have been obtained in other SS systems by doping antibacterial elements. However, the current research on the preparation of antibacterial 316L SS is not comprehensive, and the quantitative analysis of the antibacterial mechanism and doping elements is still unclear. In this paper, the SS with Cu and Ce added were prepared by vacuum induction melting. Then the homogenization treatment combined with hot rolling was used to improve the structure segregation and mechanical properties. Further, the weight loss tests and electrochemical tests were conducted to evaluate the corrosion resistance of SS, the corrosion products and morphology were analysed, and the deformation structure was characterized to clarify the corrosion mechanism of the modified SS and quantify the doping elements. The results indicate that the microstructure after homogenization is mainly austenite, and with the increase of Ce content, the Ce-rich phase segregates. The inhibitory effect of Cu on SRB can be explained by the destructive effect of Cu ions on cell membranes. On this basis, adding a low content of Ce element can increase the permeability of the SRB cell wall and further enhance the attack effect of Cu ions on the cell membrane. The corrosion behavior of alloys shows the deformation structure dependence, with crystal defects and segregation increasing the corrosion rate. The optimal addition amount of Ce is 0.18 wt%, and the strength and elongation of SS are 511.18 MPa and 108.2%, respectively.

A promising perspective in improving corrosion and wear resistance of plain steel through electrodeposition of thick Ni–Mo–W ternary alloy

In this study, thick Ni–Mo–W ternary alloy coatings (∼24 μm) with 13–27 wt% Mo and 4–11 wt% W were electrodeposited from an alkaline citrate-ammonia bath using direct current. The effect of current density (20–100 mA/cm2) on the composition, current efficiency, morphology, structure, surface topography, tribological behavior, and corrosion resistance of coatings was investigated. The findings revealed an advantageous induced co-deposition of Mo in an electrolyte containing equimolar Mo and W ions. While increasing the current density decreased the Mo content of the coatings, they always had more Mo than W. Increasing the current density, according to SEM and AFM observations, changed the smooth and nodular morphology of Ni–Mo–W coatings to a relatively rough and cauliflower shape. The microhardness of the produced nanocrystalline solid solution coatings was 3.8–4.9 times higher than that of the plain carbon steel substrate. While the hardest coating (793 Hv) deposited at 100 mA/cm2 had the best wear resistance with a volume loss value of 0.04 mm3, it had the worst corrosion resistance among the coatings with icorr = 4.4 μA/cm2. The least hard coating (607 Hv), deposited at 40 mA/cm2, with the highest wear volume loss value of 0.11 mm3, however, was the most corrosion resistant sample with icorr = 1.9 μA/cm2.

Roles of Al and Mg on the Microstructure and Corrosion Resistance of Zn-Al-Mg Hot-Dipped Coated Steel.

In this work, a novel zinc-aluminum-magnesium (Zn-Al-Mg, ZM) coated steel was prepared using the hot-dip method. The microstructure and corrosion resistance of the ZM-coated steel were investigated. Compared to the conventional galvanized steel (GI), the ZM coating demonstrated a distinctive phase structure, consisting of Zn phase, binary eutectic (Zn/MgZn2), and ternary eutectic (Zn/Al/MgZn2). The corrosion resistance of the ZM-coated and GI-coated steels was evaluated by neutral salt spray test (NSST), polarization and electrochemical impedance spectroscopy (EIS). The results indicated that ZM-coated steel provided superior long-term corrosion protection in a NaCl environment compared to GI-coated steel. The scanning vibrating electrode technique (SVET) proved to be an effective method for investigating the evolution of the anodic and cathodic on the local coating surface. GI-coated steel exhibited a potential and current density distribution between the cathodic and anodic sites nearly three orders of magnitude higher than that of ZM-coated steel, suggesting a higher corrosion rate for GI-coated steel.

Effect of Nitrogen on the Corrosion Resistance of 6Mo Super Austenitic Stainless Steel

6Mo super austenitic stainless steel (SASS) with nitrogen contents of 0.2 and 0.4 (wt.%) was melted, and solution treatments at 1100, 1180, and 1250 °C for 30 min were performed. The effects of nitrogen on the microstructure and pitting resistance of the two steels that signed as 0.2N and 0.4N samples were investigated. At a heat-treatment temperature of 1180 °C, the alloy demonstrates the highest corrosion resistance, attributed to the combined effects of grain size and precipitates. The structure of the passivation film changes with increasing nitrogen content, with the Cr/Fe ratio is significantly higher in the 0.4N sample compared to the 0.2N sample. Moreover, the increase in nitrogen content results in thicker Cr and Mo oxide layers and higher levels of NH3 and NH4+, thereby improving the corrosion resistance of the stainless steel.

Effect of tempering temperature on stress corrosion resistance of a low alloy high strength steel with high vanadium content

The stress corrosion resistance of a low alloy high strength steel with high vanadium content, tempered at different temperatures, was examined by electrochemical measurements and slow strain rate tensile test under different environments. Combined with scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM), the results show that three different tempering temperatures had an influence on the microstructure of this steel as well as its electrochemical behavior and stress corrosion sensitivity. With the increase of tempering temperature, the ferrite grains coarsened, the average dislocation density lowered as well as the number of vanadium carbide also decreased, though the size of vanadium carbide increased. However, the interface distortion between vanadium carbide and matrix exacerbated, resulting in the increase of the local dislocation density. Therefore, the corrosion potential and impedance decreased, meantime, the stress corrosion sensitivity aggravated.

Electrochemical properties of MnSe inclusions and improving the pitting corrosion resistance of stainless steel via Se microalloying

Controlling the electrochemical properties of non-metallic inclusions is of substantial interest in the design of corrosion-resistant alloys. To the best of our knowledge, the dissolution and pitting corrosion behavior of selenide inclusions in stainless steels and the improvement of the pitting corrosion resistance of type 304 stainless steels via Se microalloying have not been investigated. In this study, stainless steel specimens containing artificial MnS and MnSe inclusions were fabricated via spark plasma sintering to systematically investigate their electrochemical properties. The superior pitting corrosion resistance and dissolution resistance of MnSe to those of MnS were demonstrated. The results obtained from the sintered specimens were applied to improve the pitting corrosion resistance of type 304 stainless steels via Se microalloying. Adding a trace amount of Se (0.005 mass%) altered the readily soluble sulfide inclusions to dissolution-resistant selenide-type inclusions, resulting in improved pitting corrosion resistance of type 304 stainless steel.

CORROSION EVALUATION OF LPBF-MANUFACTURED DUPLEX STAINLESS STEEL

In this study, the effect of as built and heat-treated additively manufactured 2507 super duplex stainless steel (SDSS) on electrochemical corrosion performance was examined. The corrosion was studied by Tafel polarization and electrochemical impedance spectroscopy (EIS) methods in a 3.5% NaCl solution. For this purpose, the as-built and heat-treated printed samples (solution annealed and stress-relieved) were examined by LOM/SEM and X-ray diffraction to evaluate the phase changes of steel at different processing stages. The correlation between corrosion resistance, structure, and heat treatment was assessed. As a result of the very fast cooling rate of the LPBF process, SDSS reveals ferrite as the major phase in the printed samples. To enhance the corrosion resistance of LPBF-produced duplex stainless steel, it's crucial to balance its two-phase structure and minimize residual stresses. The ferrite grains are elongated in the build direction, with some austenite precipitation along the grain boundaries or as Widmanstatten laths. The stress-relieved and as-printed SDSS exhibits reduced corrosion characteristics by around 20% compared to the solution-annealed SDSS, according to anodic polarization curves. Based on EIS results, the solution-annealed SDSS revealed an almost double increase in corrosion resistance (based on charge transfer resistance values) compared to the as-printed and stress-relieved conditions.

Investigating the effect of Cr content on the microstructure and electrochemical measurement of low alloy steel

In this study, the effect of Cr content on microstructure and electrochemical measurement of low alloy steel in 3.5 wt% NaCl solution was investigated using scanning electron microscope (SEM), X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical workstation, and the CCT curves of the samples were calculated using JMatPro software. The results showed that the augmentation of Cr content inhibits the formation of ferrite and promotes the development of cementite in low alloy steels. And the reduction of Ar3 (the temperature at which austenite transforms to ferrite) and the increase in Ar1 (the temperature at which ferrite transforms to pearlite) also contribute to the expansion of the pearlite area. The XRD results show that the samples primarily consist of Fe-Cr solid solution with a body-centered cubic structure. As the Cr content increases, the peaks corresponding to the (110), (200), and (211) planes gradually enhance which means the improvement in the crystallinity of the samples. The improvement in the crystallinity can result in a decrease of grain size. Due to the suitable ratio of cementite to pearlite and the synergistic effect of grain size refinement, the Cr2 sample exhibits the best tensile property when the Cr content is 0.970 wt%. Cr(OH)3 and Cr2O3 with protective effects are generated in the corrosion film on the surface of Cr-containing low-alloy steels. And Cr also promotes the transformation of γ-FeOOH to α-FeOOH in the corrosion film because of the atomic radius of Cr3+ being smaller than that of Fe3+. These substances enhance the ability of the corrosion film to block corrosive media and protect the matrix. The results of the electrochemical measurement showed that the increasing Cr content from 0.970 to 4.657 wt% resulted in the enhancement of steel's corrosion resistance. The Cr4 sample exhibits the best corrosion resistance when the Cr content is 4.657 wt%.

In situ chemical analysis of duplex stainless steel weld by laser induced breakdown spectroscopy

The high corrosion resistance and good mechanical properties of duplex stainless steel (DSS) are due to its special chemical composition, which is a balanced phase ratio of ferrite (α) and austenite (γ). Many industrial applications require the integration of DSS components. For this, Gas tungsten arc welding (GTAW) is an excellent choice, as it allows an automated operation with high reproducibility. However, when the weld pool solidifies, critical ratios of α- and γ- phases can occur, which lead to solidification cracking, increased susceptibility to corrosion, and a decrease in ductility and critical strength. Previous studies have shown that these defects can be caused by the accumulation of manganese and chromium in the heat affected zone (HAZ), requiring ongoing monitoring of this accumulation. A suitable method for such monitoring is laser-induced breakdown spectroscopy (LIBS), which can be used in two operating modes: calibration using standard reference samples and calibration-free. Unlike conventional quantitative LIBS measurements, which require reference samples to generate a calibration curve, calibration-free LIBS (CF-LIBS) allows chemical compositions to be determined solely from the emission spectrum of the plasma. Numerous publications show that CF-LIBS is a fast and efficient analytical method for the quantitative analysis of metal samples. In this work, CF-LIBS is applied to spectra obtained during GTAW DSS welding and the result is compared with those obtained by PLS analysis. A good correlation was found between both types of analysis, demonstrating the suitability of the CF-LIBS method for this application. The CF-LIBS method has a significant advantage over conventional LIBS due to the rapid in situ measurement of concentrations of major alloying elements without calibration procedure. This, combined with fast feedback and appropriate adjustment of welding parameters, helps prevent welding defects.

Development of Self-Passivating, High Strength Ferritic Alloys for CSP and TES Application

The addition of aluminum to ferritic stainless steels can result in self-passivation by the formation of a compact Al2O3 top layer, which exhibits significantly higher corrosion resistance to solar salt compared to a Cr2O3 surface layer. The development and qualification of realistic experimental methods for fatigue testing under superimposed salt corrosion attack will enable safe component design. Salt corrosion experiments were carried out at 600 °C with and without mechanical fatigue loading at a novel, self-passivating trial steel, using “solar salt” (60 wt.% NaNO3 and 40 wt.% KNO3). Cyclic salt corrosion tests at 600 °C under flowing synthetic air (without mechanical loading) showed that self-passivation to molten salt attack and mechanical strengthening by precipitation of fine Laves phase particles is possible in novel ferritic HiperFerSCR (Salt Corrosion Resistant) steel. A compact, continuous Al2O3 layer was formed on the surface of the model alloys with Al contents of 5 wt.% and higher. A distribution of fine, strengthening Laves phase precipitates was achieved in the metal matrix.

Mechanical, wear and corrosion behaviours of laser additive manufactured iron-based heterogeneous composite coatings for tillage tools

Steel is commonly used in engineering components, and it has a high tendency to wear and corrosion attacks when exposed to unfavourable working conditions. The use of chromium-vanadium-iron-rich carbide reinforced iron-based hard facings has become more important in improving the corrosion and wear resistance of such steel subjected to abrasive and impact conditions. In this study, the chromium-vanadium-iron carbide reinforced coatings were developed using in-situ by depositing FeCrV15+Cr powder through laser cladding on carbon steel. The influence of the reinforcement on the microstructure of the coating in relation to its laser processing condition and extra chromium addition was investigated. Furthermore, the effect of the coating's reinforcement on the hardness, microstructures, anti-corrosion, and anti-wear properties of the carbon steel used in tillage and mining operations was investigated. The result is a defect free deposits with a solid metallurgical attachment to the substrate and improved microhardness. FeCrV15 deposits had a wear-resistant (with a wear rate of 2.42 × 10−6 mm3/N/m) and anti-corrosion capability (with a corrosion rate of 0.001869 mm/yr) that were several folds higher than the steel substrate (with wear rate of 1.72 × 10−3 mm3/N/m and corrosion rate of 0.1168 mm/yr). The general grain refinement of the FeCrV15 deposits was richly enhanced in the iron base matrix. This resulted in outstanding wear and corrosion resistance attributed to the better production of VC–Cr3C2–Cr7C3 particles and better grain refinement of the microstructural formation.

Tribology, corrosion, and tribocorrosion performance of aged lightweight steels: Effects of oxide film and carbide

The study investigated the tribology, corrosion, and tribocorrosion performance of aged Fe–30Mn–8Al–1.2 C–0.1Ti–(2Cr/Mo) steel, with a focus on oxide film and carbide. The precipitates changed from κ carbide to Cr7C3/MoC with the addition of Cr/Mo. The inhomogeneous precipitation of Cr7C3/MoC created zones of varying hardness, one being hard with strong strengthening and the other soft with weak strengthening. The inhomogeneous hardness distribution deteriorates the tribology performance of the steel. By minimizing galvanic coupling corrosion and improving the protectiveness of the oxide film, the addition of Cr/Mo can improve the corrosion and tribocorrosion resistance of lightweight steel.

Surface Modification of 42CrMo Steels: A Review from Wear and Corrosion Resistance

This work reviews surface modification techniques for improving the wear and corrosion resistance of 42CrMo steel. The advantages and disadvantages of various methods, including thermal spraying, deposition, hardfacing, laser cladding, nitriding, and laser surface treatment, are discussed. The review elaborates on the materials commonly employed in laser cladding technology, including iron-based, cobalt-based, nickel-based, and high-entropy alloys and reinforced composite coatings. Furthermore, the mechanisms and methods of improving the wear and corrosion resistance of 42CrMo steel are summarized. Finally, this review presents research shortcomings and future opportunities of surface modification techniques. This review also provides a theoretical guide for the application of 42CrMo steel.

Effect of ionic liquids on the corrosion behaviour of X80 pipeline steel

The study encompasses the synthesis of an ionic liquid corrosion inhibitor using the ion exchange method. Its impact on the corrosion and hydrogen permeation behaviour of X80 pipeline steel in a CO2 environment is thoroughly investigated. The findings reveal that the corrosion resistance and hydrogen atom diffusion of X80 pipeline steel exhibit an initial decline, followed by an increase with escalating inhibitor concentration. The nadir values are recorded at an inhibitor concentration of 500 mg·L−1, attaining a remarkable maximum inhibition efficiency of 97%. Following the addition of corrosion inhibitors, the formation of corrosion products notably decreases, indicating a positive inhibition effect on both corrosion and hydrogen permeation. Additionally, a correlation is successfully established between hydrogen permeation parameters and inhibitor concentration.

Effect of Tempering Time on the Microstructure and Properties of Martensitic Stainless Steel

Martensitic stainless steels (MSSs) have been widely used in the manufacture of turbine blades, surgical instruments, and cutting tools because of their hardness and corrosion resistance. The MSSs are usually tempered at a temperature no higher than 250 °C after quenching to avoid the decline in the hardness, strength, and corrosion resistance of the steels. However, some short-time thermal shocks are inevitable in processes like welding, water grinding, laser marking, etc., in the manufacturing of kitchen knives, all of which may have negative effects on the mechanical properties and corrosion resistance. The effects of these short-time thermal shocks have rarely been studied. In this paper, the martensitic stainless steel 5Cr15MoV (X50CrMoV15 is European Standards) was selected to be tempered at the sensitization temperatures (480 to 600 °C) for a series of times (0.5 to 128 min) after quenching, and the microstructures, hardness, and corrosion resistance of the steel after tempering were investigated. It was shown that the variation in hardness and corrosion resistance of the 5Cr15MoV steel could be divided into four stages over time during tempering at the sensitization temperatures. The hardness of steel was found to increase at first and then decrease with time; accordingly, good corrosion resistance was retained in the initial few minutes of tempering, which then deteriorated fast. The variation in hardness and corrosion resistance of the 5Cr15MoV steel is related to the diffusion of C and Cr atoms at different tempering temperatures. The mechanism of the mechanical properties and corrosion resistance variation caused by the diffusion of C and Cr atoms during tempering at the sensitization temperatures was also discussed.

Improving wear and corrosion resistance of U71Mn rail steel subjected to laser in-situ fabrication of Fe based Cr–V coatings

With purpose of improving wear and corrosion resistance of U71Mn railroad switch, Fe based Cr–V coating was designed and in-situ fabricated on the surface of U71Mn rail steel using laser alloying technology. The phase constituents, effect of V content on the grain size, the microstructure, wear and corrosion resistance were investigated. Grain size refinement effect was observed due to more content of V content in the raw powder. The microhardness and wear resistance of the obtained Fe based Cr–V coatings presented a positive correlation with the content of V addition. The coating with more content of V addition presented a nobler Ecorr and a lower passivation current density icorr, indicating a more excellent corrosion resistance performance.

Function of Cu-Sb or Al microalloying on the corrosion resistance of 9Cr steel exposed to simulated concrete pore solution

The role of Cu-Sb or Al on the passivation and Cl-induced depassivation of 9Cr steel in simulated concrete pore solution was systematically obtained via electrochemical tests and microstructure characterization. Both microalloying enhanced electrochemical passivation even if the solution pH dropped. Cu and Al participated in the formation of natural passive film, and the properties of passive film were optimized in terms of resistance, composition, and inner film thickness. However, the chloride threshold level (CTL) was not increased with Cu-Sb microalloying and even decreased with Al microalloying, which is understood from the stability of Al-containing products and the hazards of inclusions.

Development of targeted chloride-responsive Ag/Ca-MoO4-LDH for synergistic corrosion resistance

Layered double hydroxides (LDHs), as novel corrosion inhibitor in reinforced concrete, face instability in chloride consolidation due to sensitivity to environmental anions. This study explored the use of nano-Ag loaded on MoO4-intercalated CaAl-LDH (Ag/Ca-MoO4-LDH), based on isomorphic substitutes for cement hydration products (AFm), to target and stabilize chloride ion fixation in alkaline environments, thereby enhancing steel corrosion resistance. The mechanism of targeting and the enhancement of corrosion resistance were explored through comprehensive experimental and theoretical analyses. Results showed that Ag/Ca-MoO4-LDH enhanced chloride ion consolidation stability, increased the threshold of chlorides needed to trigger corrosion in simulated chloride-contaminated concrete pore (SCCP) solutions, and boosted steel’s anti-corrosion effectiveness. Unlike direct application methods, Ag/Ca-MoO4-LDH released MoO42− in response to chloride presence, providing superior corrosion prevention. The study elaborated on the stability of Ag+ and Cl− interactions in SCCP solutions, the spontaneous exchange reactions between LDH-MoO4 and both LDH-OH and LDH-Cl, and various anti-corrosion mechanisms, including the formation of protective oxide films on steel surfaces and the precipitation of CaMoO4.