Q235 Steel Research Articles

Solanum tuberosum leaf extract as an eco-friendly corrosion inhibitor for Q235-steel in HCl medium: experimental and theoretical evaluation

Solanum tuberosum leaf extract (STLs), used as a biodegradable corrosion inhibitor, was prepared to mitigate the corrosion rate of Q235 steel in HCl medium. The active inhibitory components existing in STLs were tracked by Fourier transform infrared spectroscopy. Electrochemical measurements, morphological characterization and contact angle tests were combined to evaluate the anti-corrosion performance of STLs at various concentrations and different temperatures, and the results show that the addition of STLs can evidently magnify the charge transfer resistance, expand the double layer capacitance at electric /solution interface, and simultaneously reduce the corrosion current density of Q235 steel in HCl medium with the maximum inhibition efficiency of 91.89%. The adsorption behavior of STLs on steel was investigated using X-ray photoelectron spectroscopy and adsorption models. It is revealed that the molecules of STLs spontaneously bind to the substrate through chemical and physical action, forming a protective layer to block the diffusion pathway of harsh ions. Furthermore, theoretical calculations confirm that Solanum tuberosum leaves components were adsorbed on steel substrates through donor-acceptor interactions.

Corrosion Behavior of High-Pressure Cold-Sprayed Zn30Al Alloy Coating on Q235 Steel

This study employed a high-pressure cold spray to apply a Zn30Al alloy coating to Q235 steel substrates to provide corrosion protection for steel in marine environments. The corrosion resistance of the coatings was investigated through full immersion tests, and the corrosion mechanisms were further analyzed using electrochemical experiments. The results were compared with those of traditional flame-sprayed Zn30Al alloy coating. The findings indicate that the high-pressure cold-sprayed Zn30Al alloy coating possesses a dense microstructure with a porosity of only 0.32%, providing effective cathodic protection to the substrate during the immersion tests. The cold-sprayed Zn30Al alloy coating maintained good integrity after 720 h immersion in 3.5 wt.% NaCl solution, whereas the flame-sprayed Zn30Al alloy coating exhibited significant pitting corrosion.

Study on the influence of high permeability magnetic iron on energy consumption reduction in high gradient magnetic separator

The green processing of weakly magnetic iron ore is inseparable from high-intensity and high-gradient magnetic separator (HGMS), which is one of the most energy-intensive magnetic separation equipment. Iron (Fe) armor serves as the key primary structure for enhancing magnetic field conduction efficiency within the magnetic system. The order of magnetic properties of commonly used magnetic yoke materials is: ordinary carbon structural steel < Q235 steel < DT4 electrical pure iron. But the utilization cost of DT4 electrical pure iron is the highest, especially the magnetic properties of DT4C super electrical pure iron are unstable and the yield is low. On the basis of ordinary pure iron materials, this article has developed a new type of 411 pure iron (411) upon controlling the levels of harmful elements, while increasing the concentration of beneficial elements.intensity Furthermore, through the utilization of magnetic field simulation software, the impact of 411 on the background magnetic field intensity of HGMS was analyzed. The results indicated that the newly developed 411 pure Fe exhibited a coercivity of 24.07 A/m, a saturation magnetization intensity of ∼ 1.69 T, a maximum relative magnetic permeability of 24.38 × 10-3H/m, demonstrating superior magnetic properties in comparison with Q235 and DT4C. When using 411 pure iron as the magnetic yoke material, the background magnetic field intensity of the HGMS can be increased by 6.85 % − 14.64 % compared with using DT4C super pure iron under the same excitation current conditions. The magnetic yoke with better magnetic conductivity will enhance the magnetic field utilization efficiency of the magnetic system, a reduce the excitation energy consumption, and improve the sorting performance of HGMS.

Comparison of destructive and non-destructive fracture toughness measurements for Q235 steel butt-welded joint

As a critical component of a welded structure, the integrity of the welded joint significantly affects the safety and reliability of the structure in service. Therefore, it is essential to investigate the integrity of welded joints. However, given the harshness of standard measurements renders them unsuitable for application to small volume zones, welded structures or in-service structures. In this study, the fracture properties of a Q235 steel butt-welded joint was evaluated by boundary effect modelling (BEM) method and the ball indentation (BI) method. The results demonstrate that the fracture toughness distribution obtained by the two methods are consistent, with the highest fracture toughness in the weld metal, followed by the heat-affected zone and the base metal, and the lowest fracture toughness in the fusion zone, which is in agreement with the results of the metallographic testing. Furthermore, the relative errors of the zones obtained by the ball indentation method and the boundary effect modelling method ranging from 10.16 to 19.05%, which indicates safety margin ought to be considered for employing the BI method to determine fracture properties of in-service structures.

Proteomics and EPS Compositional Analysis Reveals Desulfovibrio bisertensis SY-1 Induced Corrosion on Q235 Steel by Biofilm Formation

Microorganisms that exist in the seawater form microbial biofilms on materials used in marine construction, especially on metal surfaces submerged in seawater, where they form biofilms and cause severe corrosion. Biofilms are mainly composed of bacteria and their secreted polymeric substances. In order to understand how biofilms promote metal corrosion, planktonic and biofilm cells of Desulfovibrio bizertensis SY-1 (D. bizertensis) from Q235 steel were collected and analyzed as to their intracellular proteome and extracellular polymeric substances (EPS). The intracellular proteome analysis showed that the cellular proteins were strongly regulated in biofilm cells compared to planktonic cells, e.g., along with flagellar proteins, signaling-related proteins were significantly increased, whereas energy production and conversion proteins and DNA replication proteins were significantly regulated. The up-and-down regulation of proteins revealed that biofilm formation by bacteria on metal surfaces is affected by flagellar and signaling proteins. A significant decrease in DNA replication proteins indicated that DNA is no longer replicated and transcribed in mature biofilms, thus reducing energy consumption. Quantitative analysis and lectin staining of the biofilm on the metal’s surface revealed that the bacteria secreted a substantial amount of EPS when they began to attach to the surface, and proteins dominated the main components of EPS. Further, the infrared analysis showed that the secondary structure of the proteins in the EPS of the biofilm was mainly dominated by β-sheet and 3-turn helix, which may help to enhance the adhesion of EPS. The functional groups of EPS analyzed using XPS showed that the C element of EPS in the biofilm mainly existed in the form of combinations with N. Furthermore, the hydroxyl structure in the EPS extracted from the biofilm had a stronger hydrogen bonding effect, which could maintain the stability of the EPS structure and biofilm. The study results revealed that D. bizertensis regulates the metabolic pathways and their secreted EPS structure to affect biofilm formation and cause metal corrosion, which has a certain reference significance for the study of the microbially influenced corrosion (MIC) mechanism.

Thermal creep strain test and model of Q460GJ steel at elevated temperatures

Q460GJ steel is a typical high strength and high-performance structural steel. The thermal creep test on two thicknesses (8 mm and 12 mm) of Q460GJ steel plates at elevated temperatures (400–800 °C) was carried out. The test results showed that the thermal creep strain increases with the increases of temperature and stress. When the temperature exceeds about 500 °C and the stress ratio is greater than about 0.55, the Q460GJ steel plate specimens has obvious creep deformations, so it is necessary to consider the thermal creep deformation of steel at elevated temperatures for steel structural design. The difference in plate thickness does not affect the creep properties of the 8 mm and 12 mm Q460GJ steel plates at elevated temperatures. When the temperature is no more than 600 °C, the second stage creep strain rates of Q460 steel are obviously higher than that of Q460GJ steel while the stress levels are close. The Fields & Fields creep model is suitable for fitting the thermal creep strain-time curves for Q460GJ steel. The findings will contribute to providing theoretical support for design of high-performance steel engineering structures under fire.

Anti-Corrosion and Wave-Absorbing Properties of Epoxy-Based Coatings on Q235 Steel

Carbon nanotube/epoxy resin (CNE) coatings and carbon nanotube/carboxy iron powder/epoxy resin (CIE) coatings were applied on the surface of Q235 steel, and their corrosion, absorption properties and other characteristics were measured in this work. The results indicate that the average thickness of a single application was approximately 400 μm, and the surface of the CNE coating was still smooth and intact after a 3000 h copper ion accelerated salt spray test without bubbles, falling off or other corrosion phenomena. The same was true for 28 days of full immersion in solutions of 10% hydrochloric acid (HCl) and 10% sodium hydroxide (NaOH) of the coating. The electrochemical testing exhibited the corrosion current of the CNE coating as being markedly lower than that of Q235 steel, with a protection efficiency of 81.68% for the Q235 steel. The CNE-0.6 coating had the maximum corrosion voltage (−0.390 V), and the CNE-0.3 coating had the minimum corrosion current of 2.07 × 10−6 A·cm2. The adhesion between the coating and Q235 could reach level 0, and the tensile strength of the coating was up to 18.75 MPa. The coating was observed to remain intact and free from detachment upon undergoing a drop test from a height of 50 cm. In addition, the CIE-0.6 coating exhibited an effective absorption band of 9.1 GHz, covering the range from 8.2 to 13.7 GHz, and it achieved a maximum reflection loss of −15.1 dB at a frequency of 8.6 GHz.

Damage and Crack Propagation Mechanism of Q345 Specimen Based on Peridynamics with Temperature and Bolt Holes

With the increasing demand for the performance and design refinement of steel structures (including houses, bridges, and infrastructure), many structures have adopted ultimate bearing capacity in service. The design service lives of steel building structures are generally more than 50 years, and most of them contain bolted connections, which suffer from extreme conditions such as fire (high temperature) during service. When the structure contains defects or cracks and bolt holes, it is easy to produce stress concentration at the defect location, which leads to crack nucleation and crack propagation, reduces the bearing capacity of the structure, and causes the collapse of the structure and causes disasters. In the process of structural damage and crack propagation, the traditional method has some disadvantages, such as stress singularity, the mesh needing to be redivided, and the crack being restricted to mesh; however, the integral method of peridynamics (PD) can completely avoid these problems. Therefore, in this paper, the constitutive equation of PD in high temperature is derived according to the variation law of steel material properties when changed by temperature increase and peridynamics parameters; the damage and crack expansion characteristics of Q345 steel specimens with bolt holes and a central double-crack at 20 °C, 200 °C, 400 °C, and 600 °C were analyzed to clarify the structural damage and failure mechanism. This study is helpful for providing theoretical support for the design of high-temperature steel structures, improving the stability of the structure, and ensuring the bearing capacity of the structure and the safety of people’s lives and property.

Diffusion Interface Evolution of Low-Alloy Steel Q235 and Ti by Electro-Assisted Hot-Pressing Bond

Diffusion Interface Evolution of Low-Alloy Steel Q235 and Ti by Electro-Assisted Hot-Pressing Bond

Experimental and theoretical investigations of a novel imidazoline quaternary ammonium salt as an effective inhibitor of Q235 steel in 1 M HCl

In this paper, the inhibition efficiency and mechanism of a newly synthesized imidazoline-pyridine quaternary amine salt (IPS) as a corrosion inhibitor for carbon steel in 1.00 mol/L HCl at different temperatures were investigated experimentally and theoretically. The inhibitor is confirmed by nuclear magnetic resonance spectroscopy (NMR) and fourier transform infrared spectroscopy (FT-IR). Electrochemical and weight loss indicate that the IPS displays a stable protection performance at different temperatures. Moreover, scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS) indicates that the IPS can be stably adsorbed on Q235 steel surface. Molecular dynamics (MD) show that mainly imidazole and pyridine rings of IPS are adsorbed on the surface of Fe. Moreover, radial distribution function (RDF) and the mean-square displacement (MSD) were used to study inhibitor/metal interactions and migration rate of corrosive species, respectively. The results can provide useful guidance for further study on the corrosion inhibition of imidazole-pyridine quaternary amine salts.

Research on Pipeline Stress Detection Method Based on Double Magnetic Coupling Technology.

Oil and gas pipelines are subject to soil corrosion and medium pressure factors, resulting in stress concentration and pipe rupture and explosion. Non-destructive testing technology can identify the stress concentration and defect corrosion area of the pipeline to ensure the safety of pipeline transportation. In view of the problem that the traditional pipeline inspection cannot identify the stress signal at the defect, this paper proposes a detection method using strong and weak magnetic coupling technology. Based on the traditional J-A (Jiles-Atherton) model, the pinning coefficient is optimized and the stress demagnetization factor is added to establish the defect of the ferromagnetic material. The force-magnetic relationship optimization model is used to calculate the best detection magnetic field strength. The force-magnetic coupling simulation of Q235 steel material is carried out by ANSYS 2019 R1 software based on the improved J-A force-magnetic model. The results show that the effect of the stress on the pipe on the magnetic induction increases first and then decreases with the increase in the excitation magnetic field strength, and the magnetic signal has the maximum proportion of the stress signal during the excitation process; the magnetic induction at the pipe defect increases linearly with the increase in the stress trend. Through the strong and weak magnetic scanning detection of cracked pipeline materials, the correctness of the theoretical analysis and the validity of the engineering application of the strong and weak magnetic detection method are verified.

Improving microstructure and frictional wear behavior of plasma cladding FeCoCrNiMo high-entropy alloy layers by annealing treatment

The application of high-strength, wear-resistant materials for the restoration of large-scale coal development equipment is pivotal in ensuring efficient production and energy conservation within the industry. In this study, FeCoCrNiMo high-entropy alloy (HEA) cladding layers were fabricated on Q235 steel using plasma cladding techniques and subsequently subjected to annealing at 700°C, 800°C, 900°C, and 1000°C, respectively. The microstructural evolution, hardness, and wear resistance of the annealed cladding layers were thoroughly investigated. The results indicated that the microstructure of FeCoCrNiMo HEAs predominantly consisted of alternating eutectic formations of FCC, σ, and μ phases. The content of σ phase initially increased and then decreased with the increase of the annealing temperature. As the σ phase increased, both the microhardness and wear resistance were enhanced. Compared to HEA layers annealed at other temperatures, the HEA layer annealed at 900°C exhibited the highest hardness (700 HV). The wear mechanisms of the cladding layers were predominantly characterized by oxidative wear and adhesive wear. Notably, a stable oxide film was observed on the surface of the cladding layer treated at 900°C, with a wear rate as low as 1.27×10-7mm3N-1mm-1. This study provided a technological basis and theoretical support for the repair of coal equipment.

Corrosion mitigation potential of N-(2-(2-pentadecyl-2,5-dihydro-1H-imidazol-1-yl)ethyl)palmitamide palmitate on Q235 steel in sulfuric acid: experimental and theoretical analysis

Corrosion mitigation potential of N-(2-(2-pentadecyl-2,5-dihydro-1H-imidazol-1-yl)ethyl)palmitamide palmitate on Q235 steel in sulfuric acid: experimental and theoretical analysis

Microstructure and wear behavior of WC-reinforced AlCoCrFeNiSi high entropy alloy coatings prepared by high-velocity arc spraying

In this study, AlCoCrFeNiSi/WC (WC from 0 to 40 wt%) high entropy alloys (HEAs) coatings were deposited on Q235 steel substrates using high-velocity arc spraying technique. The coatings' phases, microstructure, microhardness, nano-hardness, wear properties, and the mechanisms of wear were examined. The results have shown that the WC reinforced HEA had faced-centered cubic, body-centered cubic solid solution and carbide phases, while faced-centered cubic solution and Cr3Si, Al2O3 phase were observed in AlCoCrFeNiSi coating. The coatings possess a dense, lamellar structure and strong adhesion to the substrates. With the addition of reinforced particles, the porosity of the coatings initially decreases and then increases. The average microhardness of the coatings is significantly improved as WC content increased, reaching a maximum of 530 HV0.1. The ratio of nano-hardness to reduced elastic modulus rises as more WC is introduced. The coatings with the WC particles exhibit good wear resistance with the optimum wear rate at WC content of 40 wt%. Under the same conditions, the coating with 40 wt% of WC displayed the lowest wear rate, which decreased by 60.5 % compared to the AlCoCrFeNiSi coating. The AlCoCrFeNiSi coating experienced a mix of adhesive, abrasive, oxidative, and fatigue wear mechanisms. The wear mechanism changed to more abrasive, adhesive, and oxidative in the reinforced coatings. The load-bearing capacity and secondary phase strengthening effects of WC reduce the wear rate of the coatings.

Microstructure and corrosion properties of CrMnFeCoNi high entropy alloy coating by temperature field-assisted laser cladding

The CrMnFeCoNi high entropy alloy coatings were prepared on the surface of Q345 steel using a temperature field-assisted laser cladding process, and the effects of the applied temperature field on the cladding coatings were studied. The microstructures and corrosion morphologies of the coatings were observed, and the elemental distribution, hardness, effective elastic modulus, electrochemical corrosion performance, and corrosion products of different coatings were analyzed. The results show that the porosity of the HEA coatings prepared with a temperature field is reduced to below 50 % of the initial level. The microstructure of the coating changed, with the nanoindentation hardness of the coating increasing by up to 0.55 GPa, enhancing the mechanical properties. Among all the coatings, the coating prepared at 250 °C temperature field exhibited the best corrosion resistance, with corrosion potential and current density of −0.27 V and 0.15 μA/cm2, respectively, improving the corrosion potential by 0.1 V and reducing the current density by 1.08 μA/cm2 compared to the sample prepared at room temperature. After incorporating the temperature field, the stability of the passive film on the coating during corrosion improved, and the nucleation rate of pitting decreased. Therefore, incorporating an appropriate temperature field during laser cladding can effectively enhance the overall performance of the CrMnFeCoNi HEA coating.

Effect of sulfur on synergistic corrosion behavior of Q235 and 16Mn steel in sodium aluminate solution

In this study, the corrosion electrochemistry and corrosion behavior of two steels were studied under the simulated alumina production conditions. The corrosion rate of 16Mn steel is greater than that of Q235 steel. The effect of S2− concentration on corrosion rate was significantly higher than that of S2O32−. The synergistic corrosion rates of Q235 and 16Mn steels increase at first and then decrease with the sulfur content, and the peak value appears when the concentration of S2− and S2O32− is 4 g/L and 3 g/L respectively. There are two main types of corrosion products: one is surface octahedral grain, which is composed of Fe2O3, Fe3O4 and Al2O3.The other is the interlayer corrosion between the surface layer and the matrix, which is composed of FeS, FeS2 and NaFeO2.The formation mechanism of the corrosion and corrosion mechanism were obtained by analyzing the phenomenon of ion competitive adsorption. Further validation and analysis of ion competition adsorption phenomenon were conducted using first-principles calculations based on density functional theory (DFT). The formation of corrosion products on the steel surface was investigated at an ion level, and the adsorption energies of OH− and S2− at the top site of Fe(110) surface were calculated. It was found that S2− is more likely to be adsorbed on the Fe(110) surface compared to OH−. The corrosion mechanism of steel is discussed preliminarily.

A self-healing MoS2/GO hybrid polyurethane-based coating with superior anticorrosion performance for Q235 steel

The application of conventional organic coatings as a method of surface protection for carbon steel materials is a widely adopted practice. Nevertheless, the protective capacity of the coating is limited by the occurrence of defects during the curing process and the rapid intrusion of acidic media. In this work, a self-healing anti-corrosion hybrid coating, designated as MoS2-APTES-GO-PU, has been successfully fabricated on Q235 steel, which exhibits excellent protection in acidic oil well formation water. Molybdenum disulfide (MoS2) is grafted onto the surface of graphene oxide (GO), through a facile 3-aminopropyltriethoxysilane (APTES) hydrolysis method to forming a highly cross-linked three-dimensional network structure, which is homogeneously dispersed in self-healing polyurethane (PU). The incorporation of GO has been found to result in a labyrinth effect, which can be attributed to the extensive specific surface area. Furthermore, the uniform distribution of MoS2 on the surface can remarkably improve the anticorrosion properties. This phenomenon can be ascribed to the MoS2 effectively limiting the rapid galvanic corrosion between GO and substrates in acidic corrosive media. MoS2-APTES-GO rectifies the phenomenon that APTES-GO depletes the dynamic hydrogen bonding groups in PU due to the abundance of active groups on the surface, thereby improving the self-healing ability of the coating. Additionally, the MoS2-APTES-GO maintains a stable chemical structure when subjected to acidic conditions own to the excellent chemical stability of GO and MoS2, which can effectively delay the rapid penetration of corrosive media. Based on the electrochemical tests, the corrosion current density of 0.4 wt% MoS2-APTES-GO-PU coating is reduced to 7.35 × 10−11 A/cm2 from 1.03 × 10−8 A/cm2 of pure PU coating and the self-healing efficiency reaches 1.98 × 107 Ω cm2/h. The current 0.4 wt% MoS2-APTES-GO-PU coating is self-healing and has favorable corrosion resistance for application in acidic environment.

The effect of alkyl chain on the corrosion inhibition of benzyldimethylammonium chloride in acidic environments

Incorporating quaternary ammonium salts (QAS) during pickling is an efficient and eco-friendly approach to mitigating metal corrosion. This study investigated the effectiveness of Benzyldimethylhexadecylammonium chloride (HDBAC) and Benzyldimethyltetradecylammonium chloride (TDBAC) in inhibiting the corrosion of Q235 steel in H2SO4, utilizing electrochemical methods, atomic force microscopy (AFM), scanning electron microscopy (SEM), and theoretical calculations. The electrochemical results demonstrated that compared with the blank impedance value of 40.68Ω cm2, HDBAC and TDBAC at 5 mM concentration showed impedance values of 997.69Ω cm2 and 676.17 Ω cm2 at 298 K, indicating that they can effectively prevent the corrosion of Q235. SEM and AFM further showed the formation of a protective barrier film by HDBAC and TDBAC on the steel surface, effectively isolating it from the corrosive medium. Theoretical calculations further elucidated the mechanism by which these inhibitors create this protective barrier. The experiment also verified the hypothesis that the length of the hydrophobic chain of surfactants affects the adsorption behavior and the inhibition efficiency. When comparing their inhibitory effects at 5 mM concentrations, HDBAC exhibited superior performance (95.92 %) against Q235 in 0.5 M H2SO4, compared to TDBAC (94.09 %). These findings provide valuable insights for developing more effective and sustainable corrosion inhibitors for industrial applications.

Insight into the Anti-Corrosion Mechanism of Halogen Anions in Bisimidazoline Derivatives as Corrosion Inhibitor for Q235 Steel in 1.0 mol/L HCl

Insight into the Anti-Corrosion Mechanism of Halogen Anions in Bisimidazoline Derivatives as Corrosion Inhibitor for Q235 Steel in 1.0 mol/L HCl

The influence of Cu on the microstructure and properties of TC4/Q345 high-entropy joints by laser welding

FeCoNiCrCu high-entropy alloy (HEA) and Cu foils were utilized as the intermediate layer to conduct laser welding of TC4 titanium alloy and Q345 steel. Welding is performed by adding single HEA and Cu/HEA double foils as interlayer respectively. We conducted in-depth studies on the microstructure and mechanical properties of the joint by stereomicroscopy, metallographic microscope, scanning electron microscope (SEM), micro-area X-ray diffraction (XRD), nanoindentation, electron backscatter diffraction (EBSD), and tensile testing. The results indicate that the position of the copper foil significantly affects the microstructure and performance of the joint. When the copper foil is on the TC4 side, its lower melting point causes a deeper keyhole, resulting in a narrower weld bead and then reduced content of Fe and Ti in the weld. Simultaneously, the increased proportion of Cu in the weld significantly enhances the content of Cu-rich phases. In the weld zone, we observed freely distributed Cu-rich phases and Ti-rich phases generated along the interface. Under tensile loads, cracks primarily initiate and propagate along the Cu-rich phases, leading to typical delamination on the fracture surface. With the copper foil on the TC4 side, due to the increased copper content in the microstructure, the hardness of the interface between the titanium alloy and the weld decreases, while the joint exhibits the highest tensile strength, reaching a maximum of 417 MPa.