Composite Steel Research Articles

Unified artificial neural network, linear and nonlinear statistics methods for forecasting the capacity of axially loaded concrete-filled steel tube (CFST) members

Due to the fast development of technology that facilitates human work, there is an urgent need to use artificial intelligence as a new and accurate technology in Structural Engineering to design structural members. This paper presents unified statistical linear regression (LR) and nonlinear regression (NLR) analysis using the statistical package for the social sciences (SPSS) and unified advanced design methods of artificial neural network (ANN) using MATLAB for forecasting the capacity of the composite concrete-filled steel tube (CFST) columns with different cross-sections under axial loads. Overall, test data of about 390 specimens were collected, including 13 specimens used to validate the mentioned methods. The unified ANN method gives the best conservative and save results with an average value of the test to ANN analysis result of 1.01, followed by the statistical NLR analysis method with an average value of the test to NLR analysis result of 0.992, and then the statistical LR analysis method with an average value of the test to LR analysis result of 0.971. The results of the proposed method based on statistical LR analysis have shown negative values for the predicted ultimate capacity, which means this method does not capture the ultimate capacity behavior well. Validating the accuracy of the predicted analysis results with four available design codes has been done. The ACI 318–19 and DBJ 13–51-2010 gave conservative and save predictions with average test values to calculate results equal to 1.115 and 1.126, respectively; the unified ANN model provides the most accurate assessment predictions compared to available design codes.

Indirect measurement of corrosion in reinforced concrete using optical sensor composed of polydimethylsiloxane/titanium oxide composite and sacrificial steel plate

Indirect measurement of corrosion in reinforced concrete using optical sensor composed of polydimethylsiloxane/titanium oxide composite and sacrificial steel plate

Application Strategy of Composite Steel Composite Beams in Bridge Design

The combined prefabricated steel-hybrid stacked girder structure is very common in modern bridge design. An actual bridge engineering design project is taken as an example in this paper to analyze the application strategy of this structure, encompassing overall design strategy, structural design strategy, and structural calculation strategy. The aim is to offer insights that can enhance the quality of bridge design.

Development of a High Ductility DP Steel Using a Segregation Neutralization Approach: Benchmarked Against a Commercial Dual Phase Steel

Commercial dual-phase steels are typically synonymous with a banded distribution of martensite in their microstructures, which can degrade ductility and increase the anisotropy of mechanical properties. The concept of neutralizing the effect of Mn segregation is employed to change the distribution of martensite to a non-banded distribution. To this end, the ratio of austenite and ferrite stabilizer elements has been changed in the composition of dual-phase steel. Microstructural analysis has been carried out on both hot-rolled (ferrite + pearlite) and heat-treated (ferrite + martensite) microstructures by optical microscope and EBSD, respectively. The microstructural examinations have confirmed the non-banded distribution of second phase and more equiaxed ferrite grains in the segregated neutralized grade microstructures compared to a commercially benchmarked dual-phase steel. Tensile properties of two grades have also been assessed in hot-rolled and heat-treated conditions in RD, TD, and 45 deg tensile directions. In the case of heat-treated condition, total elongation in RD direction has been improved from 20.9 pct in benchmark dual-phase steel to 25.4 pct in segregated neutralized dual-phase steel. Tensile anisotropy results showed a significant difference in tensile strength by tensile direction in benchmark dual-phase steel in both hot-rolled (~ 85 MPa) and heat-treated conditions (~ 48 MPa), while the corresponding differences for the segregated neutralized grades were 14 and 15 MPa, respectively.

Heat Treatment Optimization of Laser Powder Bed Fusion Formed WC/18Ni300 Maraging Steel Composites

Heat Treatment Optimization of Laser Powder Bed Fusion Formed WC/18Ni300 Maraging Steel Composites

Celastrus paniculatus seeds as a green corrosion inhibitor for stainless steel in H2SO4 acidic solution

Corrosion poses a significant threat to the durability and safety of metallic structures, particularly in aggressive environments such as sulfuric acid solutions. In this study, the corrosion inhibition performance of Celastrus paniculatus for steel in 0.5 M H2SO4 is investigated. Celastrus paniculatus, a natural plant extract known for its potential corrosion-inhibitive properties, is explored as a green alternative to synthetic inhibitors.The experimental methodology involves the immersion of steel specimens in 0.5 M H2SO4 solutions containing various concentrations of Celastrus paniculatus extract. Electrochemical techniques, such as potentiodynamic polarization and electrochemical impedance spectroscopy, assess corrosion inhibition efficiency. Surface analysis techniques, i.e., scanning electron microscopy (SEM), were employed to investigate the steel surfaces' morphological changes and elemental composition also Quantum Chemical Computations were conducted to find the energy levels of the Lowest Unoccupied Molecular Orbital (ELUMO) and Highest Occupied Molecular Orbital (EHOMO) and the energy gap (ΔE) between HUMO and LUMO from the optimized structure to find of which phytochemical absorb on the surface of the metal and this, we can clear that lower energy containing phytochemical will absorb more on the metal surface and have their greater efficiency. The study contributes to the development of environmentally friendly and sustainable corrosion inhibitors for steel in corrosive media, with potential applications in various industrial sectors. In metallic industries during acid cleaning or pickling processes metal undergoes acidic corrosion. This acidic corrosion can be prevented by many ways including alloying or dealloying of metals, anodic and cathodic protection or application of inhibitors. In this study, we have used the Celastrus paniculatus seed extract. Although its medicinal applications were explored but it was not used as a anticorrosive agent. So here we have determined the anticorrosive effects of Celastrus paniculatus seed in 0.5 M H2SO4 and used this as a novel and highly effective during acid cleaning.

Investigation on physical characteristics, chemical composition and mechanism of pipeline steel subjected to laser rust removal

Investigation on physical characteristics, chemical composition and mechanism of pipeline steel subjected to laser rust removal

Thermodynamic Prediction and Experimental Verification of Transformation‐Induced Plasticity/Twinning‐Induced Plasticity Effects in Advanced Low‐C High‐Mn Steel at Different Deformation Temperatures

The effectiveness of transformation‐induced plasticity (TRIP)/twinning‐induced plasticity (TWIP) effects in Fe–0.06C–26Mn–3Si–3Al advanced ferrous alloy is analyzed over a wide temperature range of −40 to 200 °C. The specific deformation mechanisms in the steel are experimentally investigated and predicted using thermodynamic calculations of stacking fault energy (SFE). These predictions were correlated with the microstructure of the steel and its mechanical behavior. The study finds that applied thermodynamic models effectively predict the occurrence of TRIP/TWIP effects at different deformation temperatures, aligning well with experimental observations in terms of ε/α′ martensite formation, indicative of the TRIP mechanism. Some discrepancies in SFE results are observed at Mn contents significantly higher or lower than the nominal composition of steel.

Composition and treatment of wear resistant steel for application in mining industry

The service life of machines in the mining industry is in the most cases determined by wear rate of parts in contact with the rock and soil. This work demonstrates the results of investigation on wear resistance of high-carbon low-alloy steel under abrasive wear. Steel samples containing 1.2 wt.% of carbon, 3 wt.% of manganese and 2 wt.% of silicon were hardened from 900 °C and 1000 °C and subjected to two-body and three-body abrasion tests. It has been established that after heat treatment this steel has increased abrasive wear resistance due to the phase transformation of unstable austenite into deformation-induced martensite. The results of study of near-surface region microstructure of samples after wear are presented. X-ray diffraction analysis and measurement of the microhardness of the worn surface were also carried out. It has been established that during abrasive wear a continuous layer of deformation martensite with a microhardness of 1300-1400 HV 0.05 is formed at a depth of up to 10 μm. Such a microhardness significantly exceeds the microhardness of quenching martensite. The results of the work can be used to increase the service life of wear parts of mining equipment.

Study on high-temperature friction and wear properties of Arc Ion plating Cr coating

In order to improve the high-temperature resistance and wear resistance of the D60 steel surface, arc ion plating technology is used to deposit Cr coating on the surface of D60 steel. A friction and wear testing machine is used to test the friction coefficient of D60 steel and Cr coating. Scanning electron microscope and Energy dispersive spectrometer are used to characterize the microstructure, composition, and phase composition of D60 steel and Cr coating. The research results indicate that when the temperature is 300°C and the load is 100 N, the friction coefficient of arc ion-plated Cr coating is higher than that of D60 steel. In addition, on the wear morphology, there are adherents and local peeling phenomena on the surface of the Cr coating.

Paedodontic preformed crowns in primary teeth and relative degree of dental wear.

Prosthetic rehabilitation of deciduous teeth in paediatric age using pre-formed crowns has been considered one of the best methods of dental restoration since their introduction. Their main advantages are related to durability, longevity and a low rate of recurrent cavities. Since stainless steel crowns do not coincide with aesthetic needs of parents and patients, preformed paedodontic crowns made of zirconia and nano-hybrid composite was introduced. The aim of the study is to evaluate the degree of wear on the enamel and on themselves of the different paedodontic crowns. Nine bovine teeth and nine paedodontic crowns for deciduous molars were selected for the study, three of which in zirconia, three in nano-hybrid composite and three in stainless steel. Wear test was carried out on the Rtech™ Instruments tribometer applying a force of 50 N. After that, both the bovine teeth and the paedodontic crowns were observed using a stereo microscope (Zeiss Stemi C-500) and a scanning electron microscope (SEM, Cambridge Stereoscan 440). The areas of wear were calculated with a software [ImageJ, version 1x, Wayne Rasband, Maryland, USA]. Pre-formed paediatric crowns in zirconia, nano-hybrid composite and stainless steel are a valid aid for the restoration of deciduous teeth and do not compromise the physiological wear characteristic of the phases of the dental exchange. The stainless steel crown is preferable for the restorations in the posterior sectors as its behaviour is the most similar to that of a natural tooth. Zirconia and nano-hybrid composite crowns showed an inversely proportional behaviour between their wear volume and that of the opposing tooth.

Axial compressive performance of cruciform timber-encased steel composite columns: Experimental investigation and buckling analysis through 3D laser scanning

Timber-encased steel composite (TESC) columns have garnered increasing attention owing to their high mechanical performance. However, limited studies have focused on the compressive performance of cruciform TESC columns and accurate evaluations of the full-field deformation of embedded steel components. In this paper, a novel cruciform TESC column embedded with a thin-walled cruciform steel component was proposed. 22 specimens including TESC columns, bare steel columns and bare glulam columns were tested under axial compression. Parameters such as the width and thickness of the cruciform steel component were considered. 3D laser scanning technologies were applied to measure the full-field deformation of 20 steel members, thus quantitatively assessing the reduction in the deformation of steel components resulting from the lateral restraint of timber. Finally, a nonlinear fitting equation was established to predict the load-carrying capacity. The results showed that the TESC columns exhibited significant enhancements in stiffness and load-carrying capacity. The lateral restraint of timber caused the buckling modes of the steel to change from torsional buckling to mainly local buckling. Moreover, the high post-yield stiffness of the steel components before reaching the maximum load indicated that the timber offered sufficient lateral restraint to make full use of the steel strength. The 3D laser scanning method accurately measured the full-field deformation of the steel at the failure state. Compared to bare steel columns, the torsional rotation of the steel components decreased by up to 83.14 %, while the maximum absolute lateral deflection decreased by up to 80.89 %. The suggested strength formula offered sufficient accuracy in predicting the load-carrying capacity of short TESC columns, with ratios between the calculated and experimental values ranging from 0.908 to 1.120.

Capturing the Interaction Between Mold Flux and Different Steel Compositions During Industrial-Scale Continuous Casting Trials

Capturing the Interaction Between Mold Flux and Different Steel Compositions During Industrial-Scale Continuous Casting Trials

Elevating carbon diffusion: deciphering the interplay of alloy composition and carburizing treatment in low carbon steels

Elevating carbon diffusion: deciphering the interplay of alloy composition and carburizing treatment in low carbon steels

Mechanisms of microstructural evolution in high-volume TiC reinforced steel composites: Insights into particle coarsening, morphology, and thermochemical reactions

Titanium carbides reinforced steel matrix (TiC-steel) composites exhibit a range of excellent properties, including increased strength-to-weight ratio, high-temperature strength, and outstanding wear resistance. Prior research has demonstrated that the mechanical properties of TiC-steel composites are significantly affected by particle coarsening and the associated core-rim structure. Nevertheless, the fundamental mechanisms of thermochemical reactions that govern the formation of the final microstructure in these composites, including the core-rim structure, remain incompletely explored. This study elucidates the microstructure evolution mechanism of high-volume TiC-steel composites, particularly particle coarsening, through thermodynamic calculations and chemical analysis. The investigation unveils the coarsening process, shedding light on the formation of more stable phases and associated compositional changes, including the incorporation of substitutional elements and carbon depletion (resulting in low stoichiometry, x < 1) within the newly developed (Ti,M)Cx. Additionally, the increased carbon content contributes to pearlite emergence within the steel matrix. Notably, key factors influencing the distinct morphologies observed in growing TiC particles are identified, attributed to variations in Mo, V, and W concentrations, as elucidated by rigorous thermodynamic and first-principles calculations. This study represents significant progress in understanding the intricate microstructure development of high-volume TiC-steel composites.

Theoretical evaluation of tapered composite plate girders subjected to shear loads

The behavior of prismatic composite steel plate girders subjected to shear loads was thoroughly investigated, and different theories were evaluated. However, the behavior of tapered composite plate girders with and without openings has not yet been investigated. Therefore, this paper presents a new method for predicting the ultimate capacity of tapered composite plate girders subjected to shear loads. The shear capacities of tapered composite plate girders with and without web openings were developed based on the classical theory of tension-field action for prismatic composite plate girders. It is assumed that the shear capacity of such girders can be predicted from the steel plate girder and reinforced concrete slab anchored using shear studs. The effect of the composite action on the top flange owing to the shear studs was considered in the derivation of the equations to calculate the shear capacity of the steel plate girders. In addition, the shape and size of the opening were also considered. The proposed method was verified by comparing the results of the shear capacity with experimental results from previous studies. It can be concluded that the proposed method can predict the shear capacities of tapered composite plate girders with solid and open webs with acceptable accuracy.

Corrosion of Zinc Cold Spray Coatings in a Wet Sweet and Sour Gas Environment

Internal corrosion is a problem for steel pipelines transporting natural gas or CO2 containing water and partial pressures of H2S higher than 0.3 kPa (0.05 psi). This work aims to mitigate internal corrosion in steel pipelines transporting natural gas containing H2S using cold spray coatings. Two types of the cold spray binary metallic coatings (zinc chromium [ZnCr]. zinc niobium [ZnNb]) were studied using electrochemical techniques: potentiodynamic polarization, linear polarization resistance, and electrochemical impedance spectroscopy. The corrosion resistance of cold spray coatings (ZnCr, ZnNb) was evaluated in an environment containing 4 bar CO2 pressure, simulating the partial pressures found in gas transmission lines over a solution of 3.5 wt% NaCl heated to 40°C. A concentration of 0.003 M Na2S2O3·5H2O, corresponding to H2S partial pressures around 0.079 bar (1.146 psi), was used to simulate sour conditions. Postcorrosion surface characterization was performed using a scanning electron microscope (SEM) equipped with an energy-dispersive x-ray spectroscope (EDS) and x-ray diffraction analysis. The data showed that the presence of 0.003 M Na2S2O3·5H2O shifted the corrosion potential to more anodic values and decreased the corrosion current density. Both coatings showed similar behavior after 1 h of exposure in the CO2/H2S environment, indicating that similar electrochemical reactions were occurring on ZnNb and ZnCr. SEM images and EDS surface analyses for specimens showed a significant change in the surface chemical composition of carbon steel coated with ZnNb and ZnCr after 24 h of immersion. In the presence of thiosulfate (under sour conditions), the formation of corrosion product layers (ZnCO3 and ZnS) on top of ZnNb and ZnCr coatings increased their corrosion resistance, which helped to reduce their corrosion by a factor of 2. Under a sweet environment, the corrosion rates for steel coated with cold spray coatings after 14 d of exposure are lower than that for galvanized steel by a factor of 5 due to the ZnCO3 layer formed on top of the coatings. The ZnCO3 layer formed on the steel surface acts as a physical barrier against corrosion by blocking the diffusion of corrosive species to the surface. No localized attack was observed. ZnCr Cold spray coating with defect showed promising corrosion protection against CO2 corrosion (sweet corrosion) after 14 d of exposure to a CO2 environment. The scratch on the coating simulated damage created in service, and it was deep enough to expose the substrate material (steel). The formation of zinc oxide (ZnO) and zinc carbonate (ZnCO3) on the scratch confirmed the cathodic protection of the steel by ZnCr and ZnNb coatings.

The inhibitor effect of migrating corrosion inhibitors on Q235 steel in high alkaline environment under cathodic polarization

PurposeThis study aims to investigate the corrosion inhibitor effect of migrating corrosion inhibitor (MCI) on Q235 steel in high alkaline environment under cathodic polarization.Design/methodology/approachThis study investigated the electrochemical characteristics of Q235 steel with and without MCI by polarization curve and electrochemical impedance spectroscopy. Besides, the surface composition of Q235 steel under different environments was analyzed by X-ray photoelectron spectroscopy. In addition, the migration characteristic of MCI and the adsorption behavior of MCI under cathodic polarization were studied using Raman spectroscopy.FindingsDiethanolamine (DEA) and N, N-dimethylethanolamine (DMEA) can inhibit the increase of Fe(II) in the oxide film of Q235 steel under cathodic polarization. The adsorption stability of DMEA film was higher under cathodic polarization potential, showing a higher corrosion inhibition ability. The corrosion inhibition mechanism of DEA and DMEA under cathodic polarization potential was proposed.Originality/valueThe MCI has a broad application prospect in the repair of damaged reinforced concrete due to its unique migratory characteristics. The interaction between MCIs, rebar and concrete with different compositions has been studied, but the passivation behavior of the steel interface in the presence of both the migrating electric field and corrosion inhibitors has been neglected. And it was investigated in this paper.

METHODOLOGICAL APPROACH TO THE DETERMINATION OF THE EFFECTIVE COMPONENT COMPOSITION OF CARBON STEELS FOR THE RESPONSIBLE APPOINTMENT

Of particular importance in the metallurgical industry is the issue of optimizing the chemical composition of steel in order to ensure the required level of properties. However, a significant number of modern complex approaches are based on the application of information technologies. The purpose of the work is to study the influence of the chemical composition of carbon steels on the formation of their microstructure and hardness. As part of the research, experimental ingots of carbon steels of various compositions were melted, which were then subjected to hot plastic deformation (HPD) followed by heat treatment (HPD+HT). The research material was laboratory steels, which are comparable in chemical composition to steels for railway axles according to the state standard, European and American standard. During the research, it was found that the chemical composition affects the number of structural components and the hardness of the studied steels in different states, such as cast, after HPD and HPD +TO. It was found that for a certain chemical composition, in which the value of the integral parameter of the state of charge (ZY) is less than 0.20 e, the hardness of steel in the state after HPD exceeds the hardness of steel in the state after HPD +TO.

DEVELOPMENT OF CRITERIA FOR EVALUATING STEEL REFINING PROCESSES USING INTERATOMIC INTERACTION PARAMETERS IN MELTS

To evaluate the efficiency of steel refining processes, the results of the physicochemical interaction of elements in the metal-slag system of ten steel grades smelted in modern conditions in Ukraine were analysed. As a result of the analysis of the patterns of changes in the distribution coefficients of sulphur and phosphorus depending on the chemical composition of steel and slag, physicochemical criteria for assessing the degree of completeness of ion exchange processes during steel dephosphorisation and desulphurisation have been developed using integral parameters of interatomic interaction in melts. Along with the use of integral physicochemical parameters of the chemical and charge state of the system ZY, e and Ze, the key role of the influence of the "recharge" parameter of the element ∆Ze on the process of sulfur and phosphorus distribution between metal and slag is shown and its use as a criterion for assessing the degree of deviation of the system from equilibrium is substantiated.