Search Results (132)

The growing use of weathering steel in bridge engineering has highlighted the increasing impact of fatigue damage caused by the combined effects of welding residual stress and vehicular loading. This study investigates the fatigue performance of Q500qENH weathering steel bridge decks by proposing a coupled analysis method for residual stress and fatigue crack growth, utilizing collaborative simulations with Abaqus 2023 and Franc3D 7.0. An interaction model integrating welding-induced residual stress fields and dynamic vehicular loads is developed to systematically examine crack propagation patterns in critical regions, including the weld toes of the top plate and the weld seams of the U-ribs. The results indicate that the crack propagation rate at the top plate weld toe exhibits the most rapid progression, reaching the critical dimension (two-thirds of plate thickness) at 6.98 million cycles, establishing this location as the most vulnerable failure point. Residual stresses significantly amplify the stress amplitude under tension–compression cyclic loading, with life degradation effects showing 48.9% greater severity compared to pure tensile stress conditions. Furthermore, parametric analysis demonstrates that increasing the top plate thickness to 16 mm effectively retards crack propagation, while wheel load pressures exceeding 1.0 MPa induce nonlinear acceleration of life deterioration. Based on these findings, engineering countermeasures including welding defect control, optimized top plate thickness (≥16 mm), and wheel load pressure limitation (≤1.0 MPa) are proposed, providing theoretical support for fatigue-resistant design and maintenance of weathering steel bridge decks. Full article

In high-altitude corrosive environments, weathering steel is widely applied due to its excellent corrosion resistance. However, the welded joint regions, where the chemical composition and microstructure undergo changes, are susceptible to the corrosion-induced degradation of mechanical properties. This study investigates the corrosion–mechanical synergistic degradation behavior of a 16 mm thick Q500 qENH base metal and its V-type and Y-type welded joint specimens. Periodic immersion corrosion tests were conducted to simulate plateau atmospheric conditions, followed by mechanical performance evaluations. Corrosion metrics—including corrosion rate, cross-sectional loss, penetration depth, and corrosion progression speed—were analyzed in relation to mechanical indicators such as the fracture location, yield load, ultimate load, yield strength, and tensile strength at varying exposure durations. The results indicate that the corrosion process exhibits distinct layering, with a two-stage characteristic of rapid initial corrosion followed by slower progression. Welded joints consistently exhibit higher corrosion rates than the base metal, with the rate difference evolving nonlinearly in an “increase–decrease–stabilization” trend. After corrosion, the mechanical performance degradation of welded joint specimens is more severe than that of base metal specimens. Full article

Weathering steel (WS) is widely used in bridge construction due to its high corrosion resistance, durability, and low maintenance requirements. This paper reviews the performance of WS bridges in Canadian climates, focusing on the formation of protective patina, influencing factors, and long-term maintenance strategies. The protective patina, composed of stable iron oxyhydroxides, develops over time under favorable wet–dry cycles but can be disrupted by environmental aggressors such as chlorides, sulfur dioxide, and prolonged moisture exposure. Key alloying elements like Cu, Cr, Ni, and Nb enhance corrosion resistance, while design considerations—such as drainage optimization and avoidance of crevices—are critical for performance. The study highlights the vulnerability of WS bridges to microenvironments, including de-icing salt exposure, coastal humidity, and debris accumulation. Regular inspections and maintenance, such as debris removal, drainage system upkeep, and targeted cleaning, are essential to mitigate corrosion risks. Climate change exacerbates challenges, with rising temperatures, altered precipitation patterns, and ocean acidification accelerating corrosion in coastal regions. Future research directions include optimizing WS compositions with advanced alloys (e.g., rare earth elements) and integrating climate-resilient design practices. This review highlights the need for a holistic approach combining material science, proactive maintenance, and adaptive design to ensure the longevity of WS bridges in evolving environmental conditions. Full article

The influence of the copper (Cu) content on the corrosion resistance of 3.5%Ni low-carbon weathering steel was investigated using periodic dry–wet cycle accelerated corrosion tests. The mechanical properties of the steels were assessed via tensile and low-temperature impact tests, while corrosion resistance was evaluated based on weight loss measurements. Surface oxide layers were characterized using three-dimensional laser confocal microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and electrochemical methods. Electron probe microanalysis (EPMA) was employed to examine the cross-sectional morphology of the oxide layer after 72 h of accelerated corrosion tests. The results indicate that the solution state of Cu increased the strength of 3.5%Ni steels but significantly damaged the low-temperature toughness. As the Cu content increased from 0.75% to 1.25%, the corrosion rate decreased from 4.65 to 3.74 g/m² h. However, when there was a further increase in the Cu content to 2.15%, there was little decrease in the corrosion rate. With the increase in the Cu content from 0.75% to 2.15%, the surface roughness of 3.5%Ni weathering steel after corrosion decreased from 5.543 to 5.019 μm, and the corrosion behavior was more uniform. Additionally, the α/γ protective factor of the oxide layer of the surface layer increased from 2.58 to 2.84 with an increase in the Cu content from 0.75% to 1.25%, resulting in the oxide layer of the surface layer being more protective. For 1.25%Cu steel, the corrosion current density of rusted samples is lower (ranging from 1.2609 × 10⁻⁴ A/cm² to 3.7376 × 10⁻⁴ A/cm²), and the corrosion potential is higher (ranging from −0.85544 V to −0.40243 V). Therefore, the rusted samples are more corrosion resistant. The Cu in the oxide layer of the surface layer forms CuO and CuFeO₂, which are helpful for increasing corrosion resistance, which inhibits the penetration of Cl⁻. Full article

Diverging from conventional dephosphorization approaches, this study employs a novel pre-reduction and smelting separation (PR-SS) to efficiently co-recover iron and phosphorus from high-phosphorus oolitic iron ore, directly yielding Fe–P alloy, and the Fe–P alloy shows potential as feedstock for high-phosphorus weathering steel or wear-resistant cast iron, indicating promising application prospects. Using oolitic magnetite concentrate (52.06% Fe, 0.37% P) as feedstock, optimized conditions including pre-reduction at 1050 °C for 2 h with C/Fe mass ratio of 2, followed by smelting separation at 1550 °C for 20 min with 5% coke, produced a metallic phase containing 99.24% Fe and 0.73% P. Iron and phosphorus recoveries reached 99.73% and 99.15%, respectively. EPMA microanalysis confirmed spatial correlation between iron and phosphorus in the metallic phase, with undetectable phosphorus signals in vitreous slag. This evidence suggests preferential phosphorus enrichment through interfacial mass transfer along the pathway of the slag phase to the metal interface and finally the iron matrix, forming homogeneous Fe–P solid solutions. The phosphorus migration mechanism involves sequential stages: apatite lattice decomposition liberates reactive P₂O₅ under SiO₂/Al₂O₃ influence; slag–iron interfacial co-reduction generates Fe₃P intermediates; Fe₃P incorporation into the iron matrix establishes stable solid solutions. Full article

By applying different heat treatment processes (furnace cooling, air cooling, and water cooling), the stress–strain behavior of the localized interfacial region in weathering steel–stainless steel clad plates was investigated using nanoindentation, along with an analysis of interfacial microstructure formation and strengthening mechanisms. The results show that samples in the as-rolled (R), furnace-cooled (FC), air-cooled (AC), and water-cooled (WC) conditions exhibit distinct interfacial morphologies and local mechanical properties. A well-defined interfacial layer forms between the base and cladding materials, where a high density of dislocations, grain boundaries, precipitates, and nanoscale oxides significantly enhances interfacial strength, resulting in a yield strength (R_p0.2) much higher than that of either adjacent metal. Across the transition from weathering steel to stainless steel, the interfacial region consists of ferrite—interfacial layer—“new austenite”—stainless steel austenite. Its formation is predominantly governed by element diffusion, which is strongly influenced by the applied heat treatment. Variations in diffusion behavior significantly affect the microstructural evolution of the dual-phase transition zone at the interface, thereby altering the local mechanical response. Full article

To investigate the corrosion resistance of 60Si2MnA spring steel coated with Zn-Al in a domestic atmospheric environment containing harmful salts, the corrosion environmental factors (temperature, humidity, deposited salts, and pH) were obtained through field research. The deliquescence and weathering behavior of harmful salts were studied using impedance methods to establish their characteristic curves. Additionally, a self-designed salt deposition test apparatus was employed to conduct accelerated atmospheric corrosion tests under constant salt deposition (10 g/m²) and controlled temperature and humidity conditions (20 °C/75% RH and 40 °C/75% RH) over different corrosion periods. The results show that noticeable red rust appeared on the samples after one month of corrosion. As the temperature increased, the consumption of the coating accelerated. XRD and Raman analyses reveal that the main corrosion products of the coating materials were ZnO, Zn(OH)₂, and Zn₅(CO₃)₂(OH)₆, while the red rust primarily consisted of iron oxides and hydroxides. In the early stages of corrosion, the self-corrosion current density was relatively low due to the protective effects of the coating and the corrosion product layer, indicating good corrosion resistance. However, in the later stages, the integrity of the coating and the corrosion product layer deteriorated, leading to a significant increase in the self-corrosion current density and a decline in corrosion resistance. This study provides a data foundation for understanding the corrosion behavior of Zn-Al-coated spring steel in atmospheric environments and offers theoretical insights for developing more corrosion-resistant coatings and optimizing anti-corrosion measures. Full article

Weathering steel has a fascinating history that dates back to the 1930s, and its evolution has left an indelible mark on various industries, from railways to architecture. Thanks to its high corrosion resistance with respect to conventional steel, weathering steel has assumed key roles in structural applications (buildings, bridges, railways, etc.), non-structural elements (facades, decorative elements), and installations at archaeological sites (retrofitting, sculptures), especially when exposed to aggressive environments. This paper is aimed at providing a state-of-the-art overview of the application of weathering steel in architecture and engineering applications, focusing on the development of scientific and technical knowledge on the subject and on future directions arising from current utilization. An evolution timeline of weathering steel-based constructions and their structural/typological classification is illustrated and discussed. In such a context, pros and cons related to maintenance aspects of weathering steel structures are also discussed, accounting for costs relative to structural and nonstructural maintenance and those related to environmental sustainability with respect to other traditional constructions. From a structural design point of view, the rules and recommendations provided by the main national and international standards—concerning material properties and types, design, and checks on structural members made with weathering steel—are analyzed, critically discussed, and compared, also with the aim of identifying possible gaps in comparison with other construction materials. Full article

This study investigates the influence of rare earth element Ce addition on the nanoscale precipitation, microstructure, and mechanical properties of Ti-containing secondary phases in high-strength low-alloy weathering steel. Mechanical property testing and microstructural characterization were performed on experimental samples subjected to rolling-aging treatment. The results demonstrate that the addition of Ce promotes coarsening of nanoscale precipitates, thereby diminishing their precipitation strengthening effect. At a 0.11% Ce content, an increase in inclusions was observed, leading to crack formation during hot deformation. However, Ce addition also refines inclusion size and modifies inclusion types, contributing to steel purification. Through austenite recrystallization zone rolling combined with an isothermal process, a high-strength ferritic weathering steel with nanoscale precipitates was fabricated, exhibiting a yield strength of 635 MPa, tensile strength of 750 MPa, and elongation of 21.2%. Precipitation strengthening plays a critical role in enhancing the room-temperature strength of ferritic steel. Full article

The high moisture content of wheat grains in extreme weather, such as continuous rain, can easily cause mildew, and we lack accurate discrete element parameters when conducting a simulation analysis of the rapid dehumidification of high-moisture grains. Based on the material characteristics of wheat grains with a moisture content ranging from 10.41% to 32.51%, the key parameters of discrete element simulation were calibrated. Firstly, the stacking angle under different moisture contents was determined by a physical experiment, and the regression equation was established as R² = 0.9981. Subsequently, three significant parameters, namely, the static friction coefficient between the grains and steel plates, the static friction coefficient between grains, and the rolling friction coefficient, were selected from nine parameters using the Plackett–Burman test and the steepest climbing test. Furthermore, the stacking angle–discrete element parameter model was established using the Box–Behnken test as R² = 0.98, with a relative error of less than or equal to 3.28%. Finally, the moisture content–discrete element parameter model was derived and constructed based on the moisture content–stacking angle model and the stacking angle–discrete element parameter model, with a relative error of less than or equal to 3.92%. The results indicate that the discrete element simulation parameters of wheat grains can be directly predicted by the moisture content and used for the discrete element simulation testing of high-moisture wheat grains. This universal calibration method not only provides convenient and reliable technical support for optimizing the emergency rapid dehumidification process for high-moisture wheat grains but also provides a reference method for the calibration of other grains. Full article

In this study, the Fe/Cu-based two-electrode corrosion monitoring technique was employed to monitor the long-term atmospheric corrosion of carbon steel at five different outdoor sites within the China National Environmental Corrosion Platform. Based on the fitted monitoring data, the variation trend of corrosion-critical humidity as a function of exposure time at different monitoring locations was obtained. The cross-sectional rust layer of corrosion coupons from different experimental periods at each location was characterized using scanning electron microscopy and Raman spectroscopy to identify variations in the thickness and phase composition of the carbon steel rust layer. The influence of rust layer thickness and phase structure on the critical humidity of carbon steel in atmospheric environments was investigated. Finally, the corrosion resistance of weathering steel in Tianjin, China, was validated using corrosion monitoring techniques, and the corrosion mechanism of weathering steel was elucidated by analyzing the influence of the acquired rust layer phase structure on the critical humidity of carbon steel in atmospheric environments. Full article

Transmission towers in coastal and industrial areas have experienced significant corrosion due to prolonged exposure to atmospheric pollutants and saline moisture, which poses a risk to structural safety. To evaluate the impact of corrosion depth on wind-induced collapse performance of an angle steel transmission tower, a survey of 18 angle steel towers in Ningbo, China, was conducted. Finite element models (FEMs) incorporating observed corrosion patterns were developed to analyze natural vibration characteristics and progressive collapse. The collapse modes of both corroded and uncorroded towers were identified, and high-risk failure member was determined. The results indicate that the corrosion depth below the lower cross-arm can be considered representative of the overall corrosion condition of the tower. Torsional natural frequency of the angle steel tower is particularly sensitive to corrosion due to the critical role of diagonal members. Collapse analysis further reveals that moderate corrosion levels can reduce the tower’s wind resistance to below the design threshold, potentially compromising safety under extreme weather conditions. The diagonal member below the lower cross-arm is identified as a high-risk failure component. Strengthening this member, by up-grading from L75×6 to L90×6, can significantly enhance the tower’s tolerance to corrosion. Full article

To address the challenge of reducing carbon dioxide emissions, this study focuses on carbon dioxide sequestration in calcareous fly ash and its use in mortar and concrete specimens, including reinforced structures. Calcareous fly ash was used in this study because it contains more reactive Ca phases, enabling efficient CO₂ capture and long-term storage through mineral carbonation. The research examines the influence of incorporating carbonated fly ash on the protective properties of the concrete cover for steel reinforcement, along with an analysis of the mechanical behavior of the specimens, resistance to weathering carbonation, and the modeling of the service life of reinforced concrete structures. The results indicate that the compressive strength of concrete specimens decreases with the addition of carbonated ash, though by no more than 9% after 90 days. The carbonation rate of concrete increases with the addition of ash; however, a roughly 4% lower rate was observed for carbonated ash compared to non-carbonated ash. No significant impact of ash carbonation on chloride diffusion or the corrosion process of reinforcement in mortars was detected. As a result, the estimated service life of concrete containing both ash and carbonated ash is over 20 times longer than that of the reference concrete. Full article

Hybrid building construction, in which the steel frame is filled with modular panels made of wood, is a relatively new technical solution. This type of structure allows the integration of large window surfaces. The aim of this study is to indicate the optimal glazing system, taking into account energy consumption, thermal comfort and economic indicators. A house made using new hybrid technology with an area of 152.4 m², located in Bialystok (Northeastern Poland) and in Kiruna (Northern Sweden), was selected as the reference object. Energy simulations of this building were performed with DesignBuilder v. 6.1.8.021 software. Due to the large format of the glazing, the assessment of the thermal environment was performed using the PMV index. An economic analysis aimed at selecting the optimal type of glazing was carried out. It was based on the most commonly used indicators such as LCC, NPV and IRR. The results of this study indicated that the selection of triple-glazed windows in the reference house reduced energy demand by over 22% for Bialystok and about 24% for Kiruna compared to double-glazed windows. Even greater effects can be achieved by using quadruple-glazed windows, as they provide energy savings of 36% and 39%, respectively, for these locations. The results of the analysis performed for a 2% increase in energy prices showed that triple and quadruple windows had a similar LCC value when the discount rate was lower than 2.5% for the Bialystok site. Quadruple-glazed windows were the best option for the Kiruna site when the discount rate was less than 5%. This research study found that, assuming a stable financial situation and a small increase in energy prices, it is recommended to use triple-glazed windows in the climate of Northeastern Poland. In more severe weather conditions, for example those characteristic of the area of Northern Sweden, quadruple-glazed windows are recommended. Full article

This study focuses on researching the influence of Mo on the corrosion mechanism of 1%Ni weathering steel (WS) in simulated marine atmospheric conditions. The Mo element is involved in the reaction, and after hydrolysis, MoO₂ and MoO₃ are produced. The deposition of MoO₂ and MoO₃ occurs in cracks and fissures, rendering the rust layer more uniform and homogeneous. It also furnishes nucleation sites for amorphous oxyhydroxide, which in turn promotes the interweaving of a nanosized oxyhydroxide network. As a result, the rust layer develops into a physical barrier that acquires a protective capacity. Only some of the Mo ions migrate to the vicinity of the Ni element for the hydrolysis reaction, which leads to the difficulty in improving the corrosion rate of the steel with a high Mo content. Hence, the content of Mo element can be controlled within 0.3–0.5% for the 1Ni WS. Full article