Search

In the construction area, as well as in the restoration of old and historical buildings, different metallic materials are frequently in contact with gypsum plaster. Due to the high porosity of gypsum plaster, and particularly in high relative humidity environments, the risk of corrosion exists. In the present work, carbon, galvanized and stainless steel, as well as copper, were embedded in gypsum plaster (with varying water/gypsum ratios) and exposed to different environmental conditions, and the corrosion rate was assessed by electrochemical techniques. Stainless steel showed very low corrosion rates, carbon and galvanized steel showed considerable corrosion rates, and copper showed moderate corrosion rates. The higher the humidity, the higher the corrosion rate, independently of the water/gypsum ratio. A comparison with results obtained for the same materials embedded in mortar was performed. Except for stainless steel, the corrosion rates obtained in gypsum are higher than those obtained in mortar, being this difference up to two orders of magnitude. The differences in the pH of both matrices explained the lower corrosion rates measured in mortar. [ABSTRACT FROM AUTHOR]

Purpose: Hexavalent chromium has been a benchmark corrosion inhibitor before it was phased out because of its carcinogenic properties. However, because it was phased out, many alternative corrosion inhibitors have been introduced but failed to meet the performance of this benchmark inhibitor. Consequently, benzotriazole (BTA) was reported to exhibit chromate-like inhibition performance. Subsequently, Intelli-ion was reported by researchers to exhibit chromate-like performance also with claims of being a unique alternative. This paper aims to review the inhibition performance of these two alternatives. Above all, promotes the unique inhibition performance of Intelli-ion that makes it suitable for application in many sectors. Design/methodology/approach: In this paper, the corrosion inhibition performances of BTA and Intelli-ion were compared systematically by reviewing some related literatures based on the opinion of the authors. Findings: Different methodologies for measuring the inhibition performance of BTA showed that it's an inhibitor of choice. However, the cut edge corrosion performance of Intelli-ion and BTA corrosion inhibitors on galvanized steel of 55% Wt.% Al, 44% Wt.% Zn and 1% Wt.% Si in 5 Wt.% NaCl solution was compared when subjected to scanning vibrating electrode technique (SVET) for 24 h. The results showed faint blue-colored region depicting negative cathodic current density for the Intelli-ion while there was a high-intensity of red-colored region depicting a positive anodic current density for BTA. In other words, the Intelli-ion inhibitor had a better overall cut-edge corrosion inhibition performance than the BTA inhibitor. Originality/value: This paper compares and further, summarizes the corrosion inhibition performance of Intelli-ion and BTA by evaluating SVET results from the literature. In addition, it serves as an overview and reference for the unique inhibition performance of Intelli-ion when applied in field applications. [ABSTRACT FROM AUTHOR]

In this paper, an attempt was made to determine the load-bearing capacity of a bonded joint of galvanized steel elements with carbon fiber reinforced polymer (CFRP) fabric. This issue is extremely relevant to the use of bonded carbon fiber fabric as a mean of reinforcing hot-dip galvanized steel structures. This technique is used in engineering practice for both hot-rolled and cold-formed steel elements. In order to obtain the necessary parameters for modelling bonded joints of galvanised steel thin-walled elements, laboratory tests were carried out. In the first stage, four specimens made of 50 mm diameter steel cylinders bonded to 16 mm thick hot-dip galvanised steel sheet of S350 GD were subjected to the pull-off test. In this connection the SikaWrap 230C composite fabric embedded in SikaDur 330 adhesive layer was investigated. In the second stage, the axial tensile test of the bonded butt joint using the same materials was performed. In this stage, 10 hot-dip galvanised steel sheet samples of S350 GD and 16 mm thickness were tested. The discussion on the failure mechanism in the context of the bonding capacity of the composite joint was carried out. Moreover the advanced numerical model using the commercial FE program ABAQUS/Standard and the coupled Cohesive Zone Model was developed. The significant influence of the preparation method of steel element surface and the thickness of the adhesive layer on the failure mechanism of the joint and the value of the maximum failure force was shown. [ABSTRACT FROM AUTHOR]

This study seeks to integrate steel shear walls with precast concrete systems into stable and resistant structures against lateral loads. It is desired to study the ductility factor, lateral strength, and behavior as well as the energy absorption of this integrated system compared to the precast concrete frame without a shear wall. For this purpose, two steel shear wall samples made of mild steel and galvanized steel plates are constructed within a precast concrete frame. The assembly is tested under a cyclic lateral load. The integrity of the connections of steel strips of the wall together, and the boundary of the wall to the frame, is observed to be excellent. The main failure mode is composed of the diagonal yielding of the steel wall. The system benefits from large hysteresis loops and no degradation because of any instability. The beam‐column connections remain almost intact even at large cycles of deformation. Moreover, a bare precast concrete frame is tested in the same way to compare the lateral behavior. The utilized ductile beam‐column connections are successful in retaining the integrity of the system until large drifts. However, the seismic design characteristics of the bare frame turn out to be inferior to the steel shear wall system. Results of the cyclic tests show that by proper design of the interior and exterior connections of the shear wall as well as the beam‐column connections, the steel shear wall system can largely increase the stiffness, ultimate strength, and energy dissipation capacity of a bare precast moment resisting reinforced concrete frame. On top of that, the system is able to retain its integrity up to lateral drifts over 2%. [ABSTRACT FROM AUTHOR]

This article presents a composite tunnel rockfall protection structure (CPRC) employing galvanized corrugated steel plates as the inner formwork for reinforced concrete structures. It addresses the threats posed by frequent rockfall disasters in mountainous regions with complex geology. The research investigates impact damage from various rockfall shapes through numerical simulations and experiments on five representative forms, comparing traditional reinforced concrete structures RC with CPRC. The study highlights both structures' dynamic responses and damage characteristics across different impact scenarios, introducing the Residual Resistance Index RRI as a measure of post-impact safety performance. Results show that the numerical simulations align with laboratory tests, with discrepancies within 10%, validating the simulation method's accuracy in predicting impact resistance. Following impacts, both structures primarily displayed brittle concrete damage; however, the CPRC structure demonstrated a 79.46% reduction in concrete damage and an 86.31% decrease in reinforcement damage. The energy-dissipating properties of the corrugated plates significantly lowered rockfall penetration depth and impact energy transfer ratio, with an RRI exceeding 0.88 post-event. Additionally, the study reveals varying damage effects from different rockfall shapes, further supporting the CPRC structure's superior impact resistance and its effectiveness in preventing secondary disasters in tunnel engineering within mountainous terrains. [ABSTRACT FROM AUTHOR]

As vehicle body structures become stronger and part designs more complex for lightweight, controlling frictional properties in automotive press forming has gained critical importance. Friction, a key factor in formability, is influenced by variables such as contact pressure, sliding velocity, sheet strength, and coatings. This study investigates the friction characteristics of steels with tensile strengths of 340 MPa and 980 MPa, under galvanized (GI) and galvannealed (GA) zinc coatings. Experimental results reveal that asperity flattening, a significant factor in determining friction, increases with contact pressure normalized by tensile strength, particularly for GI-coated steels. However, the relationship between friction and surface flattening deviates from conventional expectations, with the friction coefficient initially rising with increased flattening area up to ~20% before decreasing as flattening progresses. These findings suggest that traditional empirical formulas may not fully capture friction behavior under specific conditions. By understanding this inflection point, where friction reduces under high contact pressure, the study provides valuable insights for optimizing formability and improving sheet metal forming processes, especially in scenarios where precise friction control is critical for producing high-quality automotive parts. [ABSTRACT FROM AUTHOR]

Corrosion in the sheets produced leads to significant material losses, including the loss of resources, capital, labor, energy and knowledge. Corrosion control is significant for sheets produced and sent to customers in iron and steel factories. Surface corrosion testing of produced sheets and the accurate detection of corrosion levels are of great importance. The corrosion detection process for sheets in steel factories is performed visually with the naked eye. This is a subjective and time-consuming method. Identifying corrosion damage by visual detection and accurately determining the type and extent of corrosion requires expertise. Wrong decisions at this stage lead to losses during the production phase. Therefore, there is a need for systems that can automate this process and make it human-independent. In this study, a decision support system was designed to automatically detect the level of corrosion in galvanized sheets using convolutional neural networks. The average accuracy of the system is 97.5%, the average precision is 0.98, the average recall is 1 and the average F1 score is 0.99. The results we obtained indicate that a successful system has been developed for the detection and determination of corrosion levels. The high performance of the convolutional neural network models used for corrosion detection supports the practical applicability of the developed system. This system will increase the reliability and efficiency of industrial processes by enabling the accurate and automatic classification of corrosion. This system, which meets a significant need in this area for industrial organizations, reduces production costs and also makes the corrosion detection process more consistent and faster. [ABSTRACT FROM AUTHOR]

Lack of coating adhesion and bare spot defects of hot-dip galvanized steel plates were experimentally investigated, and the Fe-Al alloy layer was analyzed by both experimental methods and kinetic calculations. Scanning electron microscopy, electron probe micro-analyzer and glow discharge spectrometer method were utilized to determine the microstructures and the distribution of elements of the galvanized steel plates. It is discovered that lack of coating adhesion and bare spot defects depend on the quality of the Fe-Al alloy layer. Fe-Al alloy layer (alias inhibition layer) affects the adhesiveness of the alloy coating to the steel plate, and prevents the interdiffusion process of elements between the zinc pot and the coated steel. The kinetic analysis was carried out by means of CALPHAD (CALculation of PHAse Diagrams) method. Because the main constitutuent of Fe-Al alloy layer is Fe2Al5 phase when the Al content in the liquid Zn is kept below 1 wt.%, diffusion models with Fe2Al5 were constructed to investigate the element distribution during the galvanizing process, and the calculated results can reasonably predict the element distribution trend in both the alloy coating and the steel plate. It is shown that besides the wetting reactions of Fe and Al during the galvanizing process, the diffusion behavior of elements also influences the coating quality. In summary, the appropriate control of Fe-Al alloy layer can prominently benefit the surface quality of the galvanized coatings, and the manufacturing parameters, such as strip speed, galvanizing time and zinc pot temperature, act as important factors on the formation of the Fe-Al alloy layer. The optimum combination of the aforementioned parameters may contribute to the improvement of the coating quality. [ABSTRACT FROM AUTHOR]

In this paper, flexible conductive composite materials were prepared from flexible graphite and carbon fiber by mould pressing, and their micromorphology was studied by SEM. The influence of carbon fiber content on the mechanical properties and electrical conductivity of the flexible conductive composite material was studied, and the corrosion rate of the flexible conductive composite material coupling with galvanized steel in soil with different SO42− concentrations was studied. The results showed that the tensile strength reached 5.82 MPa when the mass ratio of carbon fiber to flexible graphite was 1:20, and the volume resistivity achieved 4.76 × 10−5 Ω·m when the mass ratio of carbon fiber to flexible graphite was 1:30. With the increase in molding pressure, tensile strength and electrical conductivity had a slight increase. When the flexible conductive composite material was coupled with galvanized steel, sulfate could accelerate the galvanic cell corrosion between the flexible graphite grounding material and galvanized steel. The increase in the sulfate concentration led to more corrosion acceleration. With the increase in corrosion time, the corrosion potential of the flexible graphite grounding material and galvanized steel coupling body decreased to its lowest at 30 days, and then increased gradually. The corrosion current was the highest at 30 days, and then decreased gradually. [ABSTRACT FROM AUTHOR]

In this work, graphene oxide (GO) and epoxy‐functionalized graphene oxide (GOSi) are chosen as additives and incorporated into epoxy resin (EP) for nanocomposite photo‐coating films (GO/EP and GOSi/EP series). Compared to GO/EP, the GOSi/EP nanocomposite demonstrates strong binding and excellent dispersibility, highlighting covalent bonding between GOSi and the epoxy coating. Furthermore, GOSi/EP‐based films demonstrated superior thermal stability and adhesion performance on galvanized steel plates. The corrosion performance of the coated galvanized steel is investigated using electrochemical impedance spectroscopy (EIS) and polarization curve analysis (Tafel). The effectiveness of corrosion protection is evaluated based on a combination of photoreactivity, crosslinking density, dispersity, and adhesion properties. Out of all the treated films, the film based on 0.1GOSi/EP exhibited the highest percentage of inhibition (98.89%) and demonstrated superior long‐term anticorrosion stability. In addition, the 0.1GOSi/EP based formulation showed remarkable antibacterial activity against S. aureus, resulting in a 92% reduction. This work demonstrates the development of a facile, environmentally friendly functionalized graphene oxide/epoxy photocured film with superior dual functionalities in both anticorrosion and antibacterial properties. These advancements hold promising potential for impactful practical applications. [ABSTRACT FROM AUTHOR]

The corrosion behavior of galvanized steels and zinc components under atmospheric exposure depends mostly on the corrosion product‐based cover layer formation under the prevailing conditions. The use of agar‐based gel electrolytes makes it possible to use electrochemical methods to obtain a characteristic value from these cover layers that describe their current and future protective capacity. It is shown here that different states of galvanized steel can be distinguished very well under laboratory conditions and that this method is also suitable for use under practical conditions. Based on the characteristic values and assuming future time of wetness, it is very easy to draw up a forecast for the future corrosion rate, which provides plausible values. [ABSTRACT FROM AUTHOR]

Corrosion is one of the most significant problems in irrigation systems, and fertigation may increase its damage. One of the solutions to mitigate this phenomenon would be using cathodic protection combined with piping coating, so it is essential to evaluate the type of sacrificial anodes and the cathode/anode area ratio, variables that change the performance of cathodic protection and its application cost. Thus, this study aimed to validate the effect of Al anodes on the protection against the mass loss of galvanized steel used in fertigation with white KCl solution at 10 g L−1 and verify the influence of the cathode/anode area ratio on the galvanized steel protection and anode consumption. Thus, we conducted immersion tests by simulating 10 years of fertigation to determine the mass loss of the galvanized steel and Al anodes. The results showed that Al anodes significantly reduce the mass loss in galvanized steel exposed to KCl solution, but there is no significant difference in its mass loss with the increase in the cathode/anode area ratio. Regarding the Al anodes, there was also no significant difference in mass loss with the increase in the cathode/anode area ratio. [ABSTRACT FROM AUTHOR]

Intumescent fireproof coatings protect steel structures and cables by forming a thick, fire-resistant layer under high temperatures. These coatings can deteriorate over time, impacting their fire resistance. Current testing methods are largely lab-based, lacking in-service evaluation platforms. Laser-Induced Breakdown Spectroscopy (LIBS) is emerging as a promising in situ detection technology but is influenced by low air pressure in high-altitude areas. This study investigates how air pressure affects LIBS signals in intumescent coatings on galvanized steel. Using pressures between 35 and 101 kPa, a linear model was developed to correlate laser pulses to ablation depth for characterizing coating thickness. Results show that spectral intensity decreases with lower air pressure. However, a strong linear relationship persists between laser pulses and ablation depth, with a fitting accuracy above 0.9. The coating thickness is identified by the number of laser pulses required to detect the Zn spectral line from the underlying galvanized steel. As air pressure decreases, the ablation depth increases. The study effectively models and corrects for air pressure effects on LIBS data, enabling its application for field detection of fireproof coatings. This advancement enhances the reliability of LIBS technology in assessing the fire performance of these materials, providing a reference for their in situ evaluation and ensuring better fire safety standards for building steel structures and cables. [ABSTRACT FROM AUTHOR]

Cold metal transfer (CMT) welding is an advanced arc welding technology, which is promising for joining dissimilar materials such as aluminum, magnesium, titanium alloys and steels for automotive and aerospace industries, as their high demands on reliable lightweight structures. Meanwhile, medium entropy alloys (MEAs) are a kind of highly promising new materials because of the excellent functional and mechanical performances. In this work, AA5052 Al/galvanized steel dissimilar joints were obtained by CMT-CS (cycle step) lap welding technology with CoCrNi MEA powder interlayer. When the MEA interlayer was applied, the contact angle reduced from 53.6° to 31.5°, and brazed width increased from 6.1 to 6.9 mm, which improved the wettability and spreadability of the molten filler on the steel substrate. In terms of interfacial microsture, the addition of the MEA layer with Co, Cr, Ni elements promoted the geneation of a relatively ductile Fe-rich Fe-Al IMCs, i.e., FeAl and Fe3Al, and thus enhanced the mechanical propeties of the laser joints. The maximum tensile load of the joints with interlayer reached 274 N/mm, which was 27.4% higher than that of the joints without interlayer. The introduction of MEA interlayer also improved the corrosion resistance and reduced the corrosion rate of the dissimilar joints. [ABSTRACT FROM AUTHOR]

Cold-formed steel (CFS) sections, increasingly favored in the construction industry due to their numerous advantages over hot-rolled steel, have received limited attention in research concerning the flexural behavior of galvanized iron (GI)-based CFS at elevated temperatures. Understanding how these materials and structures behave under elevated temperatures is crucial for fire safety. The authors have performed experimental studies previously on GI-based CFS under elevated temperatures. In that study, CFS sections made of GI of grade E350 of 1.5 m long and 2 mm thickness were used. Built-up beam sections were tested under two-point loading after heating to 60 and 90 min durations and subsequently cooling them down using air and water. This study aims to uncover the influence of different stiffener configurations on the load carrying capacity of sections under elevated temperature parametrically. With the experimental study results from previous studies as a reference, authors used FEM analysis to comprehensively study the behavior of GI-based CFS sections under fire. Vertical, horizontal, and not providing a stiffener were the configurations selected to study the beams parametrically. Parametric analysis confirmed that different stiffener configurations did not alter the predominant failure mode, which remained distortional buckling across all specimens. Beams with vertical stiffeners demonstrated superior performance compared to those with horizontal stiffeners in parametric analysis. Lateral–torsional buckling was observed in the reference specimen, lacking stiffeners due to inadequate restraint at the supports. [ABSTRACT FROM AUTHOR]

In this study, a series of photocured epoxied films (SAU-0, SAU-5, SAU-10 and SAU-15) were prepared and applied to the galvanized steel surface for corrosion prevention. These photopolymers were synthesized via cationic photopolymerization using Doublecure®1172 as a cationic photoinitiator. To discuss the crosslinking effect in these photopolymers, various amounts of multifunctional epoxy resin (SU-8) were added into the photoinitiating formulations. The photoreactivity, thermal, mechanical, and morphology properties of all photopolymers were investigated. The results demonstrated that the inclusion of SU-8 epoxy resin not only increased the crosslinking density but also did not sacrifice the interfacial interaction with steel. Finally, the potential dynamic polarization curve of the coated film was studied to realize its corrosion protection performance. As a result, the SAU-15 based photopolymer film, containing the highest amount of SU-8, exhibits the best corrosion protection value (PI = 99.2%) under testing with a 3 M NaCl solution. Furthermore, the SAU-15 based sample demonstrated good long-term storage stability, retaining over 96% of its original corrosion protection value under ambient air atmosphere and room temperature conditions after 28 days. Additionally, all the samples were immersed in 3 M NaCl solution and seawater for long-term stability testing. Once again, the SAU-15 based sample exhibited the best stability after being immersed in the testing solution for 28 days. This paper introduces a concept of SU-8 based photopolymer for corrosion protection and aims to provide a comprehensive understanding of the organic photocured layer technique and its potential for anticorrosion performance. [ABSTRACT FROM AUTHOR]

Energy savings in air-conditioning systems are important for achieving energy efficient buildings. A central airconditioning system in the large building is installed with air ductwork. Alternative materials are replacing conventional (Galvanized Iron Steel) air ducts for supplying air to the air-conditioned area. This research studies the objective function relationship between exergy and economic variables in the alternative air ductwork compared with conventional air ductwork. The optimization method to identify the optimal type and thickness of air ducts in Thailand’s buildings. The result shows that the alternative ductwork has achieved maximum worthiness with more useful exergy than conventional air ductwork. The Pre-insulated duct (PID) with 30.00 mm wall thickness is 82.14 %. It is the maximum of all exergies generated by the Air Handling Unit. [ABSTRACT FROM AUTHOR]

The reliability and efficiency of the grounding system in substations is of utmost importance for the safety of the electrical grid. In China, the grounding grids of substations are primarily composed of galvanized steel, carbon steel, and copper, all of which are susceptible to corrosion from soil during operation. This study thoroughly examines the effects of typical Cl− ions and soil water content on the corrosion behavior of a Q235 steel in situ. The data suggest that there is a negative correlation between soil moisture and grounding grid corrosion, whereas dissolved salts, particularly Cl− ions in soil, correlate positively. [ABSTRACT FROM AUTHOR]

Hot stamping of steel is an innovative process for producing components of higher strength with a significant weight reduction. Conventional hot stamping process is carried out at an elevated temperature in the range of 800 to 950 °C in atmospheric condition. So, a coating is a must to restrict high temperature oxidation and decarburization of the steel substrate. Majorly, Al-Si coating and Zn-based coatings are used for the purpose. However, Al-Si-based coatings are not able to provide sacrificial cathodic protection to steel substrate and the Zn-based coating suffer from the problem of microcracking. In the present study, the pre-Ni coated galvanized boron steels are investigated to understand high temperature phase transformation during austenitization step. Thermodynamic calculations along with Gleeble heat treatment experiments and coating characterizations with SEM, EDS, WDS and XRD shows initial melting of the coating. Subsequent Fe-enrichment in the coating has led to formation of BCC phase which is high melting as well as softer phase compared to Ni-Zn intermetallic. Moreover, the corrosion performance of the prior Ni coated galvanized steel has been evaluated. The presence of zinc in the coating shows sacrificial corrosion protection behavior and the Ni and Fe in the coating have further improved the corrosion rate owing to their barrier protection to the steel. [ABSTRACT FROM AUTHOR]

The paper describes the existing technologies and challenges associated with galvanized metal production at the Novolipetsk Steel (NLMK) plant. Possible ways to improve the process using machine-learning tools are proposed. [ABSTRACT FROM AUTHOR]

In this study, the theoretical welding parameters influencing porosity formation were examined with the aim of reducing or minimizing porosity levels. An experimental design was implemented using the Taguchi methodology for data analysis, resulting in an L9 orthogonal array matrix of experiments. The welding variables considered in the orthogonal array were peak current, peak time, and frequency. Nine lap welds were performed on CP780 steel using the gas metal arc welding process with pulsed arc (GMAW-P), employing an ER70S-3 electrode as filler metal. The percentage of porosity was determined as a response variable, and the actual heat input was treated as a covariable, thereby identifying the welding parameters with the predicted values. Three repetitions were conducted with the optimal welding parameters to validate the Taguchi prediction. The quality of the welds was assessed through radiographic inspection, and metallographic preparation was performed, revealing the microstructure with 5% Nital for 12 s. The samples were analyzed using an optical microscope, and images were obtained with the collage technique. The results showed that the welding parameters predicted by the Taguchi statistics were favorable for all three predicted welded joints. The maximum percentage of porosity obtained was 19%, which was reduced to 1% using the Taguchi methodology, demonstrating the effectiveness of this statistical tool for process optimization. It was observed that for heat input values of 230 to 250 J/mm, the presence of porosities is dramatically reduced, finding a very small window that allows the gases generated by the burning of zinc to be expelled to the surface. [ABSTRACT FROM AUTHOR]

When the high-density polyethylene sheath of bridge cables is not cracked, the galvanized high-strength steel wires are not corroded and only subjected to the fatigue loads of vehicles (called prefatigue). Some studies have confirmed that the corrosion rate and fatigue life of certain alloy materials can be affected by the prefatigue, which is not clear for the corroded steel wires in bridge cables. In this paper, the mechanical properties of high-strength steel wires considering the prefatigue effect under fatigue-corrosion alternating loading were studied, and the residual fatigue life was predicted. First, the corrosion characteristics of high-strength steel wires with different degrees of prefatigue and corrosion were explored through an optical microscope and a surface roughness measuring instrument. Then, the static mechanical properties and fatigue life of corroded steel wires were obtained. The results show that when the prefatigue effect is greater than the corrosion effect, the surface roughness of the corroded steel wires decreases significantly, leading to a smoother surface and a weaker stress concentration. Compared with the results in the "corrosion + fatigue" case, the fatigue life of the steel wires in the "fatigue (prefatigue) + corrosion + fatigue" case may increase. The prefatigue effect has no significant effect on the static performance of the corroded steel wires. Finally, a fatigue life prediction model of corroded steel wires considering the effect of prefatigue was established based on the aforementioned experimental data. [ABSTRACT FROM AUTHOR]

Underground diaphragm walls are commonly used as a support system for the construction of subway stations, working together with inner side walls of subway stations to withstand the pressure from surrounding soils. However, the effect of diaphragm walls on the seismic response of subway stations is still not well understood yet, or at least not well considered during design. In this paper, a series of 1 g shaking table tests is designed to investigate the seismic response of a typical two‐story and three‐span subway station considering the influence of underground diaphragm walls. The stratum is simulated by synthetic model soil (a mixture of sand and sawdust), and the model structure and diaphragm walls are made by granular concrete with galvanized steel wires. A test case of the structure without diaphragm walls is also involved and taken as a benchmark comparison to understand the impact of diaphragm walls on the seismic response of subway station. The seismic excitations for the test include actual seismic records with the amplitude of 0.2, 0.4, and 0.8 g, respectively. Based on the test data analysis, a comprehensive discussion is conducted on the influence of diaphragm walls on the seismic design of underground structures. Current misconceptions that ignoring the role of diaphragm walls is a conservative way in seismic design of underground structures are also reviewed. Results show that the presence of underground diaphragm walls would enhance the lateral stiffness of the structure, and thus significantly reduce the lateral deformation of subway stations during earthquakes. Notably, the structure with diaphragm walls also exhibits a significant amplification in acceleration response and experiences greater dynamic earth pressures on the sidewalls, and furthermore the strains at the connection between the sidewalls and diaphragm walls are dramatically amplified during the earthquake. It is worth noting that these adverse effects of the diaphragm walls on the amplification of dynamic earth pressures on the structure as well as the increase of internal forces at the sidewalls end‐diaphragm walls connection should be carefully considered in the seismic design of underground structures. [ABSTRACT FROM AUTHOR]

Aluminum–steel joints are increasingly used in the automotive industry to meet the requirements for energy saving and emission reduction. Among various joining technologies, self-pierce riveting (SPR) and resistance spot welding (RSW) are two well-established technologies for fabricating dissimilar joints with stable and high mechanical performance. However, corrosion will occur in these joints inevitably due to different electrochemical properties, which can degrade the surface quality and the mechanical performance, such as strength. This paper presents a method of understanding the corrosion mechanisms in joining aluminum and steel. For this understanding, a hybrid method combining experimental observations, mechanical properties identification, and analytical approaches was used to assess the evolution of the impact of corrosion on the joining performance, such as traction separation curves. The study was conducted on common combinations used in the vehicles, e.g., a 1.2 mm thickness aluminum alloy (AA 6022) and 2.0 mm thickness hot deep galvanized steel (HDG HSLA 340) joined by SPR and RSW. After the fabrication of these joints, accelerated cyclic corrosion tests of up to 104 cycles were performed, which reproduced the environmental conditions to which a vehicle was exposed. By investigating the microstructural evolution within the joints, the corrosion mechanisms of SPR and RSW joints were revealed, including the initiation and propagation. Moreover, the intrinsic impact of the corrosion on the mechanical performance, including the strength, axial stiffness, and crashworthiness, was analyzed by performing a lap-shear test. It showed that as corrosion proceeds, the fracture modes and mechanical performance are affected significantly. [ABSTRACT FROM AUTHOR]

Background: Zinc fever is well described in medical literature, particularly in workers after handling zinc-containing materials at high temperatures e.g., in the welding of hot-dip galvanized steel sheets. It is not known whether zinc fever also occurs at low temperatures. Case presentation: We present the case of a 33-year-old Caucasian atopic painter and varnisher with work-related dyspnea, sweating, as well as multiple occurrences of fever. He was sent to Institute for Prevention and Occupational medicine of the German Social Accident Insurance, Institute of the Ruhr-Universität Bochum (IPA) for the evaluation of isocyanate asthma, but an inhalative challenge with hexamethylene diisocyanate was negative. Since symptoms were closely related to the use of zinc coatings at room temperature without adequate protective measures, the diagnosis of zinc fever was made. After exposure cessation the worker immediately became symptom-free. The work as painter and varnisher may be associated with various exposures to hazardous substances. Besides solvents, epoxy compounds and isocyanates, which can cause obstructive respiratory diseases; additionally, zinc-containing agents should be considered as health hazards. Conclusions: This case demonstrates that zinc fever may occur also after application of zinc coatings by spray painting at low temperatures. [ABSTRACT FROM AUTHOR]

In the hot stamping process, the friction and wear interaction between the high-temperature sheet metal and the water-cooled die has a significant impact on the final quality of the product and the durability of the die. Currently, most research on the wear of the stamped parts during the hot stamping process mainly involves analyzing the wear morphology and wear mechanism of the sheet surface, and there is little research on its wear assessment. In this study, to better assess the forming quality of hot stamping parts, the research takes the direct hot stamping of galvanized ultra-high-strength steel sheets as the object and proposes a wear amount calculation method of galvanized ultra-high-strength steel sheets based on the real contact area of the high-temperature sheet metal and the water-cooled tools. At different temperature conditions, the galvanized layer and steel substrate have different mechanical properties. The model is validated using the sheet characteristics at 650 °C, 700 °C, and 750 °C. The results indicate that the model can predict the wear of the galvanized steel sheet under different conditions within a certain range. [ABSTRACT FROM AUTHOR]

The introduction of new regulations needs to develop eco-friendly systems to prevent corrosion. In this work, a natural corrosion inhibitor caffeine (CAF) was encapsulated in polysaccharide-based nanoparticles, capable of the responsive release of CAF during corrosion. The nanoparticles were prepared using electrostatic complexation between two natural polysaccharides which are oppositely charged—chitosan (CHI) and sodium alginate (ALG), crosslinked by tripolyphosphate (TPP). The particle size distribution and zeta potential were evaluated using dynamic light scattering and laser Doppler velocimetry. The encapsulation efficiency and release of CAF from nanocontainers was evaluated with UV-spectroscopy. The nanoparticles were incorporated via electrodeposition into the zinc coating on low-carbon steel to ensure self-healing. Cyclic voltammetry demonstrated the cathodic and anodic processes in the starting electrolytes. Surface hydrophobicity was investigated by water contact angle (WCA). The corrosion resistance of the coatings was estimated with polarization resistance (Rp) measurements and potentiodynamic polarization (PDP) curves. The study of the chemical composition of the coatings was carried out with X-ray photoelectron spectroscopy. The data obtained confirm the indisputable influence of the nanoparticles/nanocontainers on the protective feature of the hybrids—the latter have about twice-higher Rp values compared to the ordinary zinc. [ABSTRACT FROM AUTHOR]

Friction stir welding (FSW) of galvanized steel offers unique advantages as it can avoid the extensive metallurgical problems associated with fusion welding. However, conventional FSW still leads to a higher temperature in the stir zone, which deteriorates the microstructure. To obtain a satisfactory weld, the welded joints of galvanized steel were created by FSW with different cooling rates employing a W–Re rotary tool with a large-diameter needle. The correlation between the microstructure evolution and mechanical behavior of joints at different cooling rates was systematically studied. The results demonstrate that the rapid cooling rate favors the refinement of ferrite and diffuse distribution of Fe3C. In addition, weakening of the texture and dispersion of dislocations were also observed after fast cooling FSW. It can be concluded that the microstructural evolution mechanism of the stirring zone (SZ) is continuous dynamic recrystallization at a slow cooling rate, while the microstructure has discontinuous dynamic recrystallization as the primary evolution mechanism at a fast cooling rate. Based on these advantages, the tensile specimens with fast cooling FSW obtained a synergistic improvement in strength-ductility, even surpassing the base material. This work provides new ideas for welding galvanized steel. [ABSTRACT FROM AUTHOR]

Aiming at the problem of porosity in laser brazing of galvanized sheet, three-spot laser brazing technology was used to solve the problem of pores caused by evaporation of zinc vapor. The surface morphology and mechanical properties of galvanized sheet laser brazed joints with or without three spots were studied. The results showed that when the three-spot laser brazing technology was applied, the zinc coating on the surface of galvanized steel was removed by coating removal laser in advance, zinc vapor escaped completely, and there were no visible pores on the surface of the weld. For the tensile strength and microhardness of brazed joints, when the laser power was 2500-3200 W, the welding speed was 40-50 mm/s, the wire feeding speed was 3.0-3.5 m/min, and the beam-spot size was 4.2-5.5 mm; the tensile strength of the brazed joint reached more than 80% of the base metal. The tensile strength of the brazed joint was sensitive to welding speed. The microhardness of fusion zone was higher than base metal, and the microhardness reached 120 HV. [ABSTRACT FROM AUTHOR]

The effect of coating a flat blade surface with titanium nitride nano coatings (TiN), nano tantalum carbide (TaC), Fiberglass (Glass Fiber-Reinforced Polymer) (GFRP), Galvanized Steel (GAS), and St37 (SST37) was investigated in order to decrease the adhesion of soil on tilling tools, external friction and, ultimately, the draft force. The soil tank, which was filled with soil of the desired conditions, was pulled on the bearing on the rail. A S-shaped load cell was used to measure the draft force. Tests were conducted at a distance of 2 m and speeds of 0.1, 0.2, and 0.3 m·s−1 at a depth of 10 cm. A model based on input factors, including blade travel speed, rake angle, and cohesion and adhesion of soil–blade, was developed in an adaptive neuro-fuzzy inference system (ANFIS), and draft force was the output parameter. To verify the performance of the developed model using ANFIS, a relative error(ε) of 6.1% and coefficient of determination (R2) of 0.956 were computed. It was found that blades coated with Nano (TiN-TaC), due to its hydrophobic surface, flatness, and self-cleaning properties, have considerable ability to decrease adhesion in wet soils and showed a linear relationship with draft force reduction. [ABSTRACT FROM AUTHOR]

The possibility of representing the process of temper rolling for a galvanized cold-rolled strip as a simultaneous deformation of a binary zinc-steel system is demonstrated. It is confirmed that the simultaneous plastic deformation of the components of the galvanized strip during its temper rolling occurs when the critical thickness of zinc is achieved. The process of reproducing the microgeometry of the textured surface of the roll on a galvanized cold-rolled strip during its temper rolling is considered the process of filling the micro-cavities of the roll with the material in contact with it. A mathematical dependence is obtained for calculating the reproducibility ratio of the parameters of the textured surface on a cold roll on a galvanized cold-rolled strip, depending on the thickness and mechanical properties of the galvanized coating and steel strip, equipment characteristics, modes, and conditions of its temper rolling, as well as on the roughness parameters S, Ra, and Pc of the roll surface. A comparative assessment of the influence of the technological parameters of temper rolling on the reproduction ratio of the microgeometry of the roll surface on a galvanized cold-rolled strip is provided. [ABSTRACT FROM AUTHOR]

Corrosion behavior is critical to the application of lightweight aluminum/steel joints using new resistance spot welding (RSW) technology. The study investigated the corrosion mechanism and the shear strength of RSW joints comprising 1.2 mm 5182 aluminum and 1.5 mm DP780 galvanized steel. Electrochemical corrosion tests were conducted on the base materials and various positions of the welds in a 3.5% NaCl solution. This result revealed that the corrosion susceptibility of the interfacial intermetallic compound (IMC) layer was not accelerated by the aluminum nugget because of the noble corrosion potential. Subsequently, the spray acceleration test was employed to investigate the corrosion mechanism. It is noteworthy that microcracks, as well as regions enriched with silicon and oxygen at the interface front, are preferential to corrosion during salt spray exposure, instead of the IMC layer. Moreover, the shear strength of the joints decreases with the reduction in the effective joint area after the salt spray exposure of the weld joints. This research systematically explored the corrosion behavior and its relationship with the mechanical properties of Al alloy/steel RSW joints. [ABSTRACT FROM AUTHOR]

This article presents the improved properties of GI (hot-dip galvanized) steel plates in combination with a special permanent surface treatment. The substrate used was hot-dip galvanized deep-drawn steel sheets of grade DX56D + Z. Subsequently, various surface treatments were applied to their surface. The coefficient of friction of the metal sheets without surface treatment, with a temporary surface treatment called passivation, and a thin organic coating (TOC) based on hydroxyl resins dissolved in water, Ti and Cr3+ were determined by a cup test. The surface quality and corrosion resistance of all tested samples were also determined by exposing them for up to 288 h in an atmosphere of neutral salt spray. The surface microgeometry parameters Ra, RPc and Rz(I), which have a significant influence on the pressing process itself, were also determined. The TOC deposited on the Zn substrate was the only one to exhibit excellent lubrication and anticorrosion properties, resulting in the lowest surface microgeometry values owing to the uniform and continuous layer of the thin organic coating compared to the GI substrate and passivation surface treatment, respectively. [ABSTRACT FROM AUTHOR]

In this paper, MIG welding–brazing was employed to join a 1.5-mm-thick 6060 aluminum alloy and a 2-mm-thick galvanized steel, using a 1.2-mm ER4043 welding wire as the filler. The microstructure, phase structure, and element distribution of the welded joint interface layer were analyzed using SEM, XRD, and EDS. The tensile strength of the joint and the hardness distribution of the interface layer were tested. The study found that when the welding current was around 60 A, the interface layer formed optimally, and the tensile strength of the welded joint reached a maximum value of approximately 200 MPa. During the welding process, an intermetallic compound (IMC) Fe2Al5 with lower free energy was formed at the joint interface. As aluminum atoms continuously diffused toward the steel side and reacted with iron, a compound FeAl3 precipitated on the side closer to aluminum. [ABSTRACT FROM AUTHOR]

This article provides a comprehensive overview of the potential use of organofunctional silane coatings in the corrosion protection of concrete reinforcement in close relation to other commercially used coating technologies—i.e., epoxy coatings and bath hot-dip galvanizing coatings. The application technology of the steel surface is described in detail, and the corrosion performance and bond strength in concrete are compared. The paper also points out the possibility of improving the durability of epoxy coatings by the addition of silanes and, in the case of application to the surface of hot-dip galvanized steel, they can prevent corrosion of the coating by hydrogen evolution. The application potential of organofunctional silanes is also presented in the form of hydrophobic coatings on concrete surfaces or as corrosion inhibitors in simulated concrete pore solutions. The use of a suitable type of modified silane coating on the surface of carbon steel reinforcement can increase the corrosion performance and can also increase the bond strength in concrete. However, these facts need to be experimentally verified. [ABSTRACT FROM AUTHOR]

Purpose: The main purpose of the research is to investigate the effects of spot weld-brazing variables, such as cold metal transfer (CMT) modes and current, on the tensile shear strength of 5052 aluminium alloy for dissimilar joining to SS400 galvanized steel. Design/methodology/approach: The method employed in the study was a 3k full factorial design with three replications. Analysis of variance (ANOVA) techniques were employed to identify the variables that influenced the responses of interest. The response optimiser method displayed which factors affected the variables and their impact on strength. In addition, the response optimiser method was employed to find which factors produced the best value for the response variable. A mathematical model was developed to predict the strength of the joints. An optical microscope (OM) and scanning electron microscope (SEM) were also employed to confirm the microstructure. Energy dispersive spectroscopy (EDS) was used to determine the chemical composition of the microstructure. Findings: The strength of the weld-brazing joints was affected by the modes and currents used in the joining process. The weld-brazing mode selection was found to have an impact on strength. The synergic mode was shown to have a strength greater than the CMT pulse and pulse synergic modes. The excess or little weld-brazing current was shown to be unsuitable for the joint. The maximum tensile shear strength value was obtained in the synergic mode with a current of 110 A. The resulting prediction model was evaluated with the newly collected experimental data, and the average per cent error was estimated to be 2.07%. In addition, the reaction layer at the aluminium alloy and steel interface was composed of a Fe(Al, Si)3 phase. The optimal conditions for the spot weld-brazing activities resulted in a larger fracture area, a small contact angle, and excellent weld bead geometry. Research limitations/implications: The prediction accuracy of the model appeared satisfactory. However, the altered chemical composition of the filler metals and substrate materials could impact the findings. It is recommended that the electrical signal waveform be studied during spot weld-brazing, as well as the characteristics of other material joints with various other parameters. Practical implications: The weld-brazing mode and current had no significant effect on the type of interface layer of the joints. Originality/value: It is highly possible that the CMT spot weld-brazing technique could be applied to join other dissimilar materials in order to reduce the joining time, but the filler metal chosen must be appropriate. [ABSTRACT FROM AUTHOR]

This study aims to investigate the corrosion resistance of galvanized steel (GS) and AZ31 pipe materials immersed in a magnetized water treatment (MWT) applied river water source. The potentiodynamic corrosion test results showed that a better corrosion rate is obtained by the AZ31(corr.rate: 0.0442 mm/y) specimen than GS (corr.rate: 0.0764 mm/y) due to the passivation efficiency resulting from the calcite and MgO particles on the surface.

The article discusses the importance of using foot valves instead of surface mounted check valves in well systems, particularly shallow wells. The author, a professional well driller, highlights the benefits of foot valves in preventing vacuum leaks, simplifying winterization, and facilitating leak detection. Foot valves are recommended for new well systems due to their ease of installation, reduced maintenance, and improved leak identification capabilities. The author emphasizes that foot valves are not suitable for all wells, particularly older ones with corroded steel casings. Overall, the article provides valuable insights into optimizing well systems for efficiency and ease of maintenance. [Extracted from the article]

In order to evaluate the corrosion state of power grid galvanized steel components in the atmospheric environment of Anhui Province, galvanized steel samples, which were naturally exposed for 1 and 3 a, respectively, were analyzed using scanning electron microscopy(SEM), energy-dispersive X-ray spectroscopy(EDX) and X-ray diffractometer(XRD) to investigate the compositions and morphologies of the corrosion products, thereby revealing their atmospheric corrosion mechanisms. Meanwhile, the corrosion rates of the galvanized steel samples were determined using the weight-loss method, combined with grey correlation analysis, to ascertain the influence law of major environmental factors on the atmospheric corrosion rate of the galvanized steel samples. Results showed that the atmospheric corrosion products of the galvanized steel samples consisted of ZnO and minor amounts of Zn5(OH)6(CO3)2 and Zn4(OH)6SO4. The surface of the corrosion layer featured cellular protrusions composed of flaky Zn5(OH)6(CO3)2 and Zn4(OH)6SO4, forming chrysanthemum-like patterns. The structure of the corrosion layer was dense and closely bonded to the galvanized layer, providing effective protection, and thus, the corrosion degree of the galvanized steel was low. The major environmental factors affecting the atmospheric corrosion rate of the galvanized steel samples in Anhui Province were ranked as follows: temperature > relative humidity > O3 > NO2 > PM2.5 > PM10 > SO2. Temperature and atmospheric relative humidity had a more significant impact, whereas the influence of SO2 was minimal.

Traditional hot-dip galvanized coatings, typically single-silver in color, present increasing aesthetic challenges in diverse applications, while prevailing organic coating methods involve complex processes with high energy consumption and pollution emissions. In this study, a novel hot-dip process for in-situ synthesis of color coating on steel was proposed, capable of producing various uniform color coating. The microstructure of color coatings on steel was systematically examined, and an assessment of their corrosion and weather resistance was conducted. The results demonstrate the sequence of typical color variation is gold, purple, blue, cyan, red, green, and grey. By controlling the immersion temperature range, and regulating the final stable color of the oxide film. The coloration mechanism mainly is attributed to the light interference on the Mn oxide film. The cyan and brown coatings mainly consist of the dense rod-like ζ-FeZn13 phases which provide a structural foundation for corrosion resistance. Furthermore, the brown coating exhibited excellent weather resistance.

The increasing amount of plastic waste generated globally has led to a growing demand for efficient and sustainable methods of disposal. Pyrolysis has emerged as a promising technology for converting plastic waste into fuel. This project has designed and fabricated a pyrolysis reactor to convert plastic waste into fuel oil. The reactor was designed to operate at a temperature range of 250-450 °C with a residence time of 30-90 min. The reactor was fabricated using high-quality galvanized steel for the inner chamber and mild steel for the outer chamber to withstand the high temperatures and corrosive environment. The reactor was also equipped with a Liquified Petroleum Gas (LPG) heating system, three condensers, and a collection system to recover the produced fuel. The heating system was designed to provide uniform heating across the reactor to ensure efficient pyrolysis. The performance of the reactor was evaluated by pyrolyzing LPDE type plastic waste; the parameters of pyrolysis reactors like temperature, mass of yield and time of yield were determined. The reactor's high efficiency, low cost, and eco-friendliness make it a promising solution for managing plastic waste, while also providing an alternative source of fuel. [ABSTRACT FROM AUTHOR]

The work is focused on experimental research of deformation characteristics on three grades of hot-dip galvanized steels for the automotive industry. Deformation maps were obtained using the DIC (Digital Image Correlation) method. The map documents the development of longitudinal and transverse deformations under tensile stress. In addition to uniaxial tension, the investigated specimens were subjected to eccentric tension. The stable crack growth (SCG) was evaluated using a non-contact measurement technique on CT (compact tension) specimens. The deformation of steels, which affects the resistance to stable crack growth (confirmed by the Design of Experiments—DOE method), was manifested in the first stages of eccentric loading of specimens. The notch root radius varies considerably due to the blunting of the starting fatigue crack. The resistance to stable crack growth, which represents a safety reserve during a vehicle crash, was obtained. [ABSTRACT FROM AUTHOR]

The corrosion and degradation behavior of high-strength steel wires during service directly affect the safety and usability of suspenders in steel pipe concrete arch bridges. In this study, three different types of specimens were fabricated using steel wires extracted from the suspenders of an 11-year-old in-service arch bridge and subjected to accelerated corrosion tests with acetic acid. Considering the differential diffusion processes of corrosion factors caused by varying degrees of damage to the suspender sheath, the spatial corrosion variability of steel wires at different positions within the suspender cross-section was investigated. Experimental results indicated a two-stage characteristic in the corrosion process of individual galvanized steel wire samples. In the first corrosion stage, the microstructure on the corroded steel wire surface evolved from a dense crystalline structure to a porous one. In the second corrosion stage, corrosion products accumulate on the steel wire substrate, subsequently further aggregating into sheet-like structures. The maximum pitting factor of individual steel wire samples from a specific area could be described by a Type I extreme value distribution. In the time-dependent model that was established, the location parameter and scale parameter exhibited an exponential decrease during the first corrosion stage and a linear decrease during the second corrosion stage. In the absence of sheath protection, the coefficient of variation in corrosion among adjacent steel wires in the suspender followed a normal distribution. The spatial corrosion variability of the wires inside the suspender is significantly influenced by the shape of the suspender sheath damage. As the corrosion time increased, the overall discrepancy in corrosion levels among different layers of wires diminished. [ABSTRACT FROM AUTHOR]