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Structural bonding of batch hot-dip galvanized components poses a particular challenge against the background of the build-up of the zinc coating in the form of different zinc-iron phases. As part of a research project, parameters influencing the zinc coating, the pre-treatment of the zinc substrate, and the adhesive were investigated with regard to the load-bearing capacity of a bonded joint. The variation of the zinc coatings was achieved by using four different steel grades in combination with four batch galvanizing processes. Therefore, small-scale, thick shear tensile specimens were uniformly fabricated, galvanized, bonded in pairs, and mechanically tested. A second series of tests was aimed at the feasibility of an adhesive bond of batch galvanized, medium-scale components under realistic boundary conditions. The test specimens were produced by varying the surface preparation and the adhesive and tested mechanically to shear failure. The results of both test series show that zinc-coated components can be adhesively bonded well and reliably, and, by this, a high load-bearing capacity can be achieved in the bonded joint. The small-scale tests clearly show that the type of zinc coating and its structure obviously have a significant influence on the load-bearing capacity. In summary, it can be stated that the relevant material and process-related influences on the shear load-bearing behavior of bonded joints of batch hot-dip galvanized components were demonstrated by means of the two test series, and the basis for implementing such joints on real load-bearing structures was laid. The presented procedure (small-scale tests and component tests) can be used as a suggestion for a later application in practice. [ABSTRACT FROM AUTHOR]

Territorial contenders are political entities that control populated territories but lack recognition as sovereigns. They pose existential threats to their host states by reshaping recognized borders and generating zones of contested authority. States have strong incentives to eliminate them, and yet they persist—developing countries host an average of three territorial contenders within their borders. Understanding why territorial contenders survive and how they die is a critical puzzle in the study of state making. International forces offer important, if overlooked, explanations for these seemingly domestic processes. First, we argue that international rivals perpetuate the existence of territorial contenders by undermining a state's ability to reintegrate them through peaceful negotiations or by force. Secondly, the international human rights treaty regime provides a mechanism by which territorial contenders can galvanize support from potential allies, increasing a state's willingness and ability to resolve these disputes through peaceful reintegration processes. [ABSTRACT FROM AUTHOR]

Emissivity of zinc‐aluminum coatings under fire loading and effect on the fire resistance In the recent past, a reduced emissivity under fire load has been proofen for classic hot‐dip galvanized steel, which proves to be advantageous compared to an unprotected steel member in the fire design according to DIN EN 1993‐1‐2. In the course of further investigations, the emissivity of modern zinc‐aluminum coatings, which are characterized by a coating characteristic that differs from the standard coatings depending on the aluminum content, was determined on the basis of small scale samples, with various configurations being tested. The results for all variants show that ZnAl coatings exhibit a further improvement in emissivity compared with pure zinc or quasi‐pure zinc coatings, and in particular a reduction in emissivity at higher temperatures. The application of these coatings has a positive effect on the fire resistance of steel components galvanized with ZnAl alloys in the form of a slower heating and thus a higher load‐bearing capacity under fire load determined in the course of the fire design, and the potential for reducing the steel profile cross‐section and thus saving resources by a relevant order of magnitude. [ABSTRACT FROM AUTHOR]

Pins are installed in rock mass to prevent rocks and debris from falling on infrastructure and workers. During the transportation and installation process, the galvanized protective layer of the pins can suffer several types of damage that reduces their service-life against corrosion. In this context, laboratory tests were carried out in order to evaluate the performance of the galvanizing layer under different aggressive conditions. Accelerated corrosion tests were applied to three configurations; two with pins embedded in sand and one with pin grouted in concrete. For each configuration, three states of damage were compared: undamaged galvanized pin (NDGP), damaged galvanized pin (DGP), and non-galvanized pin (NGP). The assessment of the pin condition was performed using non-destructive techniques (pulse echo, acoustic emission and current corrosion measurements). The results provided insightful information about the limits of the galvanization depending on the initial damage state and the surrounding environment. The main result showed that the zinc layer offers the highest protection even if damaged, however, the inverse was observed when leaching rates from sand was possible. [ABSTRACT FROM AUTHOR]

This scientific paper aims to determine the optimal economic roughness of galvanized surfaces by studying the influence of turning surface roughness on the quality of galvanizing. The thickness of the zinc layer, its corrosion resistance, and the precision of the galvanized parts were also examined. S235J0 steel samples were processed using a turning operation to obtain different roughness values. Three galvanizing technologies, galvanic galvanizing, hot dip galvanizing, and hot dip galvanizing with centrifugation, were used in the experiments. The surface evolution from turning to zinc layer deposition was monitored, and parts were subjected to salt spray corrosion resistance testing. Statistical analysis confirmed the stability of the technologies used and the accuracy of the experimental data. Optimal roughness ranges for galvanizing were determined based on the quality of the surface before galvanizing and the galvanizing technology used. The findings show that avoiding small roughness values leads to savings in the machining phases. From the dimensional accuracy perspective, the parts have smaller dimensions after galvanizing, and the dimensional accuracy decreases. The study confirms that steel parts are protected from corrosion, and degradation of the zinc layer is more advanced in sections with less roughness. The optimal surface roughness values before galvanizing were determined to be Ra < 3.657 m in the case of HDG, Ra < 3.344 m in the case of HDG+C, and Ra > 2.928 μm in the case of ZP. The conclusions drawn from this study introduce new directions of research. [ABSTRACT FROM AUTHOR]

In the present work, zinc (Zn) coating was developed on an interstitial-free (IF) steel from Zn sulfate bath using direct current (DC) and pulse current (PC) electrodeposition techniques at different current densities of 10, 30, and 60 mA/cm2. The x-ray diffraction (XRD) analysis of the coatings reveals that the higher atomically dense (0002) crystal plane of the pure Zn in the PC deposits is pronounced as compared to the DC deposits. The scanning electron microscopic (SEM) study displays finer and compact morphology of the PC deposits as compared to the DC deposits. The electrodeposits change from coarser to finer morphology with an increase in current density in both the electrodeposition techniques. All the PC deposits show a higher water contact angle (WCA) as compared to the DC deposits at each applied current density. The finer and compact coating morphology, higher WCA values with the dominance of a higher atomically dense (0002) crystal plane as well as the higher fraction of simonkolleite phase lead to the higher corrosion resistance of the PC deposits than the DC deposits. [ABSTRACT FROM AUTHOR]

Commercial harvesting of snow crabs (Chionoecetes opilio) began in Newfoundland and Labrador, Canada, in 1967. Today, the fishery consists of 2188 active fishing licenses and has grown into the province’s most economically valuable fishery. Snow crabs are captured using conical traps consisting of a mild carbon steel frame, hard plastic entry funnel and a jacket of polyethylene netting. The frames of these traps corrode over time, which is expedited by being deployed in marine environments and stored on land near the ocean when not in use. As a result, there is interest within the community to increase the longevity of crab traps. One solution is to galvanize the steel frames prior to installing the funnel and netting. However, before harvesters transition to galvanized traps, two questions must be answered. Will the use of galvanized steel negatively impact catch rates? Will the life cycle of a crab trap be extended sufficiently to justify the additional cost of galvanizing? This study employed a generalized linear mixed model to evaluate the catch of legal-sized male crabs (CPUE) during the commercial fishery as a function of three trap frame treatments (old traditional, new traditional and new galvanized). We also assessed the economic viability of galvanizing trap frames by evaluating the life cycle cost (LCC) of traditional and galvanized traps to the harvester. The LCC was calculated over a range of inflation (0–6%) and discount (3–20%) rates. Our results found no significant difference in CPUE between new traps (traditional vs. galvanized) and concluded that except during instances of very high discount rates (12.9–19.9%), it is economically favourable to galvanize crab trap frames.

As research on socio-technical transitions has repeatedly shown, positive or negative narratives can play a key role in galvanizing public support for or resistance against socio-technical transitions. In the mobility sector, many countries have recently seen some indications of beginning socio-technical change dynamics. In the case of Germany, key practices of a low-carbon transport system – such as cycling, substitution of travel through home office or 'shared mobility services' – are moving from niches to mainstream, while grassroots initiatives are successfully demanding improvements for cycling and walking. In this dynamic situation competing narratives of change begin to emerge, which claim to define what a transition towards 'sustainable' mobility should look like and how it could be accomplished. Against the backdrop of these recent discursive shifts the article highlights three key conflictual dimensions, along which competing narratives of a mobility transition in Germany, but also in other European countries, are likely going to diverge. The article suggests that research into mobility transitions should focus on the intensifying discursive struggles, in which different social groups with highly differing power will attempt to shape the broader socio-technical vision of a 'sustainable' mobility future. [ABSTRACT FROM AUTHOR]

The aim of the presented feasibility study was to systematically investigate the automation of the skimming (i.e., removal) of zinc ash from the surface of the zinc bath in order to minimise the risks for workers due to mechanical hazards (risk of falling into the zinc kettle) and chemical hazards (inhalation exposure to zinc vapours) by eliminating this activity. As part of the feasibility study, automatic separation and skimming systems from various applications, such as removal systems of slags and metal foam, were identified. For this purpose, their technical feasibility and suitability were considered. Two automated techniques, a mechanical and a gas-based skimming system, were selected for the subsequent laboratory-based evaluation. In the scope of the practical feasibility study, the selected skimming techniques were designed, constructed, and evaluated based on near-process prototype tests on a laboratory scale. The focus was on the efficiency of the skimming systems, related to the removal of zinc ash from the free surface of the molten zinc (general efficiency), as well as to the zinc ash removal with a simulated attachment system of the samples to be galvanised (task-related efficiency). The desired complete removal of zinc ash from the zinc bath surface was demonstrated with two automated methods: a pulse wave method of the mechanical skimming system and a gas-based skimming system in general, operating independently from the attachment system. Additionally, as part of the process-related simulation of the complete batch galvanising process, a fully automated combination of the zinc ash skimming and extraction system was achieved on a laboratory scale. [ABSTRACT FROM AUTHOR]

Steel fasteners were mechanically plated with different deposition sequence of Zn and Sn and heat treated at 340 °C for 30 min. After heat treatment and irrespective of the plating sequence, a dense iron-zinc (Fe-Zn)-rich interfacial layer was formed adjacent to the substrate while the outer coating layer was Sn-rich and appeared more porous. Energy-dispersive x-ray spectroscopy (EDS) and x-ray diffractometry (XRD) analyses confirmed the presence of ζ-FeZn13, δ1p-FeZn10, δ1k-FeZn7, and Γ-Fe3Zn10 phases within the interfacial layer. Post-mechanical plating heat treatment was diffusion controlled, with Fe and Zn atoms diffusing in opposite direction, but the process was dominated by the diffusion of Zn toward the steel substrate, and this was facilitated by Sn. Microhardness test indicated that the hardness of steel substrate was not affected by post-mechanical plating heat treatment. Cyclic salt spray testing showed that the heat-treated coatings exhibited better corrosion resistance (in terms of red rust appearance) despite the presence of porosity. In the early stage of corrosion, Zn at the Sn-rich outer layer dissolved preferentially, followed by the dissolution of Sn. When the anodic reaction at the outer layer approached the Fe-Zn intermetallic layer, the anodic site changed to the Fe-Zn layer. The Fe-Zn intermetallic layer acted as an effective barrier to the corrosion of underlying steel substrate because Zn from Fe-Zn layer dissolved slower than pure Zn. [ABSTRACT FROM AUTHOR]

This research compares the corrosion rate of galvanized pipe which is currently installed on a 60-meter patrol boat with CuNiFe pipe using the weight loss method with parameters for testing variations in salinity of 3% and 6% NaCl solution at 25 °C, 3% salinity at 50 °C and 60 °C, 3% salinity at 50 °C and 60 °C and given a rotating speed of 250 RPM using the ASTM G31-72 standard. The results of the corrosion rate of each specimen were compared and their age was predicted using API 570 and the Indonesian classification Berau volume 3 in 2014. Based on the experimental data obtained the highest corrosion rate in zinc and CuNiFe specimens at 3% salinity test parameters at 60 °C temperature and given a rotating speed of 250 RPM. The results of the corrosion rate calculation on the galvanized pipe are 1.973948 mmpy with a Lifetime of 2.1108 years and the calculation of the economic value of Rp. 502.800/meter, while the CuNiFe pipe has a corrosion rate of 0.083499 mmpy with a lifetime of 7.5808 years and the calculation of the economic value of Rp. 4.148.100/meters. The corrosion rate of galvanized pipe is greater than CuNiFe pipe in all conditions. CuNiFe pipe has a higher lifetime than galvanized pipe. While the calculation of the economic value, galvanized pipe is more economical than CuNife pipe, but when viewed from the lifetime of the pipe, galvanized pipe is less efficient because of its relatively short lifetime. Based on lifetime calculation, the seawater pipe to be used on the patrol boat 60 meters is CuNife pipe because the replacement of the piping system in the Patrol Boat is based on predictive maintenance. [ABSTRACT FROM AUTHOR]

Prior research has evidenced the importance of collaboration and multi-agency partnership work in responding to human trafficking in both the UK and US. Three previous key studies are synthesized in this paper. We situate multi-agency anti-trafficking collaborative work within conceptualizations of "resilience" and mechanisms by which to achieve it, and draw comparisons between the structure, organization, and activities of anti-trafficking partnerships in the UK and US. We present results, reflections, and discussion regarding the utility of local-problem diagnosis and multi-agency, using collaborative intelligence analysis as a mechanism to galvanize and organize local partnership action, resulting from action research conducted in one police force area. We posit the replication of this "problem profile" exercise as a mechanism for anti-trafficking collaborators to galvanize their aims and day-to-day efforts to make their communities resilient to human trafficking. We close by arguing for resilience as a framing for this mechanism and for local collaborative efforts. [ABSTRACT FROM AUTHOR]

This study analyzes the limitations of the low-frequency EIS impedance modulus as a tool to describe the protective properties of organic coatings subjected to accelerated aging tests. Acrylic clear-coated steel and hot-dip galvanized steel were exposed to accelerated test methods such as the neutral salt spray chamber and the Prohesion test for up to 2000 and 3000 h, respectively. During exposure, the protective properties of the coatings were monitored by EIS and visual inspection. We observed a significant discrepancy between the measured impedance modulus in the low frequency range (|Z0.01Hz|), and the actual deterioration of the metal–paint interface. The degradation of the two painted substrates is independent of the accelerated test considered. The |Z0.01Hz| values do not represent the actual degradation state of the metal–polymer interface. The manuscript discusses the reasons for the lack of agreement between EIS and visual inspection. The limitations of using the low-frequency EIS impedance modulus to describe the protective properties of organic coatings are highlighted, and several cautions for interpreting the raw EIS data are suggested. The reliability of possible thresholds of |Z0.01Hz| (e.g., failure below 106 ohm∙cm2) to define the protective performance of the coating turned out to be misleading. [ABSTRACT FROM AUTHOR]

At present, the common protection technology of power-transmission and transformation equipment is mainly coating protection and hot-dip zinc protection. However, due to the low adhesion of epoxy zinc-rich coating, and the poor compatibility with top paint, environmental pollution, complex processing, high energy consumption and other defects of the hot-dip zinc process, its development is limited. In view of the above deficiencies, new anti-corrosion coating materials and processes were investigated in this study. Zinc coatings and Al-Zn coatings were prepared on the C45 steel matrix by hot-spraying and cold-spraying processes. The macro appearance, micromorphology and phase composition analysis of the coatings were evaluated. The adhesion of the coating to the substrate after the salt-spray test was tested. The results showed that the hot dip zinc coating and hot spray zinc coating had obvious cracking after the salt-spray test. The surface structure of cold-sprayed Al-Zn coating was relatively dense after the salt-spray test. The critical load of the cold-sprayed Al-Zn coating after the salt-spray test was higher than that of the other two coatings. The corrosion resistance to salt spray of cold-sprayed Al-Zn coating was demonstrated to be better than the hot-dip zinc coating, and thus has great application prospects. [ABSTRACT FROM AUTHOR]

To study the protective effect of thermal spraying cobalt-based carbide coatings on hot-dip galvanized sinker rolls, a WC-12Co coating was prepared on a 316 L stainless steel substrate using the supersonic flame spraying method. The coating was corroded in a molten liquid zinc at 430 °C to analyze the coating service life and failure process. The results show that the coating provided good protection of the base metal. The process of coating failure was that Zn first diffused into the coating and reacted chemically with the Co between the carbide particles, forming a Co-Zn compound. Then, some transverse cracks appeared through the Co-Zn compound layer, resulting in the coating microstructure falling off in blocks and into the liquid zinc, causing a gradual thinning of the coating thickness, which eventually failed and loosened its protective effect. The types of Co-Zn compounds in the coating were analyzed by energy-dispersive spectroscopy (EDS) and x-ray diffraction (XRD), and the formation process of Co-Zn compounds was further investigated by placing pure Co rods into the liquid zinc at the same temperature. It was found that there were two types of Co-Zn compounds formed, Co5Zn21 and CoZn13, which were produced by forming Co5Zn21 at first and then transformed into CoZn13 with further diffusion and aggregation of Zn, which was the main cause of the cracking of coatings. [ABSTRACT FROM AUTHOR]

Dross in a Zn-55wt%Al-1.6wt%Si metal coating bath is a mixture of bath metal and the quaternary intermetallic phase τ5c-Al20Fe5Si2(+Zn). Understanding the properties and formation of dross in a hot-dip Al-Zn galvanizing bath at the processing temperature (~600 °C) is critical for improving the production quality of steel sheet coating. However, dross analysis is usually conducted at room temperature with dross samples taken from the hot-dip bath and it is not known how representative these samples are of the phase(s) existing at high temperature. Using in-situ synchrotron X-ray diffraction (XRD), the crystal lattice and the coefficient of thermal expansion (CTE) of the intermetallic phase have been determined in the temperature range of 30 °C to 660 °C. Phase formation and phase stability of the intermetallic phase in the dross powder have been determined, providing fundamental knowledge for optimizing the production and quality of steel sheet coating. [ABSTRACT FROM AUTHOR]

In industrial hot-dip galvanizing lines, the crossbow flatness defect of steel strips constitutes one of the main sources for coating thickness deviations and inhomogeneities. In this work, a novel algorithm for online minimization of the crossbow flatness defect based on the automatic adjustment of the pot roll intermesh is developed. The devised model-free control algorithm can be easily implemented on an industrial programmable logic controller, even with very limited computational resources. The controller uses measurement data from an electromagnetic strip stabilization device and avoids the use of the delayed measurement data from the downstream radiometric coating thickness gauges. Assuming that a hot-dip galvanizing line is already equipped with an electromagnetic strip stabilization device, additional hardware is not required for implementation. The control algorithm can also be easily adapted to processing lines without an electromagnetic strip stabilizer. A detailed stability analysis allows to derive some basic guidelines to guarantee the convergence of the overall control scheme. A short- and long-term evaluation of measurement results from an industrial hot-dip galvanizing line demonstrates the effectiveness and robustness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

The article is aimed at the mathematical and optimization modeling of technological processes of surface treatments, specifically the zincing process. In surface engineering, it is necessary to eliminate the risk that the resulting product quality will not be in line with the reliability requirements or needs of customers. To date, a number of research studies deal with the applications of mathematical modeling and optimization methods to control technological processes and eliminate uncertainties in the technological response variables. The situation is somewhat different with the acid zinc plating process, and we perceive their lack more. This article reacts to the specific requirements from practice for the prescribed thickness and quality of the zinc layer deposited in the acid electrolyte, which stimulated our interest in creating a statistical nonlinear model predicting the thickness of the resulting zinc coating (ZC). The determination of optimal process conditions for acid galvanizing is a complex problem; therefore, we propose an effective solving strategy based on the (i) experiment performed by using the design of experiments (DOE) approach; (ii) exploratory and confirmatory statistical analysis of experimentally obtained data; (iii) nonlinear regression model development; (iv) implementation of nonlinear programming (NLP) methods by the usage of MATLAB toolboxes. The main goal is achieved—regression model for eight input variables, including their interactions, is developed (the coefficient of determination reaches the value of R2 = 0.959403); the optimal values of the factors acting during the zincing process to achieve the maximum thickness of the resulting protective zinc layer (the achieved optimum value th* = 12.7036 μm), are determined. [ABSTRACT FROM AUTHOR]

This paper follows sorghum, an indigenous, but currently underutilized, grain in South Africa, through six encounters to discover its potential to transform the country's food system. By listening to stories from diverse perspectives, it shows that the re-inclusion of sorghum could not only diversify diets, but could also move toward breaking colonial stereotypes of what constitutes aspirational food. It employs a Follow the Thing method to unpack the multiple identities of sorghum and the role it could play in galvanizing a healthier, more diverse food system. By opening up to a radical following method that does not constrain the researcher, the underlying stories associated with sorghum are highlighted, which coincides with a shift in perception of the multiple potentialities that the crop embodies. The research highlights that a strong cultural link to sorghum remains in South Africa and that if innovation could be broadly interpreted, this might invigorate a richer engagement with sorghum, not just as a commodity, but as a culturally significant food. [ABSTRACT FROM AUTHOR]

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Recent investigations paved the way for hot dip galvanizing in the field of bridge constructions [1]. Due to technical limitations of hot dip galvanizing, steel girders longer than 16 meters have to be divided and connected afterwards. The Chair of Metal Structures works in cooperation with the Chair of Concrete Structures of the Technical University of Munich (TUM) and the Bundesanstalt für Materialforschung und ‐prüfung (BAM), to develop a grouted joint connection, which is suitable for hot dip galvanizing. In contrast to welding the segments on site or using prestressed bolt connections, the hot dip galvanization of the grouted joint remains undamaged for the whole service life time of the structure. As part of this research, the main component of the grouted joint ‐ a hot dip galvanized T‐stud ‐ is investigated regarding its fatigue behaviour. The present paper outlines the idea and the structure of the grouted joint and classifies the hot dip galvanized T‐stud according to a fatigue class given in EN 1993‐1‐9 [2]. Furthermore, the fatigue assessment for the grouted joint and an optimization of the geometry of the T‐Studs is carried out using finite element analysis. [ABSTRACT FROM AUTHOR]

For corrosion and anticorrosion of alloys/metals, the steel/zinc metal material pair is by far the most important. It includes basic and applied research related to the mechanisms and modeling of corrosion of metal materials and the processes of their protection and reduction in the effects of corrosion. 26-28 June 2001: 153-160 27 Tsujimura T., Komatsu A., Andoh A. Influence of Mg content in coating layer and coating structure on corrosion resistance of hot-dip Zn-Al-Mg alloy coated steel sheet. However, in most environments, the corrosion rate of zinc is low because its surface is quickly covered with corrosion products that inhibit further corrosion [[8]]. [Extracted from the article]

Fatigue strength of tension rods with threads In the project "Zyklische Bemessung von Zugstäben mit Endgewinden", extensive fatigue tests have been carried out on tension rods of different manufacturing types (cut, rolled, with and without hot‐dip galvanizing). The diameters M16, M48, M68 and M100 were investigated. The results of the 214 fatigue tests show increased fatigue strengths for tension rods with rolled threads. Fatigue detail category 50 is confirmed for cut threads. The effect of production and assembly tolerances were investigated using the strain notch concept. A proposal for the classification of the fatigue detail "tension rods with threads" made of structural steel is provided as an outcome of the research project. Fatigue detail categories dependent on the manufacturing process type of thread and on whether hot‐dip galvanization is performed or not are proposed. [ABSTRACT FROM AUTHOR]

Endovascular surgery through flow diverters and coils is increasingly used for the minimally invasive treatment of intracranial aneurysms. To study the effectiveness of these devices, in vitro tests are performed in which synthetic vascular phantoms are typically used to reproduce in vivo conditions. In this paper, we propose a manufacturing process to obtain compliant and transparent hollow vessel replicas to assess the mechanical behaviour of endovascular devices and perform flow measurements. The vessel models were obtained in three main steps. First, a mould was 3D-printed in a water-soluble material; two techniques, fusion deposition modelling and stereolithography, were compared for this purpose. Then, the mould was covered with a thin layer of silicone through spin–dip coating, and finally, when the silicone layer solidified, it was dissolved in a hot water bath. The final models were tested in terms of the quality of the final results, the mechanical properties of the silicone, thickness uniformity, and transparency properties. The proposed approach makes it possible to produce models of different sizes and complexity whose transparency and mechanical properties are suitable for in vitro experiments. Its applicability is demonstrated through idealised and patient-specific cases. [ABSTRACT FROM AUTHOR]

Hot-dip galvanization is a common corrosion-prevention technique for steel structures. The steel is submerged in a molten zinc bath, which forms a zinc coating on the steel's surface. This provides a barrier against the corrosive elements. However, the galvanized covering can still deteriorate, especially in harsh environments. As a consequence, several studies have been conducted to improve the corrosion resistance of galvanized steel by adding metallic elements to the zinc coating. The aim of this study is to look at how metallic additions (Al addition up to 1%, Bi addition up to 1%, Pb addition up to 1%, Sb addition up to (1% and 2%), Sn addition up to 5%, Zn-Bi-Pb 1% addition, Zn-Sb-Sn 1% addition) affect the zinc coating by hot dipping galvanization. The microhardness, thickness, adherence, microstructure test, coating adhesion (Pull-Off test), and corrosion rate are studied. [ABSTRACT FROM AUTHOR]

Accurate and computationally accessible models of liquid film flows allow for optimizing coating processes, such as hot-dip galvanization and vertical slot-die coating. This paper extends a classic three-dimensional integral boundary layer model for falling liquid films (FFs) to account for a moving substrate (MS). We analyze the stability of the liquid films on vertically moving substrates in a linear and in a nonlinear setting. In the linear analysis, we derive the dispersion relation and the temporal growth rates of an infinitesimal disturbance using normal modes and linearized governing equations. In the nonlinear analysis, we consider disturbances of finite size and numerically compute their evolution using the set of nonlinear equations in which surface tension has been removed. We present the region of (linear) stability of both FF and MS configurations, and we place the operating conditions of an industrial galvanizing line in these maps. A wide range of flow conditions was analyzed and shown to be stable according to linear and nonlinear stability analyses. Moreover, the nonlinear analysis, carried out in the absence of surface tension, reveals a nonlinear stabilizing mechanism for the interface dynamics of a liquid film dragged by an upward-moving substrate. [ABSTRACT FROM AUTHOR]

Electrode degradation in the continuous resistance spot-welding process of baked hardening (BH) 220 steel was evaluated by an electrode life test, and weldability tests were conducted by geometry feature measurement, mechanical property analysis, and electrode diameter measurement with 88 or 176 weld intervals. The analysis of weld geometry shows that the heat-affected zone (HAZ) width, nugget diameter, and nugget area tend to decrease rapidly, while the nugget height tends to increase with the weld repetitions until the welding heat input becomes too small to form an effective nugget. The maximum displacement and failure energy of the welded joints show a decreasing trend during the welding electrode failure process, while the peak load increases slightly until the 88th weld and then decreases. The cavities and pores in the nugget mainly appear after the 176th spot weld. The electrode diameter increases during welding. The reason for the increase in electrode diameter may be that the contact area between the electrode and the BH 220 steel sheets becomes smaller in the welding process, which causes the continuous sticking phenomenon between the electrode and the BH 220 steel sheets. In the absence of alloying, the edge of the electrode is geometrically deformed, while Cu–Zn–Fe alloying occurs in the area in contact with the BH 220 steel sheet. [ABSTRACT FROM AUTHOR]

MAB/MAX phases with high corrosion resistances have gained significant attention because of their promising in energy and catalysis applications. Sn/Zn whisker could grow on these Sn/Zn-containing MAB phase solid solutions as reported in our previous work. Herein, a comprehensive investigation on the effects of the combinations of Zn and Sn in different forms (atom during hot-dip aluminizing and cation during immersion in molten chloride salt) on the microstructure and whisker growth on the hot-dip aluminized coating on Fe-Cr-B cast steel was conducted by hot-dip aluminizing-thermal diffusion treatment, and immersion in molten chloride salts. We demonstrated that all the interactions of the combinations of Zn and Sn in different forms (atom and cation) with the Cr-Al-B MAB phases could partially replace the Al atoms in the Cr-Al-B MAB phases contained in the periodic layered structure, leading to the formation of the corresponding Cr-Al-B MAB phase solid solutions and the spontaneous growth of whiskers. The replacement ability during immersion in molten chloride salt was stronger than that during hot-dip aluminizing under the driving force of formation of the volatile chlorides (like AlCl 3). The replacement ability of Zn and Sn in different forms as they substituted the Al atoms in the Cr-Al-B MAB phase was in the order: Sn2+＞Zn2+＞Sn＞Zn. Sn facilitates the formation of Zn vacancy, which promoted that whisker with complex compositions (head being Zn and body being Sn and head being Sn and body being Zn) grew on the Cr-(Al, Sn, Zn)-B MAB phase solid solution. The matter source to feed the growth of whisker played a key role in the spontaneous growth of whisker under the both mechanisms of diffusion and stress. Our work would expand the MAB phase family and tailor the growth of whisker, also enrich the theory on the growth of whisker on the MAB/MAX phase. [Display omitted] • Interaction of the combinations of Zn and Sn in different forms (atom and cation) with the Cr-Al-B MAB phase was studied for the first time. • The replacement ability of Zn and Sn in different forms as they substituted the Al atoms in the Cr-Al-B MAB phase was in the order: Sn2+＞Zn2+＞Sn＞Zn. • Whiskers with head being Zn and body being Sn and head being Sn and body being Zn could grow on the Cr-(Al, Sn, Zn)-B MAB phase solid solution. [ABSTRACT FROM AUTHOR]

In this study, the electrochemical corrosion behavior of outburst and flat ζ-FeZn 13 phase layers was investigated using scanning electron microscopy, field emission scanning electron microscopy, electrochemical workstation, and Raman spectroscopy instrument. The ζ phase layer is composed of the η phase, coarse ζ phase, and fine ζ phase. Their corrosion potential is E η-Zn =-1.140±0.003 V, E fine-ζ =-1.052±0.003 V, and E coarse-ζ =-1.036±0.002 V. The presence of fine ζ phases can form a thick passivation film on the surface of the coating. The thickness of the passivation film for the outburst and flat ζ phase layers is 5.31 nm and 6.47 nm, respectively. The more uniform the distribution of fine ζ phases, the thicker the passivation film. The corrosion types of the outburst phase layer are mainly local corrosion and pitting corrosion, and the flat phase layer is mainly uniform corrosion. The corrosion products of η phase are ε-Zn(OH) 2 , 4Zn(OH) 2 .ZnCl 2 , Zn 5 (CO 3) 2 (OH) 6 , and Zn 5 (Cl 2)(OH) 8 .H 2 O. The corrosion products of ζ phase are Fe 2 O 3 , ZnO, and Zn(OH) 2. • In the ζ-FeZn 13 sublayer, the order of initial dissolution potential is E η-Zn < E fine-ζ < E coarse-ζ. • The corrosion types of the outburst layer are local corrosion and pitting corrosion, and the flat layer is uniform corrosion. • The corrosion products of η phase are ε-Zn(OH) 2 , 4Zn(OH) 2 .ZnCl 2 , Zn 5 (CO 3) 2 (OH) 6 , and Zn 5 (Cl 2)(OH) 8 .H 2 O. [ABSTRACT FROM AUTHOR]

Background. The object of the research is the modes of heat treatment of steel strip on continuous hot-dip galvanizing units. The complexity of controlling the heat treatment of steel is one of the main reasons why guaranteed heat treatment modes have become widespread in enterprises. In such modes, interference in the operation of furnaces and the metal cooling system is minimized. This leads to a number of negative consequences, such as: reduced productivity; limited range of products for a particular unit; difficulties in determining rational modes for new types of products. In an unstable market situation, enterprises can miss out on benefits due to insufficient production flexibility, when, instead of switching to the efficient production of new types of products, units are temporarily decommissioned. The purpose of this work is to systematize the reasons for the spread of guaranteed heat treatment modes and to identify measures aimed at ensuring production flexibility. Production flexibility is understood as the possibility of producing a wide range of products at different capacities on a separate unit. Materials and methods. The conducted studies are based on a review of known proposals in the field of improving the heat treatment control of steel strip. Results. The problems of controlling the heat treatment of steel in the flexible production of galvanized sheet metal with varying productivity were formulated. The authors reviewed the proposals in the field of improving the heat treatment control of steel strip and assessed them from the standpoint of ensuring production flexibility. Problems requiring further solution were formulated. Conclusions. The paper shows that the main difficulties in the flexible production of galvanized strip with varying productivity are associated with the creation of models adequate to the tasks of predictive control of the steel heat treatment.

In particular, the corrosion resistance of the coating was much better than that of the substrate due to the excellent corrosion resistance of Mo. Since corrosion and tribocorrosion are surface- and subsurface-related material degradation phenomena, surface engineering and coating technologies are the most effective to tackle the corrosion and tribocorrosion problems of a wide range of engineering materials. Corrosion of materials not only accounts for about 3 to 4% of economic losses in GDP in an industrial nation, but it also contributes significantly to greenhouse emissions and climate change because material production is one of the largest greenhouse emitters. The results show that, compared to the cold-formed state, hot forming followed by appropriate cooling resulted in the formation of a hard and tough martensitic/bainitic structure, which possessed much better corrosion resistance and tribocorrosion resistance in 3.5% NaCl solution. [Extracted from the article]

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In accordance with the requirements of hot-rolled aluminum-zinc plating and cold-rolled aluminum-zinc plating mixed line for producing construction steel and the production process characteristics of hot-dip aluminum-zinc products, the critical process control points are put forward by combining theoretical analysis with experimental verification. We should select proper raw materials, ensure the cleanliness of strip steel surface, strictly control the annealing temperature, the temperature of the strip steel entering the zinc pan, the temperature and composition of the plating bath, and explore reasonable and feasible process parameters such as air knife and cooling after plating, so as to produce qualified products. This study is of great significance for the improvement and process control of hot-rolled aluminum-zinc plating plates in steel plate production enterprises. [ABSTRACT FROM AUTHOR]

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Dross particle formation in the hot-dip galvanizing zinc bath and dross build-up on the sink rolls can cause surface defects on the steel-strip. State-of-the-art approaches in zinc bath dross reaction modeling in CFD simulations rely on thermodynamics considerations, where the formation or dissolution of dross occurs instantaneously whenever the system is out of equilibrium. These approaches totally ignore the finite time required for the reaction which leads to an imperfect representation of the actual spatial distribution of the concentration fields. To overcome this drawback, a reversible kinetics model for the Fe 2 Al 5 Zn -phase dross particles is presented that is coupled to species transport equations. Model parameters were determined by fitting with innovative lab-scale GalvaLIBS experiments. [ABSTRACT FROM AUTHOR]

Background: Integrating nutrition actions into service delivery in different policy sectors is an increasing concern. Nutrition literature recognizes the discrepancies existing between policies as adopted and actual service delivery. This study applies a street-level bureaucracy (SLB) perspective to understand frontline workers' practices that enact or impede nutrition integration in services and the conditions galvanizing them. Methods: This qualitative exploratory study assesses the contextual conditions and practices of 45 frontline workers employed by the agriculture, health and community development departments in two Ugandan districts. Results: Frontline workers incur different demands and resources arising at societal, organizational, and individual level. Hence, they adopt nine co-existing practices that ultimately shape nutrition service delivery. Nutrition integration is accomplished through: (1) ritualizing task performance; (2) bundling with established services; (3) scheduling services on a specific day; and (4) piggybacking on services in other domains. Disintegration results from (5) non-involvement and (6) shifting blame to other entities. Other practices display both integrative and disintegrative effects: (7) creaming off citizens; (8) down prioritization by fixating on a few nutrition actions; and (9) following the bureaucratic 'jobs worth'. Integrative practices are driven mostly by donors. Conclusion: Understanding frontline workers' practices is crucial for identifying policy solutions to sustain nutrition improvements. Sustaining services beyond timebound projects necessitates institutionalizing demands and resources within government systems. Interventions to facilitate effective nutrition service delivery should strengthen the integrative capacities of actors across different government levels. This includes investing in integrative leadership, facilitating frontline workers across sectors to provide nutrition services, and adjusting the nutrition monitoring systems to capture cross-sector data and support policy learning. [ABSTRACT FROM AUTHOR]

Partial replacement of Si by Al improves the coatability (or galvanizing property) of Si-Mn advanced high-strength steel (AHSS) sheets. In this paper, the effects of the partial replacement on the microstructure, tensile property, and cold formability are reported for the low-carbon third-generation AHSS sheets, which are classified into two groups, "Group I" and "Group II". The partial replacement by 1.2 mass% Al increases the carbon concentration or mechanical stability of retained austenite and decreases its volume fraction in the AHSSs, compared to Al-free AHSSs. The partial replacement deteriorates the tensile ductility and stretch formability in the AHSSs with a tensile strength above 1.2 GPa. On the other hand, it achieves the same excellent stretch-flangeability as Al-free AHSSs. A complex addition of Al and Nb/Mo further enhances the stretch-flangeability. The cold formabilities are related to the heat treatment condition and microstructural and tensile properties, and the stress state. [ABSTRACT FROM AUTHOR]

Hot dip galvanizing is among the cheapest methods for protecting ferrous alloys against corrosion. The success is due to both the low cost of the process and the high degree of protection in many corrosive environments, where the coatings serve as sacrificial protection. The purpose of this analysis is to study the mechanical characteristics of steel plates, that have been hot dip coated with five different zinc alloy molten bath for different time periods. The mechanical tests performed is a non-standardized four-point bending test considering three distinct bending angles. Results are examined in terms of both mechanical behaviour and coating phase damage. The development of intermetallic phases and their damage are both influenced by the chemical compositions of the zinc bath, demonstrating that fractures arise mostly at the substrate-coating interface. All the coatings showed the arising of micro-cracks except for the Aluminium, which demonstrated its ductility. In addition, Zn-Ti coatings showed the arising of a new compact phase rich in iron, characterized by a great hardness. More research is needed to explore the aluminium impact on the zinc bath, the lack of tiny fractures in the phase, and the lesser thickness compared to the other coatings tested. [ABSTRACT FROM AUTHOR]

This study analyzes the cause of two explosions that occurred during maintenance on a sprinkler system to examine the risk of such an explosion. In both incidences, the explosion occurred after the system was drained into the water‐collecting tank and shortly after the work began. Sprinkler systems in Korea generally use galvanized pipes to prevent corrosion and extend their lifetime. Zinc is the most common element used as a coating material. Although such a system is not usually perceived as dangerous, our study shows that it can contribute to a build‐up of hazardous factors, which ultimately can lead to accidents. As a common metal oxidation reaction, zinc produces hydrogen gas while oxidizing within the water‐filled pipes. Such hydrogen gas can become explosive when stagnating inside the water‐collecting tank as the sprinkler pipes are drained. In both explosion cases, the automatic water level control system of the water‐collecting tank is suspected to have acted as an ignition source for hydrogen gas explosion by electrical contact. By understanding these two cases, we can provide better safety standards for explosion protection for sprinkler systems that are already installed in buildings and those that will be installed in the future. [ABSTRACT FROM AUTHOR]

In the present article, the seam lap joining of the Al6061 and galvanized steel sheet is carried out using friction stir welding. A unique metallographic feature named 'hook' is observed near the stir zone boundary in the weld nugget. The influence of hooks and the related stress zones on fracture of the joint is discussed in brief. Three different types of fracture are observed during tensile shear testing of the welded joints. The mechanisms of the various types of fracture are understood comprehensively. Further, a correlation between the sizes of the hooks and the type of fracture is presented. The optimum size of the advancing side hook was found to be about 8–15% of the plate thickness, and the retreating side to advancing side hook ratio should be greater than 1.5 for a strong and ductile joint. Metallographic and mechanical testing such as scanning electron microscopy, energy-dispersive X-ray spectroscopy, stereo micrography, tensile testing, and microhardness testing were performed to validate the analysis. [ABSTRACT FROM AUTHOR]

The Si-NbSi2 composite coatings were prepared on Nb substrated by hot dip plating process. The surface and cross section microstructure, element distribution and formation mechanism of the coating were analyzed and summarized. Moreover, the surface roughness and micro-hardness of the coating were also measured. The results show that the composite coating has a dense and homogeneous structure. The outermost layer of the coating is composed of NbSi2 and pure Si phase, and the inner layer is columnar NbSi2 phase. It is noteworthy that there is a Nb5Si3 transition layer between NbSi2 layer and Nb substrate. With the increase of experimental temperature, the number of NbSi2 grains decreases gradually, while the grain size gradually increases. With the increase in the temperature, the surface roughness of the coating tends to increase. With the increase in experimental temperature, the surface roughness of the coating tends to increase, but it is still in the submicron size (Ra = 0.239–0.464 μm), and still has a relatively smooth and flat surface structure. In addition, with the increase of experimental temperature, more Si element are accumulated on the coating surface, and the micro-hardness of the coating increases from 176.55 to 373.65 MPa. The results of coating scratch test show that the critical load of coating cracks increases from 20.4 to 26.5 N with the increase of experimental temperature, and the coating bond strength increases gradually with the increase of temperature. [ABSTRACT FROM AUTHOR]

The Al80Mg5Li5Zn5Cu5 light-weight high-entropy alloy with globular microstructure was fabricated by isothermal heat treatment. The effects of isothermal temperatures and holding times on the semi-solid microstructure evolution were investigated. The results indicate that, with increase of the isothermal temperature, the average grain size increases and the spheroidization time shortens. With prolongation of holding time, the shape factor increases firstly and then decreases, and the average grain size decreases at first and then increases when the isothermal temperature is below 520 °C, however it increases gradually at 540 °C. The optimal semi-solid microstructure is obtained at 520 °C for 30 min, whose shape factor and average grain size are 0.90 and 56.4 µm, respectively. Compared with as-cast Al80Mg5Li5Zn5Cu5 light-weight high-entropy alloy, the compressive strength and plasticity of semi-solid Al80Mg5Li5Zn5Cu5 light-weight high-entropy alloy are increased by 36% and 108%, respectively. The formation of semi-solid microstructures includes three stages: melting separation, spheroidization, and coarsening growth. The sluggish diffusion effect of Al80Mg5Li5Zn5Cu5 light-weight high-entropy alloy leads to a low coarsening rate, resulting in slow grain growth. [ABSTRACT FROM AUTHOR]

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The effects of wire feeding voltage (equivalent to wire feeding rate), spraying current, and zinc wire diameter on the quality of thermally sprayed zinc coating with a thickness about 200 μm were studied. When the wire feeding voltage and the spraying current are 20 V and 200 A respectively, the coating was well formed with low energy consumption, and had an adhesion strength up to 8.4 MPa. The loss rate of zinc wire 2.0 mm in diameter during thermal spraying was 67% and 35% lower than that of zinc wires with a diameter of 1.6 mm and 3.0 mm, respectively. The presented zinc thermal spraying process is simple, controllable in quality, and cost-efficient, and has been well applied and verified in engineering. [ABSTRACT FROM AUTHOR]

The paper presents the impact of the drawing method on the microstructure and corrosion resistance of galvanized steel wires. The microstructural tests confirmed that, in the drawing speed range v = 5–20 m/s, the use of hydrodynamic dies creates more favorable conditions for the deformation of the soft zinc coating on the hard steel core. The increase in friction at the wire/die interface in the conventional method, as compared to the hydrodynamic method, contributed to the decrease in coating thickness and the increase in the diffusion layer, and the higher the drawing speed, the greater the differences between the analyzed drawing methods. In the conventional method, while drawing at high speeds v = 20 m/s, there was a two-way diffusion and complete remodeling of the ζ phase in δ1. In the hydrodynamic method, at the speed of 20 m/s, in the analyzed micro-areas, places showing the presence of the ζ phase, partially dispersed in the layer with pure zinc, were observed. A corrosion tests comparison between conventionally and hydrodynamically drawn wires showed an improved behavior of the latter. The greater mass in the surface layer of pure zinc, a substrate for the corrosion product in hydrodynamically drawn wires, reacted, creating insulation from the white corrosion produced. The compressive stresses in the hydrodynamic dies caused by the high pressure of the lubricant on the circumference of the wire closed the microcracks on its surface, which additionally sealed the zinc coating. [ABSTRACT FROM AUTHOR]

Herein, the bending behavior of hot‐dip galvanizing hot‐rolled hypersandelin plates, together with the corresponding crack pattern, is numerically investigated by using a hybrid model developed in Ansys LS‐DYNA environment, by combining the discrete element method (DEM) with finite element method (FEM). The experimental bending tests here simulated and available in the literature are performed by considering two types of bath, that is, a pure zinc bath and a technological bath, consisting in a zinc bath with 3% Sn addition by weight. The results related to the bending behavior are compared with both experimental data and other FE numerical results, previously obtained by some of the present authors. Moreover, the numerical crack patterns are compared with the experimental observations of the longitudinal section of the plates at the end of testing, by means of a light optical microscope. A quite satisfactory agreement is observed. [ABSTRACT FROM AUTHOR]

The forming of zinc dross floating on the surface of molten zinc in zinc pot is inevitable during hot-dip galvanizing production. The cleaning of zinc dross has always been a challenge and a difficult problem to solve. Based on the electromagnetic field theory and its application, a new electromagnetic dross removal technology was proposed, and the zinc dross driven by flowing molten zinc was possible to remove in an electromagnetic field circumstance. Through the coupling simulation of electromagnetic field and flow field, the electromagnetic force acting on molten zinc and the flow situation of molten zinc were simulated. The results showed that electromagnetic field can effectively act on the top surface of molten zinc and affect the flow of molten zinc. Different load conditions of electromagnetic field and the distance between the bottom surface of the iron core and the top surface of molten zinc related to zinc dross removal effect were discussed. Finally, the optimal application parameters of the electromagnetic dross removal technology were put forward. [ABSTRACT FROM AUTHOR]