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In 1742, the French chemist Melouin presented a paper to the French Royal Academy in which he described how a zinc coating could be applied to iron by dipping it into molten zinc. The first patents covering the ‘galvanizing’ process were taken out in France and England during the 1830's; the name being taken from that of the Italian physiologist Luigi Galvani who observed that electric current could be generated when dissimilar metals are brought into contact.

There is an ever‐increasing awareness that worthwhile long‐term savings can be made by reducing maintenance costs through better initial protection of steel. This article, based on the Galvanising Guide produced by the Zinc Development Association, 34 Berkeley Square, London W1X 6AJ, explains the advantages of galvanising.

In the hot dip galvanizing process two different fluxes are used to remove the zinc oxide layer, always present on the liquid zinc surface. When this oxide layer, which contains also aluminium oxide, is dragged into the zinc by the articles, interfering the reaction zinc‐iron. In former days a flux floating on a part of the liquid zinc surface was rather common, at present this wet flux is almost completely replaced by the dry galvanizing process. Since the chemical reactions taking place in the wet flux, partly take place in the flux for dry galvanizing too, first this wet flux will be discussed in brief.

Zinc coatings are applied commercially by hot‐dipping, electro‐deposition, metal‐spraying, cementation and vacuum deposition (see Table 5). Galvanizing (zinc hot‐dipping) has been done for more than 200 years now and is undoubtedly the most widely‐used form of metal coating. The production and pro‐perties of these coatings have received intensive study over the last 10 years; much of this has been reported at the ‘International Conferences on Hot‐Dip Galvanizing’.

THE advantages of a combination of galvanising and painting in increasing the durability of steel sheets appear to be more generally recognised in the United States than in Europe. In combination with paint, galvanising performs the double function of providing, after a suitable surface treatment, an excellent basis for the paint, and of giving additional protection to the steel by preventing rust from spreading under the paint film from any imperfections in it. Minor discontinuities in the paint film are quickly closed by zinc corrosion products.

The purpose of this paper is to study the effect of chemical composition on the selective oxidation on the surface of bake hardenable steel, and on the surface of modified bake hardenable steel with titanium addition, annealed at different dew points.

The subject scope of the paper is the selective oxidation. The methodology used is the annealing of steels at different dew points, and the surface characterization by using atomic force microscopy, X‐ray photo electronic spectroscopy, and glow discharge optical emission spectroscopy.

The modified bake hardenable steel showed a higher oxidized area than the bake hardenable steel. The optimum condition for annealing of the bake hardenable steel was at 800°C with −30°C dp and −60°C dp as selective oxidation is less voluminous.

One suggestion for future works is the use of transmission electron microscopy for the evaluation of selective oxidation on the steel surfaces.

One practical implication is the determination of the optimum condition for annealing of the bake hardenable steel in the steel plant, decreasing the selective oxidation and increasing the quality of galvanized steels. Another implication is the discard by the steel industry of the development of the modified bake hardenable steel.

The originality of the present work is to use advanced surface analysis techniques to quantify the selective oxidation on the surface of commercial steels. The selective oxidation on the surface of steels must be minimized in order to increase the wet ability of zinc layer on the steel surface.

This article aims to focus on implementing Lean Six Sigma (LSS) in steel manufacturing to enhance productivity and quality in the galvanizing process line. In recent trends, manufacturing organizations have expressed strong interest in the LSS since they attempt to enhance its overall operations without imposing significant financial burdens.

This article used lean tools and Six Sigma's DMAIC (Define, Measure, Analyze, Improve and Control) with Yin's case study approach. This study tried to implement the LSS for the steel galvanizing process in order to reduce the number of defects using various LSS tools, including 5S, Value stream map (VSM), Pareto chart, cause and effect diagram, Design of experiments (DoE).

Results revealed a significant reduction in nonvalue-added time in the process, which led to improved productivity and Process cycle efficiency (PCE) attributed to applying lean-Kaizen techniques. By deploying the LSS, the overall PCE improved from 22% to 62%, and lead time was reduced from 1,347 min to 501 min. DoE results showed that the optimum process parameter levels decreased defects per unit steel sheet.

This research demonstrated how successful LSS implementation eliminates waste, improves process performance and accomplishes operational distinction in steel manufacturing.

Since low-cost/high-effect improvement initiatives have not been adequately presented, further research studies on adopting LSS in manufacturing sectors are needed. The cost-effective method of process improvement can be considered as an innovation.

Based on the advantages of conventional hot-dip galvanizing made from quasi-pure zinc melts in the event of fire, this article aims to perform a series of tests to verify whether a similar effect can be achieved with zinc-aluminum coatings.

The emissivity of galvanized surfaces, which were applied to steel specimens by the batch hot-dip galvanizing process, was experimentally determined under continuously increasing temperature load. In addition to a quasi-pure zinc melt serving as a reference, a zinc melt alloyed with 500 ppm aluminum and thin-film galvanized with a melt of zinc and 5% aluminum were used. For the latter, variants of post-treatment measures in terms of a passivation and sealing of the galvanizing were also investigated.

The results show that lower emissivity can be achieved at higher temperatures by adding aluminum to the zinc melt and thereby into the zinc coating. The design values required for the structural fire design were proposed, and an exemplary calculation of the temperature development in the case of fire was carried out based on the values. The result of this calculation indicates that the savings potential becomes apparent, when using zinc-aluminum coatings.

The presented novel tests describe the behavior of zinc-aluminum coatings under the influence of elevated temperatures and their positive effect on the emissivity of steel components galvanized by this method. The results provide valuable insights and information on the performance in the event of fire and the associated potential savings for steel construction.

Hot Dip Galvanizing is used extensively throughout industry to protect steel products from environmental corrosion. However, the process of lowering the work into the galvanizing bath, then completely immersing it and finally withdrawing it produces emissions of fine particulate pollutants in the form of a “white cloud” which rises rapidly from the galvanizing bath as a result of the thermal currents.

The purpose of this work was to investigate the effect of Si content of steel substrate on the performance of the hot-dip galvanized layer. Moreover, the structure of the galvanized layers and the corrosion performance of the galvanized steel in 3.5 per cent NaCl solution have been studied.

The galvanized layer has been formed by the hot-dip technique, and the influence of silicon content in the steel composition on the corrosion performance of the galvanized steel was estimated. The surface morphologies and chemical compositions of the coated layers were assessed using scanning electron microscopy and energy-dispersive X-ray analysis, respectively. Potentiodynamic polarization Tafel lines and electrochemical impedance spectroscopy (EIS) tests were used to evaluate the corrosion resistance of the galvanized steel in 3.5 per cent NaCl solution.

The results proved that adhere, compact and continuous coatings were formed with steel containing 0.56 Wt.% Si, while cracks and overly thick coatings were obtained with steel containing 1.46 Wt.% Si. Tafel plots illustrated that the corrosion rate of galvanized steel containing 0.08 and 0.56 Wt.% Si was lower than that of the galvanized steel containing 1.46 Wt.% Si. Also, the results of the EIS reveal that the impedance of the galvanized steel containing 0.08 and 0.56 Wt.% Si was the highest and the lowest, respectively, with the steel containing 1.46 Wt.% Si.

Generally, in industry steels containing high amounts of silicon (0.15-0.25 Wt.%) can be galvanized satisfactory either by controlling the temperature (440°C) or adding Ni to the galvanized bath. The low temperature reduces the coating thickness; nickel amount must be controlled to prevent the formation of higher amounts of dross. This study proved that high Si steel of up to 0.56 Wt.% can be galvanized at 460°C without adding Ni to the galvanized bath and form adhere, compact, free cracks and have good corrosion resistance. Consequently, a social benefit can be associated with galvanizing high Si steel, leading to an increase in the cost of the process.

The results presented in this work are an insight into understanding the hot-dip galvanizing of high Si steel. The corrosion resistance of galvanized steel containing 0.56 Wt.% Si alloys has been considered as a promising behavior. In this work, a consistent assessment of the results was achieved on the laboratory scale.