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Electrical science and principles
Published in Trevor Linsley, Electrical Installation Work Level 2, 2019
Zinc is a non-ferrous metal which is used mainly to protect steel against corrosion and in making the alloy brass. Mild steel coated with zinc is sometimes called galvanized steel, and this coating considerably improves steel's resistance to corrosion. Conduit, trunking, tray, SWA, outside luminaires and electricity pylons are made of galvanized steel.
C&G Unit 202: Principles of electrical science
Published in Trevor Linsley, Basic Electrical Installation Work, 2018
Zinc is a non-ferrous metal which is used mainly to protect steel against corrosion and in making the alloy brass. Mild steel coated with zinc is sometimes called galvanized steel, and this coating considerably improves steel’s resistance to corrosion. Conduit, trunking, tray, SWA, outside luminaires and electricity pylons are made of galvanized steel.
Monitoring of weld defects of visual sensing assisted GMAW process with galvanized steel
Published in Materials and Manufacturing Processes, 2021
Guohong Ma, Haitao Yuan, Lesheng Yu, Yinshui He
At present, with the introduction of intelligence manufacturing and sensor technology, welding automation is a significant part in the growth of modern industry. It is extensively applied in the fields of large splicing parts such as aerospace, ships, automobiles, etc.[1–4] To achieve the research and growth of welding automation, intelligence and flexibility, it should satisfy at least four requirements: initialize weld position, weld seam tracking, weld quality control and weld defect detection.[5,6] Galvanized steel, because of its excellent corrosion resistance, compatibility, and mechanical properties, is widely used in automobile body and building structures.[7,8] However, galvanized steel needs additional welding current and time, internal force than ordinary carbon steel, because the zinc metal coating on the surface of galvanized steel will produce a special shunting effect, which makes welding parameters difficult to control,[9] and the zinc metal on the surface coating of the galvanized steel sheet will evaporate and melt. Meanwhile, GMAW is a complex process with poor stability, easy to produce spatter, and unstable heat output,[10,11] which will affect the quality of the weld, so weld defects are usually unavoidable. In fact, if experienced workers locate and evaluate weld defects manually, this inspection method may lead to high cost, low efficiency, subjectivity and even bias, because the detection results of welding defects basically depend on actual experiences and knowledge accumulation of workers, visual accuracy, and image quality.
Corrosion protection behaviour of electrogalvanised steel sheet by tetravalent vanadium ion
Published in Transactions of the IMF, 2023
Takeshi Matsuda, Shinichi Furuya, Rie Kaneko, Koji Fushimi
Galvanised steel sheets are widely used in automobiles, electrical machinery and buildings because the zinc coating has the effect of suppressing the corrosion of the steel substrate. Among these products, electrogalvanised steel sheets (EG) are used in electrical machinery such as electrical appliances and office automation equipment due to the appearance of a uniform metallic lustre. It is important to protect the zinc coating from corrosion because corrosion products such as zinc oxide deteriorate the appearance of electrical machinery. Chromate coatings composed of chromium(III) oxides and a small amount of chromium(VI) had been applied to prevent the corrosion of EG.1–4 Chromate coatings are characterised by a high barrier property to corrosive species and an adhesion property with metal substrates because chromium(III) oxides can be polymerised and combined with the metal substrate.1,5–9 A self-healing ability is also a distinctive feature, as the reduction reaction of chromium(VI) ions forms a polymerised coating consisting of chromium(III) oxide in areas where the coating is defective or damaged.2,8–10 Thus, chromate coatings can achieve superior corrosion protection with a thin coating layer, maintaining the metal-like appearance of the substrate. However, strict regulations have been applied to the use of certain heavy metals such as Cd, Pb, Hg and Cr(VI) due to their high toxicities, as seen, for example, in the ‘Restriction of Hazardous Substances (RoHS) Directive’ enforced in Europe from 2003.11 Thus, alternative coating systems are required for corrosion protection of EG.
Effect of elemental additions on hot-dipping galvanization behavior
Published in Cogent Engineering, 2023
Murtadha A. Jabbar, Mohammed Y. Yousif, Nuha H. Jasim
Hot-dip galvanization begins with thoroughly cleaning the steel surface to remove any oil, grease, or other contaminants that may interfere with the zinc’s bonding. At approximately 450°C, the steel is immersed in liquid zinc. In steel, zinc reacts with iron to produce intermetallic layers that prevent corrosion. Galvanizing steel is an effective and cost-effective method of protecting it from corrosion because it gives it a long-lasting, low-maintenance coating. The excellent corrosion resistance and the high strength-to-weight ratio of galvanized steel make it ideal for construction, automotive, and manufacturing applications.