Zinc Coated Wire
Zinc coated wire lasts much longer than uncoated wire, zinc coating of wire is designed to protect the steel surface from moisture or aggressive environments. Zinc coated steel wire is not subject to corrosion and serves for many years in conditions of high humidity, in the open air or under the influence of other aggressive environments. Zinc coating is one of the best ways to protect steel wire against corrosion, and various methods are used to apply zinc. Zinc protects the steel wire by forming an oxide film on its surface, which is resistant to corrosive factors. The electrochemical potential of zinc, which is higher than the potential of the protected iron, also plays its role in rust protection, due to which only the zinc coating is gradually destroyed in the process of exposure to external factors, and the steel wire remains intact.
Wire Hot Dip Zinc Coating
Hot dip zinc coating of the wire consists in immersing it in a bath of molten zinc at a temperature of about 450°C. Hot dip zinc coating is the most common method of applying zinc, using this technology, the highest quality, durable and resistant zinc coating of the wire is obtained. To obtain a better zinc coating, the wire can be immersed in a bath of molten zinc several times - this is how the highest quality zinc coated wire is made.
The hot-dip zinc coating method requires a rather complex technology of preparatory and final measures that require accuracy and strict adherence. But exact observance of all stages of hot-dip zinc coating technology makes it possible to obtain zinc coated wire and other types of metal products that are well protected from corrosion.
Galvanic zinc plating or electrolytic method of applying zinc coating consists in immersing the wire in a bath with a solution of zinc salts and deposition of zinc on the surface of the wire by passing an electric current through the electrolyte. Zinc is applied to the wire by the method of galvanic galvanizing in a uniform layer of a given thickness, but the coating thickness cannot exceed 60 microns.
Galvanic zinc coating technology is simpler than hot dip technology, but this method has limitations on the thickness of the resulting zinc coating, for this reason it may not be enough to operate the galvanized wire obtained by this technology in difficult atmospheric conditions, at chemical plants and other cases, when galvanized wire is exposed to an aggressive environment.
Wire Drawing Zinc Coating
Drawing zinc coated wire, in fact, is not a technology for applying zinc, but a method of obtaining zinc coated wire of a larger diameter from a zinc coated wire of a smaller diameter. When drawing through a filler, the diameter of the zinc coated wire decreases, and a significant part of the zinc coating is erased, so this method is not the best from the point of view of obtaining zinc coated wire with a high-quality protective coating.
Other Zinc Coating Methods
There are other methods of applying zinc, but they are used in the production of zinc coated wire. In some cases, the cold galvanizing method is used, which consists in applying a composition with a high zinc content to the surface of metal parts, in fact, this is painting with a special paint that contains up to 95% zinc. This method is suitable for the protection of various, already installed metal structures, pipelines, tanks and other products. Zinc coating applied by cold galvanizing is poorly resistant to mechanical damage and is not used for the manufacture of zinc coated wire. In some cases, to obtain zinc coated products, the methods of electric arc and flame spraying of zinc are used, which make it possible to obtain a durable but porous zinc coating, or the thermal diffusion method of applying zinc, which makes it possible to obtain a strong and wear-resistant zinc coating, but these methods are also not used for the production of zinc coated wire.