Focus on Steel 2017 | Page 26

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Hot galvanizing - The ideal solution for a century of use for metal structures

By hot galvanizing any steel product can be coated with a zinc protective layer that prolongs the life of the steel and reduces the maintenance costs of the construction .
The hot zinc coating procedure , also called hot galvanizing , provides a very good corrosion resistance in many environments . The hot zinc coating procedure provides complete coverage of the surface of the steel piece and seals the steel against the corrosive action of the environment . The use of galvanized steel is the best solution for increasing the life of metal structures , this fact being proved by two centuries of use . It is not unusual for galvanized steel structures to last for more than 100 years . An example in the support of this affirmation is the Lydlinch - Dorset bridge ( UK ).
No trace of rust after 50 years !
The hot galvanizing process is carried out by immersing the steel piece in molten zinc , thus forming a series of layers of zinc and iron alloys which ensure a resistant layer for abrasion and corrosion . The procedure is carried out in a very short time , practically in just a few minutes . The fact that the steel is immersed in a fused zinc bath means hot galvanizing can provide protection to the exterior and interior surfaces of the components .
By minimizing the use of energy resources and the resulting durability of materials , the environmental impact is relatively low . The minimization of the budgets allocated to the subsequent maintenance and the sustainability of the use of hot galvanized structures are supported by the elimination of the need to repaint the structures .
The zinc sacrificial behaviour protects the steel even when a minor damage or discontinuity occurs in the coating . Finally , galvanizing results in the development of an additional layer of protection . The surface of the galvanized piece is coated in a zinc patina , the full development of which can last 6-12 months , being practically almost immune to rain or snow thanks to the fact that it is not water-soluble .
The galvanized bridge in Dorset - 1944