All of Zaun’s gates and railings are hot-dip galvanised to BS EN ISO1461:1999. Hot-dip galvanising is a dipping process in which molten fluid zinc consists of layers of zinc-iron alloys caused by the reaction of zinc with iron in the steel. As the galvanized components are withdrawn from the molten zinc a further layer of zinc will adhere to the steel surface. Giving it the bright silver finish.
Hollow tubes like posts and gate frames are ‘vented’, which allows the flow of molten zinc inside the tube, meaning that a protective coating is applied to the inside of the steelwork and the outside. Before dipping, the steelwork first goes through 17 stages of pre-treatment. Firstly this involves 6 acid tanks of increasing strength, which decreases the surface and remove impurities.
The steel is then rinsed in ion-free water before being heated to 70 degrees in the flux tank, evaporating all the water from the surfaces of the steel. The steel is then dipped in a bath of molten zinc heated to between 440 & 460 °, The components are then removed from the tank at a specific angle to help excess zinc flow off, during which if required an air knife can be used to remove excess zinc from mesh etc. The metalwork is then cooled in water before fettling if required. To limit the effects of distortion. If the components being galvanized are manufactured/fabricated using thin sheet metal then they are left to air cool.
When steel is galvanized it will have a bright silver finish. This will dull down over time and is a natural process called oxidisation. Oxidation also helps to protect the zinc coating.
