What is Hot Dip Galvanizing?
Hot Dip Galvanizing is a factory controlled metallurgical combination of zinc and steel that provides corrosion resistance in a wide variety of environments. Hot Dip Galvanizing protects steel from corrosion in two ways. It provides cathodic protection and barrier protection. It is one of the oldest methods of zinc coating which includes the immersion of a fastener in molten zinc by which Tanya Galvanizers provides corrosion protect finish. This zinc coating provides sacrificial protection to the steel. The process of hot-dip galvanizing results in a metallurgical bond between zinc and steel with a series of distinct iron-zinc alloys. The resulting coated steel can be used in much the same way as uncoated. Galvanized steel can be welded. As zinc is more reactive than iron, the zinc galvanized coating corrodes first, protecting the steel substrate.
At Tanya Galvanizers we take care of the Hot Dip Galvanizing method. Here at the Tanya Galvanizers the Hot Dip Galvanizing process starts by carefully cleaning the surface of the steel to prepare it for galvanizing. After cleaning, the parts are dipped in a flux tank containing (typically) an aqueous solution of zinc ammonium chloride or they are fluxed by passing through a layer of molten zinc ammonium chloride floating on the top of the molten zinc. In the galvanizing tank, the parts are completely immersed in a molten bath consisting of a minimum of 98% zinc. After slowly withdrawing the parts from the molten zinc, the fasteners are spun in a centrifuge while the zinc is still liquid to remove excess zinc. The parts are then either air or water cooled to solidify the zinc and to permit handling.
For over 150 years Hot Dip Galvanizing has had a proven track record of protection in a myriad of applications. Hot-dip galvanized steel strip (also sometimes loosely referred to as galvanized iron) is extensively used for applications requiring the strength of steel combined with the resistance to corrosion of zinc. Applications include: roofing and walling, safety barriers, handrails, consumer appliances and automotive body parts. One common use is in metal pails. Galvanized steel is also used in most heating and cooling duct systems in buildings. The most important method of inspection for galvanized articles is visual. At Tanya Galvanizers variety of simple physical and laboratory tests may be performed for:
- Adherence of the coating
- Uniformity of the coating