Hot-dip Galvanizing Process
Hot dip galvanized is most used method to protect steel products from external
This method consists in cover all the steel surface with a metallic coat that in this
case is zinc. Zinc is a metal that has optimum non corrosion characteristics. In fact
it is characterized by a first phase of rapid activation during which on the surface of
the coat forms a layer of zinc oxide that forms a moment of corrosion that allows
protection of the product for several years.
Moreover Galvanizing process offers protection from corrosion even in presence of
interruption of coat (scratches and incisions). Being zinc chemically less noble than
the steel, it sacrifices itself oxidizing instead of the steel (cathode protection).
Steps to perform a correct hot dipped galvanizing process are:
• surface cleanness of the product (remove trace of paint, glue, cement etc)
• removing the grease in alkaline solution (remove grease trace)
• pickled process in chloride acid HCL = 120/130 (remove all the oxide layer)
• wash (remove trace of acid)
• flowing in solution of ZnCl2-NH4Cl
• drying in drier
• immersion in fused zinc (440°-460°)
The most important aim is to protect steel products used for housing and industry,
from external atmospheric agents.