Hot-dip galvanizing (HDG) is the process of immersing fabricated steel or iron into a kettle (bath) of molten zinc. While in the kettle, iron in the steel metallurgically reacts with the zinc to form a tightly-bonded alloy coating. The origins of the process date back more than 250 years; however, new technologies and creative chemistry contribute to the continued evolution of this proven process.
Hot-dip galvanizing resists corrosion by providing barrier and cathodic protection, as well as through the development of the zinc patina. These three levels of corrosion protection provide galvanized steel with maintenance-free longevity for decades. Learn more in the hot-dip galvanizing section.
The term “galvanizing” is often incorrectly used to describe various zinc coatings for steel. The AGA, our members, and this website support the process commonly called batch, general, or after-fabrication hot-dip galvanizing. All of the information in the hot-dip galvanizing section pertains to this process and should not be applied to other zinc coatings.
It is important to also understand the hot-dip galvanizing process is NOT the same as in-line or continuous sheet galvanizing.