Cold galvanizing

Cold galvanizing is a marketing term, not a metallurgical process, used to describe the application of a zinc-rich paint or coating to steel surfaces.

Process and Difference

Unlike true galvanizing—which involves metallurgically bonding steel with molten zinc at high temperatures (approx 450 degree celsius), such as in hot-dip or inline galvanizing—cold galvanizing is a sacrificial coating applied at ambient temperatures (cold) using methods like brushing, rolling, or spraying

The coating contains a very high concentration of zinc dust.  When applied, the zinc particles in the paint establish electrical contact with the steel substrate. If the coating is scratched, the zinc preferentially corrodes, thereby protecting the steel electrochemically (cathodically), similar to true galvanizing. However, the thickness and durability of cold galvanizing are generally significantly lower than that of hot-dip galvanizing, making it better suited for repair work or smaller, non-structural applications.