Galvanized steel is coated with a thin layer of zinc. The zinc coating protects the steel beneath it from rust. It's used to make nuts, bolts, screws, and nails resistant to degradation when they are exposed to the weather. Galvanized steel stands up to water well — as long as it's not salt water.

Due to the risk of hydrogen embrittlement, A490 bolts cannot be galvanized like A325 bolts. Instead, a zinc/aluminum corrosion protective coating or a zinc-rich base coat and aluminum coating must be used.

Yes, galvanized steel resistance to rust corrosion depends largely on the type and thickness of the protective galvanized zinc coating, but the type of corrosive environment is also a critical factor. Factors that rust and corrode galvanized steel: Relative humidity above 60% Sodium chloride (salt) in water or air.