Steel is an ideal construction material—it is easy to shape, strong, and easy to manufacture. It can also be remelted and recycled, making it very “sustainable” and eco-friendly.
However, like all metals it is prone to rust and corrosion, especially when it is exposed to the elements. To solve this problem, chemical engineers created galvanized steel. The steel is treated with zinc, which is rust-proof. The zinc acts like a shield, though it is not simply a protective layer—the iron molecules in the steel bonds with the zinc, in a chemical reaction that yields a permanent and comprehensive defense against the elements. Thus the outer layer is completely made of zinc, but even the underlying layers are a zinc-and-steel combination. Only the centermost layer is made of pure steel.
There are instances when rust starts to eat at the building or object. However, the zinc acts as the first line of defense—it will be the first to be corroded, and the rust spreads across the surface rather than immediately getting into the steel core.
Galvanized steel is more expensive to produce, but it is absolutely crucial in any building or equipment that will be exposed to moisture, or (in marine industries) actually submerged in water. Most homes use galvanized steel frames, while offices make use of galvanized steel roofing. Cars are also made of steel parts.
Pure steel is easier to mold, so it is typical for manufacturing companies to shape it first before galvanizing it. This is particularly true for small parts, like nails or beams. However, it is possible to get raw galvanized sheets. Though a galvanized steel sheet is still stiff in comparison to pure steel, it can take simple bending before it starts to break or flake.