What happens to iron in a bolt as the bolt rusts?

As a bolt rusts, iron reacts with oxygen and moisture in the environment to form iron oxide, commonly known as rust. This process, called oxidation, leads to the deterioration of the metal, weakening its structural integrity. Over time, rust can flake off, exposing more iron to moisture and oxygen, which accelerates further corrosion. Ultimately, the bolt may become structurally unsound and lose its functionality.