Rusting is a chemical process, which is common with the metals containing iron. In other words, the corrosion process taking place when there is iron, is known as rusting…
For rusting to take place, there should be certain conditions. In the presence of oxygen and moisture or water, iron undergoes this reaction and form a series of iron oxide. This reddish-brown color compound is known as rust.
So, rust contains hydrated iron (III) oxide Fe2O3·nH2O, and iron (III) oxide-hydroxide (FeO(OH), Fe(OH)3). If rusting starts at one place, it will eventually spread, and the whole metal will be disintegrated. Not only iron but the metals containing iron (alloys) also undergo rusting. Check the videos before and after.