Coated steel is steel that has an extra finish applied to the natural steel surface. The extra coating or finish applied can be tin, chrome, zinc, paint or plastic. The application of the coating is done in order to protect the surface of the steel from oxidation and it is also used to enhance the appearance of the material. Coated steel can be divided into several different categories. These include hot-dip galvanized, galvannealed, galvalume, galfan, electrolytic zinc (electro-galvanized) and pre-painted steel.