When iron is oxidised by open air, a layer of oxide is formed which is known as rusting. Although rusting has no impact on the quality of product, it is quite common since reaction of air and moisture forming rust is a regular phenomenon. It spreads on the surface uniformly. Corrosion is a chemical or an electrochemical reaction between an engineered material and its environment which causes its disintegration. Other compounds are also formed along with oxides and this leads to the metal surface being unevenly eroded. This is detrimental to the product quality.