Mild steel, also known as low carbon steel, is one of the most widely used metals in the construction industry. The percentage of carbon found in this steel ranges from 0.05% to 0.25% by weight, making it more weldable, more ductile and easier to handle than steel with higher carbon content. Due to the lack of alloying materials in mild steel, it is more subjected to oxidation, unless properly coated.
Mild steel is also affected by natural elements such as water, air, environmental pollutants, chemicals, etc. that can result in corrosion. The cost of corrosion is estimated to be USD 2.5 trillion, which is equivalent to 3.4% of global GDP (Figure 1). There is an extensive amount of data published worldwide stating that a thousand tonnes of steel is lost every year due to corrosion, resulting in a loss of millions of dollars every year. This has led to the development of various methods to protect the steel from rusting. These methods include protective coatings, chemical conversion, alloying and cathodic protection – protective coating being the most widely used.