Cast iron is a type of iron that usually has a high carbon content, making it a strong, brittle material. It is used in a variety of industrial and domestic applications, from the construction of bridges to the manufacture of cookware.
The chemical composition of cast iron is of great importance in determining its properties. Of particular note are the levels of carbon, silicon, manganese and sulphur.
The carbon content of cast iron is highest of all the iron alloys. Typically it will range from between 2% and 4%. This high level of carbon gives cast iron its strength and brittleness, as well as aiding in the formation of its unique shape when heated and cooled.
Silicon is an important addition to cast iron that helps to produce a quality cast product. It is usually added at a rate of 0.5% - 4%. Silicon has a strong influence on the casting process, aiding in the formation of the product and reducing the amount of shrinkage.
Manganese is also present in most types of cast iron, usually at levels of 0.5% - 2%. It helps to protect the iron against corrosion and improves the material’s mechanical properties.
Finally, sulphur is an important element in cast iron, usually added at a rate of between 0.05% and 0.15%. Sulphur helps to reduce the brittleness of the iron, however, can also cause the iron to become more brittle if too much is added.
The chemical composition of cast iron is essential in controlling the properties of the material, and influences its uses in many practical applications. It is for this reason that so much emphasis is placed on controlling the levels of the major elements in cast iron.
