The Chemical Composition of Forgable Cast Iron
The chemical composition of a forgable cast iron is important because it affects the macrostructure as well as the mechanical properties of the cast iron. As with any other material, different levels of alloying elements, such as carbon, silicon, manganese, nickel, chromium, and molybdenum, are used to change the chemical composition for different applications. Depending on the use of the forgable cast iron, the desired properties can be achieved through careful selection of the chemical composition.
Forgable cast iron is made up of two components: graphite and matrix. The graphite is composed of elemental carbon that is crystalline in nature, while the matrix is composed of pearlite, ferrite, and other alloying elements. Depending on the alloying elements present in the matrix, the strength and hardness of the forgable cast iron can be controlled.
The carbon content of forgable cast iron is also critically important, as it affects the hardness and strength of the material. Carbon is the primary agent that controls the hardness and strength of cast iron and increases the elastic limit. Generally, the carbon content of forgable cast iron should range from 2.5 % to 3.5%. But for certain applications, higher carbon levels are required to achieve the desired level of hardness or strength.
Silicon increases the resistance of the forgable cast iron to oxidation and wear, as well as its ductility and strength. For most forgable cast iron applications, silicon should range from 0.5% to 2.5%. As silicon increases, the strength of the forgable cast iron increases as well.
The presence of manganese in forgable cast iron helps to reduce the impact of brittleness when increasing the carbon content. Manganese is also important for increasing the irons ability to resist corrosion. In most forgable cast iron applications, the manganese content should range between 0.8% and 1.2%.
Nickel helps to increase the strength and hardness of the forgable cast iron while reducing the risk of brittleness. It also helps to increase the weldability of the forgable cast iron. The nickel content of forgable cast iron should range between 0.5% and 1%.
Chromium and molybdenum are important for controlling the hardness and wear resistance of forgable cast iron. Chromium increases the hardness of the forgable cast iron while molybdenum helps to increase its wear resistance. Chromium should range between 0.3% and 0.7%. For most forgable cast iron applications, the molybdenum content should range between 0.45% and 0.55%.
The chemical composition of forgable cast iron is a complex mixture of alloying elements and its properties can be altered by carefully balancing the levels of these elements. With careful selection of alloying elements, forgable cast iron can be tailored to the desired properties required for the application.
