The Iron-Carbon System is a crucial phase diagram that illustrates the relationship between iron and carbon at various temperatures and carbon concentrations. It is essential for understanding the properties of steel and cast iron, as it shows how different compositions affect the material's structure and performance. The diagram includes key phases such as ferrite, austenite, and cementite. In this system, the maximum solubility of carbon in ferrite is about 0.02%, while in austenite, it can reach up to 2.14%. The eutectoid reaction occurs at 0.76% carbon, leading to the formation of pearlite, a mixture of ferrite and cementite. Understanding this system helps in the design and treatment of steel for various applications.