The term "iron-carbon" refers to an alloy primarily composed of iron and carbon. This combination is crucial in metallurgy, as it significantly influences the properties of steel and cast iron. The carbon content typically ranges from 0.02% to 6.7%, affecting hardness, strength, and ductility. In the iron-carbon phase diagram, different phases such as ferrite, austenite, and cementite are identified, each with unique characteristics. Understanding these phases helps in the production and treatment of various steel grades, making iron-carbon alloys essential in construction, manufacturing, and many other industries.