Iron carbide, also known as cementite, is a chemical compound made up of iron and carbon. It has the formula Fe3C and is an important component in steel and cast iron, influencing their hardness and strength. Iron carbide forms during the cooling process of molten iron and can exist in various microstructures within these materials. In metallurgy, the presence of iron carbide affects the properties of steel, making it harder and more wear-resistant. It plays a crucial role in the iron-carbon phase diagram, which helps engineers understand how different compositions of iron and carbon will behave during processing and use.