what is cementite
Cementite, also known as iron carbide, is a chemical compound of iron and carbon, with the formula Fe 3 C (or Fe 2 C:Fe).n the ironâcarbon system (i.e. plain-carbon steels and cast irons) it is a common constituent because ferrite can contain at most 0.02wt% of uncombined carbon. Therefore, in carbon steels and cast irons that are slowly cooled a portion of the element is in the form of cementite.