My watch list
my.chemeurope.com  
Login  

Cementite



v  d  e
Iron alloy phases

Austenite (γ-iron; hard)
Bainite
Martensite
Cementite (iron carbide; Fe3C)
Ledeburite (ferrite - cementite eutectic, 4.3% carbon)
Ferrite (α-iron, δ-iron; soft)
Pearlite (88% ferrite, 12% cementite)
Spheroidite

Types of Steel

Plain-carbon steel (up to 2.1% carbon)
Stainless steel (alloy with chromium)
HSLA steel (high strength low alloy)
Tool steel (very hard; heat-treated)

Other Iron-based materials

Cast iron (>2.1% carbon)
Wrought iron (almost no carbon)
Ductile iron

Cementite or iron carbide is a chemical compound with the formula Fe3C, and an orthorhombic crystal structure. It is a hard, brittle material, normally classified as a ceramic in its pure form, though it is more important in metallurgy.

Additional recommended knowledge

It forms directly from the melt in the case of white cast iron. In carbon steel, it either forms from austenite during cooling or from martensite during tempering. It mixes with ferrite, the other product of austenite, to form lamellar structures called pearlite and bainite. Much larger lamellae, visible to the naked eye, make up the structure of Damascus steel, though the process has been lost to history (see article for information on attempted reconstruction of the process).

Fe3C is also known as cohenite, particularly when found mixed with nickel and cobalt carbides in meteorites. This form, a hard, shiny silver mineral, was first described by E. Weinschenk in 1889.

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Cementite". A list of authors is available in Wikipedia.
Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE