Decarburization

The most common reactions are: :C + CO2 2CO also called the Boudouard reaction :C + H2O CO + H2 :C + 2H2 CH4 Other reactions are :C + 1/2O2 -> CO :C + O2 -> CO2 :C + FeO -> CO + Fe ==Electrical steel==

Electrical steel is one material that uses decarburization in its production. To prevent the atmospheric gases from reacting with the metal itself, electrical steel is annealed in an atmosphere of nitrogen, hydrogen, and water vapor, where oxidation of the iron is specifically prevented by the proportions of hydrogen and water vapor so that the only reacting substance is carbon being oxidized into carbon monoxide (CO). ==Stainless steel==

Stainless steel contains additives which are highly oxidizable, such as chromium and molybdenum. Such steels can only be decarburized by reacting with dry hydrogen, which has no water content, unlike wet hydrogen, which is produced in a way that includes some water and can otherwise be used for decarburization. ==As a secondary effect==

Incidental decarburization can be detrimental to surface properties in products (where carbon content is desirable) when done during heat treatment or after rolling or forging, because the material is only affected to a certain depth according to the temperature and duration of heating. This can be prevented by using an inert or reduced-pressure atmosphere, applying resistive heating for a short duration, by limiting the time that the material is submitted to a high heat, as it is done in a walking-beam furnace, or through restorative carburization, which uses a hydrocarbon atmosphere to transfer carbon into the surface of the material during annealing. The decarburized surface of the material can also be removed by grinding. ==See also==