Argon Oxygen Decarburization

Argon oxygen decarburization, usually abbreviated AOD, is a steel-refining process that lowers the carbon content of molten stainless steel by blowing a carefully controlled mixture of argon and oxygen gas up through the melt from the bottom of a converter vessel, the diluting argon lowering the effective partial pressure of the carbon monoxide produced so that carbon can be oxidized and removed without also burning away the melt's valuable chromium. The process was developed jointly by the Union Carbide Corporation's Linde Division and the steelmaker Joslyn Stainless Steels between 1954 and 1968, solving a problem that had made stainless steel unusually costly to produce, since older refining methods lost far more chromium to oxidation along with the unwanted carbon. AOD was rapidly adopted across the stainless steel industry after its introduction and remains the standard method of refining stainless and other chromium-bearing steels worldwide.