Difference between AOD & VOD stainless steel making process

AOD production (Argon-Oxygen-Decarburization)

    In this process the merger is implemented in conventional furnace. Subsequently, the liquid passes to the converter, within which the steel undergoes the refining chemical analysis through redox reactions. Blowing argon and oxygen, using sheets, maintain a continuous mixing

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   The insufflation of argon and oxygen, using sheets, maintain a continuous mixing. In addition, the redox reactions raise the temperature up to 1650° C. What is it the main reaction? The decarburization. During this reaction the excess carbon binds with oxygen and other gases are inflated. This allows the formation of carbon monoxide leading to get carbon levels in the order of 0.015%. The loss of Chromium by oxidation is contained by the ratio calibrated for oxygen and argon. What happens to steel after “centered” the chemical analysis? Switch to continuous in casting or in ingot moulds.

VOD production (Vacuum-Oxygen-Decarburization)

  The melting of scrap practiced for VOD is the same as AOD. With the only variation of the liquid steel is poured into a ladle, entered into a plant (tank) capable of creating an initial 3 mbar vacuum and then stabilize in 0.6 mbar. What happens? The vacuum action:

• enhances the decarburization reaction

• preserves the chromium from over-oxidation.

     Argon plugs is entered from the bottom of the ladle through porous. Just to keep agitated steel-washed. Then the oxygen is introduced from above using a spear. The latter spreads on the surface of the liquid thus accelerating the formation of carbon monoxide. Bringing carbon up to limits of 0.015%, allowing the decarburization. After reaching the specific settings, we proceed to the adjustment of other chemical elements. (e.g. chrome) How much electricity is used to keep the high temperatures needed to proceedings? This process produces heat thanks to decarburization reaction will be like request a smaller amount of energy. Only we proceed to the task of ingot-mould.

Final comments

   The AOD process is fast and cheap. Today, it is certainly more used in the specialized steel mills with continuity in the production of stainless steels. Indeed, the VOD process is particularly suitable for mixed production of stainless steel. Where the share is more modest and produced steels stainless also.