AOD

AOD (Argon oxygen decarburization) refining furnace

   AOD is the refining equipment of argon oxygen decarburization. It’snamed after the acronym of its English name. Its configuration is similar toconverter which is set on a support ring tilting front and back and is fixedwith dowel. On the side bottom of the furnace, spray lances are set to blowgases towards the horizontal direction of the molten pool. The number of spraylance is different according to the tonnage of the furnace, generally 2-3. Theextension cord of spray lance coincides with the vertical spindle of furnace.Spray lance is made up of inner pipe (copper) and outer pipe (stainless steel).Inner pipe is used to import the main blowing gases (made up of Ar-O2 orAr-N2). Annular gap between inner pipe and outer pipe imports Ar, N2 or air tocool the spray lance. Spray lance is depletion type. It is imbedded intorefractory layers when constructing furnace. It is burned up during the periodof smelting synchronizing with furnace lining. The blown oxygen is used to heatcarbon oxide. Blown argon is used to strong convection agitation. The blownnitrogen is used to alloy when producing high nitrogen alloy. Lots of metalnitride are saved during the production process of 21-4N kinds of steel. Forexample, the amount of chromium nitride is reduced and cost of production issaved a lot.

   The furnace body is built by magnesia-calcium brick, chrome magnesiumbrick or magnesium dolomite brick. Higher quality of electric smelting chromemagnesium brick is used around the spray lance to bear scour of hightemperature and molten steel. Removable furnace lid is built with chromemagnesium brick or alumina-magnesia brick. It also can be made byheat-resistant concrete. Dimensional proportion of furnace hearth is pooldepth: inside diameter:

total furnace height = 1:2:3. In thesituation of furnace tilting forwards a certain angle, the primary molten steelis poured into by swiveling ladle. At this time, pneumatic lance is on thesurface of molten steel. When the furnace is back to the upright position, spraylance is submerged into the deep molten steel and begins to blow and refine.After refining, steel is still out from furnace lid.