The liquid metal is transferred from transfer ladle to AOD converter. The liquid steel, which contains most of the chromium and nickel needed to meet the final heat composition, is tapped at a temperature of 1500 to 1600 deg C from the EAF or the IF into a transfer ladle. The input of the AOD process is the output of the EAF or IF process. These are (i) decarburization, (ii) reduction, and (iii) final chemistry and temperature trimming. The intimate gas – metal contact and excellent slag – metal mixing facilitate refining reactions.ĪOD process refining has three major steps. The amount of stirring energy from the gas blown through the subsurface tuyeres and the formation of the carbon monoxide deep within the metal bath results in the converter processes being among the most intensely stirred metallurgical reactors. The injection of inert gas (argon or nitrogen) lowers the partial pressure of CO in the bath, thus allowing higher chromium content to be in equilibrium with lower carbon contents. The end result is a cleaner metal coupled with increased productivity.ĪOD process uses dilution technique for the decarburization of steel bath. Other benefits of AOD process include pinpoint accuracy in chemistry control down to 0.01 % carbon and lower, rapid desulfurization to less than 0.001 %, and lead removal to less than 0.001 %. This argon dilution of oxygen minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium. The key feature in the AOD converter is that oxygen for decarburization is mixed with inert gas such as argon or nitrogen and injected through submerged tuyeres.

The molten metal is then decarburized and refined in an AOD converter to less than 0.05 % carbon. It is part of a duplex process in which scrap or virgin raw materials are first melted in an electric arc furnace (EAF) or induction furnace (IF). It provides an economical way to produce stainless steel with a minimum loss of precious elements. The process is very popular because it combines higher metallic yields with lower material costs. Today, over 75 % of the world’s stainless steel is made using the AOD process. AOD was invented in 1954 by the Lindé division of The Union Carbide Corporation, which became Praxair in 1992. and it's quite a big company: SchottArgon oxygen decarburization (AOD) is a process primarily used in production of stainless steel and other high grade alloys such as silicon steels, tool steels, nickel-base alloys and cobalt-base alloys with oxidizable elements such as chromium and aluminum. I am adding the Duran link as they are based in the U.S.

There are a couple of companies using pear-shaped flasks in their catalogues, but as far as I know there's not a specific name to distinguish between what is illustrated in picture 1 from what's shown in picture 3, apart from the term 'round-bottom' or indeed pear shape. Note added at 11 hrs 42 mins ( 14:23:53 GMT)įor flasks (20417-01 -but also 2- and 3) different names are used in your link and I fail to see how this is possible (look for example at the slightly more pointed 20417-3, described as a kjeldahl flask, I thought you were referring to this: Round-bottomed: having a rounded bottom 'round-bottom flasks' Note added at 5 hrs 48 mins ( 08:29:30 GMT)Īlso, for 'round-bottom' (condensers) if it fits your context: The mark on the flask was placed there at the factory, providing a precise volume reading. Notes The pear-shaped flask is called a volumetric flask. I think you are referring to a volumetric flask. Selected answer: volumetric flask/pear shaped flask

Pear-shaped flask English translation: volumetric flask/pear shaped flask

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Chinese pear shaped vessel meaning