Learn more about Praxair’s Argon Oxygen Decarburization process that is used to make over 75% of the world’s stainless steel. Argon oxygen decarburization (AOD) converter is popularly used in the stainless steel making process. AOD has a top lance for oxygen injection and several.
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Another modification of the AOD process involves applying vacuum on the converter to reduce the consumption of argon and silicon as well as the process time when making low carbon grades. The desire to increase the productivity agron led to continuous charging of raw materials during the blow period as well as reduction period. Bottom blown converters have a variety of tuyere configurations depending on flow rates required.
Argon Oxygen Decarburization Process
Lime and dolomitic lime are sometimes added before the end of the blow to cool the bath and to reduce the volume of reduction additions. Special designs exist for normalizing the flow in the annular gap. Donate Grateful for your donation! Since the blowing is decrburization along with argon it is possible to carry out the decarburization at a lower temperature.
There are two basic choices of refractory type, magnesite-chromite, and dolomite. Haynes International Case Study Video. Phosphorus, which requires oxidizing conditions, cannot be removed in the converter processing.
Chromium pickup from the proess is possible. Additional silicon addition is needed if requirement of silicon is there to meet the silicon specification of some of the stainless steels.
Other benefits of AOD process include pinpoint accuracy in chemistry control down to 0. Careful manipulation of slag, as it precipitates in the reaction, is important. The converter in the trunnion ring typically can be replaced with a preheated converter in less than an hour. Porcess has a removable, conical cover in place. For more Praxair videos, please visit our YouTube channel.
Argon oxygen decarburization – Wikipedia
This page was decarburisation edited on 4 Octoberat During the final stage of blowing, the ratio of oxygen to argon is changed to 1: Desulphurization to very low levels is generally easier in dolomitic refractories because very basic slags can be used without detrimental effects on the bricks. Any chromium oxide not reduced by carbon ends up in the slag, which can form a complex spinel.
In case of those steel grades which can tolerate nitrogen, a mixture of oxygen and nitrogen can also be blown. Sidewall mounted tuyeres are submerged while processing. So, additions of lime are added to dilute sulfur in the metal bath.
During decarburization, additions are made for obtaining the proper final chemical composition. Side wall injection usually imparts maximum stirring energy to the bath for greatest efficiency of mixing.
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For converters that tap into a ladle held by a crane, a sliced cone top section is often used. Please help improve this article by adding citations to reliable sources. Praxair can quote a server-only option for these systems. Magnesite chromite refractories have high wear resistance but have a higher unit cost than dolomitic refractories.
A major modification of the AOD process involves the use of top blowing lance in addition to the side blowing fecarburization. The molten metal is then decarburized and refined in an AOD converter to less than 0. After the transfer of liquid steel containing iron, chromium, carbon and nickel from EAF or IF to the AOD converter, high carbon ferro chrome is added and the blow is started with the blowing of inert gas argon, nitrogen and oxygen mixture.
Refractory costs are a significant fraction of total operating costs. It is part of a duplex process in which scrap or virgin raw materials are first melted in an decarbjrization arc furnace EAF or induction argpn IF. Oxjgen ratios can be done in any number of phases to facilitate the reaction.
Such an approach is usually practiced by steelmakers to reduce argon usage and costs and still achieve a desired nitrogen specification. History of ferrous metallurgy List of steel producers.