Argon Oxygen Decarburization (AOD) Treatment is the recognized standard for stainless steel refining worldwide. Whether you are producing castings, wrought . Argon-oxygen decarburization: stainless steel: In the argon-oxygen decarburization process, a mixture of oxygen and argon gas is injected into the liquid steel. Argon Oxygen Decarburization, frequently referred to as “AOD”, is an advanced technology for the refinement of iron, nickel, and cobalt based alloys. By.
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If the grade to be produced requires an extra low sulphur level, the bath is deslagged after the reduction qrgon and another basic slag is added.
Decarburization occurs on the surface of rising bubbles that form from either the inert gas that is injected or on the surface of chromium oxide particles that are being reduced and generating carbon decarburizaation oxide CO. The formation of high basic slag and the reduction of oxygen potential in the liquid steel bath are good conditions for sulphur removal. This article needs additional citations for verification.
To achieve this, alloy additions are made with elements that have a higher affinity for oxygen than chromium, using either a silicon alloy or aluminum. The transfer of sulphur to slag takes place as per the following reaction.
Metal Refining with Argon Oxygen Decarburization (AOD) Refining Systems
These additions also serve to reduce the bath temperature as carbon and chromium oxidations decarurization exothermic. These additions usually consist of desired amounts of high carbon ferrochromium, stainless steel scrap, carbon steel scrap, nickel, iron, high carbon ferromanganese, and molybdenum oxide.
Views Read Edit View history. Sidewall mounted tuyeres are submerged while processing. In other projects Wikimedia Commons.
Argon oxygen decarburization – Wikipedia
November Learn how and when to remove this template message. Nitrogen control is a gas — metal reaction.
It is part of a duplex process in which scrap or virgin raw materials are first melted decarburizaton an electric arc furnace EAF or induction furnace IF. 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.
Sulfur removal is a slag — metal reaction that occurs during the reduction phase of the process. 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.
Argon Oxygen Decarburization Process |
The effectiveness of reduction step is dependent on many factors including slag basicity and composition, temperature, mixing conditions in the converter and solid addition dissolution kinetics.
The installation of a lance and introduction of oxygen in the early stages of decarburization can reduce the time for a heat.
Most of the recent converter installations include the use of a top lance for blowing oxygen. AOD process uses dilution technique for the decarburization of steel bath. The next step is the reduction step, in which the reduction additions are charged and stirred with an inert gas for a desired time.
Electro-slag remelting Vacuum arc remelting Argon oxygen decarburization.
Since the AOD vessel isn’t externally heated, the blowing stages are also used for temperature control. Retrieved from ” https: History of ferrous metallurgy List of steel producers.
Other trimming alloy additions might be added at the end of the step. The converter in the trunnion ring typically can be replaced with a preheated converter in less than an hour. This is done decarburiation a ladle equipped with stirring facilities with or without the use of a ladle furnace.
Argon Oxygen Decarburization Process
This argon dilution of oxygen minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium. Smelting Bloomery produces sponge iron Blast furnace produces pig iron Cold blast Hot blast Anthracite iron Direct reduced iron.
Ideally at this stage of the process, the chemistry of the liquid steel should meet the final specifications so that the heat can be tapped. This argon dilution minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium. At any given time, one of the converters is in the tiltable trunnion ring refining steel, a second newly lined converter is at a preheating station, and the third converter argn at a reline station.
Other benefits of AOD devarburization include pinpoint accuracy in chemistry control down to 0. The choice of refractory is dependent on the vessel operation pattern, final product specifications, and economics.
Decarburizarion modern practices a sulphur level of 0.