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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For example, with a start sulphur of 0. The bath is then stirred with inert gas, typically for around five to eight minutes. Modern instrumentation has been decarburuzation which can take melt samples as well as steel temperatures using a specially designed sub lance with the converter in the upright position. In modern practices a sulphur level of 0. An AOD converter is shown in Fig 1. Desulphurization is achieved by having a high lime concentration in the slag and a low oxygen activity in the metal bath.
Argon Oxygen Decarburization Process |
Bessemer process Open hearth furnace Electric arc furnace Basic oxygen process. This is due to the very low oxygen potential of the gas mixture, which minimizes chromium oxidation. The transfer of sulphur to slag takes place as per the following reaction. Low hydrogen Short circuit. Unsourced material may be challenged and removed. Argon oxygen decarburization for metal production Share Print.
In case of those steel grades which can tolerate nitrogen, a mixture of oxygen and nitrogen can also be blown. Usually, the converter is turned down to a decarbuization position and a sample of the liquid steel is taken for analyses at a carbon level of about 0.
Argon oxygen decarburization
High wear areas of the converter, usually the tuyere wall, slag line, and transfer pad are zoned thicker and with higher quality refractory than other parts of the converter.
Depending on final nitrogen specification for the stainless steel grade, the inert gas during the initial stages of decarburization can be nitrogen. This argon dilution of oxygen minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium.
Dolomitic refractories are usually less costly than magnesite chromite refractories and chromium pickup is not a factor.
If the grade to be produced requires an extra low sulphur level, the bath is deslagged after the reduction step and another basic slag is added.
The choice of refractory is dependent on the vessel operation pattern, final product specifications, and economics. Retrieved from ” https: The ratios can be done in decarburizahion number of phases to facilitate the reaction. During odygen final stage of blowing, the ratio of oxygen to argon is oxyggen to 1: AOD provides an economical way to produce stainless steel with a minimal loss of precious elements.
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. The liquid steel and the fluxes are then mixed to complete the desulfurization reaction. The formation of high basic slag and the reduction of oxygen potential in the liquid steel bath are good conditions for sulphur removal.
Argon oxygen decarburization – Wikipedia
The AOD converter can be rotated downwards so that the side mounted tuyeres are above the bath level during charging of the liquid steel. The molten metal is then decarburized and refined in a special AOD vessel to less than 0. AOD process refining has three major steps. The number and relative arfon of tuyeres is determined in part by converter size, range of heat sizes, process gas flow rates and types of alloys refined.
Sidewall mounted tuyeres are submerged while processing. The stages of blowing remove decarbugization by the combination of oxygen and carbon forming CO gas.
Views Read Edit View history. Nitrogen control is a gas — metal reaction. These additions usually consist of desired amounts of high carbon ferrochromium, stainless steel scrap, carbon steel scrap, nickel, iron, high carbon ferromanganese, and arfon oxide.