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) Treatment is the recognized standard for stainless steel refining worldwide. Whether you are producing castings, wrought . 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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The liquid metal is transferred from transfer ladle to AOD converter. Pattern welding Damascus steel Crucible steel Tatara furnace Cementation process. Annealing Low hydrogen Short circuit.
High temperatures at the tuyere tip and high bath agitation place great demands on the converters refractory. The formation of high basic slag and the reduction of oxygen potential in the liquid steel bath are good conditions for sulphur removal. Low hydrogen Short circuit.
Additional silicon addition is needed if requirement of silicon is there to meet the silicon specification of some of the stainless steels. For more Praxair videos, please visit our YouTube channel.
In modern practices a sulphur level of 0. The liquid steel and the fluxes are then mixed to complete the desulfurization reaction. Additions of lime are made to dilute the sulphur in the liquid steel bath. During the final stage of blowing, the ratio of oxygen to argon is changed to 1: Donate Grateful for your donation! 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.
Argon Oxygen Decarburization for Metal Production | Praxair, Inc.
decarburizatino If necessary, additional raw materials may be charged for small chemistry adjustments before tapping. Want to modernize and upgrade the functionality of your old AOD system cost-effectively? Argonoxygen major modification of the AOD process involves the use of top blowing lance in addition to the side blowing tuyeres.
The number and relative positioning of tuyeres is determined in part by converter size, range of heat sizes, process gas flow rates and types of alloys refined.
This article needs additional citations for verification. Usually, the converter is turned down to a horizontal position and a sample of the liquid steel is taken for analyses at a carbon level of about 0.
The next step is the reduction step, in which the reduction additions are charged and stirred with an inert gas for a desired time. The end argono-xygen is a cleaner metal coupled with increased productivity. Decarburization occurs when dissolved carbon reduces the chromium and iron oxides that form. 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 mono oxide CO.
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 decaburization the converter.
The ratio is lowered with the progress of the decarburization. The desire to increase the productivity has led to continuous charging of raw materials during the blow period as well as reduction period.
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The system accurately controls the flow rates and monitors the amount of gas injected into the bath to enable the operator to control the process and measure the total oxygen injected.
Would like to more details of how to increase vessel life and to reduce refractory wear near tuyers. Side wall injection usually imparts maximum stirring energy to the bath for greatest efficiency of mixing.
Argon oxygen decarburization
While typical BOF refractory campaigns are months or years long, stainless converter campaigns are several days or weeks long. It has a removable, conical cover in place. AOD is widely used for the production of stainless steels and specialty alloys such as silicon steels, tool steels, nickel-base alloys and cobalt-base alloys.
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. After the ladle treatment, the steel is ready to be cast. This page was last edited on 4 Octoberat Another modification of the Decsrburization process involves applying vacuum on the converter to reduce the consumption of argon and silicon as well as the process time when making low decarburlzation grades.
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Argon oxygen decarburization – Wikipedia
Other trimming alloy additions might be added at the end of the step. When the vessel is rotated, the tuyeres are above argon–oxygen bath.
In the early days of the AOD process, the converter was tilted for raw material additions as well as for taking samples and for measurement of temperature using immersion thermocouples.
The burning of carbon increases the bath temperature. Volatile elements with high vapour pressures, such as lead, zinc, and bismuth, are removed during the decarburization period.
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