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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Electro-slag remelting Vacuum arc remelting Argon oxygen decarburization. After the transfer of liquid steel containing iron, chromium, carbon and nickel decarburizatikn 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.

The ratio is lowered with the progress of the decarburization. Careful manipulation of slag, as it precipitates in the reaction, is important.

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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 decarbrization using immersion thermocouples. The AOD converter has tuyeres mounted in the sidewall or in the bottom.

This is done in a ladle equipped with stirring facilities with or without the use of a ladle furnace. There are usually two to four tuyeres in the bottom. Dolomitic refractories are usually less costly than magnesite chromite refractories and chromium pickup is not a factor.


Argon-oxygen decarburization | metallurgy |

In other projects Wikimedia Commons. Cooling gases blown through the outer annulus shroud form a metal or oxide accretion called a mushroom at the tuyere tip. Volatile elements with high vapour pressures, such as lead, zinc, and bismuth, are procss during the decarburization period.

Converters are typically zoned by thickness and brick quality to maximize lining life and minimize costs. The addition of lime and fluorspar help with driving the reduction of Cr 2 O 3 and managing the slag, keeping the slag fluid and volume small.

Argon-oxygen decarburization

Desulphurization is achieved by having a high lime concentration in the slag and a low oxygen activity in the metal bath. Argon oxygen decarburization for metal production Oxygrn Print. After sulfur levels have been achieved the slag is removed from the AOD vessel and the metal bath is ready for tapping. Such an approach is usually practiced by steelmakers to reduce argon usage and costs and still achieve a desired nitrogen specification.

Modern instrumentation has been developed which can take melt samples as well as steel temperatures using a specially designed sub lance with the converter in the upright position. Phosphorus, which requires oxidizing conditions, cannot be removed in the converter processing.

Argon Oxygen Decarburization Process |

Any chromium oxide not reduced by carbon ends up in the slag, which can form a complex spinel. Since the AOD vessel isn’t externally heated, the blowing stages are also used for temperature control. The top lance can also be designed for blowing mixed gases such as inert gas — oxygen mixtures. So, additions of lime are added to dilute sulfur argob the metal bath.


The liquid steel and the fluxes are then mixed to complete the desulfurization reaction. Donate Grateful for your donation!

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. These are achieved by having a high lime concentration in the slag and a low oxygen activity in the metal bath.

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. An annulus is formed between the copper and stainless tubes.

Magnesite chromite bricks are simultaneously acidic and basic and strict slag compositions must be maintained to prevent rapid wear. For more Praxair videos, please visit our YouTube channel. This accretion protects the tuyere and surrounding refractory. 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.

In the initial stage, oxygen to argon in the ratio ranging from 5: Iron and steel production.