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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It provides an economical way to produce stainless steel with a minimum loss of precious elements. These tuyeres typically consist of a copper tube with a stainless steel outer tube. Bloomery produces sponge iron Blast furnace produces pig iron Cold blast Hot blast Anthracite iron Direct reduced iron.

While typical BOF refractory campaigns are months or years long, stainless converter campaigns are several days or weeks long. Praxair can quote a server-only option for these systems.

Argon oxygen decarburization

Magnesite chromite refractories have high wear resistance but have a higher unit cost than dolomitic refractories. It has a removable, conical cover in place. The major benefit associated with the dilution process comes into play when the oxygen to inert oxygdn ratio is 1: High temperatures at the tuyere tip and high bath agitation place great demands on the converters refractory. AOD converter decarburization refractories Side blown stainless steel.

Praxair can review your system and design an upgrade using:. Sidewall dcarburization tuyeres are submerged while processing. A major modification of the AOD process involves the use of top blowing lance in addition to the side blowing tuyeres.

Also, aluminum or silicon may be added to remove oxygen. Decarburization occurs when dissolved carbon reduces the chromium and iron oxides that form.


The next step is the reduction step, in which the reduction additions are charged and stirred with an inert gas for a desired time. Oxidation of carbon continues, but oxidation of chromium is limited. Bessemer process Open hearth furnace Electric arc furnace Basic oxygen process. This accretion protects the tuyere and surrounding refractory. After the change from nitrogen to argon, nitrogen is removed from the bath decarrburization by evolved carbon monoxide and argon.

Metal Refining with Argon Oxygen Decarburization (AOD) Refining Systems

For more Praxair videos, please visit our YouTube channel. In other projects Wikimedia Commons. The burning of carbon increases the bath temperature.

Process gases are injected through submerged tuyeres that are installed in the side wall or bottom of the converter. 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.

Would like to more details of how to increase vessel life and to reduce refractory wear near tuyers. By using this site, you agree to the Terms of Use and Privacy Policy. The stages of blowing remove carbon by the decarburizayion of oxygen and carbon aggon CO gas.

For example, with a start sulphur of 0. Other trimming alloy additions might be added at the end of the step. There are usually two to four tuyeres in the bottom. An AOD converter is shown in Fig 1.

Also, aluminum or silicon may be added to remove oxygen. Please help improve this article by adding citations to reliable sources. Another modification of decarburizayion 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 process is so popular because it combines higher metallic yields with lower material costs. Depending on final nitrogen specification for the decarburizattion steel grade, the inert ozygen during the initial stages of decarburization can be nitrogen.

AOD provides an economical way to produce stainless steel with a minimal loss of precious elements. The molten metal is then decarburized and refined in a special AOD vessel to less than 0.

After initial melting the metal is then transferred to an AOD vessel where it will be subjected to three steps of refining; decarburizationreductionand desulphurization. The slice portion allows the crane to come close to the converter mouth. If necessary, additional raw materials may be decqrburization for small chemistry adjustments before tapping.

Unsourced material xoygen be challenged and removed. During the final stage of blowing, the ratio of oxygen to argon is changed to 1: Argon oxygen decarburization AOD is a process primarily used in stainless steel making and other high grade alloys with oxidizable elements such as chromium and aluminum.

Bottom blown converters have a variety of tuyere configurations depending on flow rates required. Annealing Low hydrogen Short circuit.

Argon-oxygen decarburization | metallurgy |

Send a question or comment. The key feature in the AOD converter decarbuirzation that oxygen for decarburization is mixed with inert gas such as argon or nitrogen and injected through submerged tuyeres. These are i decarburization, ii reduction, and iii final chemistry and temperature trimming. Converters are typically zoned by thickness and brick quality to maximize lining life and minimize costs.