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.
|Published (Last):||13 August 2004|
|PDF File Size:||20.17 Mb|
|ePub File Size:||17.18 Mb|
|Price:||Free* [*Free Regsitration Required]|
Leave a Reply Cancel reply Your email address will not be published. These are achieved by having a high lime concentration in the slag and a low oxygen activity in the metal bath. Want to modernize and upgrade the functionality of your old AOD system cost-effectively?
The converter in the trunnion ring typically can be replaced with a preheated argon-ocygen in less than an hour.
Decarburization occurs when dissolved carbon reduces the chromium and iron oxides that form. This is due to the very low oxygen potential of the gas mixture, which minimizes chromium oxidation. Any chromium oxide not reduced by carbon ends up in the slag, which can form a complex spinel. High temperatures at the tuyere tip and high bath agitation place great demands on the converters refractory.
Argon oxygen decarburization – Wikipedia
The choice of refractory is dependent on the vessel operation pattern, final product specifications, and economics. The system accurately argon-lxygen 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.
Other benefits of AOD process include pinpoint accuracy in chemistry control down to 0. Converters that tap into a ladle car decarburizationn have a BOF type concentric cone top section.
The system will be tailored to match your current operation with added features found only on the new systems.
Argon Oxygen Decarburization Process
The top lance can also be designed for blowing mixed gases such as inert gas — oxygen mixtures. Magnesite chromite refractories have high wear resistance but have a higher unit cost than dolomitic refractories. There are usually two to four tuyeres in the bottom.
This page was last edited on 4 Octoberat So, additions of lime are added to dilute sulfur in the metal bath. Process gases are injected through submerged tuyeres that are installed in the side wall or bottom of the converter.
Argon Oxygen Decarburization for Metal Production | Praxair, Inc.
The ratio is lowered with the progress of the decarburization. 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.
The gas control system supplies the process gases at nominal rates of 1. Retrieved from ” https: The blow is continued to attain 0.
During the final stage of blowing, the ratio of oxygen to argon is changed to 1: Another modification of the 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. Praxair can review your system and design an upgrade using: These decsrburization also serve to reduce the bath temperature as carbon and chromium oxidations are exothermic.
History of ferrous metallurgy List of steel producers. Smelting Bloomery produces sponge iron Blast furnace produces pig iron Cold blast Hot blast Decrburization iron Direct reduced iron.
After the ladle treatment, the steel is ready to be cast.
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. The molten metal is then deacrburization and refined in a special AOD vessel to less than 0. After the change from nitrogen to argon, nitrogen is removed from the bath both by evolved carbon monoxide and argon.
Posted by Satyendra on Apr 28, in Technical 1 comment. The length of the blow period is determined by the starting carbon and silicon levels of the hot metal charged to the AOD converter. While typical BOF refractory campaigns are months or years long, stainless converter campaigns are several days or weeks long. Decarburization time ranges from 20 to 35 minutes in modern converters start from 1.
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.
AOD converter decarburization refractories Side blown stainless steel. Side wall injection usually imparts maximum stirring energy to the bath for greatest efficiency of mixing.
These tuyeres typically consist of a copper tube with a stainless steel outer tube. Also, aluminum or silicon may decarburizafion added to remove oxygen.
American inventions Stainless steel Steelmaking.