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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Process gases are injected through submerged tuyeres that are installed in the side wall or bottom of the converter. In modern practices a sulphur level of 0.
Argon-oxygen decarburization | metallurgy |
After sulphur levels have been achieved the slag is removed from the AOD vessel and the metal bath is ready for tapping. Articles needing additional references from November All articles needing additional references.
Send a question or comment. The slice portion allows the crane to come close to the converter mouth.
Any chromium oxide not reduced by carbon ends up in the slag, which can form a complex spinel. Oxidation of carbon continues, but oxidation of decaburization is limited. 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. Additions of lime are made to dilute the sulphur in the liquid steel bath.
High temperatures at the tuyere tip and high bath agitation place great demands on the converters refractory. This argon dilution minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium.
AOD converter is a pear shaped vessel usually lined with basic argon-oxtgen lining. In the initial stage, oxygen to argon in the ratio ranging from 5: Your email address will not be published. The system accurately controls the flow rates and monitors the amount of gas injected into the bath to enable the operator argob-oxygen control the process and measure the total oxygen injected.
An AOD converter is shown in Fig 1. There are two basic choices of refractory type, magnesite-chromite, and dolomite.
Argon oxygen decarburization
This accretion protects the tuyere and surrounding refractory. An annulus is formed between the copper and stainless tubes. 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 intimate gas — metal contact and excellent decarburiztaion — metal mixing facilitate refining reactions. Annealing Low hydrogen Short circuit.
Smelting Bloomery produces sponge iron Blast furnace produces pig iron Cold blast Hot blast Anthracite iron Direct reduced decaeburization. If necessary, additional raw materials may be charged for atgon-oxygen chemistry adjustments before tapping. AOD process uses dilution technique for the decarburization of steel bath.
The major benefit associated with the dilution process comes into play when the oxygen to inert gas ratio is 1: Bottom blown converters have a variety of tuyere configurations depending on flow rates required.
Argon oxygen decarburization – Wikipedia
Want to modernize and upgrade the functionality of your old AOD system cost-effectively? After sulfur levels have been achieved the slag is removed from the AOD vessel and the metal bath is ready for tapping.
A dfcarburization modification of the AOD process involves the use of top blowing lance in addition to the side blowing tuyeres. The formation of a high basicity slag and the reduction of oxygen potential in the metal bath are good conditions for sulfur removal.
In other projects Wikimedia Commons. Also, aluminum or silicon may be added to remove oxygen. Unsourced material may be challenged and removed. The choice of refractory is dependent on the vessel operation pattern, final product specifications, and economics.
Other trimming alloy additions might be added at the end of the step. The converter in the trunnion ring typically can be replaced with a preheated converter in less than an hour. Converters that tap into a ladle car usually have a BOF type concentric cone top section.