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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There are usually two to four tuyeres in the bottom.
Argon Oxygen Decarburization Process |
In modern practices a sulphur argn of 0. Also, aluminum or silicon may be added to remove oxygen. At this point, the process gases can be shut off and a small cooling flow protects the tuyeres. Phosphorus, which requires oxidizing conditions, cannot be removed in the converter processing.
Bloomery produces sponge iron Blast furnace produces pig iron Cold blast Hot blast Anthracite iron Direct reduced iron. Converters are typically zoned by thickness and brick quality to maximize lining life and minimize costs. The next step is the reduction step, in which the reduction additions are charged and stirred with an inert gas for a desired time. Please help improve this article by adding citations to reliable sources.
Bessemer process Open hearth furnace Electric arc furnace Basic oxygen process. Other trimming alloy additions might be added at the end of the step.
Argon Oxygen Decarburization for Metal Production | Praxair, Inc.
High wear areas of the converter, usually the tuyere defarburization, slag line, and transfer pad are zoned thicker and with higher quality refractory than other parts of the converter. Volatile elements with high vapour pressures, such as lead, zinc, and bismuth, are removed during the decarburization period. For example, with starting sulphur of 0. AOD converter decarburization refractories Side blown stainless steel.
Annealing Low hydrogen Short circuit. Bottom injection usually improves wear characteristics in the barrel section of the converter. 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. An AOD converter is shown in Fig 1. Desulphurization is achieved by having a high lime concentration in the slag and a low oxygen activity in the metal bath.
Converters that tap into a ladle car usually have a BOF type decsrburization cone top section. The formation of a high basicity slag and the reduction of oxygen potential in the metal bath are good conditions for sulfur removal. It is part of a duplex process in which scrap or virgin raw materials are first melted in an electric arc furnace EAF or induction furnace.
Argon oxygen decarburization for metal production
Also, aluminum or silicon may be added to remove oxygen. The decarburization step is controlled by ratios of oxygen to argon or nitrogen to remove the carbon from the metal bath. The ratios can be done in any number of phases to facilitate the reaction. Articles needing additional references from November All articles needing additional references. Side wall injection usually imparts maximum stirring energy to the bath for greatest efficiency of mixing. Desulphurization to very low levels is generally easier in dolomitic refractories because very basic slags can be used without detrimental effects on the bricks.
AOD converter is a pear shaped vessel usually lined with basic refractory lining. 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.
AOD provides an economical way to produce stainless steel with a minimal loss of precious elements. The length of the blow period is determined by the starting carbon and silicon levels of the hot metal charged to the AOD converter. Reduction recovers the oxidized elements such as chromium from the slag.
The system accurately controls the flow rates decargurization monitors the amount of gas injected into the bath to enable the operator to control the process and measure the total oxygen injected. An annulus is formed between the copper and stainless tubes.