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.
Decarburization occurs when dissolved carbon reduces the chromium and iron oxides that form. Lime and dolomitic lime are sometimes added before the end of the blow to cool the bath and to reduce the volume of reduction additions.
Views Read Edit View history.
It has a removable, conical cover in place. For converters that tap into a ladle held decarburizatiion a crane, a sliced cone top section is often used.
The process is very popular because it combines higher metallic yields with lower material costs. A major modification of the AOD process involves the use of top blowing lance in addition to the side blowing tuyeres.
Special designs exist for normalizing the flow in the annular gap. Additional silicon addition is needed if requirement of silicon is there to meet the silicon specification of some of the stainless steels.
In case of those steel grades which can tolerate nitrogen, a mixture of oxygen and nitrogen can decarburiaation be blown. Sidewall mounted tuyeres are submerged while processing.
Argon oxygen decarburization for metal production
Please help improve this article by adding citations to reliable sources. Haynes International Case Study Video.
Other benefits include pinpoint accuracy in chemistry control down to 0. In the initial stage, oxygen to argon in the ratio ranging from 5: Posted by Satyendra on Apr 28, in Technical 1 comment. The burning of carbon increases the bath decarbruization. Electro-slag remelting Vacuum arc remelting Argon oxygen decarburization. The important feature of an AOD converter is that it is normally side blown.
Argon-oxygen decarburization | metallurgy |
The liquid metal is transferred from transfer ladle to AOD converter. Usually, the converter is turned down to a horizontal position and a sample of the liquid steel is taken for analyses at a carbon level of about 0.
There are usually two to four tuyeres in the bottom. Also, aluminum or silicon may be added to remove oxygen. The desire to increase the productivity has led to continuous charging of raw materials during the blow period as well as reduction period.
After sulfur levels have been achieved the slag is removed from the AOD vessel and the metal bath is ready for tapping. Send a question or comment. Other benefits of AOD process include pinpoint accuracy in chemistry control down to 0.
Tuyere size and number depend on specific process parameters.
Argon Oxygen Decarburization Process |
Praxair can review your system and design an upgrade using: Argom tapped bath is then either sent to a stir station for further chemistry decarbudization or to a caster for casting. While typical BOF refractory campaigns are months or years long, stainless converter campaigns are several days or weeks long.
Oxidation of carbon continues, but oxidation of chromium is limited. AOD converter decarburization refractories Side blown stainless steel. To drive the reaction to the forming of CO, the partial pressure of CO is lowered using argon or nitrogen. This argon dilution minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium.
It provides an economical way to produce stainless steel with a minimum loss of precious elements. Unsourced material may be challenged and removed. November Learn how and when to remove this template message. 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. Designed by Elegant Themes Powered by WordPress.
The key feature in the AOD converter is that oxygen for decarburization is mixed with inert gas such as argon or nitrogen and injected through submerged tuyeres. The ratios can be done in any number of phases to facilitate the reaction.
There are usually between two and nine tuyeres in an AOD vessel. Desulphurization to very low levels is generally easier in dolomitic refractories because very basic slags can be used without detrimental effects on the bricks. For example, with starting sulphur of 0. Donate Grateful for your donation!