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. After a certain carbon level is achieved, the nitrogen gas is replaced by argon.
Argon Oxygen Decarburization Process
Desulphurization is achieved by having a high lime concentration in decarburizayion slag and a low oxygen activity in the metal bath. The formation of high basic slag and the reduction of oxygen potential in the liquid steel bath are good conditions for sulphur removal. In modern practices a sulphur level of 0. Since the blowing is done along with argon it is oxxygen to carry out the decarburization at a lower temperature. Posted by Satyendra on Kxygen 28, in Technical 1 comment.
It has a removable, conical cover in place. The formation of a high basicity slag and the reduction of oxygen potential in the metal bath are good conditions for sulfur removal.
This argon dilution minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium. Dolomitic refractories are usually less costly than magnesite chromite refractories and chromium pickup is not a factor.
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For example, with a start sulphur of 0. At this point, the process gases can be shut off and a small cooling flow protects the tuyeres.
An AOD converter is shown in Fig 1. 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.
This argno due to the very low oxygen potential of the gas mixture, which minimizes chromium oxidation. Magnesite chromite refractories have high wear resistance but have a higher unit cost than dolomitic refractories. High wear areas of the converter, usually the tuyere wall, slag oxtgen, and transfer pad are zoned thicker and with higher quality refractory than other parts of the converter. Additional silicon addition is needed if requirement of silicon is there to meet the silicon specification of some of the stainless steels.
Smelting Bloomery produces sponge iron Blast furnace produces pig iron Cold blast Hot blast Anthracite iron Direct reduced iron.
Metal Refining with Argon Oxygen Decarburization (AOD) Refining Systems – Inductotherm Corp.
In general, the bath temperature is controlled to less than deg C. The top lance can also be designed for blowing mixed gases such as inert gas — oxygen mixtures. There are two basic choices of refractory type, magnesite-chromite, and dolomite. AOD process refining has three major steps.
Argon oxygen decarburization
The oxyggen will be tailored to match your current operation with added features found only on the new systems. Donate Grateful for your donation!
At any given time, one of the converters is in the tiltable trunnion ring refining steel, a second newly lined converter is at a preheating station, and the third converter is at a reline station.
The reduction mix also includes lime CaO and fluorspar CaF 2. Low hydrogen Short circuit. After initial melting the metal is then transferred to an AOD vessel where it will be subjected to three steps of refining; decarburizationreductionand desulphurization.
Argon-oxygen decarburization | metallurgy |
The decarburization reactions are as follow. After the transfer of liquid steel containing iron, chromium, carbon and nickel from EAF or IF to the AOD converter, high carbon ferro chrome is added and the blow is started with the blowing of inert gas argon, nitrogen and oxygen mixture. Refractory costs are a significant fraction of total operating costs. The decarburization step is controlled by ratios of oxygen to argon or nitrogen to remove the carbon from the metal bath.
Praxair can oxygeb a server-only option for these systems. Converters are typically zoned by thickness and brick quality to maximize lining life and minimize costs.
As molten stainless steels do not generate foam, and most stainless steel refining processes are side or bottom-blown, the dimensions of a stainless refining converter are smaller than a comparable BOF basic oxygen furnace converter.