ARGON OXYGEN DECARBURIZATION PDF
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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Argon Oxygen Decarburization Process
After a desired carbon and temperature level have been reached the process moves to reduction. To drive the reaction to the forming of CO, the partial pressure of CO is lowered using argon or nitrogen. The choice of refractory is dependent on the vessel operation pattern, final product specifications, and economics.
So, additions of lime are added to dilute sulfur in the metal bath.
Argon oxygen decarburization – Wikipedia
History of ferrous metallurgy Argom of steel producers. The installation of a lance and introduction of oxygen in the early stages of decarburization can reduce the time for a heat. Pattern welding Damascus steel Crucible steel Tatara furnace Cementation process. If the grade to be produced requires an extra low sulphur level, the bath is deslagged after the reduction step and another basic slag is added.
For converters that dearburization into a ladle held by a crane, a sliced cone top section is often used.
Argon Oxygen Decarburization for Metal Production | Praxair, Inc.
Since the blowing is done along with argon it is possible to carry out the decarburization at a lower temperature. Most of the recent converter decatburization include the use of a top lance for blowing oxygen.
These are i decarburization, ii reduction, and iii final chemistry and temperature trimming. During the oxygen blow, silicon is oxidized before carbon. AOD is widely used for the production of stainless steels and specialty alloys such as silicon steels, tool steels, nickel-base alloys and cobalt-base alloys. The AOD converter can be rotated downwards so that the side mounted tuyeres are above the bath level during charging of the liquid steel.
Desulphurization to very low levels is generally easier in dolomitic refractories because very basic slags can be used without detrimental effects on the bricks.
This article needs additional citations for verification. The molten metal is then decarburized and refined in an AOD converter to less than 0. Reduction recovers the oxidized elements such as chromium from the slag. Donate Grateful for your donation! Cooling gases decarbudization through the outer annulus shroud form a metal or oxide accretion called a mushroom at the tuyere tip. decarburizaion
There are two basic choices of refractory type, magnesite-chromite, and dolomite. These additions usually consist of desired amounts of high carbon ferrochromium, stainless steel scrap, carbon steel scrap, decarvurization, iron, high carbon ferromanganese, and molybdenum oxide. Dolomitic refractories are usually less costly than magnesite chromite refractories and chromium pickup is not a factor.
Process gases are injected through submerged tuyeres that are installed in the side wall or bottom of the converter. Tuyere size and number depend on specific process decarburizaion.
The end result is a cleaner metal coupled with increased productivity. American inventions Stainless steel Steelmaking.
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.
Other benefits of AOD process include pinpoint accuracy in chemistry control down to 0. Posted by Satyendra on Apr 28, in Technical 1 comment. If necessary, additional raw materials may be charged for small chemistry adjustments before tapping. It is part of a duplex process in which scrap or virgin raw materials are first melted in an arhon arc furnace EAF or induction furnace.
Side wall injection usually imparts maximum stirring energy to the bath for greatest efficiency of mixing. This is done in a ladle equipped with stirring facilities with or without the use of a ladle furnace. The process is very popular because it combines decarburiization metallic yields with lower material costs. Oxygeen desire to increase the productivity has led to continuous charging of raw materials during the blow period ocygen well as reduction period.
Decarburization time ranges from 20 to 35 minutes in modern converters start from 1. Other trimming alloy additions might be added at the end of the step.