Other articles where vacuum oxygen decarburization is discussed. Decarburization occurs when metals are subjected to high temperatures, and the carbon present on the surface reacts with oxygen or hydrogen and diffuses. This page was last edited on 16 august 2018, at 20. Measuring and preventing decarburization in steel paulo. Aod refining argon oxygen decarburization metaltek. Worlds largest argon oxygen decarburization aod unit, 175 ton capacity twin station ladle metallurgy furnace two doublestrand continuous casters slab reheat furnaces and slab conditioning facilities fivestand hot rolling mill anneal and pickle lines electric box annealing furnaces two tandem cold rolling mills. Translation find a translation for argon oxygen decarburization in other languages.
The effect of flow rate of oxygen on decarburization rate, decarburization time, and total oxygen consumption was determined. Needs very high temperatures about 19000 c for decarburization requiring high cost refractories. Our soudoxar lance heads are equipped with laminar flow technology and are the fruit of advanced design and highquality production, to improve. The reaction between carbon and the atmospheric gases usually begins around 700c 1292f. Today, over 75% of the worlds stainless steel is made using the argon oxygen decarburization aod process invented by praxair. Argon oxygen decarburization aod is a decarburizatikn primarily used in stainless steel making and other high grade alloys with oxidizable elements such as chromium and aluminum. Jul 10, 2017 argon oxygen decarburization aod is a process primarily used in production of stainless steel and other high grade alloys such as silicon steels, tool steels, nickelbase alloys and cobaltbase. Argon oxygen decarburization aod what a process for further refinement of stainless steel through reduction of carbon content. Aod abbreviation stands for argon oxygen decarburization. Invesitigation of air entrapment into an argon oxygen decarburization converter at the reduction stage yong tang timo fabritius and jouko harkki laboratory of process metallurgy, university of oulu, fin90014, finland abstract some argon oxygen decarburization aod converter workers found the nitrogen content in the low nitrogen. The mathematical model proposed and presented in part i of the present work has been used to deal with and analyze the austenitic stainless steel making i. It is based on a stepwise comparison of the reaction free energies, and it allows the continuous calculation of the change of the metal, slag, and gas composition throughout the duration of the vod process. Decarburization basics arburization occurs when cardec bon atoms at the steel surface interact with the furnace atmosphere and are removed from the steel as a gaseous phase18. Pdf the oscillation of argon oxygen decarburization aod converters is flow related and depends on the process parameters e.
This process takes place when carbon existing in metals reacts with gases containing hydrogen or oxygen during heating at 700c. Argon oxygen decarburization aod is a process primarily used in stainless steel making and. Aug 29, 2017 one such risk is decarburization, which can weaken steel parts and put them at greater risk of failure during their service. Argon oxygen decarburization aod converter is popularly used in the stainless steel making process. Decarburization is a classic surface degradation phenomenon in the forging and heat treating of steel. The removal of carbon removes hard carbide phases resulting in a softening of the metal, primarily at the surfaces which are in contact with the decarburizing gas. Mathematical modeling of the argonoxygen decarburization refining. It is inevitable that the furnace atmosphere contains oxygen. Decarburization definition of decarburization by the free. Argon oxygen decarburization aod is a process primarily used in production of stainless steel and other high grade alloys such as silicon steels, tool steels, nickelbase alloys and cobaltbase. Several parameters come into play deciding the outcome of the process. Kinetics of decarburization reaction in oxygen steelmaking. Aod argon oxygen decarburization soudobeam has developed a range of oxygen and inert gas topblowing products in stainless steelmaking, for aod argon oxygen decarburization converters. The vod is often used to lower the carbon content of highalloy steels without also overoxidizing such oxidizable alloying elements as chromium.
Decarburization occurs when the metal is heated to temperatures of 700 c or above when carbon in the metal reacts with gases containing oxygen or hydrogen. Modeling of the vacuum oxygen decarburization refining process article pdf available in metallurgical and materials transactions b 311. A mathematical model for reactions during topblowing in. Why the amount of carbon in stainless steel must be lower than that in carbon steel or lower alloy steel i. Invented in the late 1960s, praxairs proprietary argon oxygen decarburization. What is the abbreviation for argon oxygen decarburization. A parabolic relationship was assumed between the decarburization rate and the carbon content c. What is called argon oxygen decarburization aod process.
May 08, 2017 today, over 75% of the worlds stainless steel is made using the argon oxygen decarburization aod process invented by praxair. Therefore, it is valuable to study not only the effect of temperature on depth of decarburization, but also the affect that stable carbide forming and additional alloying elements have on the decarburization response of a particular alloy. All structured data from the file and property namespaces is available under the creative commons cc0 license. Decarburization was controlled by dissociative adsorption of oxygen. Kth optimization of the ao stainless steel processing cost by the ut as system chay tauar 800521t290 the argon oxygen decarburization aod process is one. Argon oxygen decarburization aod treatment is the recognized standard for stainless steel refining worldwide. It is normally used for deep decarburization of ighalloy steel grades usually to remove carbon without affecting chromium content in the production of. More accurately, the chemical potential of carbon in the atmosphere may be lower than that in the steel being heat treated. The argon oxygen decarburization aod process is used to make stainless steel and specialty grades of steel, including tool steels, silicon steels, lowalloy steels, and lowcarbon steels. Pdf modeling of the vacuum oxygen decarburization refining.
Modeling of the vacuum oxygen decarburization refining process. Simulation of oxygen penetration and decarburisation in eaf using supersonic injection system francesco memoli, carlo mapelli, 1 pietro ravanelli 2 and marco corbella. What links here related changes upload file special pages permanent link page. Argon oxygen decarburization, frequently referred to as aod, is an advanced technology for the refinement of iron, nickel, and cobalt based alloys. Argon oxygen decarburization furnace steel slag aod mineralproducts1. The argonoxygen decarburization aod process is the most common process for refining stainless. Modeling of gas flows in steelmaking decarburization processes. Carbon from the interior diffuses towards the surface, moving from high to low concentration and continues until the maximum depth of decarburization is established.
Argon oxygen decarburization aod harbisonwalker international. Practical model to simulate and to operate vacuum oxygen decarburization vod plant for stainless steelmaking conference paper pdf available may 2012 with 1,077 reads how we measure reads. This program has measured the decarburization of 300m alloy steel, as a function of temperature and oxygen concentration, and evaluated the results by way of models based on diffusion of carbon and on the effects of oxidation. Argon oxygen decarburization aod is a process primarily used in stainless steel making and other high grade alloys with oxidizable elements such as chromium and aluminum. The argon oxygen decarburization process total materia article. Our facility our products major production facilities. More specifically, two delaval nozzles from a vod vaccum oxygen decarburization process, which is used for producing stainless steels with ultralow carbon grades, was investigated for different vessel pressures. Control of decarburization of steel paul shefsiek introduction historically, heating steel for forming, forging or rolling, was done in electrical resistance or natural gas heated furnaces. For high carbon melts at low partial pressures of oxygen, the decarburization rate was found to be independent of gas flow rate and was a linear function of oxygen partial pressure. May 06, 2016 argon oxygen decarburization furnace steel slag aod mineralproducts1. A comparison study on depth of decarburization and the role. Jun 01, 2018 decarburization normally takes place when steel goes through the heating process in an environment where oxygen is present, resulting in loss of carbon and oxidation. The new source performance standards nsps for steel plants. Pdf simulation of fluid flow and oscillation of the argon oxygen.
Optimization of the ao stainless steel processing cost by the ut as system chay tauar 800521t290 the argon oxygen decarburization aod process is one of the major stainless steel refining routes. A dynamic model for the vacuum oxygen decarburization vod refining process is presented. Theres even an industry standard astm e1077 dedicated to decarburization depth measurement. During heat treatment of metals, decarburization happens as a side effect, which is undesirable. Argon oxygen decarburization furnace steel slag aod. Aod process was first used exclusively for stainless steel production. In a controlled trial, 7 samples were decarburized and results measured for both low oxygen level atmospheres and air table 1. Argon oxygen decarburization aod is a process primarily used in steelmaking foundries and other highgrade alloys with oxidizable elements such as chrome and aluminum. In the argonoxygen decarburization process, a mixture of oxygen and argon gas is injected into the liquid steel.
Argon oxygen decarburization aod is a unique refinement process for iron, nickel, and cobalt alloys whereby huge quality and efficiency gains can be made. Aod, argon oxygen decarburization, refining provides tight chemistry control and high levels of metal purity for your application. After initial melting the metal is then transferred to an aod vessel where it will be subjected to three steps of refining. By using only eaf for the production of stainless steel the following difficulties were arise. Argon oxygen decarburization furnace steel slag aod youtube. Preventing decarburization in steel requires metallurgists and their customers to pay attention to the details. The installation of a lance and introduction of oxygen in the early stages of decarburization can reduce the time for a heat. Argon oxygen decarburization converter aod tuyer pipe. Learn more about praxairs argon oxygen decarburization process that is used to make over 75% of the worlds stainless steel. In the production of stainless steel and other highalloy grades that contain highly oxidizable elements such as chromium, lowering the levels of carbon by regular oxygen injection has the undesirable consequence of oxidizing the alloying elements as well. It was inevitable that these furnaces contained oxygen and decarburization of the steel surface occurred. In this process the tuyeres are submerged, resulting in high element recovery, rapid and efficient desulfurization, and good control of the slag chemistry. Due to the reduced co partial pressure under vacuum conditions, decarburisation of highalloyed steel grades to very low carbon contents is possible. Electric arc furnaces eafs and argonoxygen decarburization.
Modeling of the vacuum oxygen decarburization refining. The plant is basically designed as a tank degassing plant which is additionally equipped with an oxygen blowing lance and other related equipment. Astm e1077 14 standard test methods for estimating the. Decarburization occurs if carbon atoms in the heated steel component have both a a mechanism for migrating and b a desire to migrate to the surface. Through the management of an additional high oxygen partial pressure gas mix and argon, the metal is refined and can reduce carbon levels to 0. This introduction causes significant agitation and, therefore, intimate slagmetal contact. Vacuum oxygen decarburization metallurgy britannica. Electric arc furnaces and argon oxygen decarburization vessels were proposed on october 21, 1974, promulgated on september 23, 1975, and mostrecently amended on february 22, 2005. In an aod, metal is subjected to three steps of refining.
If decarburization is occurring, then a continuous surface layer of soft ferrite is being produced together with ferrite formation around austenite grains further away from the surface. Aod provides an economical way to produce stainless steel with a minimal loss of precious elements. This ingot refining process produces steel with low carbon properties. Rhamdhani swinburne university of technology, hawthorn, vic 3122 australia key words. Files are available under licenses specified on their description page. Recovery of valuable metals from argon oxygen decarburization aod dusts by leaching, filtration and solvent extraction. A new method is used to calculate the oxygen distribution in the metalgas reactions. May 06, 2016 decarburization is not only dependent on the presence of oxygen but also the interaction with other oxidizing gases in the atmosphere, most notably water vapor and carbon dioxide.
The chemical composition of steel m0 is approximately fe0. Optimization of the ao stainless steel processing cost by. Argonoxygen decarburization aod engineering dictionary. Pdf practical model to simulate and to operate vacuum.
Kinetics of decarburization reaction in oxygen steelmaking process neslihan dogan, geoffrey a. Obtained 1045, and steel placed in furnace at 1700 deg. Simulation of oxygen penetration and decarburisation in eaf. Astm e107714, standard test methods for estimating the depth of decarburization of steel specimens, astm international, west conshohocken, pa, 2014. Aod provides an economical way to produce stainless steel with a. Optimization of the ao stainless steel processing cost by the. Carbon will therefore be removed from the steel by the process commonly known as decarburization. Exclude inputs or outputs that can be documented to contribute less than 1 percent of the total mass of carbon into or out of the process.
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