Carbonation of argon oxygen decarburization stainless steel slag and its effect on chromium leachability. Several parameters come into play deciding the outcome of the. Argon oxygen decarburization converter manufacturer from. The argon oxygen decarburisation aod and the vacuum oxygen decarburisation vod processes are the. Unlimited viewing of the articlechapter pdf and any associated. Mathematical modeling of the argonoxygen decarburization refining. Metal refining with argon oxygen decarburization aod. 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 file is licensed under the creative commons attributionshare alike 2. Ladle service under the conditions of vacuum oxygen decarburization 187 a were mainly wom in the slag line. Aod provides an economical way to produce stainless steel with a. The key feature in the aod vessel is that oxygen for decarburization is mixed with argon or nitrogen inert gases and injected through submerged tuyeres.
Argon oxygen decarburization aod is a process primarily used in stainless steel making and. Recovery of valuable metals from argon oxygen decarburization. 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. Blowing argon and oxygen, using sheets, maintain a continuous mixing. By using only eaf for the production of stainless steel the following difficulties were arise. This page was decarburisation edited on 4 octoberat during the final stage of blowing, the ratio of oxygen to argon is changed to 1. Metal refining with argon oxygen decarburization aod refining systems allow precise gas manipulation to achieve the desired end result. Argon is colorless, odorless, nonflammable and nontoxic as a solid, liquid or gas. Eaf followed by refining by argon oxygen decarburization aod to adjust the carbon content and remove impurities. Pdf the oscillation of argon oxygen decarburization aod converters is flow related and depends on the process parameters e. 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.
In this process the tuyeres are submerged, resulting in high element recovery, rapid and efficient desulfurization, and good control of the slag chemistry. 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 alloys with oxidizable elements such as chromium and aluminum. Vcvacuum casting device steelmaking dedusting ironmaking dedusting material handling dedusting dedusting facilitie. Why the amount of carbon in stainless steel must be lower than that in carbon steel or lower alloy steel i. Argon oxygen decarburization aod converter slags are known to consist of both liquid and solid phases, but limited information on the slag characteristics has been published in the open literature. Chemical analysis of argonoxygen decarburization slags in. Vodvacuum oxygen decarburization aod argon oxygen decarburization vodvacuum oxygen decarburization.
Physical and mathematical modeling of the argonoxygen decarburization refining process of stainless steel. Invented in the late 1960s, praxair s proprietary argon oxygen decarburization aod process was first used exclusively for stainless steel production. Modeling of gas flows in steelmaking decarburization. Resourcesaving operation of stainless steel refining in vod and. Pdf simulation of fluid flow and oscillation of the. This argon dilution minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium. The aod process argon, oxygen, decarburization is the first production process for stainless steel grades in which the treatment time in a converter under atmospheric conditions corresponds to the casting time of a slab caster for many steel grades. In the argonoxygen decarburization process, a mixture of oxygen and argon gas is injected into the liquid steel. Argon oxygen decarburization aod treatment is the recognized standard for stainless steel refining worldwide. Argonoxygen decarburization aod what a process for further refinement of stainless steel through reduction of carbon content. Decarburization or decarbonization is the process opposite to carburization, namely the reduction of carbon content the term is typically used in metallurgy, describing the reduction of the content of carbon in metals usually steel. Melting and refining of stainless steels is, however, most frequently.
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. The erosion of this zone amounted to 20 mm per heat. In a second and third embodiment, the invention is directed to a method for recovering argon from a feed mixture comprising argon, carbon monoxide, carbon dioxide, nitrogen, and oxygen, wherein oxygen is removed from the argon rich fraction exiting the pressure swing adsorption system in step c by passing the fraction to a second pressure. Argon oxygen decarburization for metal production praxair, inc. It brings the tightest chemistry control to deliver the highest levels of metal purity.
Recovery of valuable metals from argon oxygen decarburization aod dusts by. After initial melting the metal is then transferred to an aod vessel where it will be subjected to three steps of refining. After 3 4 heats, through slots formed in the joints of the bricks as well as ovalshaped washouts through which the metal leaked between the functional and the intermediate layer. Some available mathematical models for the argonoxygen decarburization aod stainless steelmaking process have. Argon oxygen decarburization aod is used during the refining process to produce steel with low carbon properties and low silicon levels, while creating a metal more weldable and more corrosion and heat resistant. 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. Carbon from the interior diffuses towards the surface, moving from high to low concentration and continues until the maximum depth of decarburization is established. In the aod process, steel from the eaf is transferred into an aod vessel and gaseous mixtures containing argon and oxygen or. Pdf simulation of fluid flow and oscillation of the argon oxygen. In the aod process, steel from the eaf is transferred into an aod vessel and gaseous mixtures containing argon and. The argon oxygen decarburization process total materia.
Argon oxygen decarburization aod converter is popularly used in the stainless steel making process. Author links open overlay panel yajun wang a b yanan zeng b junguo li b yuzhu zhang a b yajing zhang c qingzhong zhao b. Product center success case project gallery download recruitment. Subsequently, the liquid passes to the converter, within which the steel undergoes the refining chemical analysis through redox reactions. Not only decarburization, you could also find another pics such as measurement, steel, argon oxygen, surface after heat treat, diagram, press hardened steel, type 2, vacuum oxygen, praxair argon oxygen, imperfections, microstructure, and vd tank. Two industrial vod nozzles were numerically studied and compared at different temperatures and ambient pressures. This process permits the production of high chromium steels and alloys in a technically and commercially advantageous way extremely low carbon contents together with high chromium recovery, with minimal consumption. Alternative, melting and refining steps include vacuum induction melting, vacuum arc remelting, electroslag remelting, and electron beam melting. Since stainless steels need to be further refined, oxygen, gradually replaced by argon, is blown through the molten steel to eliminate impurities. The process of deep decarburization of steel during argon or hydrogen argon mixture injection has been studied. Ladle service under the conditions of vacuumoxygen. Argon oxygen decarburization furnace steel slag aod.
Download fulltext pdf simulation of fluid flow and oscillation of the argon oxygen decarburization aod process article pdf available in metallurgical and materials transactions b 412. Decarburization is a loss of carbon in the surfaceadjacent zone of the material gunnarson, 1963. Mathematical modeling of the argon oxygen decarburization. Chemical analysis of argon oxygen decarburization slags in stainless steelmaking process by x. Argon oxygen decarburization furnace steel slag aod mineralproducts1. Carbonation of argon oxygen decarburization stainless. The new source performance standards nsps for steel plants.
In the argon oxygen decarburization process, a mixture of oxygen and argon gas is injected into the liquid steel. 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. D this process is mainly used for making stainless steel only of 304l, 316l grade to achieve extra low carbon content in stainless steel. You may do so in any reasonable manner, but not in. Figure 1 shows a typical vod stainless steel production furnace. Argon has approximately the same solubility in water as oxygen and is 2. By varying the ratio of oxygen and argon, it is possible to remove carbon to controlled levels by oxidizing it to carbon monoxide without also oxidizing and losing expensive. Learn more about praxairs argon oxygen decarburization process that is used to make over 75% of the worlds stainless steel.
Physical and mathematical modeling of the argonoxygen. Argon oxygen decarburization, frequently referred to as aod, is an advanced technology for the refinement of iron, nickel, and cobalt based alloys. Contributing factors are high temperatures and large amounts of oxygen in the atmosphere. Aod production argon oxygen decarburization in this process the merger is implemented in conventional furnace. View the article pdf and any associated supplements and figures for a period of 48 hours. This introduction causes significant agitation and, therefore, intimate slagmetal contact. At higher temperatures, the diffusion rate of carbon is so large that longer annealing times lead to decarburization. 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 alloys with oxidizable elements such as.
A decarburization process based on a stepwise decrease of the oxygen to inert ratio according to table 1 was gradually established. The present invention is directed to a method for recovering argon from a feed mixture comprising argon, carbon monoxide, carbon dioxide, nitrogen, and hydrogen which comprises the steps of a purifying the feed mixture to remove contaminants, b compressing the purified feed mixture to a separation pressure, and c passing the compressed purified feed mixture through a pressure swing. Optimization of the ao stainless steel processing cost by. Argon oxygen decarburization, frequently referred to as aod, is an advanced technology. Argon is chemically inert under most conditions and forms no confirmed stable compounds at room temperature although argon is a noble gas, it can form some compounds under various extreme conditions.
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. This work led to the first commercial aod installation in joslyn, usa 1968 1. Recovery of valuable metals from argon oxygen decarburization aod dusts. Mathematical modeling of the argonoxygen decarburization refining process of stainless steel. Needs very high temperatures about 19000 c for decarburization requiring high cost refractories. An argon oxygen decarburization aod refining method for molten austenitic stainless steel. Aod, argon oxygen decarburization, is a process for making stainless steel and other high grade alloys by allowing precise gas manipulation. 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 process primarily used in stainless steelmaking and other high grade alloys with oxidizable elements such as chromium and aluminum.
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