Altech specialty steel corporation, albany, new york u. The ratio is lowered with the progress of the decarburization. Electric arc furnaces and argon oxygen decarburization vessels in steel plants. In the initial stage, oxygen to argon in the ratio ranging from 5. 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. The tuyeres consist of two concentric steel tubes, with the inert gas flowing in the outer annulus and oxygen. Steel melt processing casting handbooks asm international. The argon oxygen decarburization aod process is used to make stainless steel and. Research on relationship model of dephosphorization efficiency.
This introduction causes significant agitation and, therefore, intimate slagmetal contact. Argon oxygen decarburization news newspapers books scholar jstor november 2010 learn how and when to remove this. Since the blowing is done along with argon it is possible to carry out the decarburization at a lower temperature. Electric arc furnace, revision argon oxygen decarburiztion. Some foundries have installed aod units to achieve some of the results that vacuum melting can produce. Carpenter technology corporation, reading, pennsylvania u. May 08, 2017 today, over 75% of the worlds stainless steel is made using the argon oxygen decarburization aod process invented by praxair. Most of the material melted in regal casts induction furnaces is virgin metal, which consists of commercially pure forms of the specified metal. 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. 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. Several parameters come into play deciding the outcome of the.
Our applications engineers can help you determine the proper flow and pressure control needed for each gas to help you achieve consistent results and optimal tuyere life. Two industrial vod nozzles were numerically studied and compared at different temperatures and ambient pressures. 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. Argon oxygen decarburization air products offers a full line of industrial gases, including argon, nitrogen and argon to assist with your aod operations. Beginning in the 1970s, these stainless steels have grown in number and in technical and commercial importance. After initial melting the metal is then transferred to an aod vessel where it will be subjected to three steps of refi ning. Mathematical modeling of the argonoxygen decarburization. The history of stainless steel is dedicated to my dear wife joan inman cobb.
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. Physical and mathematical modeling of the argonoxygen. Damascus steel was the forged steel of the blades of swords smithed in the near east from ingots of wootz steel imported from southern india and tamraparni. This argon dilution minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium. Aod provides an efficient way to produce consistent.
The new source performance standards nsps for steel plants. Aod abbreviation stands for argon oxygen decarburization. The reaction between carbon and the atmospheric gases usually begins around 700c 1292f. In the argonoxygendecarburization aod process, the liquid steel is tapped from the furnace into a ladle.
Gas supply modes include bulk deliveries, cylinders and onsite production units operated by air liquide. Theoretical models have been developed for an argon oxygen decarburization aod converter that also incorporated a thermodynamic description of the process 238. Hot metal pretreatment before entry into oxygen steelmaking is employed in. The largest commercial steelmaking enterprise, nippon steel in japan, was responsible for producing 26 million tons in 1987, and 11. The ladle metallurgy includes vacuum induction degassing, vacuum oxygen decarburization, and vacuum ladle degassing. Aod argon oxygen decarburization meltshop365 aod intelligent process automation for aod converters meltshop365 for aod, vodc and mrp converter ensures reproducible and documented quality and efficient and ergonomic use of resources through intelligent process automation. Learn more about praxairs argon oxygen decarburization process that is used to make over 75% of the worlds stainless steel. Needs very high temperatures about 19000 c for decarburization requiring high cost refractories. The converter metallurgy includes melt refinement in argon oxygen decarburization aod vessels and vacuum oxygen decarburization vodc in a converter vessel. Pdf simulation of fluid flow and oscillation of the. When refining stainless steel, inert gasesar, n2 are blown in at the same time as oxygen is under standard atmospheric pressure. 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. By using only eaf for the production of stainless steel the following difficulties were arise. Argon oxygen decarburization wikimili, the best wikipedia.
Our applications engineers can help you determine the proper flow and pressure control needed for each gas to. Argon oxygen decarburization aod converter slags are known to. These swords are characterized by distinctive patterns of banding and mottling reminiscent of flowing water, or in a ladder or teardrop pattern. To minimize cost, argon is sometimes replaced by nitrogen or compressed air at the beginning of the blow. Buy electric arc furnace, revision argon oxygen decarburization.
Argon oxygen decarburization aod continuous casting 4500ton forge press sx65 rotary forge sx32 rotary forge inline cogging mills ho tr o llin g wire rolling mills bar rolling mills custom lotmills handmills tocarpenter servicecenters directlyto customers millorders distributio n cold finishing largebar finishing bar finishing wire. The steel industry has grown from ancient times, when a few men may have operated, periodically, a small furnace producing 10 kilograms, to the modern integrated iron and steelworks, with annual steel production of about 1 million tons. Contributing factors are high temperatures and large amounts of oxygen in the atmosphere. The argonoxygen decarburization aod process alleviates this problem by diluting the injected. Decarburization occurs when metals are subjected to high temperatures, and the carbon present on the surface reacts with oxygen or hydrogen and diffuses. Argon oxygen decarburization aod harbisonwalker international. Air products offers a full line of industrial gases, including nitrogen and argon to assist with your argonoxygen decarburization aod operations. Either argon oxygen gas mixture or pure argon is blown into the steel through tuyeres in or near the bottom of the vessel. In the argonoxygen decarburization process, a mixture of oxygen and argon gas is injected into the liquid steel. Decarburization is a surface degradation phenomenon in the forging and heat treating of steels. Today, over 75% of the worlds stainless steel is made using the argon oxygen decarburization aod process invented by praxair. Argon oxygen decarburization for metal production praxair.
Modeling of gas flows in steelmaking decarburization processes. More details about the history, development, and categories of converter. Argon oxygen decarburization furnace steel slag aod. All structured data from the file and property namespaces is available under the creative commons cc0 license. At higher temperatures, the diffusion rate of carbon is so large that longer annealing times lead to decarburization.
This book provides an introduction to these steels. Argon oxygen decarburization aod what a process for further refinement of stainless steel through reduction of carbon content. Decarburization is a loss of carbon in the surfaceadjacent zone of the material gunnarson, 1963. Why the amount of carbon in stainless steel must be lower than that in carbon steel or lower alloy steel i. In the argon oxygen decarburization aod process, the liquid steel is tapped from the furnace into a ladle and then pored into the aod vessel.
For the history of western and eastern science, see science, history of. Argon oxygen decarburization aod we supply industrial gases, related equipment, and services to steel manufacturers for argon oxygen decarburization aod. Electric arc furnace, revision argon oxygen decarburization. The taptotap time is about two hours, and consumption of oxygen and argon is about 25 and 20 cubic metres, respectively, per ton of steel. The latest advances made by the author with his research group have been summarized. 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. The argon oxygen decarburization aod process alleviates this problem by diluting the injected. Gas supply modes include pipeline, bulk deliveries, cylinders, and onsite production units operated by air liquide. Argonoxygen decarburization air products and chemicals.
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. Aod slag is a kind of alkaline material characterized by a dominance of cabearing silicate phases, and the minerals include. 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. Argon oxygen decarburization aod is a process primarily used in stainless steel making and.
Refractory wear increases at a rate proportional to the increased production rate when watercooled panels are not used. The oscillation of argon oxygen decarburization aod converters is flow related and depends on the process parameters e. Manufacturer of steel and steel products in welland, ontario. Vam book is also a good source of handling practices for vam connections.
During heat treatment of metals, decarburization happens as a side effect, which is undesirable. The company offers carbon, alloy and stainless steel, bloom products, cylindrical forging ingots, steel casting and refining methods, including argon oxygen decarburization, vacuum oxygen decarburization, vacuum degassing and ladle metallurgical station. It brings the tightest chemistry control to deliver the highest levels of metal purity. Argon oxygen decarburization wikipedia republished wiki 2. May 06, 2016 this feature is not available right now.
Carbonation of argon oxygen decarburization stainless. Background information for promulgated standards u. Modeling of gas flows in steelmaking decarburization. Even other modified converter processes like sideblown aod argon oxygen decarburization converter and vodc vacuum oxygen. Argon oxygen decarburiza tio n aod is a process primarily used in stainless steel making and other high grade alloys with oxidizable elements such as chromium and aluminum. Argon oxygen decarburization aod air liquide supplies industrial gases and related equipment and services to steel manufacturers for argon oxygen decarburization aod. Decarburization article about decarburization by the.
Electric arc furnaces and argonoxygen decarburization vessels in steel industry. Electric arc furnaces eafs and argonoxygen decarburization. Argonoxygen decarburization air products offers a full line of industrial gases, including argon, nitrogen and argon to assist with your aod operations. Melting and refining of stainless steels is, however, most frequently. 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. Metals steel making argon oxygen decarburization aod. Argon oxygen decarburization nonvacuum argon bubbling electro. Argon oxygen decarburization furnace steel slag aod youtube. Optimization of the ao stainless steel processing cost by. Basic oxygen process an overview sciencedirect topics. Rita khanna, veena sahajwalla, in treatise on process metallurgy. Aod argon oxygen decarburization process developed in 1967 and patented by william a. The aod process is carried out in a refractorylined converter similar to the bof but with two to six argon oxygen tuyeres installed in the lower side wall.
Even other modified converter processes like side blown aod argon oxygen decarburization converter and vodc vacuum oxygen. Decarburization article about decarburization by the free. Background information for proposed revisions to standards, preliminary draft u. Choose a language from the menu above to view a computertranslated version of this page. Carpenter technology corporation, reading, pennsylvania on free shipping on qualified orders. Argon oxygen decarburization aod slag, which is generated during the stainlesssteel refining process, is a byproduct of the steel industry li et al. Decarburization may be described as a metallurgical process in which the surface of steel is depleted of carbon, by heating above the lower critical temperature or by chemical action. A mixture of argon and oxygen is blown from the bottom of the vessel through the melted steel. Water injection environments featuring presence of dissolved oxygen.
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. Eaf followed by refining by argon oxygen decarburization aod to adjust the carbon content and remove impurities. Aod refining argon oxygen decarburization metaltek. After initial melting the metal is then transferred to an aod vessel where it will be subjected to three steps of refining. Electric arc furnaces and argonoxygen decarburization vessels constructed after august 17, 1983.
Cleaning agents are added to the vessel along with these gases to eliminate impurities, while the oxygen combines with carbon in the unrefined steel to reduce the carbon level. This ingot refining process produces steel with low carbon properties. Water modeling was used to investigate the fluid flow and mixing characteristics in the bath of an 18 t aod vessel, as well as the backattack. Aod is a kind of smelting equipment where final deoxidization and alloying of liquid steel take place. Pdf simulation of fluid flow and oscillation of the argon.
Jun 22, 2017 an aspect of the present disclosure may provide an argon oxygen decarburization aod refining method for molten austenitic stainless steel and, more particularly, to an argon oxygen decarburization aod refining method capable of reducing carbon and nitrogen in molten austenitic stainless steel in aod refinement. Files are available under licenses specified on their description page. Alternative, melting and refining steps include vacuum induction melting, vacuum arc remelting, electroslag remelting, and electron beam melting. Aod, argon oxygen decarburization, refining provides tight chemistry control and high levels of metal purity for your application. The history and development is quite extensively summarized in the the. 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. The term is typically used in metallurgy, describing the reduction of the content of carbon in metals usually steel. The actual situations of the aod process, including the competitive oxidation of the elements dissolved in the molten steel and the changes in the bath composition, as well as the nonisothermal nature of the process, have been analyzed. Electric arc furnaces and argonoxygen decarburization. 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. A key component in our argon oxygen decarburization aod technology, argon is used to create over 75% of the worlds stainless steel.
Praxairs argon helps produce stainless steel appliances and cookware for your precious, stainfilled memories. Innovations in refining process technique combined blowing. Argonoxygen decarburization aod engineering dictionary. Argon oxygen decarburization aod and continuous casting cc steelmaking slags, with calcium oxide contents of 56. In the argon oxygen argon oxygen decarburization, aod method refining medium and low carbon ferrochrome process, the slag basicity is one of the. Electric arc furnaces and argon oxygen decarburization vessels were proposed on october 21, 1974, promulgated on september 23, 1975, and. Simulation of fluid flow and oscillation of the argon oxygen decarburization aod process article pdf available in metallurgical and materials transactions b 412. Text within images is not translated, some features may not work properly after translation, and the translation may not accurately convey the intended meaning. Environmental protection agency epa was introduced on december 2, 1970 by president richard nixon. In this process the tuyeres are submerged, resulting in high element recovery, rapid and efficient desulfurization, and good control of the slag chemistry. History of stainless steel melting and refining the wild process the rustless process the linde argon oxygen decarburization aod process 11. What is called argon oxygen decarburization aod process. Two new classes of stainless steel duplex stainless steel precipitationhardening steel 12.
Argon oxygen decarburization for metal production praxair, inc. Other articles where argonoxygen decarburization is discussed. 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. Aod provides an economical way to produce stainless steel with a.
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