Vacuum oxygen decarburization metallurgy britannica. Abstractthe process of deep decarburization of steel during argon or hydrogen argon mixture injection has been studied. Argonoxygen decarburization air products offers a full line of industrial gases, including argon, nitrogen and argon to assist with your aod operations. A comparison study on depth of decarburization and the. 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. Two industrial vod nozzles were numerically studied and compared at different temperatures and ambient pressures. This process takes place when carbon existing in metals reacts with gases containing hydrogen or oxygen during heating at 700c. The vod is often used to lower the carbon content of highalloy steels without also overoxidizing such oxidizable alloying elements as chromium. This ingot refining process produces steel with low carbon properties. Optimization of the ao stainless steel processing cost by the.
So that, based on the pressuredependent equilibrium relationship %c x %o 0. 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. Argon oxygen decarburization aod treatment is the recognized standard for stainless steel refining worldwide. Recovery of valuable metals from argon oxygen decarburization. Decarburization definition of decarburization by the. Convertor through high blowing rate tuyers along with oxygen top lance for good mixing effect and excellent heat efficiency. Argon oxygen decarburization aod and continuous casting cc steelmaking slags, with calcium oxide contents of 56. Argon oxygen decarburization converter manufacturer from. Aod, argon oxygen decarburization, refining provides tight chemistry control and high levels of metal purity for your application. 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.
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. Step 3either electroslag remelting esr, electroflux remelting efr or vacuum arc remelting var. The list of acronyms and abbreviations related to aod argon oxygen decarburization. Pdf simulation of fluid flow and oscillation of the argon oxygen. This file is licensed under the creative commons attributionshare alike 2.
May 06, 2016 argon oxygen decarburization furnace steel slag aod mineralproducts1. 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. Decarburization article about decarburization by the free. Ladle service under the conditions of vacuumoxygen. The argon oxygen decarburization aod process is used to make stainless steel and. The latest advances made by the author with his research group have been summarized. Batch leaching of dusts with concentrated h 2 so 4 was found to be difficult to optimize for yields for the target metals zn and mo, while keeping fe. Translation find a translation for argon oxygen decarburization in other languages. 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. In the aod process, steel from the eaf is transferred into an aod vessel and gaseous mixtures containing argon and. Metal refining with argon oxygen decarburization aod refining systems allow precise gas manipulation to achieve the desired end result. Step 2either argon oxygen decarburization aod vacuum oxygen. Argonoxygen decarburization air products and chemicals. Physical and mathematical modeling of the argonoxygen.
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. The influence of argon blowing rate from bottom tuyeres on the gas flow pattern in the. Argon oxygen decarburization, frequently referred to as aod, is an advanced technology for the refinement of iron, nickel, and cobalt based alloys. The applications of the singlehole top lance, the 110threeholes top lance and the 150threeholes top lance in the speed of the decarburization are compared. Optimization of the ao stainless steel processing cost by. 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. Argon oxygen decarburization aod converter is popularly used in the stainless steel making process. 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. Metals steel making argon oxygen decarburization aod.
Aod, argon oxygen decarburization, is a process for making stainless steel and other high grade alloys by allowing precise gas manipulation. To avoid premature contact of oxygen with molten metal and ensure protection of the tuyere and the working chamber by the gas flow against. Pdf methods to determine characteristics of aodconverter. A dynamic model for the vacuum oxygen decarburization vod refining process is presented. A comparison study on depth of decarburization and the role. Metal refining with argon oxygen decarburization aod. This introduction causes significant agitation and, therefore, intimate slagmetal contact. Argon oxygen decarburization aod is a process primarily used in steelmaking foundries and other highgrade alloys with oxidizable elements such as chrome and aluminum. 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. Gas supply modes include bulk deliveries, cylinders and onsite production units operated by air liquide.
A new method is used to calculate the oxygen distribution in the metalgas reactions. In this process the tuyeres are submerged, resulting in high element recovery, rapid and efficient desulfurization, and good control of the slag chemistry. In an aod, metal is subjected to three steps of refining. 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. In the argonoxygen decarburization process, a mixture of oxygen and argon gas is injected into the liquid steel. Aod has a top lance for oxygen injection and several bottom tuyeres for blowing oxygen or inert gas during the operation. All structured data from the file and property namespaces is available under the creative commons cc0.
This argon dilution minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium. An argon oxygen decarburization aod refining method for molten austenitic stainless steel includes, preparing molten austenitic stainless steel in an electric arc furnace, pouring the molten austenitic stainless steel into an aod refining furnace by adjusting a carbon concentration of the molten austenitic stainless steel to 2. May 08, 2017 today, over 75% of the worlds stainless steel is made using the argon oxygen decarburization aod process invented by praxair. The decarburization in an aod converter is made in a series of steps with distinct oxygen. The aod vessel is a brick lined steel shell with provision for introduction of oxygen and inert gas argon or nitrogen below the surface of the molten metal. Rita khanna, veena sahajwalla, in treatise on process metallurgy.
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. Electric arc furnaces eafs and argonoxygen decarburization vessels aqd 40 cfr 60 subpart aa aaa. Abstract of ep0087328 a process to produce lowhydrogen steel by oxygen decarburization. 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. All structured data from the file and property namespaces is available under the creative commons cc0 license.
An argon oxygen decarburization aod refining method for molten austenitic stainless steel comprising. Mathematical modeling of the argon oxygen decarburization. Process gases are injected through submerged tuyeres that are installed in the side wall or bottom of the converter. Argon oxygen decarburization converter to fit the needs of our patrons, we are engaged in manufacturing and supplier a peerless range of argon oxygen decarburization a. 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. A hydrometallurgical route for the recovery of these metals from argon oxygen decarburization aod dusts, with selective leaching, filtration and solvent extraction was studied experimentally. Jun 04, 1986 process to produce low hydrogen steel by argonoxygen decarburization. Other articles where argonoxygen decarburization is discussed. Argon oxygen decarburization aod we supply industrial gases, related equipment, and services to steel manufacturers for argon oxygen decarburization aod.
Ii tenova is a worldwide supplier of advanced technologies, products and engineering services for. Pdf the oscillation of argon oxygen decarburization aod converters is flow related and depends on the process parameters e. The result shows, if the lance gap is set suitably, the 110threeholes top lance will be the most beneficial to the stainless steel. Manufactured using superiorgrade stainless steel and other basic components that are procured from reliable vendors of the industry. 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. Argon oxygen decarburization aod converter is popularly used in the stainless. When refining stainless steel, inert gasesar, n2 are blown in at the same time as oxygen is under standard atmospheric pressure. Since stainless steels need to be further refined, oxygen, gradually replaced by argon, is blown through the molten steel to eliminate impurities. Argon oxygen decarburization aod harbisonwalker international. Media in category aod converter the following 2 files are in this category, out of 2 total. The material was gun steel 4335v modified produced by electralloy corp. The analysis of the blowing process with the top lance of. Argon oxygen decarburization furnace steel slag aod youtube. Modeling of the vacuum oxygen decarburization refining process.
The amount of the chromium oxidized, and the temperatureincreasing speed of the bath is analyzed. Aod provides an economical way to produce stainless steel with a. When regal cast was established, the company installed an argon. 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.
Step 2either argon oxygen decarburization aod, vacuum oxygen decarburization vod or vacuum degassing. The functional layer is lined with bricks containing fused periclasechromite. Aod is a kind of smelting equipment where final deoxidization and alloying of liquid steel take place. Argon oxygen decarburization aod is a process primarily used in stainless steel making and. Carbon from the interior diffuses towards the surface, moving from high to low concentration and continues until the maximum depth of decarburization is established. Mathematical modeling of the argonoxygen decarburization refining. What is called argon oxygen decarburization aod process. After initial melting the metal is then transferred to an aod vessel where it will be subjected to three steps of refining.
The lining of the ladle consists o f three layers, i. It was inevitable that these furnaces contained oxygen and decarburization of the steel surface occurred. The aod process alleviates this problem by diluting the injected oxygen with argon or nitrogen. The example of decarburization strategies are explained in table 2 and figure 2. Aod converter, decarburization, refractories, side blown, stainless steel. Modeling of gas flows in steelmaking 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. The aod process is suitable for production of stainless steel and other highgrade.
The production of corrosionresistant superlowcarbon steel in the izhstal plant is based on vacuumoxygen decarburization vod in a 30ton ladle 1. 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. Hollow, two diameter, thick walled cylinders were produced via the hot extrusion process by the curtisswright corp. Then the decarburization process based on a stepwise decrease of the oxygen with inert gas ratio strategies.
Argonoxygen decarburization air products offers a full line of industrial gases, including nitrogen and argon to assist with your argonoxygen decarburization aod operations. New source performance standards stationary sources of. Today, over 75% of the worlds stainless steel is made using the argon oxygen decarburization aod process invented by praxair. Theoretical models have been developed for an argon oxygen decarburization aod converter that also incorporated a thermodynamic description of the process 238.
You may do so in any reasonable manner, but not in. Argon oxygen decarburization converter aod tuyer pipe. In the argon oxygen decarburization process, a mixture of oxygen and argon gas is injected into the liquid steel. Aod refining argon oxygen decarburization metaltek. Recovery of valuable metals from argon oxygen decarburization aod dusts by.
An aod is typically lined with refractory brick of differing types in. Recovery of valuable metals from argon oxygen decarburization aod dusts by leaching, filtration and solvent extraction. Other articles where vacuum oxygen decarburization is discussed. Argon oxygen decarburization aod is used during the refining process to produce steel with. 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. The production of corrosionresistant superlowcarbon steel in the izhstal plant is based on vacuum oxygen decarburization vod in a 30ton ladle 1. Pdf modeling of the vacuum oxygen decarburization refining. 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.