More details about the history, development, and categories of converter processes. 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. Background information for proposed revisions to standards. The oscillation of argon oxygen decarburization aod converters is flow related and depends on the process parameters e. Jun 04, 1986 abstract of ep0087328 a process to produce lowhydrogen steel by oxygen decarburization. The reputation and history of damascus steel has given rise to many legends, such as the ability to cut through a rifle barrel or to cut a hair falling across the blade. Alternative, melting and refining steps include vacuum induction melting, vacuum arc remelting, electroslag remelting, and electron beam melting. To avoid premature contact of oxygen with molten metal and ensure protection of the tuyere and the working chamber by the gas flow against.
The analysis of the blowing process with the top lance of the. Aod provides an economical way to produce stainless steel with a. Assessments of greenhouse gas ghg emissions from stainless. Carpenter technology corporation, reading, pennsylvania u. A research team in germany published a report in 2006 revealing nanowires and carbon nanotubes in a blade forged from damascus steel. Modeling of gas flows in steelmaking decarburization processes. Mathematical modeling of the argon oxygen decarburization. By varying the ratio of oxygen and argon, it is possible to remove carbon to controlled levels by oxidizing it to carbon.
Electric arc furnaces and argonoxygen decarburization vessels in steel industry background information for proposed revisions to standards emission standards and engineering division u. Electric arc furnace, revision argon oxygen decarburization. The aod process alleviates this problem by diluting the injected oxygen with argon or nitrogen. Several parameters come into play deciding the outcome of the process.
This book provides an introduction to these steels. 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. Co 2 was also introduced into the argon oxygen refining process by heise et al. 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. These swords are characterized by distinctive patterns of banding and mottling reminiscent of flowing water, or in a ladder or teardrop pattern.
The task focuses on studying an optimized processing in an aod converter using the uhts converter automation system utcas process control program. Argon oxygen decarburization pdf learn more about praxairs argon oxygen decarburization process that is used to make over 75% of the worlds stainless steel. The decarburization in an aod converter is made in a series of steps with distinct. The analysis of the blowing process with the top lance of. Cobalt alloys are cast by several different foundry methods. A dynamic model for the vacuum oxygen decarburization vod refining process is presented. Steel rolling technology handbook 2nd revised edition. Argon oxygen decarburization aod converter is popularly used in the stainless steel making process. After initial melting the metal is then transferred to an aod vessel where it will be subjected to three steps of refining. 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. Decarburization during heat treatment or during heating prior to rolling or forging extends into the. Modeling of the vacuum oxygen decarburization refining process. Argon oxygen decarburization aod and continuous casting cc steelmaking slags, with calcium oxide contents of 56. Introduction to stainless steels asm international.
The converter metallurgy includes melt refinement in argon oxygen decarburization aod vessels and vacuum oxygen decarburization vodc in a converter vessel. Simulation of fluid flow and oscillation of the argon. Melting and refining of stainless steels is, however, most frequently. Since the development of the argon oxygen decarburization aod converter 1 for re. May 08, 2017 today, over 75% of the worlds stainless steel is made using the argon oxygen decarburization aod process invented by praxair. Metals steel making argon oxygen decarburization aod. In this process the tuyeres are submerged, resulting in high element recovery, rapid and efficient desulfurization, and good control of the slag chemistry. Electric arc furnaces and argonoxygen decarburization vessels in steel industry. Aod has a top lance for oxygen injection and several bottom tuyeres for blowing oxygen or inert gas during the operation.
The latest advances made by the author with his research group have been summarized. Jan 18, 20 electric arc furnace, revision argon oxygen decarburization. In an aod, metal is subjected to three steps of refining. An argon oxygen decarburization aod refining method for molten austenitic stainless steel comprising. Theoretical models have been developed for an argon oxygen decarburization aod converter that also incorporated a thermodynamic description of the process 238. Argon oxygen decarburization furnace steel slag aod. Some authors 58 also carried out the study on the surface.
Pdf simulation of fluid flow and oscillation of the argon. Physical and mathematical modeling of the argonoxygen. A comparison study on depth of decarburization and the. Background information for proposed revisions to standards, preliminary draft u. Decarburization the reduction of the carbon concentration in steels and alloys that takes place upon heating in oxidizing media, as well as in hydrogen dry or wet. Argon oxygen decarburization aod is a process primarily used in stainless steel making and. 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. Pdf simulation of fluid flow and oscillation of the. No part of this book may be reproduced, stored in a retrieval system, or transmitted, in. 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. Abstract of ep0087328 a process to produce lowhydrogen steel by oxygen decarburization. The largest commercial steelmaking enterprise, nippon steel in japan, was responsible for producing 26 million tons in 1987, and 11. Gas supply modes include bulk deliveries, cylinders and onsite production units operated by air liquide.
Machining operations are often necessary following heat treatments to remove weakened nearsurface material from the steel 1. 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. High performance stainless steels nickel institute. Vacuum oxygen decarburization metallurgy britannica. This argon dilution minimizes unwanted oxidation of precious elements contained in specialty steels, such as chromium. The basic invention was derived from f i r s t principles of physical chemistry known to all third year college chemistry students. The argon oxygen decarburization aod process is one of the major stainless steel refining routes. 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. Electric arc furnaces and argonoxygen decarburization.
Argon oxygen decarburization converter aod tuyer pipe. Theoretical models have been developed for an argonoxygen decarburization aod converter that also incorporated a thermodynamic description of the process 238. Basic oxygen process an overview sciencedirect topics. Co 2 was also introduced into the argonoxygen refining process by heise et al. All structured data from the file and property namespaces is available under the creative commons cc0 license. Other articles where vacuum oxygen decarburization is discussed. Hot metal pretreatment before entry into oxygen steelmaking is employed in japan as a. The converter metallurgy includes melt refinement in argon oxygen decarburization aod vessels and vacuum oxygen decarburization. A comparison study on depth of decarburization and the role.
For a 120ton aod converter with seven submerged sidewall nozzles, plant tests, physical simulations on a. Pdf modeling of the vacuum oxygen decarburization refining. The vod is often used to lower the carbon content of highalloy steels without also overoxidizing such oxidizable alloying elements as chromium. The applications of the singlehole top lance, the 110threeholes top lance and the 150threeholes top lance in the speed of the decarburization are compared. Cobalt and cobalt alloy castings casting handbooks. Decarburization of steel and alloys may produce both harmful and beneficial effects. A new method is used to calculate the oxygen distribution in the metalgas reactions.
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 sri lanka. Decarburization occurs when metals are subjected to high temperatures, and the carbon present on the surface reacts with oxygen or hydrogen and diffuses. Modeling of the vacuum oxygen decarburization refining process article pdf available in metallurgical and materials transactions b 311. 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. 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. So that, based on the pressuredependent equilibrium relationship %c x %o 0. It provides information on castability and quality of the casted alloys. A mathematical fluid flow model of gas injection in an argonoxygen decarburisation aod converter process has been coupled with a high temperature. The new source performance standards nsps for steel plants. Argon oxygen decarburization for metal production praxair, inc. The lecture traces the development of the linde argon oxygen process from its conception in 1955 to its full scale and widespread utilization in the specialty steel industry on a worldwide basis at the present time. Rita khanna, veena sahajwalla, in treatise on process metallurgy. Two industrial vod nozzles were numerically studied and compared at different temperatures and ambient pressures. Optimization of the ao stainless steel processing cost by.
That being said, it is important to understand the process of decarburization the different types of steel during heat treating and hotworking operations. The ladle metallurgy includes vacuum induction degassing, vacuum oxygen decarburization, and vacuum ladle degassing. Optimization of the ao stainless steel processing cost by the. Argon oxygen decarburization, frequently referred to as aod, is an advanced technology for the refinement of iron, nickel, and cobalt based alloys. The list of acronyms and abbreviations related to aod argon oxygen decarburization.
Electric arc furnaces and argon oxygen decarburization vessels in steel industry background information for proposed revisions to standards emission standards and engineering division u. The example of decarburization strategies are explained in table 2 and figure 2. In the argon oxygen decarburization process, a mixture of oxygen and argon gas is injected into the liquid steel. The history and development is quite extensively summarized in the the. The article details postcasting treatment, including heat treatment, hot isostatic pressing, and coatings. Beginning in the 1970s, these stainless steels have grown in number and in technical and commercial importance. Then the decarburization process based on a stepwise decrease of the oxygen with inert gas ratio strategies. Affinity for oxygen basic and acid steelmaking deoxidation of steel optimization of primary steelmaking process secondary steelmaking processes purpose of secondary steelmaking vacuum stream degassing recirculation degassing vacuum ladle degassing argonoxygen decarburization nonvacuum argon bubbling electroslag remelting ladle injection. 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. Argon oxygen decarburization news newspapers books scholar jstor.
Files are available under licenses specified on their description page. What is called argon oxygen decarburization aod process. It is reported that the carbon removal efficiency in argon oxygen decarburization process aod was improved by using co 2 argon oxygen mixtures. 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. Eaf followed by refining by argon oxygen decarburization aod to adjust the carbon content and remove impurities. Argon oxygen decarburization aod converter slags are known to. Steel melt processing casting handbooks asm international. Argon oxygen decarburization wikipedia republished wiki 2. An aod is typically lined with refractory brick of differing types in. Fundamental decarburisation model of aod process request pdf. 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. Decarburization article about decarburization by the.
Modeling of gas flows in steelmaking decarburization. The vessel containing the steel melt is dried, as well as the cooling gas to the tuyere. Other articles where argonoxygen decarburization is discussed. 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. It is reported that the carbon removal efficiency in argonoxygen decarburization process aod was improved by using co 2 argonoxygen mixtures. Argonoxygen decarburization air products offers a full line of industrial gases, including nitrogen and argon to assist with your argonoxygen decarburization aod operations. During heat treatment of metals, decarburization happens as a side effect, which is undesirable. 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. Decarburization article about decarburization by the free. The result shows, if the lance gap is set suitably, the 110threeholes top lance will be the most beneficial to the stainless steel. 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. This book provides an introduction to these steels for those whose materials needs extend beyond the. Electric arc furnaces and argon oxygen decarburization vessels in steel industry.
The history and development is quite extensively summarized in the the ph. The amount of the chromium oxidized, and the temperatureincreasing speed of the bath is analyzed. This article discusses the physical metallurgy of cast cobalt alloys with emphasis on crystallography, compositions, phases and microstructure, and properties. It was inevitable that these furnaces contained oxygen and decarburization of the steel surface occurred.
May 06, 2016 this feature is not available right now. 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. 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. 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. Environmental protection agency office of air, noise, and radiation office of air quality planning and standards research triangle park, north carolina 27711. Argon oxygen decarburization aod we supply industrial gases, related equipment, and services to steel manufacturers for argon oxygen decarburization aod.
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