The eaf method, however, feeds recycled steel scrap through highpower electric arcs with temperatures of up to 1,650 degrees celsius to melt the metal and convert it into highquality steel. The oxygen steelmaking process is a generic name given to those processes in which gaseous oxygen is used as the primary agent for autothermic generation of heat as a result of the oxidation of dissolved impurities like carbon, silicon, manganese and phosphorus and to a limited extent the. Basic oxygen steelmaking bos, bop, bof, and osm, also known as linzdonawitzsteelmaking or the oxygen converter process is a method of primary steelmaking in which carbonrich molten pig iron is made into steel. Starting from its invention the process was continuously optimized and improved regarding consumption figures, productivity as well as maintenance and is nowadays used successfully in steel. A considerable portion of austrias iron and steel industry is involved with construction abroad. On the other hand, to eliminate phosphorus and sulphur, the reverse reaction rate can only be suppressed if the slag contains a good amount of stronger base than as is internally available in the form of feo and mno. The earliest known production of steel are pieces of ironware excavated from an archaeological site in. You will take charge of a ladle of molten steel from the basic oxygen furnace bof, and attempt to deliver it to the appropriate caster at the specified time, composition, temperature and inclusion content cleanness. Ironmaking and steelmaking metallurgical and materials. Physical and chemical and mineralogical characteristics of ld steel slag. Profile of a blast furnace and its dimensions are adapted to technology of process, see figure. So all the used steel products are collected back to the iron and steel making plant, now we call this scrap. In a conventional eaf, as hot metal charge increases, the need for oxygen injection is bigger. The basic automation systems level 1 for converters.
Jun 21, 2016 apart from secondary steelmaking process, there is hisarna steelmaking process which goes under primary steelmaking. The oh process started as an acid process with acid lining in the furnace, and then adopted the basic lining and new steelmaking practice as well. Slopping is the technical term used in steelmaking to describe the event when the slag foam cannot be contained within the process vessel, but is forced out through its opening. Hybrid process for steelmaking of scrap and hot metal another particular furnace design comes from the interest in enlarging the flexibility in raw materials, particularly hot metal. In the first step, the raw inputs iron ore, coke, and lime are melted in a blast furnace. Basic oxygen furnace bof is a steel making furnace, in which molten pig iron and steel scrap convert into steel due to oxidizing action of oxygen blown into the melt under a basic slag.
Introduction nippon steel corporation has endeavored to secure the worlds. In this simulation you will play the role of plant metallurgist in charge of secondary steelmaking operations. This book describes improvements in the iron and steel making process in the past few decades. The purpose of this work is to develop a mathematical model to calculate the material balance. Blowing oxygen through molten pig iron lowers the carbon content of the alloy and changes it into lowcarbon steel. A thesis submitted to the school of graduate studies in partial fulfilent of the requirements for the degree. Jan 12, 2017 a number of recent developments have widened the area of application of the ld, basic oxygen steelmaking process. The process had two main differences relative to the bessemer process. The name ld stands for linz and donawitz, these were the two places in austria where the process was born. The bottom cylindrical part of the profile is called a.
The name ld stands for linz and donawitz, these were the two places in austria where the. Direct reduction scrap ladle refining electric arc furnace steelmaking iron ore pellets electric arc furnace steelmaking continuous casting design by cover photo. The process is on a cyclone converter furnace a new type of blast furnace. More than half the worlds steel is produced in the basic oxygen process bop, which uses pure oxygen to convert a charge of liquid blastfurnace iron and scrap into steel. However, if one goes back as far as the middle of the 19th century, one finds that henry bessemer, the englishman who developed the air refining process, what we now know as the. Comparative assessment of ld converter and electric arc.
And these products are used everywhere in the world. Primary steelmaking known as linzdonawitzverfahren steelmaking 28. Ldconvertor atibir industries company limited steel. Pdf desphosphorization in ironmaking and oxygen steelmaking. The yield of ironsteel slag is about 300 kgtp per ton of pig iron for blast furnace slag and about 100150 kgts per ton of molten steel for steelmaking slag. An overview of use of linzdonawitz ld steel slag in. Basic oxygen furnace based steelmaking processes and cleanliness control at baosteel l. Merge basic oxygen steelmaking and basic oxygen furnace.
Dec 29, 2012 it is a modified bessemer process, steel is produced in a solid bottom converter by injection of oxygen into the molten iron bath from a water cooled lance inserted through the converter mouth. Experimental method and examination of inclusions in steel experimental methods. Hisarna process is more effective and energyefficient. Salzgitter the process shown above is illustrative only and is not designed to show the steelmaking process in detail.
Pig iron is divided into steelmaking pig iron, which is intended for further processing to. The basic oxygen furnace bof is a refractorylined, tiltable converter into which a vertically movable, watercooled lance is inserted to blow oxygen through nozzles at. Basic oxygen furnace based steelmaking processes and. Such a process of steelmaking is called acid steelmaking process which is carried out in an acid brick lined furnace. Once steel is made, then it undergoes casting process, rolling process, and it becomes the final product. In this method, steel is produced directly from iron ore. Development of the ld process the story of the ld process a series of experiments began on june 3, 1949 on the former voest site, using a 2tonne experimental converter.
These include ore cooling, production of highcarbon and lowalloy steels, and the utilization of highphosphorous hot metal. How steel is made using the basic oxygen steelmaking process. Chemistry of steelmaking by basic oxygen furnace ispatguru. A number of recent developments have widened the area of application of the ld, basic oxygen steelmaking process. Bos is the most common and dominant primary steelmaking process used in the world today. Apart from secondary steelmaking process, there is hisarna steelmaking process which goes under primary steelmaking. Converter process control and technological packages the fundamental basis of high quality process operations our automation systems comprise the complete range of carbon steelmaking converters ld, bof, kobm as well as stainless steelmaking technologies aod, clu and kobms. The purpose of the basic oxygen steelmaking bos process is to refine the hot metal produced in the blast furnace into raw liquid steel, which may be subsequently refined in the secondary. Because of high production costs, which are closely tied to the. Dissolution of scrap in hot metal under linzdonawitz ld. Request pdf a new lance design for bof steelmaking this article summarizes the outcome of research work carried out to improve the performance of the oxygen lance in the ld steelmaking process. For many years production was limited to specialty steels supplying niche applications for industry in the united states and the world. Steelmaking the refining of iron to make steel is where the carbon content of hot metal is lowered, usually to less than 1 % by an oxidation process in a. The major phases present in ld slag in other parts of world are also studied, that contain some reactive mineral phase such as 2cao.
Energy balance calculations are carried out on the bof ld converter steelmaking process using the hot metal with the composition shown in table. Steelmaking is an extensive industry based on modifying the physical properties of iron to fit a wide range of applications by either adding alloying elements or removal of impurities. The basic oxygen furnace bof is a refractorylined, tiltable converter into which a vertically movable, watercooled lance is inserted to blow oxygen through nozzles at supersonic velocity. The vessel volume is more than ld vessel to accommodate extra slag volume. It has been found that the density of ld slag lies between 3. Donawitz ld converter with respect to blowing time. Modelling of basic oxygen steel making process has significant utility as productivity and lining life of basic oxygen steelmaking bos is highly dependable. Once these steel products are used, then they are supposed to be recycled. Definitions of the process technologies considered herein can be found elsewhere in these proceedings in the paper titled influence of ais chemistry on eaf steelmaking.
To develop computational and mathematical abilities to be applied for process design and control. Modern methods, however, are still based the same premise as the bessemer process, namely, how to most efficiently use oxygen to lower the carbon content in iron. Basic oxygen steelmaking bos is the process of making steel by blowing pure o2 in a liquid metal bath contained in a vessel which is known as basic oxygen furnace bof, ld converter, or simply converter. Modern steelmaking can be broken down into six steps. Secondary steelmaking involves treating the molten steel produced from both bos and eaf routes to adjust the steel composition. Top oxygen blowing, widely referred to as the ld converter process, and steelmaking in the electric arc furnace, are nowadays the two most widely used steelmaking processes. In steelmaking, impurities such as nitrogen, silicon, phosphorus, sulfur and excess carbon most important impurity are removed from the sourced iron, and alloying elements such as manganese, nickel, chromium, carbon and vanadium are added to produce different grades of steel. Be able to understand basic layout of blast furnace, steelmaking shop and continuous casting process. Control of slopping in basic oxygen steelmaking by george k. Characteristics of supersonic jets in ld steelmaking. In the linzdonawitz ld steelmaking process supersonic oxygen jets expand into the surroundings formed by hot and dense slag foam thus it is necessary to understand the innate characteristics. Steelmaking the refining of iron to make steel is where the carbon content of hot metal is lowered, usually to less than 1 % by an oxidation process in a steelmaking furnace.
Converter carbon steelmaking solutions primetals technologies. The optimization of the ld process is focused, amongst other factors, on thermodynamic and kinetic modelling. This model also contributes towards the prediction of sloping phenomenon taken place during basic oxygen steel making process. Steelmaking technologies contributing to steel industries. Thomas4 optical microscopy, total oxygen measurements and slime tests have been conducted to quantify. The steelmaking process belongs to very complicated metallurgical processes.
One of the main charging materials of the linzdonawitz oxygen steelmaking process ld is scrap. A new lance design for bof steelmaking request pdf. In 1952 the linzdonawitz ld process also known as bof process was developed in austria and soon became the standard for iron ore based steelmaking. Ironmaking and steelmaking processes greenhouse emissions, control, and reduction. The present paper describes industrial clean steel production using the bof based steelmaking process and steel cleanliness control at baosteel.
Scrap acts as a coolant for the exothermic reactions inside the ld vessel and as an iron source in addition to hot metal. Blast furnace hot metal for ld basic oxygen furnace steelmaking process ideally contains about c4. This article describes how these techniques have been used in 12 ld steel plants. Model for indirect measurements of ld steelmaking process introduction at the present time the production of steel in ld converters belongs to the most widely used technology in manufacturing pig iron. Nov 14, 2016 the purpose of the basic oxygen steelmaking bos process is to refine the hot metal produced in the blast furnace into raw liquid steel, which may be subsequently refined in the secondary. It also presents new and improved solutions to producing high. A primary steelmaking process refers to the actual process of taking the raw materials and. Modelling of basic oxygen steel making process has significant utility as. The resulting molten iron also referred to as hot metal still. Ld process is a refining process which is carried out in a ld vesselor ld converterbof. Overall both books are great references for the making, shaping, and treating of steel. Steelmaking is the process of producing steel from iron ore andor scrap. A primary steelmaking process refers to the actual process of taking the raw materials and converting them to steel steelmaking.
Steel making is mainly concerned with the removal of these impurities. This process is also called as basic oxygen process. Oxidation is carried out with high purity oxygen gas which is blown in the bof. The phosphorus content in ld slag is too high to be reused in iron making and onehundredth percent of phosphorus go to the metal phase. Overview of the steelmaking process pellets sinter limestone coke iron ore coal scrap blast furnace ironmaking converter steelmaking ladle refining blast furnace steelmaking coalnatural gas plate hotrolled bars rods tube rounds rails slab billet bloom hotrolled and coldrolled strip coils structural shapes.
32 812 1079 313 760 910 274 921 440 149 1386 234 1334 1254 1128 124 217 1248 1102 536 927 1099 1449 682 371 1421 455 102 352 594 292 420 1577 788 1241 1378 1252 890 768 845 518 869 1469 938 945 1011