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Abstract

Content

Introduction

Casting yield all metals. But not all metals have the same casting properties, in particular the fluidity – the ability to fill a mold of any shape. Casting properties depend mainly on the chemical composition and structure of the metal. Important to the melting point. Metals with low melting points are easy to industrial castings. Of common metal highest melting point of steel. Metals are divided into black and colored. Black metal – a steel, ductile iron and cast iron. To include all other non-ferrous metals do not contain significant amounts of iron. Casting applied, in particular, copper-based alloys, nickel, aluminum, magnesium, lead and zinc.

Thermal processes in the steel casting at each stage are very complex and not amenable to analytical solution due to the large number of variables,   affecting the value of the temperature drop. The experimental method in solving such problems requires huge investment and, Sophisticated equipment, addressing modeling the real world. Modern development of numerical methods and performance of computers makes the most attractive numerical approach in solving thermal problems for continuous casting[1].

1. Relevance of topic

Modern CCM is a high-tech unit, almost completely protected from oxidation of the metal through the use of high-quality refractory isostatically compressible (protective pipe, submerged nozzle, etc.), to provide the best swing operation (through the use of hydraulic drive) and automatic maintenance of the level of metal in the mold, the automatic prevention breakthroughs metal, improve the quality of the internal structure of the workpiece by applying the liquid phase of the electromagnetic field and the "soft" compression workpiece with a liquid core, etc.

In general, the beginning of XXI century in the qualitative and quantitative aspects was almost complete saturation of steel companies in the world various caster and appropriate technological support. One of the defining trends in the development of the concept of the continuous casting of steel has been the decline in investment and payback period, both in the construction of new plants and the renovation of existing[2]. With a special focus on reducing the unit cost of production of steel products. The world's leading manufacturers of equipment for continuous casting achieved the highest ratings for the classic CCM (casting slab, bloom, circle, billet), and concentrated his attention on the basic concept of creating alternative casting and rolling machines for flat products. Technology development and construction of machines for continuous casting will take place in the part of the creation of highly productive units that become flexible technology relationship with a combination of steel-making process, its casting and subsequent rolling billets[3 ].

2. The purpose and objectives of research

The aim research is to study thermal processes hardening steel in continuous casting machines, as well as algorithm development program, enabling a three-dimensional model of the processes of heat transfer and crystallization ingot continuous casting of steel.

Main objectives of the study:

  1. Review of existing software solutions.
  2. Selecting the right mathematical model.
  3. Research of the continuous casting in CCM.
  4. Overview of the implementation of the software.
  5. Design algorithm for constructing a three-dimensional model of the ingot.

Object of study : the processes of heat transfer and crystallization ingot continuous casting machine.

Subject of study : methods of calculation and visualization of temperature field billets.

3. Scope of applications

Continuous casting is the most important process steps in the manufacture of metal products, as it provides for the transfer of steel from liquid to solid with giving her a definite geometric shape. Besides the cooling conditions and hardness of the steel during continuous casting largely determine the high quality steel products compared to a conservative system ingot casting.

Using the continuous casting in steel making saves investment costs due to removal of the park molds, construction preparation shop compositions stripping branches, blooming, and provides significant cost savings due to the reduction of metal scrap, saving energy wasted on heating ingots in soaking pits, reduces the environmental burden on the atmosphere, improve the quality of metal casting process to automate and improve the working conditions of staff.

Design solutions used to create the continuous casting machines, contain knowledge from a variety of disciplines in the field of metallurgy, materials science, the theory of hardening, electrical engineering, fluid dynamics, thermal physics, the theory of measurement and automatic control systems, etc. This integrated approach has counterparts in creating high units and machines for processing circuits of iron and steel.

Process and the continuous casting machines are constantly evolving and improving, expanding their scope and creates conditions for the transformation of steel redistribution in whole. The level of use of technology for continuous casting of steel is taken into account when creating new plants and modernization of existing ones. This in turn stimulates further development of structural steel continuous casting machines, providing them more attractive design and competitive[4].

Despite some minor differences, the key technological and design features of the caster rather well studied and developed. The further development and improvement is achieved by providing the flexibility and functionality of continuous casting machines (CCM), including a combination of casting and rolling.

4. Review of research and development

Process of hardening steel is an important part of the steel industry. This process is widely studied by scientists from all over the world. Studies of solidification have continued today.

4.1 Review of international sources

Steel - is not an invention of modern times. Method of preparation was already known 1000 years ago. However, until the XIX century. Steel almost never used. Because its production was too complex and expensive.  Faster and more affordable, it was only after Henry Bessemer invented in 1856 called his name converter. Having undergone a number of changes, this method has now become central to the steel industry.

Carbon content and other unwanted impurities is reduced so-called frishevaniem. Iron is necessary for this  again heated to a liquid state. Since 1784 it is done in the puddling furnace, heated with coal. Iron melts   on the hearth to the doughy state, stirring constantly with metal rods to increase access kistoroda.    Bessemer improved this process by building a blast furnace: through the bulk of the poor in phosphorus iron blown     compressed air, contributing to the process of oxidation. Bessemer converter in 20 minutes gave the same steel as      puddling furnace for the whole day. Is based on a similar principle, and invented in 1864 hearth process. Later       appeared oxygen converters and electric furnaces for smelting steel.

In 1742, Benjamin Huntsman began to melt steel, not in an open furnace with charcoal, and in a heated crucible.

Thanks to the French metallurgist Pierre Martin, who in 1865 patented the furnace for steel production of new model in the production of this metal may be used on scrap, which is on the planet to have accumulated an enormous amount.

However, the main revolution in steel production occurred in 1865, when the French - a father and son Pierre and Emile Martin - used for steel gas oven, built by German engineers drawings brothers Wilhelm and Friedrich Siemens. In it, due to heating of gas and air in special chambers with refractory nozzle achieved such a high temperature that the steel in the bath furnace passed is not the pasty, as in the puddling furnace, and a liquid. It can be poured into the bucket and forms produce ingots and rolled them into the rails, beams, construction profiles, sheets[5]. In addition, the ability to use large amounts of scrap iron, accumulated over many years in the steel and engineering plants.

In 1878 Sidney Gilchrist Thomas invented the "Thomas process" to remove phosphorus impurities from iron ore smelting.

In 1952 in Austria started the world's first steel plant based on the LD process. Available in cast iron impurities are removed in a technical oxygen blowing converter.

Competitors converter heats today one - is electrofusion steel, occupying about 30 percent of world production of the main metal of heavy industry. Smelting of steel in electric furnaces is based on the use of electricity for heating metal.

4.2 Review of national sources.

Nicholas T. Gudtsov, the largest Soviet FMM scientist and specialist in the structure, properties, heat treatment and alloying of steel, USSR Academy of Sciences (1939), Honored Scientist of the RSFSR. Along with other leading steelmakers FMM and Seniors - Baikov, Bardin, S. Steinberg, NA Minkevich AL Baboshin, AM Bochvar etc. Gudtsov was the leading scientists of the first half of the XX century in the development of the science of the structure and   properties of metals.

When in 1936 the Soviet engineer Nikolai Illarionovich Brain was first used to purge the iron in a converter oxygen converter steel production prospects to realistic. Metal obtained BOF process, the quality was equivalent to open-hearth steel, the cost of smelting down by almost a quarter, seriously increased productivity converter production[6].

Rauzin YR working since 1953 head of the laboratory testing of materials and structures of the Institute of Railway Transport Soviet Union was engaged in research to improve the quality, in particular, bearing steel, and enhancements heat treatment of high-chromium and high-carbon steel. YR Rauzin engaged in the development of new test methods metals in contact endurance, toughness, impact testing of full-scale at low temperatures. In for many years studied the mechanisms of the initial stages of plastic deformation, upholding the hypothesis of the crucial role rotational movements. Recent work YR Rauzina devoted to methods of evaluation of structural strength of steel and choice of ways to increase the strength of steel.

Research Rauzina were the theoretical basis for the development and deployment of Soviet industry advanced methods of thermal hardening bearing, track, instrumental and structural steel, played an important role in the transfer of railway transport of the USSR on roller bearings.

Lion's share in the study were introduced Akimov George V.. After the publication in 1940 of the monograph "The theory and methods of corrosion of metals" and the textbook "Fundamentals of Corrosion and Protection of Metals" began a series of works in the field of theoretical and experimental studies of metal corrosion. In these works involved in creating a network of corrosion stations in representative climatic zones of the country - Distant Zelentsy Zvenigorod, Vladivostok, Batumi. Structural corrosion theory and the theory of multi-electrode systems by GV Akimov, have found wide acceptance in the USSR and abroad. His work in the field marked by passivity superpassivation discovery of the phenomenon. Akimov author of over 250 scientific papers on the corrosion of metals.

4.3 Review of local sources

The Donetsk National Technical University (DNTU) together with NGOs Doniks SP Eronko, Doctor of Technical Sciences, AU Tsuprun, SA Bedarev, DA Yakovlev, EP Potapov, GS Romanov and others are developing a sliding device for technological spillovers steel. They have been designed and implemented new gate system on kotrorye already patented.

Large share research staleplavleniya brought Ph.D., Associate Professor and Chair Evgeny Smirnov. He is the author of 140 scientific papers, 20 patents and certificates of invention, and co-author of 20 training manuals and guidelines.

Conclusion

In progress Master thesis will be solved the following problems:

  1. The process of continuous casting of steel in the continuous casting machine.
  2. Analyzes the mathematical model of ingot solidification in continuous casting.
  3. The existing types of software that implement the modeling of temperature fields in the CCM.
  4. Make the choice of the implementation of the proposed software.
  5. Algorithm program to build three-dimensional models of the thermal field of a continuous ingot.

Further results of the work will be used for product development, which is planned to implement the calculation and construction of a graphical model of the temperature field in the billet continuous casting machine, based on data on the thermophysical parameters were dispensed, specifications caster, cooling, etc.

In writing this essay master's work is not yet completed. Final completion: December 2012. The full text of the work and materials on the subject can be obtained from the author or his manager after that date.

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