Abstract
Содержание
- Introduction
- 1. Theme urgency
- 2.Methods of motion control steel in the tundish
- Conclusion
- References
Introduction
The tundish is located between the ladle and the mold. Accepts steel, creates the necessary reserve, steel averages for temperature and chemical composition, creates conditions for the ascent of nonmetallic inclusions, distributes and dispenses with steel overflow into the mold. Tundish capacity of the latter in which it is possible to control the quality and composition of the steel to its full transition from liquid to solid state. Therefore, to ensure that the basic functions of tundish and the impact on the quality of the melt to optimally manage the movement of metal in the tundish.
1. Theme urgency
Motion control of the metal creates optimal conditions for the basic functions of the tundish. The quality of the metal spilled increases. Costs are reduced by the production. The increase in mass production with casting.
2.Methods of motion control steel in the tundish
The metal bottom of the tundish. The lining is destroyed. Appears turbulent zone. Changing the direction of motion steel: upwards at an angle or horizontally. Required element tundish design - hearth. The main objectives of hearth: repay the energy of the jet, protect the lining, direct the flows of steel.
To organize the movement of the metal used:
- Specific thresholds and barriers. Ensure the movement from hearth to the glass-dispenser.
- Filtration barriers.
- Purge units for blowing an inert gas. Contribute to surfacing of nonmetallic inclusions.
Location thresholds and special partitions are chosen taking into account the geometrical shape of the tundish. Their main task is to ensure overflow were sent to the mirror for the ascent of the metal inclusions. System thresholds and upper walls are widely used in the tundish. The use of filter septum increases the residence time of steel in tundish, creates optimal conditions for separation and ascent of inclusions, control melt temperature of the various additives additives. The design of filter septum is a plate with some holes. Holes can be run with different diameters, in different quantities and usually at an angle of inclination of the mirror metal. The upper horizontal flows move at slower speeds, creating favorable conditions for the ascent of nonmetallic inclusions. The main problem in choosing the design of filter septum is to determine the number of holes, their diameter and angle. The optimal choice of filter parameters septum prevents the appearance of turbulent zones between streams resulting from the steel walls of holes, which adversely affects the ascent of nonmetallic inclusions of a certain size. In addition, high pollution are non-metallic inclusions can be overgrowing the holes and, consequently, the fall in the level of metal in the chamber of the filtration barrier.
When casting of steel with special requirements for the content of nonmetallic inclusions in the bottom of the ladle may establish special porous blocks to ensure injection of the melt of an inert gas. Typically, this technology provides up to 30-40% removal of oxides directly into the bucket. Possible principles for removal of nonmetallic inclusions in the tundish by purging with argon can be classified as follows: injected gas flow changes the direction of the metal in the tundish and directs the non-metallic inclusions to the slag layer, increasing the turbulence contributes to the coagulation of non-metallic particles, non-metallic inclusions adsorbed argon bubbles. When using argon absorption rate of non-metallic inclusions of small size (less than 50 microns) is greatly increased. This suggests that as the bath blowing with argon flow direction of the metal in the ladle is transformed, so that fine particles rise to the surface of the inclusions. Injected into the molten metal as argon leads to adhesion of small particles and the destruction of large agglomerates. Consequently, the flow rate of argon in the tundish is optional. In addition, it was found that as the location of the purge unit on a glass-blowing impact the effectiveness of dosing is reduced.
Conclusion
Tundish provides an opportunity to influence the purity, chemical composition, temperature of steel. The optimal geometric form, along with the main structural elements of the tundish (hearth, specific thresholds and peregarodki, filtration peregarodki, purge units) let you organize the rational flow of steel in tundish - a necessary condition for improving the quality and performance of CCM
References
- Смирнов А. Н. Непрерывная разливка стали / Смирнов А.Н., Куберский С. В., Штепан Е.В. – Донецк: ДонНТУ, 2011.
- Ефимова В.Г. Разработка эффективных методов рафинирования стали в промежуточных ковшах МНЛЗ путем формирования гидродинамических потоков расплава: Дис. канд. техн. наук:-Киев, 2004.-190 с.
- Смирнов А.Н., Сафонов В.М., Дорохова Л.В., Цупрун А.Ю. - Металлургические мини-заводы - 2005
- Пути повышения стойкости промежуточных ковшей в ОАО ЕМЗ / С.П.Черненков, А.Г.Коваленко, Т.В.Лапшина, Е.Н.Дымченко // Сталь. 2007. №11.
- Энергосберегающий ресурс непрерывной разливки в условиях современного конвертерного цеха / А.Н.Смирнов, А.А.Ларионов, С.П.Матвеенков, А.Н.Токий // Металлургическая и горнорудная промышленность. 2003. №3.-С.