SU1412883A1

SU1412883A1 - Method of protecting metal when casting

Info

Publication number: SU1412883A1
Application number: SU864115341A
Authority: SU
Inventors: Анатолий Григорьевич Свяжин; Валерий Дмитриевич Сальников; Сергей Владимирович Кочергин; Дмитрий Александрович Романович; Михаил Павлович Клюев; Александр Михайлович Поживанов; Вячеслав Васильевич Рябов; Николай Дмитриевич Карпов; Георгий Никитович Ролдугин; Юрий Георгиевич Савватеев; Вениамин Николаевич Пестов
Original assignee: Московский институт стали и сплавов; Новолипецкий металлургический комбинат им.Ю.В.Андропова
Priority date: 1986-06-02
Filing date: 1986-06-02
Publication date: 1988-07-30

Abstract

Изобретение относитс к металлургии . Цель изобретени - повышение качества металла за счет создани на длине струи разливаемого металла пограничного сло защитного газа. Способ включает подачу защитного газа к месту истечени струи под давлением, обусловленным величиной эжекции его струей металла из подвод щего устройства, с расходом, определ емым по формуле Q 0,57dH&deg; L&deg; V&deg; , где Q - расход защитного газа, M Vc; d - диаметр струи металла в месте его истечени , м; Н - высота уровн металла над местом его истечени ; м; L - длина струи металла, м; V - кинематическа в зкость защитного газа при 1100 К, м /с. I з.п. ф-лы, I ил. SThe invention relates to metallurgy. The purpose of the invention is to improve the quality of the metal by creating a boundary layer of protective gas along the length of the jet of the cast metal. The method includes supplying the protective gas to the place of jet outflow under pressure, determined by the amount of ejection of its jet of metal from the supply device, with a flow rate determined by the formula Q 0.57dH & L & V & where Q is the protective gas flow rate, M Vc; d is the diameter of the metal jet at the point of its expiration, m; H is the height of the metal level above the point of its expiration; m; L is the length of the metal jet, m; V is the kinematic viscosity of the protective gas at 1100 K, m / s. I zp f-ly, I ill. S

Description

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Изобретение относитс к металлургии, преимущественно металлургии черных металлов , и может быть использовано при разливке стали в изложницы и на машинах непрерывного лить .The invention relates to metallurgy, primarily ferrous metallurgy, and can be used in casting steel into molds and on continuous casting machines.

Цель изобретени - повышение качества металла за счет создани на поверх- ;ности струи пограничного сло защитного газа.The purpose of the invention is to improve the quality of the metal by creating a protective gas on the surface of the jet of the boundary layer.

На чертеже изображено устройство дл ;реализации способа защиты металла при |разливке, общий вид.The drawing shows a device for the implementation of the method of protection of metal during casting, general view.

; Устройство содержит корпус 1, разливоч- ;ный коллектор 2, огнеупорную вставку 3 и га- ;зоподвод щий патрубок 4. С помощью сталь- ;ного листа 5 осуществл ют отсечку внещ- ;него сло газового потока. I Пример. На МНЛЗ разливают сталь 08Ю : из ковща емкостью 350 т. Уровень металла : в ковще в начале разливки составл ет Н 4,5 м. Диаметр выпускного отверс10; The device comprises a housing 1, a pouring manifold 2, a refractory insert 3 and a gas supply port 4. Using a steel sheet 5, the external gas flow layer is cut off. I Example. At the continuous casting machine, 08U steel is poured: from a 350 ton bucket. Metal level: in the bucket at the start of casting is H 4.5 m. The diameter of the outlet 10

1515

Но ходу разливки из промежуточного KOBnia отбирают пробы металла и анализируют их на содержание азота и кислорода . На данной плавке содержание этих элементов в начале разливки увеличиваетс на 4 , в середине разливки роста содержани азота не отмечаетс , а концентраци кислорода увеличиваетс на 6 млн , в конце разливки рост концентрации этих элементов составл ет 2 и 1 млн соответственно .But during the casting process, metal samples are taken from the intermediate KOBnia and analyzed for nitrogen and oxygen content. At this melting, the content of these elements at the beginning of casting increases by 4, in the middle of the casting the growth of nitrogen content is not observed, and the oxygen concentration increases by 6 million, at the end of casting the increase in the concentration of these elements is 2 and 1 million, respectively.

Предлагаемое изобретение позвол ет повысить качество отливаемых заготовок за счет повышени эффективности защиты струи металла от контакта с атмосферой путем создани на ее поверхности пограничного сло из защитного газа.The present invention allows improving the quality of the cast blanks by increasing the efficiency of protecting the metal jet from contact with the atmosphere by creating a boundary layer on its surface from a protective gas.

Claims

Claims. The method of protection of the metal during the spill: d 0.08 m. The length of the jet throughout the process 20 including the supply of protective gas to the casting stresses is kept constant during the outflow of the metal jet, I distinguish; equal to L 1.2 m. Argon is used as a protective gas (ViiooH 1, i CSH M- / S).

This is due to the fact that, in order to improve the quality of the metal by creating a boundary layer of a protective gas on the surface of the jet, the protective gas is supplied with a variable flow rate determined by the dependence

the receiving tank is closed with a steel sheet 5, which ensures the cut-off of the external part of the gas flow. Gas consumption set by the formula. At the height of the column H 4.5 m at the beginning of the casting, the gas consumption is 8.310 M Vc, in the middle of the casting at H 2.25 m Q 7.0-10 M Vc, at the end of the casting at H 0.45 m Q 4.8X m / s 30 s before the start of casting, protective gas begins to be supplied to the jet outflow point at a flow rate of 8.3 10 m / s. At the moment of the beginning of casting, the metal stream burns through the steel sheet covering the receiving tank, thus achieving the cut-off of the outer layer of the gas flow and preservation of the boundary layer with thickness b.

The gas is supplied with a uniformly distributed flow along the entire circumference, concentric jet, from a distance of 0.04 m from the jet's surface (the thickness of the protective layer at the initial section b 0.5d) and this gas stream thickness is kept in the area from the point of outflow of the jet to 0 , 4 m (h 5d).

But during the casting process, metal samples are taken from the intermediate KOBnia and analyzed for nitrogen and oxygen content. At this melting, the content of these elements at the beginning of casting increases by 4, in the middle of the casting the growth of nitrogen content is not observed, and the oxygen concentration increases by 6 million, at the end of casting the increase in the concentration of these elements is 2 and 1 million, respectively.

The present invention allows improving the quality of the cast blanks by increasing the efficiency of protecting the metal jet from contact with the atmosphere by creating a boundary layer on its surface from a protective gas.

Claims. The method of protecting the metal during bottling is that, in order to improve the quality of the metal by creating a boundary layer of protective gas on the surface of the jet, the protective gas is supplied with a variable flow rate determined by the dependence

Q 5,, 7dHV5L.

where Q is the gas flow

5.7 - coefficient,

d — jet diameter at the outflow, m;

H is the height of the metal column above the discharge point, m;

L — jet length, m;

V is the kinematic viscosity of the protective gas at a temperature of 1100 K m / s, while the gas pressure at the jet outflow is maintained at 0.9-1.1 atm and the thickness of the gas stream is 0.2-1.0 of the jet diameter at its location expiration on a length of 2-10 diameters.

2. A method according to claim 1, characterized in that upon entry of the metal jet into the receiving tank, the thickness of the protective gas flow is limited by the thickness of its boundary layer.