RU2443784C1 - Tuyere for bottom metal blowing in ladle - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: tuyere includes blowdown plug with through longitudinal slot channels, sleeve, stationary tube and removable gas supply tube. Tuyere is equipped with three in-series connected emitters of acoustic vibrations: external one in relation to blowdown plug, intermediate one built into removable gas supply tube, and internal one located in blowdown plug. External and internal emitters are equipped with gas nozzles and cylindrical resonators. Intermediate emitter is made in the form of a cylinder with two round holes in its edges.

EFFECT: use of invention allows improving metal degassing and removing non-metallic inclusions.

4 cl, 1 dwg

Description

The invention relates to metallurgy and, in particular, to out-of-furnace processing of steel in a ladle.

A known method of purging metal, including the supply of gas through nozzles located in the purge plug in the bottom of the bucket, and the excitation of gas by acoustic vibrations generated in the oscillation cavity of the jet emitter of acoustic vibrations, while the frequency of acoustic vibrations is controlled by changing the depth and volume of the vibration resonator [1 ]. However, the disadvantage of this method and the device that implements it is the remote location of the emitter of acoustic vibrations from the outlet cross section of the plug, since it is structurally possible to place the emitter only outside the purge plug. The loss of acoustic radiation power in the supply path from the emitter to the purge plug is significant.

It is also known a lance device for bottom purging of metal gases in a bucket, which also contains a purge plug, a resonator that excites elastic acoustic vibrations of the gas, characterized in that the acoustic vibrator is located directly in the refractory plug [2]. However, the disadvantage of this device is the practical impossibility during the purge process to change the frequency of acoustic vibrations, since the resonator is located in the body of the purge plug and it is not possible to change its length and volume, leading to a change in the frequency of vibrations. This does not allow, if necessary, to change the frequency of acoustic vibrations to effectively affect the size of the gas bubbles formed during the purge process, which ensure metal degassing, removal of non-metallic inclusions and an increase in the resistance of the purge plug.

A tuyere is also known for bottom metal purging by gases in a bucket [3], characterized in that the acoustic oscillator is made in the form of a poorly streamlined body — holes in the ends of the cylinder located directly in the gas supply device of the tuyere for bottom purging and making up a single structure with a casing of the cork. However, the disadvantage of this method is the inability to control the frequency of acoustic vibrations and the effective impact on the size of the resulting gas bubbles. In addition, the location of the poorly streamlined body in the tuyere gas supply device does not allow, if necessary, to quickly replace this emitter of acoustic vibrations when the tuyere for bottom blowing is already installed on the bucket and to use this acoustic radiator when replacing the spent purge plug.

A common disadvantage of the considered devices is the relatively low power of acoustic vibrations generated in acoustic elements — a jet emitter of acoustic vibrations or in a cylindrical radiator, presented in a lance for bottom blowing, each in the singular.

Thus, it is known a lance device for bottom purging of metal gases in a bucket containing a purge plug, characterized in that the acoustic resonator is located directly in the purge plug [1]. However, the disadvantage of this device is the inability to control the oscillation frequency and thereby effectively affect the size of the gas bubbles formed during the purge process. In addition, the acoustic power generated by this device acoustic vibrations is insufficient to effectively affect the blown metal and the formation of gas bubbles.

The technical task of this device is to increase the acoustic power of the generated acoustic vibrations while providing the ability to control the frequency of the generated acoustic vibrations to improve the conditions for the formation of gas bubbles, improve the quality of the metal and increase the service life of the purge plug.

и d_ц.2=1,2d_ц.1, при этом диаметр выходного сечения газового сопла внутреннего излучателя акустических колебаний

равен

, где

- диаметр выходного сечения газового сопла наружного излучателя акустических колебаний; d_ц.1 и d_ц.2 - диаметры первого и второго по ходу движения продувочного газа отверстий в торцах промежуточного цилиндрического излучателя акустических колебаний;

- диаметр газового сопла внутреннего излучателя акустических колебаний.This problem is solved in such a way that the lance for bottom metal blowing gas in the bucket, containing a blowing plug with through longitudinal slotted channels, a sleeve, a stationary pipe and a removable gas outlet pipe, is characterized in that the lance is equipped with three series-connected emitters of acoustic vibrations - external with respect to to the purge plug, intermediate, built into the removable gas outlet pipe, and internal, located in the purge plug, while the outer and inner radiators are equipped with gas Flame and cylindrical resonators and the intermediate emitter is formed as a cylinder with two circular holes in its ends. A lance for bottom blowing metal gases in the bucket is also characterized in that the external emitter of acoustic vibrations is configured to control the length of the resonator in the range from 50 to 300 mm. A tuyere for bottom metal purging by gases in a bucket is characterized in that a gas nozzle of an internal acoustic emitter located coaxially with a resonator located in the body of the purge plug is placed in the upper part of the tuyere sleeve along the purge gas. The lance for bottom metal blowing is also characterized in that the inner diameter of the cylinder of the intermediate emitter of acoustic vibrations is equal to the inner diameter of the removable gas supply pipe, the height of the cylinder is 1.1-1.2 of its inner diameter, and the diameters of the first and second openings along the gas are opposite the ends of the cylinder are equal

and d _c.2 = 1.2d _c.1 , while the diameter of the output section of the gas nozzle of the internal emitter of acoustic vibrations

is equal to

where

- the diameter of the output section of the gas nozzle of the external emitter of acoustic vibrations; d _c.1 and d _c.2 - the diameters of the first and second holes along the purge gas in the ends of the intermediate cylindrical emitter of acoustic vibrations;

- the diameter of the gas nozzle of the internal emitter of acoustic vibrations.

Thus, the proposed tuyere for bottom purging of metal includes three series-connected emitters of acoustic vibrations. It is known [4, pp. 110-111] that when sequentially switching on acoustic elements having certain transfer functions and amplitude-frequency characteristics, the amplitudes of their oscillations multiply and, thus, the acoustic radiation power increases significantly. At the same time, the purge gas flow rate remains relevant technological requirements. It follows that in this lance for tripping metal (at the same flow rate of purge gas, for example argon) triple acoustic power is achieved in comparison with previously known analogues. Moreover, in this design there is also the possibility of controlling the frequency of the initial acoustic vibrations by changing the height and volume of the resonator of the external acoustic emitter. In this case, as is known [5], the cavity length l _p is related to the frequency of acoustic vibrations by the formula

where from

зависит от расхода продувочного газа G_г и определяется из соотношения [6]The diameter of the gas nozzle of the external emitter of acoustic vibrations

depends on the flow rate of the purge gas G _g and is determined from the relation [6]

; P_г и T_г - давление и температура торможения газа, МПА и K соответственно, η_г - коэффициент потерь в сопле и противодавления в резонаторе η_г≈0,15-0,25;

- площадь выходного сечения газового сопла, мм².where K _g is the coefficient of proportionality (for example, for argon it is equal to

; P _g and T _g are the pressure and temperature of gas deceleration, MPA and K, respectively, η _g is the coefficient of losses in the nozzle and backpressure in the cavity η _g ≈0.15-0.25;

- the area of the outlet section of the gas nozzle, mm ² .

From formula (3) it follows

and

This jet emitter of acoustic vibrations operates in the frequency range 100-4000 Hz and the desired frequency is selected by adjusting the length of the resonator of the external emitter. For practical reasons, this length is selected in the range from 50 to 300 mm.

и принят равным

a диаметр второго отверстия также последовательно увеличен и принят равным d_ц.2=1,2d_ц.1, при этом, исходя из конструктивных соображений размещения цилиндра в съемной газоподводящей трубе, внутренний диаметр цилиндра принят равным диаметру съемной газоподводящей трубы, а высота принимается равной 1,1-1,2 его диаметра.In the direction of travel, the purge gas with acoustic vibrations already imposed passes through an intermediate emitter — a cylinder with a resonator in the form of round holes in the two ends of the cylinder. Taking into account gas-dynamic losses (constituting up to 20% of the dynamic pressure of the purge gas at each resistance element), in the section from the external to the intermediate emitter of acoustic vibrations and losses in the cylinder itself, the diameter of the first hole (in the direction of the gas flow) d _q.1 should be increased by compared to the diameter of the nozzle of the external emitter

and taken equal

a the diameter of the second hole is also sequentially increased and taken equal to d _c.2 = 1.2d _c.1 , while, based on structural considerations of placing the cylinder in the removable gas supply pipe, the inner diameter of the cylinder is taken to be the diameter of the removable gas supply pipe, and the height is taken equal to 1.1-1.2 of its diameter.

которого также с учетом газодинамических потерь по ходу движения газа принимается равным

. Длина резонатора внутреннего излучателя акустических колебаний из соображений обеспечения прочности конструкции (требуется избежать нарушения прочности продувочной пробки) выбирается с ограничением длины - равной 20-80 мм.After the intermediate acoustic oscillator, the purge gas enters the gas nozzle of the internal acoustic oscillator, diameter

which is also taken into account, taking into account the gas-dynamic losses in the direction of the gas,

. The resonator length of the internal emitter of acoustic vibrations for reasons of structural strength (to avoid violation of the strength of the purge plug) is selected with a length limit of 20-80 mm.

In accordance with the existing recommendations [5], the diameters of the resonators of the external and internal emitter of acoustic vibrations are taken equal

and the distance from the output section of the gas nozzle to the input end of the resonator is taken equal to [5]

where d _c is the diameter of the corresponding gas nozzle for the outlet of the purge gas.

The invention is illustrated by the device shown in figure 1. The device includes a purge plug 1 installed in the bottom of the bucket. The purge plug is provided with slotted holes 2 for supplying purge gas to the molten metal of the bucket and placed in a metal casing 3. In addition, the device includes a sleeve 15, a stationary pipe 6, and a removable gas supply pipe 8.

The lance for bottom blowing metal includes the following acoustic complex: an external jet emitter of acoustic vibrations 4, an intermediate cylindrical emitter of acoustic vibrations 5 and an internal jet emitter of acoustic vibrations with a gas nozzle 18 and a resonator 19. In turn, an external jet emitter of acoustic vibrations 4, mounted on removable gas supply pipe 8, consists of a gas nozzle 9, a gas supply pipe 10, a resonator 11, a reflector 12, a movable screw-in bottom of the resonator 13 and a turn from the rod 14. An intermediate cylindrical emitter of acoustic vibrations 5 is located in the upper part (in the direction of the purge gas) of the removable gas supply pipe 8 and includes a cylinder 5 and two poorly streamlined bodies in the form of round holes in the ends of the cylinder - inner 17 and outer - 16 (in purge gas flow). In the upper part (in the direction of the purge gas) of the lance sleeve 15, a nozzle 18 for supplying gas is installed. The internal jet emitter of acoustic vibrations includes a gas nozzle 18 with a resonator 19 located in the body of the purge plug 1, and a reflector 20.

Tuyere works as follows.

A purge gas (for example, argon under a pressure of 0.8-1.5 MPa) is supplied through a gas supply pipe 10 to a gas nozzle 9. Next, a gas stream enters the resonator of an external acoustic oscillator 11, in which acoustic vibrations are generated superimposed on the gas stream. The reflector 12 contributes to the effective transmission of acoustic vibrations to the removable gas supply pipe 8. Next, the gas stream with superimposed acoustic vibrations enters the intermediate cylindrical acoustic vibration emitter 5 located in the upper part (along the direction of the purge gas) of the removable gas supply pipe 8. The gas passes through the resonator, made in the form of two round holes 17 and 16 at the ends of the cylinder 5, while the amplitude and power of acoustic vibrations is amplified. Next, the purge gas enters the gas nozzle 18 of the internal jet emitter of acoustic vibrations and its resonator 19, as a result of which there is an additional (three-fold) amplification of acoustic vibrations transmitted using the reflector 20 to the slotted holes 2 of the purge plug 1. The frequency of the initial acoustic vibrations of the external radiator acoustic vibrations 4 is changed if necessary due to changes in the height and volume of the resonator 13 of the external emitter 4 by rotation of the rod 14 and a movable screw-in resonator bottom 13. If necessary, replace the elements of the external and intermediate emitter 4 and 5 with a purge lance installed on the bucket or use them on other purge lances, a removable gas supply pipe 8 together with external and intermediate acoustic oscillators 4 and 5 are screwed from the stationary pipe 6 and separated from a lance for purging metal for further use, and if necessary for structural changes.

CALCULATION EXAMPLE

The required argon flow rate for the purge bucket G _g = 100 l / min. Pressure and braking temperature of argon P _g = 0.6 MPa; T _g = 293 K. At a density of Ar under normal conditions ρ = 1.78 kg / m ³ we obtain its second flow rate

.

.

Using formula (4), we determine the area of the output section of the gas nozzle of the external acoustic oscillator

Then, according to formula (5), the diameter of the gas nozzle of the external emitter

From design considerations, taking into account possible additional argon pressure losses, we take

.

.

According to the formula (6), the diameter of the resonator of the external emitter of acoustic vibrations

.

.

The distance from the output section of the nozzle to the input end of the resonator according to the formula (7)

.

.

.The cavity length is taken equal

.

Then, according to formula (2), the base (carrier) frequency of the acoustic radiation of an external emitter

The diameters of the first and second holes (in the direction of the purge gas) of the intermediate emitter of acoustic vibrations in the form of a cylinder are respectively equal

d _C. 1 = 1.2 · 5 = 6 mm and d _{C. 2} = 6 · 1.2 = 7.2 mm.

The diameter of the gas nozzle of the internal emitter of acoustic vibrations

.

.

The diameter of the resonator of the internal emitter according to the formula (6)

.

.

The distance from the output section of the gas nozzle to the end face of the resonator of the internal emitter (according to the formula (7))

.

.

The cavity length of the internal emitter of acoustic vibrations

.

.

The base frequency of the internal emitter by analogy with an external emitter of acoustic vibrations at the same cavity length

.

.

The use of this tuyere for metal purging significantly increases the power of acoustic vibrations superimposed on the purge gas, which makes it possible to strengthen the influence of acoustic vibrations on the size of pop-up gas bubbles, to improve metal degassing and the removal of non-metallic inclusions. This is also facilitated by the ability to control the frequency of the initial acoustic vibrations.

The use of acoustic vibrations in the jet of purge gas entering the metal from the end channels of the purge plug allows you to soften the effect of the reverse hydraulic shock on the end of the plug bursting large gas bubbles and thereby increase the service life of the purge plug.

BIBLIOGRAPHY

1. Degay A.S., Osetrov V.D., Kozlov V.N. and other Method of purging metal. RF patent, No. 2238984. Publ. 10/27/2004. Bull. No. 30.

2. Lisienko V.G., Zasukhin A.L., Zuev M.V. et al. Lance for bottom purging of gases by a metal in a bucket. RF patent, No. 2291202. Publ. 01/10/2007, bull. No. 1.

3. Zelenin V.A., Grinshpun E.M., Gorokhovsky A.M. A lance for bottom blowing gas in a bucket. Utility Model No. 78798. Publ. 12/10/2008.

4. Kargu L.I., Litvinov A.P., Mayboroda L.A. and other Fundamentals of automatic regulation and control. Textbook / Ed. V.M. Ponomareva, A.P. Litvinova. - M.: Higher School, 1974. - 439 p.

5. Voronov G.V., Lisienko V.G., Shilenko B.P. et al. Gas-jet rod emitter. RF patent, No. 1455444. Publ. 10/15/1994.

6. Kitaev B.I., Zobnin B.F., Ratnikov V.F. and others. Thermotechnical calculations of metallurgical furnaces. Textbook / Ed. A.S. Telegin. - M.: Metallurgy, 1970 .-- 528 p.

Claims (4)

1. A lance for bottom purging of metal gases in the bucket, containing a purge plug with through longitudinal slotted channels, a sleeve, a stationary pipe and a removable gas supply pipe, characterized in that it is equipped with three series-connected emitters of acoustic vibrations, made in the form external to the purge plug, intermediate, built-in removable gas outlet pipe, and inner, located in the purge plug, the outer and inner radiators are equipped with gas nozzles and cylinders single resonators, and the intermediate emitter is made in the form of a cylinder with two round holes in its ends. 2. The lance according to claim 1, characterized in that the external emitter of acoustic vibrations is configured to control the length of the resonator in the range from 50 to 300 mm. 3. The tuyere according to claim 1, characterized in that in the upper direction of the purge gas part of the tuyere sleeve there is a gas nozzle of the internal acoustic emitter emitted coaxially with the resonator located in the body of the purge plug. 4. The lance according to claim 1, characterized in that the inner diameter of the cylinder of the intermediate emitter of acoustic vibrations is equal to the inner diameter of the removable gas supply pipe, the height of the cylinder is 1.1-1.2 of its inner diameter, and the diameters of the first and second openings along the gas at opposite ends of the cylinder are equal

and

while the diameter of the output section of the gas nozzle of the internal emitter of acoustic vibrations

is equal to

where

- the diameter of the outlet cross section of the gas nozzle of the external emitter of acoustic vibrations, d _c.1 and d _c.2 - the diameters of the first and second holes along the purge gas in the ends of the intermediate cylindrical emitter of acoustic vibrations, and

- the diameter of the gas nozzle of the internal emitter of acoustic vibrations.