RU101393U1 - DEVICE FOR PROTECTING A JET OF METAL FROM SECONDARY OXIDATION DURING CONTINUOUS CASTING - Google Patents

Abstract

 A device for protecting a metal stream from secondary oxidation during continuous casting, comprising a refractory pipe having a conical-cylindrical broadening along the outer surface and a conic broadening along the inner surface, a metal casing consisting of a shell covering the conical-cylindrical side section of the pipe, and a cover covering the upper edge of the pipe and forming a collector cavity with the end surface of the pipe, and with its inner conical surface - an annular nozzle, as well as a nozzle for supply shielding gas connected to the collector cavity, characterized in that it is equipped with an acoustic emitter made in the form of a hollow cylinder, closed at the ends by diaphragms with an aperture in the center, integrated in the nozzle for supplying a shielding gas, while the diameter of the aperture in the diaphragms is 1.0 -1.5 of the diameter of the gas supply pipe, the inner diameter of the resonator is 1.8-2.2 of its height, and the lid of the metal casing has radially arranged corrugations.

Description

The utility model relates to the field of ferrous metallurgy and can be used to protect a jet of liquid metal from secondary oxidation during continuous casting.

Known devices for protecting a metal stream from secondary oxidation during continuous casting, for example, RU 50892 B22D 11/06 (2006.01) [1], RU 2229955 B22D 11/106, 2004 [2], RU 2200645 B22D 11/106, 2003 [3 ], RU 7353 B22D 41/08, 1998 [4].

The closest in combination of essential features is the device RU No. 7353 B22D 41/08, 1998 [4].

It contains a refractory pipe having a conical-cylindrical broadening on the outer surface and a broadening conical on the inner surface, a metal casing, and also a pipe for supplying a protective gas. A metal casing, covering the upper part of the pipe from the outside, forms a collector cavity with its end surface, and an annular nozzle with its internal conical surface. The pipe is connected to the collector cavity through a groove in the refractory pipe. The refractory pipe is aligned coaxially with the collector glass installed in the bottom of the steel pouring ladle. The refractory pipe is designed to protect against secondary oxidation of the metal as a result of its interaction with nitrogen and oxygen.

A disadvantage of the known device is the uneven filling of the circumference of the annular nozzle with protective gas due to the small opening angle of the jet exiting into the collector cavity. This leads to suction of atmospheric air into the refractory pipe, saturation of the metal with nitrogen and oxygen, and deterioration of its quality.

The objective of the utility model is to eliminate this drawback and improve the quality of the metal.

The technical result consists in preventing the suction of atmospheric air to the metal stream and increasing the reliability of the protection of the cast metal from secondary oxidation.

To achieve a technical result, an acoustic oscillation emitter is formed in the pipe for supplying a protective gas, which forms an acoustic field in the protective gas stream. Acoustic excitation significantly increases the opening angle of the gas stream by converting it into vortex flows, which makes it possible for the protective gas to quickly and uniformly fill the collector cavity and then the annular nozzle around the perimeter. The radially located corrugations of the lid of the metal casing, resting on the end of the refractory pipe, provide a guaranteed volume of the collector cavity and form a multi-strand directed flow of protective gas into the annular nozzle, enhancing the positive effect of acoustics. As a result, a sufficient gas seal is created for the junction of the mating surfaces of the collector glass and the refractory pipe to prevent the suction of atmospheric air to the metal stream.

The utility model is illustrated by an example embodiment of the device shown in FIG. drawing in longitudinal section.

A device for protecting a steel stream from secondary oxidation during continuous casting includes a refractory pipe 1 that is joined coaxially with a refractory collector cup 2 installed in the bottom of a steel pouring tank (ladle is not shown in the drawing). The upper part of the refractory pipe 1 is covered by a metal casing, consisting of a shell 3, covering a conical-cylindrical side section of the pipe, and a cover 4, covering the upper edge of the pipe, and the cover forms a collector cavity 5 with the end surface of the pipe, and an annular one with its inner conical surface nozzle 6. The collector cavity 5 through the groove 7 in the refractory pipe 1 communicates with a gas supply pipe 8, into which an acoustic emitter 9 is built in with the help of a threaded sleeve. On the surface of the cover 4 are made for corrugated corrugations 10, with which the lid rests on the end surface of the refractory pipe 1. The shell 3 sits on the pipe 1 with a refractory mortar to ensure tightness, in the same way, the lid 4 sits on the shell 3. The pipe 8 with an acoustic emitter 9 integrated by means of a threaded sleeve is welded to the metal shell 3. A hose 11 for supplying a protective gas is connected to the acoustic emitter 9.

The acoustic emitter 9 consists of a resonator made in the form of a hollow cylinder, closed at the ends with diaphragms with a hole in the center. Shielding gas, falling under pressure into the resonator, generates an acoustic field. The frequency of acoustic vibrations of a gas jet depends on the size of the resonator and the diameter of the hole in the diaphragms. When the hole diameter in the diaphragms of 1.0-1.5 diameter of the gas supply pipe 8 and the inner diameter of the resonator is 1.8-2.2 of its height, an acoustic field is created with a frequency of 100-4000 Hz and a power of up to 60 dB, which allows ensure the achievement of a technical result.

A device for protecting a stream of metal from secondary oxidation works as follows.

When preparing the device for work on the refractory pipe 1, a casing 3 is installed from below with a landing on the refractory mortar. A gas supply pipe 8 with a built-in acoustic emitter 9 is welded to the metal casing 3. A cover 4 is put on top of the casing 3 with a fit on the fireproof mortar. The assembled device is installed coaxially to the collector glass 2 with a cone closure of their surfaces. A hose 11 for supplying a protective gas is connected to the acoustic emitter 9. During operation of the device, a protective gas, for example argon, is supplied through a hose 11 under a pressure of 0.2-1.3 MPa to an acoustic emitter 9 where an acoustic field is created. The acoustically excited protective gas through the groove 7 rushes into the collector cavity 5, distributed by radial corrugations of the cover onto the streams, quickly and uniformly fills it and the annular nozzle 6, creating a gas seal at the junction of the mating conical surfaces of the pipe 1 and glass 2, which prevents the suction of atmospheric air into the protective the pipe. In addition, the protective gas is partially injected into the inner channel of the refractory pipe 1, which destroys the laminar boundary layer of the oxide film present on the metal surface due to the acoustic effect and protects it from secondary oxidation.

Testing of the inventive device on a continuous casting machine for casting metal from a steel ladle to an intermediate ladle showed its effectiveness, ensuring that metal is obtained that meets the requirements of the standard.

Information sources:

1. RU 50892 B22D 11/06 (2006.01) [1],

2. RU 2229955 B22D 11/106, 2004 [2];

3. RU 2200645 B22D 11/106, 2003 [3];

4. RU 7353 B22D 41/08, 1998 [4].

Claims (1)

A device for protecting a metal stream from secondary oxidation during continuous casting, comprising a refractory pipe having a conical-cylindrical broadening along the outer surface and a conic broadening along the inner surface, a metal casing consisting of a shell covering the conical-cylindrical side section of the pipe, and a cover covering the upper edge of the pipe and forming a collector cavity with the end surface of the pipe, and with its inner conical surface - an annular nozzle, as well as a nozzle for supply shielding gas connected to the collector cavity, characterized in that it is equipped with an acoustic emitter made in the form of a hollow cylinder, closed at the ends by diaphragms with an aperture in the center, integrated in the nozzle for supplying a shielding gas, while the diameter of the aperture in the diaphragms is 1.0 -1.5 of the diameter of the gas supply pipe, the inner diameter of the resonator is 1.8-2.2 of its height, and the lid of the metal casing has radially arranged corrugations.