KR100833054B1 - An apparatus for preventing the confusion of slag in melting iron casting - Google Patents

Abstract

The present invention relates to a device for preventing the incorporation of slag to minimize residual molten steel at the end of casting.

The present invention, in the facility for supplying the molten steel in the ladle 110 into the tundish 120 through the immersion nozzle 107, disposed on the nozzle 105 formed on the bottom surface of the ladle 110, a plurality of A mixing prevention part (10) having a cylindrical prevention tab (11) having two molten steel inlets (12) and a slag discharge port (14) for introducing only the lowest selected molten steel (M); The heat insulating cover 51 covering the upper part of the ladle 110 to prevent the high heat in the ladle from being released into the atmosphere during casting of the gas blowing lance 31, the lower end of which is assembled on the upper surface of the prevention tab 11. It is equipped with a lance inlet 52 so as to be movable in Shanghai to ignite the flammable gas supplied into the prevention tab 11 to maintain molten steel temperature, and blow out slag S on the hot water surface of the molten steel in the ladle 110. Due to the molten steel vortex phenomenon at the end of the casting, including the gas blowing portion 30, the slag on the hot water surface is prevented from being mixed into the molten steel and supplied into the tundish, minimizing the residual molten steel in the ladle, and improving the molten steel yield. The effect of preventing a drop in temperature is obtained.

Ladle, Slag, Prevention Tap, Gas Blow Lance, Coolant, Combustible Gas

Description

Slag mixing prevention device for molten steel casting {AN APPARATUS FOR PREVENTING THE CONFUSION OF SLAG IN MELTING IRON CASTING}

1 is an overall configuration showing a molten steel casting slag mixing prevention device according to the present invention,

Figure 2 is a perspective view showing the prevention portion employed in the molten steel slag mixing prevention device according to the present invention,

3 is a configuration diagram showing a gas blowing unit employed in the molten steel casting slag mixing prevention device according to the present invention,

Figure 4 is a perspective view showing a thermal insulation cover employed in the molten steel slag mixing prevention device according to the present invention,

Figure 5 is a working state using the molten steel casting slag mixing prevention device according to the present invention.

6 is a schematic diagram showing a conventional working state for preventing the slag from being mixed into the tundish by the vortex phenomenon occurring at the end of the conventional casting.

Explanation of symbols on the main parts of the drawings

11 .... Prevention tab 12 .... Molten steel inlet

14 .... slag outlet 16 .... insertion hole

31 .... Gas blowing lance 32 .... Tap fixing member

33 .... Outer pipe 34 .... Intermediate pipe                 

35 .... Inner pipe 36a, 36b ... On-off valve

38 .... Lance Packing 51 .... Thermal Cover

52 .... Lance entrance 110 .... Ladle

The present invention relates to a device for preventing the incorporation of slag to minimize the residual molten steel at the end of the casting, in more detail due to the molten steel vortex phenomenon of the end of the casting to prevent the slag on the hot water is mixed into the molten steel and supplied into the tundish ladle The present invention relates to preventing molten steel casting slag that can minimize residual molten steel, improve molten steel yield, and prevent a drop in molten steel and ladle temperature.

In general, the molten iron is charged into the converter to be smelted, and the molten steel is secondly refined and then cast in a continuous casting machine to produce slabs.In the initial stage of the casting process, molten steel (specific gravity: 7.8) and slag (weight) Since the slag is floated on the molten steel surface due to the difference in specific gravity between 2 and 3), the pure molten steel in the ladle is cast until the end of casting, and the molten steel and the molten slag are rotated around the nozzle of the ladle. The molten slag on the hot water surface is supplied together with the molten steel to the tundish and the casting machine, which is a post-process, through the nozzle. Since the slag is injected into the mold before being cast into the surface of the slag, the slag has been a main cause of generating defective parts such as pinholes in the slab.                         

6 is a schematic view showing a conventional working state for preventing the slag from being mixed into the tundish by the vortex phenomenon occurring at the end of the conventional casting, as shown, the molten steel (M) remaining in the ladle 110 In order to prevent the slag (S) on the molten steel of the molten steel is mixed and mixed into the tundish 120, at the edge of the nozzle 105 formed on the bottom surface of the ladle 110, the ladle 110 wall The vortex prevention dam 130 extending from the installation was used, but there was a limit in increasing the error rate of the molten steel, which is merely a level of suppressing the vortex of the molten steel.

And, by installing the slag detection device AMEPA on the ladle hull between the bottom surface of the ladle 110 and the cassette 106, the slag (S) is mixed in the molten steel (M) and supplied into the tundish (130). The casting was stopped immediately when the slag was detected. However, this conventional method causes a lot of molten steel remaining in the ladle 110 to reduce the error rate of the molten steel and to slag the remaining molten steel, thereby causing the occurrence of the ingot.

In addition, the casting operation is made in a state in which the insulating cover 140 is covered on the upper portion of the ladle 110 to prevent the temperature drop of the molten steel contained in the ladle 110 while preventing the temperature of the ladle during the casting. However, at the end of the casting, because the area of the high-heat ladle 110 is in contact with the atmosphere, a large amount of heat is dissipated to the outside, thereby lowering the temperature of the ladle 110 and the molten steel 7 contained therein. Accordingly, in order to prevent such a temperature drop, the tapping temperature must be increased in the converter, which leads to an increase in manufacturing cost, such as an increase in the blow time and shortening the life of the furnace body.

In particular, the temperature drop of the molten steel M being cast decreases the temperature of the tundish 1301 and causes the clogging phenomenon of the immersion nozzle 108 to introduce the molten steel of the tundish 130 into a mold (not shown). It caused many problems such as delay of work and interruption of casting.

In FIG. 6, reference numeral 107 denotes an immersion nozzle for guiding injection of the molten steel of the ladle 110 into the tundish 130.

Therefore, the present invention has been proposed to solve the conventional problems as described above, the object of which is to prevent the vortex phenomenon of the molten steel occurring at the end of the casting, and to supply the tungdish while maintaining only the selected molten steel of the lowest layer By preventing slag from being mixed into molten steel and casting into tundish, and minimizing the temperature loss of molten steel and ladle generated during prolonged casting, it minimizes the amount of molten steel remaining in the ladle to improve molten steel error rate and play The present invention provides a molten steel casting slag incorporation preventing device that prevents the occurrence of lumps, shortens the blowing time, reduces molten steel manufacturing cost, and prevents clogging of the immersion nozzle.

As a technical configuration for achieving the above object, the present invention,

In the facility for supplying the molten steel in the ladle into the tundish through the immersion nozzle,

A mixing prevention part disposed on a nozzle formed on the bottom surface of the ladle and having a cylindrical prevention tab formed with a plurality of molten steel inlets and a slag discharge port to introduce only the lowest selected molten steel;

The gas injection lance with the lower end assembled on the upper surface of the prevention tab is provided to be movable through the lance inlet of the insulating cover covering the upper part of the ladle to prevent the high heat inside the ladle during the casting to the air. It is to provide a molten steel casting slag incorporation preventing device comprising a gas blowing unit for igniting the flammable gas supplied into the tap to maintain the molten steel temperature, and blowing the slag on the hot water surface of the molten steel in the ladle.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1 is an overall configuration diagram showing a molten steel casting slag mixing prevention device according to the present invention, Figure 2 is a perspective view showing a preventing portion employed in the molten steel casting slag mixing prevention device according to the present invention, Figure 3 Fig. 4 is a configuration diagram showing a gas blowing portion used in the molten steel casting slag mixing prevention device according to the invention, Figure 4 is a perspective view showing a thermal insulation cover employed in the molten steel casting slag mixing prevention device according to the present invention, Figure 5 Working state diagram using the molten steel casting slag mixing prevention device according to the present invention.

In the apparatus 1 of the present invention, as shown in Figs. 1 to 5, the slag of the hot water surface is mixed with the molten steel by the vortex phenomenon in the nozzle so as to increase the error rate of the molten steel remaining on the bottom surface of the ladle at the end of molten steel casting. In order to prevent the clogging of the nozzle by preserving the temperature in the ladle, the apparatus 1 is composed of a mixing prevention portion 10 and a gas blowing portion 30.

That is, only the lowermost selected molten steel flows into the nozzle 105, and the mixing prevention portion 10 for discharging the slag of the hot water surface is difficult to be mixed with the nozzle 105 formed on the bottom surface of the ladle 10 in which the molten steel is filled. It is arranged in the upper portion of the, and comprises a cylindrical prevention tab (11) made of a refractory material, the lower end of the prevention tab (11) a plurality of molten steel inlet (12) to guide the flow of the molten steel of the lowest layer to the nozzle ) Is formed in the incision, the outer surface of the slag discharge port 14 through which the ignited gas exits during ignition of the combustible gas supplied through the gas blowing class 31 which will be described later to push out the slag on the surface in the circumferential direction Multiple pieces are formed at regular intervals.

Here, it is preferable that the opening area of the molten steel inlet 12 is more than twice the opening area of the nozzle 105 so that the molten steel can be smoothly supplied through the nozzle.

In addition, the gas injection part 30 which supplies flammable gas into the prevention tab 11, ignites the supplied gas to maintain molten steel temperature in the ladle, and blows out the slag S on the water surface to the outside. A lower end is inserted into and connected to an insertion hole 16 formed through the upper surface of the upper portion 11, and a gas blowing lance 31 having a predetermined length that is lifted up and down through the lance inlet 52 of the heat insulating cover 51. The upper end of the gas injection lance 31 is made up of a hook 154 that is lifted and lowered by winding and unwinding of the trolley 152 and the wire rope 153 which are advanced back and forth along the running rail 151. It is connected to the hoist 150 and is horizontally and vertically moved to be inserted into the ladle 110 at the end of the casting.

Here, a tab fixing member having an inverted triangular cross section fitted into a lower end of the gas blowing lance 31 is fitted with a fastening groove 16a of an inner circumferential surface of the insertion hole 16 formed through the upper surface of the prevention tab 11. 32) is constituted by a plurality of.

The gas blowing lance 31 is provided with an external pipe 33 through which a coolant is supplied through a coolant supply line, an intermediate pipe 34 through which a coolant circulated through the coolant discharge line, and a gas supply line. The inner pipe 35 to which the combustible gas is supplied and the end of the outer pipe 33 and the end of the inner pipe 35 are connected to each other so that the coolant is circulated, and the lance nozzle 31a discharges only the combustible gas. .

In addition, the flexible hose so that the supply and discharge of the coolant to the gas injection lance 31 is moved between the outer, middle and inner pipes 33, 34, 35, and the combustible gas can be smoothly made. (33a) (34a) and (35a), the opening and closing valves (36a, 36b) are respectively mounted to the cooling water and gas supply line (33b) so as to control the flow of cooling water and gas, while the inner pipe ( It is preferable to install a backfire prevention valve 37 at the connection portion between the 35 and the gas supply line 35b.

In addition, the outer surface of the gas blowing lance 31 is inserted into the lance inlet 52 of the heat insulating cover 51 covering the upper portion of the ladle 110 to prevent the high heat inside the ladle during the casting to the atmosphere. The outer circumferential surface is provided with heat-resistant lance packing 38 in close contact.

Here, the lance blowing inlet 52 is provided on one side of the insulating cover 51 so as to match the nozzle 105 and the gas blowing lance 31 installed on the bottom of the ladle 110 on the same vertical line. It is eccentrically penetrated, and the thermal cover 51 is connected via a cover 54 and a chain 54 which are connected to a hydraulic device (not shown) so as to cover and separate it on the ladle 110. .                     

The operation and effects of the present invention having the configuration as described above will be described.

After the refining operation, the molten steel remaining in the ladle 110 at the end of the casting process is supplied into the tundish 120 filled in the ladle 110, and the molten steel in the tundish is supplied into the mold to form the slab. In addition, in order to prevent the mixing into the tundish 120, first, the gas blowing lance 31 having a predetermined length of the prevention tab 11 mounted on the work target by the lowering operation of the hoist 150 The lower end of the gas blowing lance 31 is inserted into the insertion hole 16.

In this case, the tab fixing member 32 on the inverted triangular cross-section mounted on the outer circumferential surface of the lower end of the gas injection lance 31 enters the engaging groove 16a of the insertion hole 16 along the inclined surface, and the gas blowing If the lower end of the lance 31 completely passes through the insertion hole 16, the lowering of the lance 31 is stopped, the tab fixing member 32 is inclined outward by the center of gravity and the fastening groove ( It is caught at the bottom of 16a).

Accordingly, when the hoist 150 is wound up, the prevention tab 11 together with the gas blowing lance 31 is lifted to the upper portion.

On the other hand, when the end of the casting to supply the molten steel in the ladle 110 to the tundish, the gas blowing lance 31 is mounted to the upper end of the ladle 110, the mounting of the prevention tab 11 at the lower end The lowering is performed by the lowering operation of the hoist 150 in a state in which it is coincided with the lance inlet 52 of the insulating cover 51.

In this case, the prevention tab 11 enters into the ladle 110 through the lance inlet 52, and the entrance prevention tab 11 is disposed directly above the nozzle 105 formed on the nozzle bottom surface. In this state, the prevention tab 11 stops the lowering of the gas blowing lance 31 to stand at a height that is not submerged in molten steel.

At this time, the lance packing 38 mounted on the gas blowing lance 31 seals the lance inlet 52 of the thermal cover 51 to prevent high heat inside the ladle 110 from being emitted to the outside. Preserve molten steel temperature. Then, the on / off valve 36a of the cooling water supply line 33b connected to the external pipe 33 of the gas injection lance 31 is opened to circulate and supply the cooling water.

Subsequently, when the hot water level of the molten steel remaining in the ladle 110 is lower than the upper end height of the slag discharge port 14 of the prevention tab 11 stopped at the upper portion of the nozzle 105, the hoist 150 is moved. By reactivating, the prevention tab 11 is completely lowered and seated on the upper surface of the nozzle 105, and at the same time, the opening / closing valve 36b of the gas supply line 35b is opened to combustible gas through the inner pipe 35. Supply.

In this case, the combustible gas supplied into the inner pipe 35 is ignited by the molten steel, and the temperature of the molten steel M remaining in the ladle 110 is reduced by the heat source of the ignited gas.

When the gas is ignited, the slag S is not introduced into the nozzle and pushed out by the ejection pressure of the flame discharged through the slag discharge port 14 of the prevention tab 11, whereas the prevention tab 11 is pushed out. Through the molten steel inlet 12 formed in the lower end of the bottom), only the pure molten steel of the lowest layer is supplied into the tundish 120 through the nozzle 105 of the bottom surface.

In addition, since the heat of combustion by the flame of the combustible gas discharged through the slag discharge port 14 plays the same role as the burner, the temperature of the inner surface of the ladle (1) in which the exposed area is increased by casting of molten steel is decreased. prevent.

Meanwhile, when the molten steel of the ladle 110 is supplied into the tundish 120 and the molten steel supplied into the tundish 120 is injected into the mold to cast the slab, the gas supply line 35 of the gas supply line 35 is completed. In a state where the supply valve of the combustible gas is closed by closing the on / off valve 36b, the hoist 150 is lifted to draw the gas injection lance 31 out of the ladle, and is mounted at the lower end of the lance 31. When the tab 11 is drawn out, close the on / off valve 36a of the cooling water supply line 33b, and judge whether to reuse the prevented tap 11 drawn out, if it is difficult to reuse, replace it with a new one and then Wait for work

According to the present invention as described above, by preventing the vortex phenomenon of the molten steel occurring at the end of the casting, and by supplying only the selected molten steel of the lowest layer to the tundish through the nozzle, it is prevented from entering the molten steel into the tundish By minimizing the molten steel remaining in the ladle, it is possible to improve the error rate of the molten steel, and to prevent the occurrence of the ingot.

In addition, by preserving the temperature loss of molten steel and ladle generated during long time casting to the maximum, it reduces the cost of manufacturing molten steel by shortening the blowing time, and prevent the clogging phenomenon of the immersion nozzle to prevent the casting is stopped. Is obtained.

While the invention has been shown and described with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit or scope of the invention as set forth in the claims below. I would like to clarify that knowledge is easy to know.

Claims (5)

In the facility for supplying the molten steel in the ladle 110 into the tundish 120 through the immersion nozzle 107, It is disposed on the nozzle 105 formed on the bottom surface of the ladle 110, and has a cylindrical prevention tab 11 formed with a plurality of molten steel inlet 12 and the slag discharge port 14, the lowest selected molten steel (M) only the mixing prevention portion 10 to flow; The heat insulating cover 51 covering the upper part of the ladle 110 to prevent the high heat in the ladle from being released into the atmosphere during casting of the gas blowing lance 31, the lower end of which is assembled on the upper surface of the prevention tab 11. It is equipped with a lance inlet 52 so as to be movable in Shanghai to ignite the flammable gas supplied into the prevention tab 11 to maintain molten steel temperature, and blow out slag S on the hot water surface of the molten steel in the ladle 110. Slag mixing prevention device for molten steel casting, characterized in that it comprises a gas blowing portion (30). The method of claim 1, Here, the molten steel inlet opening 12 of the molten steel casting slag mixing prevention device, characterized in that more than twice the opening area of the nozzle 105 so that the supply of the molten steel through the nozzle can be made smoothly. The method of claim 1, At the lower end of the gas blowing lance 31, when the gas blowing lance 31 is lowered, it is inserted into a fastening groove 16a of an inner circumferential surface of the insertion hole 16 formed through the upper surface of the prevention tab 11. When the lower end of the gas blowing lance 31 completely passes through the insertion hole 16, a plurality of tab fixing members 32 having an inverted triangular cross section, which are caught by the lower end of the fastening groove 16a, are provided. Slag mixing prevention device for molten steel casting. The method of claim 1, The gas injection lance 31 is an external pipe 33 to which cooling water is supplied through the cooling water supply line 33b, an intermediate pipe 34 for discharging the cooling water circulated through the cooling water discharge line 34b, and a gas supply. An inner pipe 35 through which the combustible gas is supplied through the line 35b and a lance nozzle connected between an end of the outer pipe 33 and an end of the inner pipe 35 to circulate the cooling water and discharge only the combustible gas ( Slag mixing prevention device for molten steel casting, characterized in that consisting of 31a). The method of claim 1, The outer surface of the gas injection lance 31 is inserted into the lance inlet 52 of the heat insulating cover 51 covering the upper portion of the ladle 110 to prevent the high heat inside the ladle during the casting to the atmosphere to the outer peripheral surface Slag mixing prevention device for molten steel casting, characterized in that it comprises a heat-resistant lance packing (38) in close contact.

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