KR20180094236A - Molten metal transfering apparatus - Google Patents

Abstract

According to the present invention, a molten metal transfer apparatus comprises: a nozzle formed to extend in a direction in which a tundish is placed from a ladle, and provided with a path in which molten metal is moved; and a gas supply unit connected to the nozzle, and provided with a gas supply unit to supply inert gas to the nozzle and a control unit differently controlling a flow rate of the inert gas supplied to the nozzle in accordance with a casting time in a casting section from a casting start time to supply the molten metal to the tundish to a casting finish time. Therefore, according to an embodiment of the present invention, in accordance with the casting time, a flow rate to supply the inert gas to the nozzle through which the molten metal of the ladle is transferred to the tundish is controlled to remove an inclusion in the tundish and prevent ladle slag from being mixed.

Description

{MOLTEN METAL TRANSFERING APPARATUS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten steel feeder, and more particularly, to a molten steel feeder capable of easily removing inclusions or preventing or suppressing inclusion of slag.

The continuous casting facility is a facility for producing cast steel by receiving refined molten steel from steelmaking facilities. It is composed of a ladle for transporting molten steel, a tundish for temporarily storing molten steel supplied from the ladle, A mold for continuously solidifying molten steel from the molten steel by a slab, and a cooling device for performing a series of molding operations by secondary cooling the cast steel continuously withdrawn from the mold. In addition, it includes a shroud nozzle for supplying the molten steel of the ladle into the turndish, and an immersion nozzle for supplying the molten steel of the turndish as a mold.

The surface quality of the cast steel is determined by the cleanliness of inclusion of molten steel. For example, if the cleanliness of the molten steel with respect to the inclusions is poor, defects may occur on the surface of the slab due to the inclusions themselves, and the immersion nozzle may be clogged by the inclusions.

Particularly, when the ladle molten steel is transferred to the tundish, the molten steel is brought into contact with the air, and nitrogen is picked up as molten steel to oxidize elements having high affinity to oxygen such as Al, Si, Cr, Ti, Reactivation occurs. Such reoxidation forms inclusions, and as inclusions are supplied to the mold without being removed from the tundish, the interior and surface quality of the cast steel are deteriorating.

In order to solve this problem, a shroud nozzle is provided between the ladle and the tundish, and the molten steel of the ladle is supplied through the shroud nozzle as a tundish. However, even in such a supply method, inclusion generation due to re-oxidation of molten steel is still occurring.

In addition, the slag in the ladle contains FeO, MnO, SiO2, TiO2 and the like which cause reoxidation. At the end of the casting in which the height of the residue in the ladle is low, a vortex is generated in the ladle, There is a problem of coming in, that is, mixing of slag.

However, if a large amount of residue is left in the ladle, it is possible to prevent the inclusion of the slag. However, since the cost for disposal of the residue and the cost of the alloy steel are wasted, the overall error rate is lowered, have.

United States Patent 4,836,508

The present invention provides a molten steel feeder which is capable of easily removing inclusions in molten steel and preventing mixing of slag when molten steel is supplied through a nozzle in a turn-dish.

The present invention relates to a molten steel feeder for feeding molten steel in a ladle to a turn-dish, comprising: a nozzle extending from the ladle in a direction in which the turn-dish is located and having a passage through which the molten steel is moved; And a gas supply unit connected to the nozzle and supplying an inert gas to the body, and a gas supply unit for supplying inert gas to the nozzle according to a casting time from a casting start point to a casting end point, And a gas supply unit having a control unit for controlling the flow rate of the inert gas differently.

Wherein the nozzle includes a body provided with a passage through which the molten steel flows, and the gas supply unit is installed in the body so that one end thereof is inserted into the body and is connected to the passage of the body, A porous member having a hollow shape opened at the center to correspond to the passage of the body and having an inner wall surface exposed through the passage of the body in the interior of the body, A second type gas supply unit including a supply member for supplying an inert gas to a member, and a pair of plate members spaced apart from each other so as to face each other in the body, wherein the inert gas passes between the pair of plate members At least one of the third type gas supply units including the slit member having a slit It should.

The gas supply unit includes two of the first to third type gas supply units, and they are vertically spaced apart.

The nozzle includes a case installed to cover an upper circumferential surface of the body including the periphery of an inlet through which molten steel flows into the body.

At least one of the first to third gas supply units is installed so as to extend to the inside of the case.

Wherein the gas supply unit supplies the inert gas to the nozzle at a first flow rate in a first section from the starting point of the casting to the end of the casting at the second section, Supplying an inert gas to the nozzle at a second flow rate that is greater than the first flow rate and supplying an inert gas to the nozzle at the first flow rate in the first section by using any one of the first to third gas supply sections do.

Wherein the gas supply unit supplies the inert gas to the nozzle at a first flow rate in a first section from the start of casting to the end of casting,

Supplying an inert gas to the nozzle at a second flow rate that is larger than the first flow rate in a second section from the end of casting to the end of casting, and in the first section, An inert gas is supplied to the nozzle at a first flow rate using one of the first and second gas supply units and an inert gas is supplied to the nozzle at a second flow rate using the other of the first to third type gas supply units in the second section .

Wherein the gas supply unit includes the first type gas supply unit and the second type gas supply unit and supplies the inert gas to the nozzle at the first flow rate using the first type gas supply unit in the first section, And the inert gas is supplied to the nozzle at a second flow rate by using the second gas supply unit in the second interval.

Wherein the gas supply unit includes the second type gas supply unit and the third type gas supply unit and supplies the inert gas to the nozzle at a first flow rate using the third type gas supply unit in the first section, And the inert gas is supplied to the nozzle at a second flow rate by using the second gas supply unit in the second interval.

Wherein the gas supply unit includes the first type gas supply unit and the third type gas supply unit and supplies the inert gas to the nozzle at the first flow rate using the third type gas supply unit in the first section, And the inert gas is supplied to the nozzle at the second flow rate using the first type gas supply unit in the second interval.

According to the molten steel feeder of the embodiment of the present invention, by controlling the supply flow rate of the inert gas to the nozzle through which the molten steel is transferred in the turndish according to the casting time, the inclusion in the tundish is removed, Can be prevented.

Therefore, when the molten steel in the turn-off is supplied to the mold through the nozzle, the inclusions can not be moved to the mold, or can be suppressed as compared with the prior art. Further, it is possible to prevent the ladle slag from being inserted into the nozzle as compared with the prior art, and to prevent the molten steel from being reoxidized by the ladle slag.

1 is a conceptual diagram showing a casting facility to which a molten steel feed apparatus according to an embodiment of the present invention is applied;
2 is a view showing a gas supply device according to a first embodiment of the present invention;
3 is a view showing a part of a first nozzle and a gas supply part connected thereto according to a modification of the first embodiment
4 is a view showing a gas supply device according to a second embodiment of the present invention;
5 is a view showing a gas supply device according to a third embodiment of the present invention
6 is a view showing a gas supply device according to a fourth embodiment of the present invention
7 is a view showing a gas supply device according to a fifth embodiment of the present invention
Fig. 8 is a conceptual illustration of the flow rate control of the inert gas according to the casting timing or the timing

Hereinafter, embodiments of the present invention will be described in detail. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.

FIG. 1 is a conceptual diagram showing a casting facility to which a molten steel conveying apparatus according to an embodiment of the present invention is applied. 2 is a view showing a gas supply apparatus according to a first embodiment of the present invention. 3 is a view showing a part of a first nozzle and a gas supply unit connected thereto according to a modification of the first embodiment. 4 is a view showing a gas supply apparatus according to a second embodiment of the present invention. 5 is a view showing a gas supply apparatus according to a third embodiment of the present invention. 6 is a view showing a gas supply device according to a fourth embodiment of the present invention. 7 is a view showing a gas supply apparatus according to a fifth embodiment of the present invention. FIG. 8 is a conceptual view illustrating the flow rate control of the inert gas according to the casting time or the time point.

1, a casting facility for casting a cast steel by solidifying molten steel includes a ladle (L) for taking molten steel, a turn-dish (100) for temporarily storing molten steel supplied from the ladle (L) A molten steel feeder 400 having a nozzle (first nozzle 200) for supplying the tundish 100 and a gas supply for regulating the flow rate of the inert gas supplied to the first nozzle 200, a tundish 100 And a nozzle (a second nozzle 600) for supplying molten steel in the tundish 100 to the mold 500. The mold 500 includes a nozzle 500 for supplying molten steel to the mold 500, Although not shown, there are provided guide rolls arranged to be arranged in the casting direction on the lower side of the mold 500 and rotationally driven so as to facilitate the movement of the casting sheet pushed out of the mold 500, and nozzles for injecting cooling water into the casting strips to be moved And a plurality of segments.

The ladle L according to the embodiment is a kind of container which is provided with the molten steel after completion of the refining of the electrolytic solution and provided to the turn-dish 100. The ladle L is a general construction in the iron making, steel making or casting field. The ladle (L) according to the embodiment may be provided in a volume capable of accommodating 270 tons (Ton) to 300 tons (Ton) of molten steel.

The tundish 100 includes a main body 110 having an inner space for receiving molten steel introduced from the ladle L and having a discharge hole 111 through which molten steel is discharged, And a dam 120 installed between the weir 130 and the discharge hole 111 so that one end of the weir 130 is connected to the bottom of the main body 110.

The main body 110 of the turn-dish 100 is a means for temporarily storing molten steel introduced from the ladle L and supplying the temporarily stored molten steel to the mold 500 located below the turn dies 100. A first nozzle 200 is provided to connect the ladle L and the tundish main body 110 and a second nozzle 600 is provided to connect the tundish main body 110 and the mold. The discharge hole 111 is an opening provided to penetrate a part of the bottom of the main body 110 and is preferably provided at one side from the center of the bottom of the main body 110.

The second nozzle 600 is a nozzle commonly referred to as a submerged entry nozzle (SEN) in the related art. The upper nozzle is communicated with the discharge hole 111 from the lower portion of the main body 110, (500). The molten steel supplied to the turn-on body 110 is injected into the mold 500 through the discharge hole and the second nozzle 600.

A dam 120 and a weir 130 are installed in the body of the tundish 100 in order to increase the residence time of the molten steel and to form an upward flow and floating the nonmetallic inclusions in the molten steel.

The dam 120 is installed on the floor inside the turn-key body 110, the lower part is connected to the bottom of the main body 110, and the upper space of the upper part has a structure for moving the molten steel. More specifically, the dam 120 has a block shape of a predetermined shape, and its length or height in the up and down direction is smaller than the height of the main body. When the dam 120 is mounted on the bottom of the main body 110, the upper space of the dam 120 serves as a passage through which the molten steel can pass.

The weir 130 is disposed between the first nozzle 200 and the dam 120 in the turn-on body 110 and the lower end of the weir 130 is spaced apart from the bottom of the main body 110, Allow the molten steel to pass through. More specifically, the weir 130 has a block shape of a predetermined shape, and its length or height in the up and down direction is smaller than the height of the body. The upper end of the weir 130 is connected to the upper part of the main body 110, the turn-dish cover or other components located above the main body 110, and the lower end is installed to be spaced apart from the bottom of the main body 110, Lt; / RTI >

1, when the weir 130 and the dam 120 are installed in the turn-on body 110, the molten steel flows through the weir 130 and the dam 120, Thereby increasing the residence time of the molten steel between the weir 130 and the dam 120. The molten steel supplied from the first nozzle 200 into the turn-on body 110 moves toward the discharge hole 111 provided at the bottom of the main body 110. At this time, The molten steel moving in the direction of the weir 130 first collides with the weir 130 to change its flow (A in FIG. 1), pass through the lower portion of the weir 130 and move between the weir 130 and the dam 120 (B and C in Fig. 1). The molten steel that has moved between the weir 130 and the dam 120 flows directly into the space above the dam 130 and moves toward the discharge hole 111 (B in FIG. 1) 1), and both flows are passed to the upper space of the dam 120 (D in FIG. 1), so that one side space of the dam 120 And is then moved toward the discharge hole 111. As shown in FIG.

The molten steel feeder 400 according to the embodiment is a device for supplying molten steel of the ladle L to the turndisc 100. The molten steel feeder 400 is connected to one end of the ladle L and the other end of the ladle L And a gas supply unit 300 connected to the first nozzle 200 and the first nozzle 200 for supplying an inert gas such as Ar (argon) gas and controlling the flow rate or the flow rate of the inert gas.

The first nozzle 200 is a means for supplying molten steel taken in the ladle L to the turn-dish 100, and may be a device commonly referred to in the art as a shroud nozzle. One end of the first nozzle 200 is connected to the ladle L to communicate with the inside of the ladle L and the other end of the first nozzle 200 is extended to be located in the turndisse 100.

Hereinafter, the molten steel conveying apparatus 400 according to the embodiments of the present invention will be described with reference to FIGS. 2 to 7. FIG.

The first nozzle 200 according to the first embodiment includes a first end opposed to the ladle L and a second end opposite to the tundish 100. The first nozzle 200 extends in one direction, And a case 220 installed to cover an outer circumferential surface of an upper part of the body 210 including one end of the body 210.

The body 210 is installed to connect between the ladle L and the turn-dish 100 and serves to supply or move the molten steel in the ladle L to the turn-dish 100. The body 210 has a shape extending from the ladle L in the direction in which the tundish 100 is positioned, that is, in the vertical direction. The upper opening (hereinafter referred to as the inlet 22) And the lower opening (the discharge port 23) is provided so as to be located inside the turn-dish 100. The body 210 serves as a passage for transferring high-temperature molten steel, and thus may be made of a material having heat resistance, for example, a refractory material. More specifically, the body 210 may be formed of a refractory material composed of at least one of Al ₂ O ₃ , SiO ₂ , SiC,

The case 220 is formed so as to surround the outer circumferential surface of the upper part of the body 210 and opens in a direction corresponding to the inlet port 22 of the body 210. At this time, the case may be installed so as to cover an outer circumferential surface corresponding to the upper side of the body 210 and an upper surface of the body 210 corresponding to the vicinity of the inlet of the body 210. Such a case may be formed of a metal.

The shape of the body 210 according to the first embodiment will be described in more detail as follows. At this time, the change in diameter of the passage 21 of the body 210 will be described.

Referring to FIG. 2, the body 210 according to the first embodiment includes a first body 211 having a first passage 21a having a diameter narrowing downward from the inlet 22, A second body 212 connected to a lower portion of the first body 211 and having a second passage 21b communicating with the first passage 21a of the first body 211 and having the same diameter in the extending direction, 212 and communicates with the second passage 21b of the second main body 212. The diameter of the second passage 21b gradually decreases from the lower end of the second passage 21b toward the lower end thereof, And a third main body 213 having a third passage 21c formed so as to have a predetermined length. The first nozzle 200 having such a shaped body 210 is referred to in the art as a bell type nozzle.

In addition, the shape of the body 210 is not limited to the first embodiment shown in Fig. 2 but can be modified as shown in Fig.

For example, the body 210 may include a first body 21a having a first passage 21a having a diameter narrowing downward from the inlet 22, as in the first modification of the first embodiment shown in Fig. 3a 211 and a second body 212 connected to a lower portion of the first body 211 and having a second passage 21b communicating with the first passage 21a of the first body 211 and having the same diameter in the extending direction, ). The extension length of the second body 212 is longer than the extension length of the second body 212 of the body 210 according to the first embodiment. The sum of the lengths of the extension portions 213 may be the same or similar. The first nozzle 200 having the body 210 of this shape is called a slit type nozzle in the related art.

As another example, the body 210 may further include a refractory member 230 made of refractory material different from the body. For example, a body 210 and other refractory members may be inserted into a lower portion of the second body 212 of the body 210 according to the first modification of FIG. 3B, FIG.

The molten steel in the ladle L is supplied to the turn-dish 100 through the first nozzle 200. However, even if the molten steel of the ladle L is supplied through the first nozzle 200 by turning, the contact between the molten steel and the air can not be completely blocked. Therefore, the nitrogen in the air of the molten steel is picked up as molten steel, or a re-oxidation phenomenon occurs in which Al, Si, Cr, Ti, Mn, and Fe in the molten steel having a high affinity with the oxides react with oxygen in the air, A nonmetallic inclusion (hereinafter referred to as an inclusion) such as Al ₂ O ₃ is formed. If molten steel having inclusions is directly supplied to the mold 500 and casting the cast steel, it may cause the inside of the cast steel and cause surface defects.

In the slag (i.e., ladle slag) on the molten steel bath surface in the ladle L, FeO, MnO, SiO ₂ , TiO ₂ When the height of the molten steel (i.e., residue) in the ladle L is lowered at the end of casting, a vortex is generated. By this eddies, the ladle slag is supplied with the molten steel together with the first nozzle 200 There is a problem that comes in and moves to the tundish.

Therefore, in the present invention, when molten steel in the ladle L is fed or supplied to the turn-dish 100 through the first nozzle 200, the inert gas is injected into the first nozzle 200, The inclusion of the molten steel is removed, and the occurrence of molten steel vapors in the ladle L is suppressed at the end of casting to prevent the slag from flowing into the turn-dish 100.

To this end, a gas supply unit 300 having a gas supply unit for supplying an inert gas to the first nozzle 200 is provided. The gas supply unit 300 is a means for supplying an inert gas into the first nozzle 200. When the molten steel is transferred or supplied to the first nozzle 200 to supply the molten steel of the ladle L in turn, Inert gas is supplied to the first nozzle 200 to prevent inclusion of molten steel in the turn-dish 100 and to prevent the ladle slag from flowing into the first nozzle 200.

The gas supply unit 300 according to the first embodiment includes a gas storage part storing an inert gas such as Ar (argon) gas, one end connected to the gas storage part and the other end connected to the upper part of the body 210, 220, and a control unit for controlling the flow of the inert gas supplied to the gas supply unit and the communication between the gas supply unit and the gas storage unit. The control unit may include a valve 330 installed on the extension path of the gas supply unit to control the communication between the gas storage unit and the gas supply unit and a mass flow meter 320 to adjust the gas supply flow rate .

The gas supply unit 310a according to the first embodiment is a pipe type having an internal space through which an inert gas flows and is referred to as a first type gas supply unit 310a for convenience of explanation.

That is, in the first embodiment, the first type gas supply unit 310a is connected to the first nozzle 200. The first type gas supply unit 310a is installed to penetrate the case 220. More specifically, the first type gas supply unit 310a includes a case 210, which is positioned on the upper surface of the body 210 corresponding to the vicinity of the inlet 22 of the body 210, And the other end is exposed to the inner circumferential surface of the case 220 so as to communicate with an inlet port located in the case 220 or an upper passageway in the body 210. [

In the first embodiment, when the molten steel of the ladle L is fed or supplied to the turn-dish 100 through the first nozzle 200 by using the gas supply unit including the first-type gas supply unit 310a, Inert gas is injected into the first nozzle 200 to remove inclusions in the molten steel in the tundish 100 and suppress the occurrence of molten steel flow in the ladle L at the end of the casting so that the slag is turned into the turn- Thereby preventing inflow.

Here, the casting end point may be a point at which the vortex starts to be generated in the ladle L. More specifically, the end of casting is divided according to the amount of molten steel remaining in the ladle L. The amount of molten steel remaining in the ladle L by continuous casting is 8% to 12% of the amount of molten steel first taken into the ladle L before casting, Is set at the end of casting. The time point at which the remaining amount of molten steel in the ladle L becomes about 10% of the amount of the molten steel which was first taken into the ladle L before casting is regarded as the end point of the casting.

In the embodiment of the present invention, in supplying or conveying the molten steel to the first nozzle 200, the flow of the inert gas from the starting point of the casting to the end point of the casting and the end of casting from the starting point of the casting end, Make the flow different. That is, until the flow of bubbles generated as the inert gas or the inert gas flows into the molten steel in the tundish becomes a downward flow that is transferred to the downside in the turn-dish 100, At the end of the casting, at least a part of the flow of the inert gas has an upward flow in the direction in which the ladle L is located.

Hereinafter, the first section from the start of casting to the end of casting is referred to as a first section, and the end of casting to the end of casting is referred to as a second section.

In the first section, the inert gas may mean that the main stream is a down stream, and there is no up stream or almost no occurrence. The reason for forming the downflow of inert gas in the first section is to generate a bubble due to collision between the downflow inert gas and the inner wall of the turn-dish 100, for example, the lower wall. When bubbles are generated, the inclusions are attached to the surface of the bubbles, and the bubbles float upward because the specific gravity is small. That is, the inclusions are attached to the surface of the bubble formed by the downward flow of the inert gas, and the inclusions are removed from the molten steel, that is, removed from the molten steel, that is, the bubbles with the inclusions floated on the molten steel bath surface.

The fact that at least a part of the flow of the inert gas in the second section generates an upward flow means that a portion of the flow of the inert gas supplied to the first nozzle 200 is a downward flow toward the turndisse 100, And a part thereof means an upward flow toward the ladle (L) side. At this time, the intensity of the ascending flow or the ascending flow rises above the flow of the molten steel conveyed through the first nozzle 200 at the end of the casting and rises to the ladle L, So that it is possible to prevent the occurrence of vortexes by interfering with the flow.

The supply of the inert gas in the first section and the second section will be described in other words as follows.

In the embodiment of the present invention, in supplying or transporting molten steel to the first nozzle 200, the flow rate of the inert gas in the first section is relatively small (hereafter referred to as the first flow rate), the flow rate of the inert gas in the second section Is larger than the first flow rate. Here, the first flow rate, which is the flow rate of the inert gas in the first section, and the second flow rate, which is the flow rate of the inert gas in the second section, are more specifically the amount of inert gas per minute .

At this time, in controlling the flow rate of the inert gas supplied and flowing into the first nozzle 200 in the first section, the bubbles generated in the molten steel in the turn-dish 100 flow downward in the turn-dish 100, 100) so that fine bubbles are generated. More specifically, in the first section, the first flow rate of the inert gas supplied and supplied into the first nozzle 200 is adjusted to 5 to 20 L / min.

In order to regulate the flow rate of the inert gas supplied and flown into the first nozzle 200 in the second section, the flow rate of the inert gas is adjusted so that the upward flow of the first nozzle 200 or the flow of the ladle L . As a more specific example, the second flow rate of the inert gas supplied and flowing into the first nozzle 200 in the second section is controlled to be not less than 100 L / min and not more than 200 L / min.

For example, when the flow rate of the inert gas is more than 20 L / min or less than 3 L / min, the amount of descending flow relatively decreases, or the amount of bubbles adsorbed by the inclusions is reduced, .

Therefore, in order to induce flotation of inclusions by bubbles in the first section, an inert gas is supplied to the first nozzle 200 through which molten steel flows at a first flow rate of 5 to 20 L / min to form a descending flow Thereby generating bubbles.

In addition, for example, when the flow rate of the inert gas is less than 100 L / min, the upflow upward flow in which the ladle L is located does not occur, or the flow of the vapors in the ladle L in the second section is prevented or suppressed A rising flow is not generated. Therefore, the ladle slag can be introduced into the turn-off by the occurrence of a vortex in the ladle L in the second section.

On the other hand, when the flow rate of the inert gas is more than 200 L / min, a hunting phenomenon occurs in which the degree of change of the flow rate of the inert gas supplied to the first nozzle 200 is too large, have.

Accordingly, in order to suppress vortex generation in the ladle L in the second section, the inert gas is supplied to the first nozzle 200 through which molten steel flows at a flow rate of 100 L / min or more and 200 L / min or less, The slag in the ladle L can be restrained or prevented from flowing into the molten steel of the turn-dish 100. As a result,

In the above description, the first type gas supply unit 310a is connected to the first nozzle 200 according to the first embodiment as shown in FIG. However, the present invention is not limited thereto. As shown in FIG. 3, the first type gas supply unit 310a may be applied to the first nozzle 200 according to the first and second modified examples.

The gas supply unit is not limited to the above-described first embodiment, and various embodiments can be applied.

Referring to Fig. 4, the gas supply unit according to the second embodiment further includes the porous member 311b as compared with the first embodiment. That is, the gas supply unit according to the second embodiment is provided inside the body 210 of the first nozzle 200, and includes a porous member 311b having a plurality of fine holes or pores and a porous member 311b having one end inserted into the body 210 And a supply member 312b connected to the porous member 311b. Hereinafter, for convenience of explanation, the gas supply unit is referred to as a second type gas supply unit 310b.

The porous member 311b is made of a porous and refractory material having fine holes or pores through which gas can pass, and may be made of, for example, ZrO ₂ -C (zirconia carbonaceous). Of course, the porous member 311b is a refractory material, and it is possible to apply various porous materials having a plurality of fine holes or pores.

The porous member 311b has a hollow shape opened at the center so as to correspond to the passage 21 of the first nozzle 200 and has an inner wall surface facing the passage in the body 210 exposed through the passage of the body 210 Respectively. In this case, in the second embodiment, the porous member 311b is installed inside the upper part of the body 210, and may be installed inside the body 210 covered by the case 220. [ That is, the porous member 311b may be installed on the body 210 corresponding to the inside of the case 220 without vertically shifting to the outside of the case 220. More specifically, when the first nozzle 200 is the bell type of the first embodiment shown in FIG. 2, the porous member (not shown) may extend from the first body 211 to a portion of the second body 212 311b may be installed.

By controlling the area of the porous member 311b, it is possible to control the gas flow rate supplied to the passage of the nozzle.

The supply member 312b is a means for supplying an inert gas to the porous member 311b and has one end connected to the gas reservoir and one end connected to one surface of the porous member 311b facing the passage of the first nozzle 200 Inner wall surface), and may be connected to a back surface opposite to the one surface, or may be installed between one surface and the back surface. The inert gas transferred by the supply member 312b is supplied to the passage 21 of the first nozzle 200 through the porous member 311b. At this time, the inert gas introduced into the porous member 311b moves and diffuses through the plurality of pores of the porous member 311b, and is transferred to the passage 21 in the first nozzle 200. [

In addition, inactive feeding at the time of feeding molten steel is the same as in the first embodiment described above. That is, an inert gas is supplied to the supply member at a flow rate of 3 to 20 L / min in the first section, and an inert gas is supplied to the supply member at a flow rate of 100 to 200 L / min in the second section.

The gas supply unit including one of the first type gas supply unit 310a and the second type gas supply unit 310b has been described above. However, the present invention is not limited to this, and may include a plurality of different types of gas supply units.

For example, the gas supply unit 300 shown in FIG. 5 includes a first type gas supply unit 310a and a second type gas supply unit 310b. At this time, the first type gas supply unit 310a may be installed on the upper side and the second type gas supply unit 310b may be installed on the lower side of the first type gas supply unit 310a. More specifically, the first type gas supply unit 310a is installed to penetrate the case 220 so as to be inserted into the upper part of the body 210, and the second type gas supply unit 310b is installed in the lower body of the case 220 As shown in FIG.

Of course, the first type gas supply unit 310a may be installed below the case 220, and the second type gas supply unit 310b may be disposed above the case 220 and the first type gas supply unit 310a .

When gas supply units of different types are installed up and down, different types of gas supply units are used in the first and second sections.

That is, when the first and second type gas supply units 310b are installed up and down, the first type gas supply unit 310a is used to supply the inert gas at a first flow rate, that is, 3 to 20 mL / min, It is effective to supply the inert gas at the second flow rate, that is, 100 L / min to 200 L / min, using the second type gas supply part 310b including the porous member 311b in the second section.

In the third embodiment described above, the gas supply unit 300 including the first type gas supply unit 310a and the second type gas supply unit 310b has been described. However, the present invention is not limited thereto, and may include a third type gas supply unit 310c described later.

The third type gas supply unit 310c includes a pair of plate members 31c spaced apart from each other to face each other and a slit 32 capable of passing an inert gas between the pair of plate members 31c And a supply member 312c for supplying an inert gas to the slit member 311c.

Here, the slit member 311c partitioned by the pair of plate members 31c is a size considerably smaller than the diameter of the pipe serving as the first type gas supply unit 310a, and is 0.1 mm or less, more specifically, several m or less . The plurality of slit members 311c may be spaced apart from each other. Hereinafter, the gas supply unit including the slit member 311c will be referred to as a third type gas supply unit 310c.

The gas supply unit 300 according to the fourth embodiment is installed such that the second type gas supply unit 310b is located on the upper side and the third type gas supply unit 310c is located on the lower side. More specifically, the porous member 311b of the second type gas supply unit 310b is installed inside the body 210 on which the case 220 is installed, and the slit member 311c of the third type gas supply unit 310c, Is installed inside the body 210 below the case 220 and the porous member 311b.

Of course, the second type gas supply unit 310b may be disposed below the case 220, and the third type gas supply unit 310c may be disposed above the case 220 and the second type gas supply unit 310b.

When the second and third gas supply units 310b and 310c are installed vertically, the inert gas is supplied at a first flow rate, that is, 3 to 20 mL / min, by using the third gas supply unit 310c in the first section. It is effective to supply the inert gas at the second flow rate, that is, 100 L / min to 200 L / min by using the second type gas supply part 310b including the porous member 311b in the second section.

In the third and fourth embodiments described above, it is described that the gas supply unit 300 includes the second type gas supply unit 310b and the first and third type gas supply units 310a, 310b, and 310c Respectively.

However, the present invention is not limited thereto and may include a first type gas supply unit 310a and a third type gas supply unit 310c which do not include the porous member 311b, as in the fifth embodiment shown in FIG.

Referring to FIG. 7, the gas supply unit 300 according to the fifth embodiment includes a third type gas supply unit 310c installed on the upper side and a first type gas supply unit 310a provided on the lower side. The slit member 311c of the third type gas supply unit 310c is installed inside the case 220 and the upper part of the body 210. The first type gas supply unit 310a includes a case 220 and a third type And is disposed below the gas supply unit 310c.

When the first and third gas supply units 310a and 310c are installed vertically, the inert gas is supplied at a first flow rate, that is, 3 to 20 mL / min, using the third gas supply unit 310c in the first section. It is effective to supply the inert gas at the second flow rate, that is, 100 L / min to 200 L / min using the first type gas supply unit 310a in the second section.

For example, when the first nozzle 200 is a vertical type and the first-type gas supply part 310a is installed on the lower side, a portion of the passage 21, which is a transport path of molten steel, (210). That is, when extending from the second passage 21b to the third passage 21c, the area from the second passage 21b to the lower section is enlarged. The third passage 21c, It is effective to connect the first type gas supply unit 310a to be connected to the third body 213 which is connected to the first type gas supply unit 310a.

This is to prevent the first type gas supply unit 310a from being clogged with molten steel flowing along the passage of the first nozzle 200 when the inert gas is not supplied to the first type gas supply unit 310a. That is, when the molten steel is transferred to the third passage 21c through the first passage 21a and the second passage 21b, the molten steel flows down at least the inner wall surface around the first and second passages 21b. When the first type gas supply unit 310a is installed in the first and second main bodies 211 and 212, the molten steel flowing through the inner wall surface around the first and second passages 21a and 21b, 1 type gas supply unit 310a may be clogged. However, when molten steel flows from the second passage 21b to the third passage 21c, the molten steel flows at a width corresponding to the area of the second passage 21b, so that molten steel flows from the second passage 21b to the third passage 21c Type gas supply portion 310a does not flow through the inner wall surface of the upper portion of the third passage 21c extending to the first-type gas supply portion 310a.

Of course, the first type gas supplying part 310a may be installed so as to penetrate the case and the upper part of the body. When the first type gas supplying part 310a is clogged, the inert gas may be supplied to the inside of the first type gas supplying part 310a. have.

The first type gas supply unit 310a and the third type gas supply unit 310c may be applied to the first nozzle 200 according to the first and second modified embodiments. 310a may be clogged, an inert gas may be supplied to the interior to once pierce the opening.

The above-described second to fifth embodiments are based on the shape of the body 210 of the first embodiment. However, one of the first to third gas supply portions 310a, 310b, and 310c, or two different types of gas supply portions may be applied to the nozzles of the first and second modified embodiments shown in Fig.

Hereinafter, with reference to FIGS. 1, 2, 5 and 8, a casting method using casting equipment to which a molten steel feed device is applied will be described in a second embodiment of the present invention.

First, the molten steel whose composition has been adjusted to the target component or has been refined is taken into the ladle L on the upper side of the turn-off screen. Thereafter, molten steel of the ladle L is turned on through the first nozzle 200, molten steel of the turn-dish 100 is continuously fed to the mold 500 through the second nozzle 600 (S100) The casting is solidified in the mold 500 to continuously cast the casting.

In this way, the molten steel is supplied to the first nozzle 200, and the inert gas is supplied to the first nozzle 200. At this time, it is judged in real time whether the current casting time point is at the end of casting or at the end of casting, and the flow rate or flow rate of the inert gas is controlled differently before the end of casting and after the end of casting.

That is, in order to transfer molten steel in the ladle L through the first nozzle 200 in a turn-by-turn manner, in the first section of the casting section, the first flow rate (3 to 20 L / min to supply the inert gas to the first nozzle 200. As a result, the inert gas supplied to the first nozzle 200 and the bubbles in the molten metal of the turn-dish 100 generated by the inert gas form a downward flow, and the bubbles of the downward flow collide with the inner wall of the turn- Create a bubble. The surface of the generated fine bubbles is provided with inclusions in the molten steel, and the bubbles float on the bath surface. As a result, inclusions in the molten steel in the turn-dish 100 are lifted and separated. Therefore, when the molten steel in the turn-dish 100 is supplied to the mold 500 through the second nozzle 600, the inclusions are not moved to the mold, And is suppressed as compared with the prior art.

In the second period, the inert gas is supplied to the first nozzle 200 at a flow rate of 100 L / min or more and 200 L / min or less (second flow rate) using the second type gas supply unit 310b. The flow of at least a part of the inert gas supplied to the first nozzle 200 becomes an upward flow that flows to the upper side of the first nozzle 200 or to the ladle L. [ The rising gas of inert gas is transferred to the ladle (L) to obstruct the swirling flow of the molten steel in the ladle (L), thereby suppressing the vortex generation. Particularly, the molten steel of the ladle L suppresses the generation of vortex around the opening to be discharged to the first nozzle 200, and the ascending flow prevents vortex generation around the opening, and the slag around the opening is moved away from the opening And to push it out. Thus, it is possible to prevent the ladle slag from being inserted into the first nozzle 200, as compared with the prior art, and to prevent the molten steel from being reoxidized by the ladle slag.

L: Ladle 100: Turn Dish
200: first nozzle 300: second nozzle
400: mold 500: gas supply part

Claims (9)

1. A molten steel feeder for feeding molten steel in a ladle by a turn-
A nozzle extending from the ladle in a direction in which the tundish is located and having a passage through which the molten steel is moved; And
A gas supply part connected to the nozzle to supply an inert gas to the nozzle and a gas supply part to supply inert gas to the nozzle during a casting period from the start of casting to the end of casting, A gas supply unit having a control unit for controlling the flow rate of gas differently;
And the molten steel conveying device. The method according to claim 1,
Wherein the nozzle includes a body provided with a passage through which the molten steel flows,
The gas supply unit includes:
A first type gas supply unit including a pipe having one end inserted into the body and communicating with the passage of the body and having an internal space for transferring the inert gas,
A hollow member having a hollow shape opened at the center to correspond to the passage of the body, a porous member provided inside the body such that an inner wall surface thereof is exposed through the passage of the body, and a supply member for supplying the inert gas to the porous member A second type gas supply unit,
And a slit member having a pair of plate members spaced apart from each other so as to face each other in the body, the slit member having a slit through which the inert gas can pass between the pair of plate members, The supply,
The molten steel conveying device comprising: The method of claim 2,
Wherein the gas supply unit includes two of the first to third gas supply units, and the gas supply unit is vertically spaced apart from the gas supply unit. The method according to claim 2 or 3,
Wherein the nozzle includes a case installed to cover an upper outer circumferential surface of the body including a periphery of an inlet through which molten steel flows into the body,
And at least one of the first to third gas supply units extends to the inside of the case. The method of claim 2,
Wherein the gas supply unit supplies the inert gas to the nozzle at a first flow rate in a first section from the start of casting to the end of casting,
Supplying an inert gas to the nozzle at a second flow rate larger than the first flow rate in a second section from the end of casting to the end of casting,
Wherein the inert gas is supplied to the nozzle at the first flow rate in the first section by using any one of the first to third gas supply sections. The method of claim 3,
Wherein the gas supply unit supplies the inert gas to the nozzle at a first flow rate in a first section from the start of casting to the end of casting,
Supplying an inert gas to the nozzle at a second flow rate larger than the first flow rate in a second section from the end of casting to the end of casting,
Supplying an inert gas to the nozzle at a first flow rate using any one of the first to third type gas supply units in the first section,
And supplies the inert gas to the nozzle at a second flow rate using the other one of the first to third type gas supply units in the second section. The method of claim 6,
Wherein the gas supply unit includes the first type gas supply unit and the second type gas supply unit,
Supplying an inert gas to the nozzle at a first flow rate using the first type gas supply unit in the first section,
And supplies an inert gas to the nozzle at a second flow rate using the second type gas supply unit in the second section. The method of claim 6,
Wherein the gas supply unit includes the second type gas supply unit and the third type gas supply unit,
Supplying an inert gas to the nozzle at a first flow rate using the third type gas supply unit in the first section,
And supplies an inert gas to the nozzle at a second flow rate using the second type gas supply unit in the second section. The method of claim 6,
Wherein the gas supply unit includes the first type gas supply unit and the third type gas supply unit,
Supplying an inert gas to the nozzle at a first flow rate using the third type gas supply unit in the first section,
And supplies the inert gas to the nozzle at a second flow rate using the first type gas supply unit in the second section.

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