KR20180064712A - A Submerged nozzle for continuous casting - Google Patents

Abstract

The present invention relates to an immersion nozzle for continuous casting of an improved structure. The immersion nozzle for casting according to the present invention comprises: a body unit provided in a tubular shape so that molten metal introduced into one side is discharged to the other side; an inflow unit provided at one side of the body unit and allowing the molten metal to flow from a tundish; and a discharging unit provided on the other side of the body unit for discharging the molten metal into a mold. The discharging unit is provided with at least one discharging opening on a side thereof, and the discharging opening is provided so that the molten metal discharged from the discharging opening swirls or rotates in the mold.

Description

[0001] The present invention relates to an improved submerged nozzle for continuous casting,

The present invention relates to an immersion nozzle and, more particularly, to a continuous casting apparatus for producing a metal cast, such as a bloom, a billet or a slab, in which the flow of molten metal is controlled to improve the quality of the metal casting. To an immersion nozzle.

The continuous casting process refers to a process of continuously producing metal casts such as blooms, billets and slabs by injecting molten metal, that is, molten metal into a mold and cooling it. The melt is injected from the ladle and the tundish into the mold through the immersion nozzle. The flow of molten metal into the mold and the initial solidification process are one of the factors that determine the quality of the metal cast which has been continuously cast.

For example, when the molten metal falls directly into the mold and flows into the mold, the depth of penetration deepens and the formation of the solidification layer in the lower part of the mold becomes unstable, and the molten metal supply to the molten metal surface is not smooth. On the other hand, if the flow of the molten metal in the molten metal in the direction of the molten metal surface is strong, the molten metal surface becomes unstable and the formation of solidification layer on the molten metal surface becomes uneven, and the quality of the metal molten metal may deteriorate. Therefore, efforts to control the flow of the molten metal in the mold by changing the structure of the immersion nozzle have been continued.

However, the conventional immersion nozzle is intended to improve the flow of the molten metal by changing the number of the discharge ports or increasing the swirl flow inside the immersion nozzle. This effort is insufficient to improve the flow of the molten metal, There is a problem in that it takes time and cost because the installation is necessary.

In addition, conventional continuous casting processes require electromagnetic equipment such as an electromagnetic stirrer (EMS) to control the flow of molten steel and additional efforts such as installation process, production cost, and management personnel are required.

Registration No. 10-1221466 (Announcement of Nov. 11, 2013)

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to improve the discharge part structure of the immersion nozzle to effectively increase the flow of the molten metal and to control the flow of the molten metal easily, To thereby provide an immersion nozzle for continuous casting.

The immersion nozzle for a continuous stocker according to the present invention comprises a body part provided in a tubular shape so that the molten metal introduced into one side is discharged to the other side, an inflow part provided at one side of the body part to receive the molten metal from the tundish, And the discharge port is provided with one or more discharge ports on a side surface thereof, and the discharge port is provided so that the molten metal discharged from the discharge port swells or rotates in the mold.

Further, at least one of an incident surface and an emission surface of the discharge port is provided in a parallelogram shape so that the molten metal discharged from the discharge port swirls or rotates.

In addition, the area of the exit surface of the ejection orifice is different from the area of the exit surface so that the molten metal ejected from the ejection orifice swirls or rotates.

The length of one side of the discharge port is not more than half the length of the other side.

In addition, four of the discharge ports are provided along the side surface of the discharge portion of the cylindrical shape, and at least one of the size, the position, and the oblique direction of the discharge port can be changed according to the type of the casting .

The discharge port may extend to an end of the discharge port so that at least one side of the discharge port is opened toward the other side of the submerged nozzle.

The discharge port may be tapered from the incident surface to the exit surface so that the molten metal discharged from the discharge port has a rotational force, or the exit surface may be provided in a parallelogram shape so that the shape of the discharge port is set so as to have a rotation angle of 45 degrees from the vertical direction .

Also, the casting immersion nozzle is used in a continuous casting apparatus for producing billets and blooms, and the casting face speed and the casting face temperature are controlled by providing the emission face area of the casting outlet at 1600 square millimeters or less.

The immersion nozzle for continuous casting according to the present invention can control the flow of the molten metal easily by improving the structure of the discharge portion and generate swirling flow of the molten metal at a low cost without additional installation or change in the continuous casting process, Can be produced.

1 is a schematic view showing a continuous casting apparatus according to the present invention,
2 is a perspective view and a partially enlarged view of the immersion nozzle according to the present invention,
3 is a side view of the immersion nozzle according to the present invention,
4 (a), 4 (b) and 4 (c) are side views of the discharging portion of the immersion nozzle according to the embodiment of the present invention,
FIG. 5 and FIG. 6 are perspective views of the discharging portion of the immersion nozzle according to the present invention,
7 is a comparative explanatory diagram for explaining an immersion nozzle discharge portion of the present invention (SW2, bloom) by simulation,
8 is a comparative explanatory diagram for explaining the bath surface speed and the bath surface temperature of the present invention (SW2, bloom) by simulation,
9 is a comparative explanatory diagram for explaining the mold pressure and the mold temperature of the present invention (CR, bloom) by simulation,
10 is a comparative explanatory diagram for explaining the flow of molten steel in a mold of the present invention (SW2, Bloom) by simulation,
Figure 11 is a graph illustrating comparative advantage through improved swirl flow in accordance with the present invention;
12 is a photograph of a number model test of the immersion nozzle of the present invention,
13 is a comparative explanatory diagram for explaining an immersion nozzle discharge portion of the present invention (Ver.1, Ver.2, Billet) by simulation,
14 is a comparative explanatory diagram for explaining the bath surface speed and the bath surface temperature of the present invention (Ver.1, Ver.2, billet) by simulation,
15 is a comparative explanatory diagram for explaining the bath surface temperature of the present invention (Ver.1, Ver.2, Billet) by simulation,
16 is a comparative explanatory diagram for explaining the mold pressures of the present invention (Ver.1, Ver.2, Billet) by simulation,
17 is a comparative explanatory diagram for explaining the mold temperature of the present invention (Ver.1, Ver.2, Billet) by simulation,
18 is a comparative explanatory view for explaining the flow of molten steel in the mold of the present invention (Ver.1, Ver.2, Billet) by simulation,
FIG. 19 is a diagram illustrating a comparative advantage by improving the swirling flow of the present invention (Ver.1, Ver.2, Billet) by simulation;
FIG. 20 is a photograph of a swirl flow model test result of the immersion nozzle according to the present invention,
Figs. 21, 22 and 23 are photographs showing the residence time in the mold during the water model test of the immersion nozzle according to the present invention.

Hereinafter, the immersion nozzle for casting according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention is not limited to the embodiments described herein, but may be embodied in various different forms. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

In the specification of the present invention, molten metal refers to a state in which a metal is molten during a casting operation. Since the metal is in a dissolved state, it cools and turns into a metal cast after cooling. The metal cast may be a slab, a bloom, a billet, and the like. Specifically, the molten steel in the steel casting can refer to molten steel.

Continuous casting is a method of making a molten metal continuously into a mold while cooling it in a mold. Billets, blooms, beam blanks and the like are produced. The billets are made of reinforcing bars and small-size steel bars, Is the material of the H-beam.

The molten metal, that is, the molten metal, is continuously injected into a mold (mold, frame) and solidified to produce sheets for plates, rods, wires and pipes. In continuous casting, the molten metal is poured continuously from above the water- You can then make a long metal cast from several meters to tens of meters by pulling the next hardened ingot downward.

The molten metal injected into the mold is solidified after it is filled in the mold, but in the continuous casting, there is no base and the molten metal is in the upper part in the shallower mold, and the lower part is solidified from the periphery. Thus, the molten metal portion in the form of a funnel is at the center, and the long metal pieces come out from the bottom in order.

Since the residues generated by the gas in the molten metal and the oxidation of the molten metal that are released when solidifying always float above the molten metal region, it is possible to make a long cast without bubbles, which is advantageous for mass production and quality. Particularly, it is used for manufacturing steel, copper alloy, and aluminum alloy.

Hereinafter, in the embodiment, the x-axis, the y-axis, and the z-axis are not limited to three axes on the orthogonal coordinate system but can be interpreted in a broad sense including the three axes. For example, the x-, y-, and z-axes may be orthogonal to each other, but may refer to different directions that are not orthogonal to each other.

1 is a schematic view showing a continuous casting apparatus for practicing the present invention. As shown in the drawing, the tundish 10, which is supplied with the molten metal from the ladle 70, and the immersion nozzle 100 are connected to the bottom surface of the tundish 10, The immersion nozzle 100 may be inserted. A plate member for controlling the amount of the upper nozzle (not shown) and the molten metal 20 may be further provided between the immersion nozzle 100 and the tundish 10 depending on circumstances.

The molten metal 20 is injected from the tundish 10 through the immersion nozzle 100 into the mold 30 to form a solidified layer and undergo an initial solidification process. The solidified layer emerging from the mold 30 is cooled by the cooling medium injected through the cooling unit 40, for example, a spray nozzle, to form a metal cast piece 80 in the shape of a slab, a bloom, a billet, or the like.

Then, the metal cast piece 80 is moved to the next step by the guide roll 50. Further, the casting piece 80 moved at the cutting point 60 can be cut according to a desired length and size.

The flow and initial solidification process of the molten metal 20 flowing into the mold 30 is an important factor that determines the quality and quality of the metal cast piece 80 that has been continuously cast. The present invention controls the flow of the molten metal (20) introduced into the mold (30) as described above to improve the quality of the cast metal (80).

2 is a perspective view and a partial enlarged view of the immersion nozzle 100 according to the present invention. As shown in the figure, the immersion nozzle 100 includes a body 130 formed in a tubular shape so that the molten metal 20 introduced into one side is discharged to the other side, a tundish 10 provided at one side of the body 130, And a discharging part 150 provided on the other side of the body part 130 and discharging the molten metal 20 by the mold 30.

The immersion nozzle 100 may be manufactured such that the body part 130, the inflow part 110, and the discharge part 150 are integrally formed with each other. In a case where the immersion nozzle 100 is integrally manufactured, the immersion nozzle 100 may be referred to according to the function of each component when the components of the immersion nozzle 100 are not clearly referred to but can be classified according to the function.

The immersion nozzle 100 may be made of a refractory material so as not to be deteriorated by the high-temperature molten metal 20. For example, the immersion nozzle 100 may be composed of an oxide, a nitride, a carbide, or a combination thereof. The material of the immersion nozzle 100 is exemplarily listed and is not limited to the range of this embodiment.

The immersion nozzle 100 may be provided in various sizes, shapes, and materials according to the temperature and type of the molten metal 20, the type, shape, and size of the metal slab 80 to be manufactured. And can be variously changed.

The discharging unit 150 is provided with at least one discharging opening 151 on the side thereof so that the discharging opening 151 is parallel to the discharging opening 151 so that the molten metal 20 discharged from the discharging opening 151 swirls or rotates in the mold 30. [ It is provided in a quadrangular shape. That is, at least one of the incident surface and the emission surface of the discharge port 151 is provided in a parallelogram.

As described above, since the shape of the discharge port 151 is formed in parallelograms and provided in plural, it is possible to smoothly supply the molten metal not only at low speed casting but also at high speed casting. The melt surface of the molten metal can be stabilized, and the quality of the molten metal can be stabilized by controlling the flow rate of the molten metal with respect to the variation of the casting speed and the casting width.

The molten metal 20 flowing through the inflow part 110 is gravity moved through the inside of the body part 130 in the form of a tube and then flows through the discharge port 151 to the side surface of the immersion nozzle 100 The discharge port 151 is formed in a parallelogram shape to produce an asymmetrical flow and the flow of the molten metal discharged from the upper portion of the discharge port 151 and the molten metal discharged from the lower portion of the discharge port 151 are controlled differently, Swirl flow and rotational motion.

When the discharge port 151 is formed in a parallelogram shape, the molten steel temperature in the mold 30 can be uniformly controlled by controlling the direction of the discharged molten metal 20 from clockwise to counterclockwise to control the flow. In addition, by increasing the residence time of the fluid in the mold 30, it is possible to secure the floating separation time of the components having a low specific gravity.

The area of the incident surface of the discharge port 151 and the surface of the exit surface may be different from each other so that the molten metal discharged from the discharge port 151 swirls or rotates. That is, when the discharge portion 150 is formed in a cylindrical shape and the discharge surface of the discharge portion 151 on the inner surface of the discharge portion 150 is different from the discharge surface of the discharge portion 151 on the outer surface of the discharge portion 150 The fluid flow in the melt can be controlled in relation to pressure and velocity.

The bottom portion of the discharging portion 150 may be formed in a shape protruding or swollen from the inward direction to the outward direction. The discharge part 150 may be formed in a cylindrical shape with a circular cross section and may be provided in the form of a polygonal column having a polygonal cross section.

The length of one side of the discharge port 151 can be set to be half or less of the length of the other side. That is, as shown in FIG. 2 to FIG. 4, when the length of one side of the discharge port 151 of the parallelogram is l, the length of the other side connected may be twice as long.

The position of the discharge port 151 may be provided at an intermediate portion of the height h2 of the discharge portion 150 or at 2/3 to 1/2 of the upper portion. This is to control the falling speed or pressure when the molten metal to be discharged falls into the mold 30. [

The discharge port 151 is provided to be inclined at a predetermined angle (a) with respect to the longitudinal direction of the immersion nozzle 100, that is, the vertical direction axis. Accordingly, the rotational force of the molten metal discharged by the tilted angle (a) is controlled, and it can be provided so as to be inclined within the range of 45 degrees upward to 45 degrees downward.

 In addition, the discharge portion 150 may be formed to have different diameters of the upper portion and the lower portion. For example, it can be manufactured in the shape of a funnel or in the opposite shape. In addition, a plurality of portions having different diameters may be provided by varying the diameter. As a result, the speed of the molten metal is changed while the molten metal moves through the discharge unit 150, thereby controlling the flow of the molten metal.

The discharge port 151 is formed horizontally in the lengthwise direction of the immersion nozzle 100, but may be disposed in an upward direction of 45 degrees to a downward direction of 70 degrees according to specifications of the equipment.

Four outlets 151 are provided along the side surface of the discharge part 150 in a cylindrical shape and at least one of the size, position, and oblique direction of the discharge hole 151 may be selected depending on the type of casting To be changed.

As described above, a plurality of the discharge ports 151 may be provided. It is possible to prevent the formation of the solidified layer from becoming unstable when the molten metal flows into the mold 30 directly and deeply.

4 is a side view according to an embodiment of the discharge port 150 of the immersion nozzle 100 and the discharge port 151 provided in the discharge port 150 according to the present invention. Fig. 4 (a) shows a configuration in which at least one of the emission surface and the incidence surface of the ejection orifice is formed in a parallelogram shape, and corner portions are rounded. Of course, the rounded portion of the corner can be made larger, and the rounded shape or the elliptical shape can be formed.

The height h1 of the discharge port 151 may be less than half of the height h2 of the discharge portion 150 or may be provided in the middle portion. Further, the inclination of the sides of the parallelogram can be inclined by a predetermined angle (a) with respect to the direction of the rotation axis, that is, the vertical direction, and is preferably changeable within a range of 45 degrees.

4B shows that the discharge port 151 is extended to the end of the discharge unit 150 so that at least one side of the discharge port 151 is opened toward the other side of the immersion nozzle 100. Of course, the size and shape of the open portion can be variously changed.

When a part of the discharge port 151 is opened as in the present embodiment, it is preferable that the discharge port 151 is used for an immersion nozzle for manufacturing a billet. 4 (c) shows that the discharge port 151 is formed into a parallelogram shape and the corner portion is formed into a rectangular shape instead of a round shape.

5 and 6 are perspective views illustrating the shape of the discharge portion 510 of the immersion nozzle 100 according to the present invention. Particularly, in the case of manufacturing a bloom or a billet, the discharge port 151 is formed in the shape of a parallelogram, and the size and position thereof can be variously changed. As shown in FIG. 6, it may be manufactured in a shape close to a circle, and the position and the number may be variously changed.

The discharge port 151 may be tapered from the incident surface to the exit surface so that the molten metal discharged from the discharge port 151 has a rotational force or may be tapered from the incident surface to the exit surface so that the exit surface has a parallelogram, The shape of the protrusion 151 can be provided.

Fig. 7 is a comparative explanatory diagram for explaining the immersion nozzle discharging portion 150 of the present invention (SW2, bloom) by simulation. The casting immersion nozzle is used in a continuous casting apparatus for producing billets and blooms, and the outlet surface area of the outlet 151 is set to 1600 square millimeters or less to control the bath surface speed and the bath surface temperature.

As shown in FIG. 7, in the case of the swirl flow in the blooming process, the area of the discharge port 151 compared to the conventional immersion nozzle is slightly reduced, and the discharge port shape of the parallelogram can be applied to improve the impact pressure in the mold 30 have.

 8 is a comparative explanatory diagram for explaining the bath surface speed and the bath surface temperature of the present invention (SW2, bloom) by simulation. The area of the discharge hole 151 for the generation of swirling flow is reduced, thereby increasing the bath surface speed, Respectively.

Fig. 9 is a comparative explanatory view for explaining the mold pressure and the mold temperature of the present invention (CR, bloom) by simulation, Fig. 10 is a graph for explaining the flow of molten steel in the mold of the present invention (SW2, bloom) Fig. It can be seen that the flow of molten steel is uniformly transmitted and the residence time is increased as shown in the figure.

FIG. 11 is a chart explaining the comparative advantage through the improvement of the swirling flow according to the present invention. As a result, it is possible to lower the possibility of breakout due to re-melting by securing a uniform bath surface temperature and reducing the pressure in the mold compared to the conventional immersion nozzle. Especially, when EMS electronic equipment is not applied, it is expected to be able to operate the speed of the bath surface at a rate of 11.5 centimeters per second.

Fig. 12 is a photograph of a number model test of the immersion nozzle 100 of the present invention, and Fig. 13 is a comparative explanatory view explaining the immersion nozzle discharging portion 150 of the present invention (Ver.1, Ver.2, Billet) .

As shown in FIG. 13, the immersion nozzle 100 according to the present invention for manufacturing a billet is manufactured by forming the discharge port 151 in a parallelogram Ver.1 and partly forming the discharging portion 150 in the bottom surface (Ver. 2) in which a part is opened.

Fig. 14 is a comparative explanatory view for explaining the bath surface speed and the bath surface temperature of the present invention (Ver.1, Ver.2, billet) by simulation, Fig. ) Of the bath surface temperature. Both the minimum and maximum values of the bath surface temperature were increased compared to the conventional single-nozzle immersion nozzle, and in the case of Ver.1, the bath surface temperature and the bath surface speed were the maximum.

 FIG. 16 is a comparative explanatory view explaining the mold pressures of the present invention (Ver.1, Ver.2, Billet) by simulation, and FIG. Fig. 18 is a comparative explanatory diagram for explaining the flow of molten steel in the mold of the present invention (Ver.1, Ver.2, Billet) by simulation.

The minimum bath surface temperature increased from 1371 ° C to 1425 ° C compared to the conventional single-shot immersion nozzle, and the minimum, average bath surface temperature was good, and the maximum and minimum temperature deviation were low.

The mold pressure rises due to the vertical discharge in the mold 30 and the maximum pressure position changes when the discharge angle downward adjustment and the mold maximum pressure decreases 151 pascal at 271 pascal.

17, the temperature of the lower end of the mold 30 is the highest, and the maximum position of the temperature of the mold 30 is different according to the positions of the respective discharge ports 151. [ Therefore, the lower the maximum temperature of the mold 30, the lower the possibility of breakout due to re-melting.

Fig. 19 is a diagram for explaining the comparative advantage by improving the swirling flow of the present invention (Ver.1, Ver.2, Billet) by simulation. Ver.2 minimizes the depth of immersion and reduces the impact pressure in the mold by increasing swirl flow. As a result, the superiority of the mold surface speed and the mold pressure can be obtained.

 FIGS. 21, 22 and 23 are views showing a comparison of the residence time of the molten steel in the mold 30 during the water model test of the immersion nozzle 100 according to the present invention. FIG. 20 is a photograph of the swirling flow number model test of the immersion nozzle according to the present invention, It is a photograph. This makes it possible to compare the flow of the fluid in the mold 30 and to generate a swirl flow compared to the existing product, which is advantageous for raising the surface temperature of the melt.

It can be seen that the immersion nozzle 100 according to the present invention requires about 20 seconds to reach the fluid through the boiling surface and the residence time of the molten steel has increased from about 10 seconds to about 25 seconds as compared with the conventional monoaxial immersion nozzle.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and simple substitution, modification and alteration within the technical spirit of the present invention will be apparent to those skilled in the art.

The immersion nozzle for continuous casting according to the present invention can be used for an immersion nozzle for continuous casting which can effectively produce a swirl flow of molten metal and obtain a metal cast with excellent performance at a low cost by improving the structure of the discharge part.

10: tundish 20: molten steel (molten steel)
30: mold (frame) 40: cooling part (cooling spray)
50: guide roller 60: cutting point
70: LADIES 80: Casting (Bloom, Billet)
100: immersion nozzle 110:
130: Body part 150: Discharge part
151:
h1: Height of discharge port h2: Height of discharge portion
ㅣ: Outlet width a: Outlet inclination angle

Claims (8)

A body portion provided in a tubular shape so that the molten metal introduced into one side is discharged to the other side;
An inflow portion provided at one side of the body portion and through which the molten metal flows from the tundish; And
A discharging portion provided on the other side of the body portion and discharging the molten metal into the mold; Lt; / RTI >
Wherein the discharge portion is provided with at least one discharge port on the side thereof, and the discharge port is provided so that the molten metal discharged from the discharge port swirls or rotates in the mold.
The method according to claim 1,
Wherein at least one of an incident surface and an emergent surface of the discharge port is provided in a parallelogram shape so that the molten metal discharged from the discharge port swirls or rotates. The method according to claim 1,
Wherein an area of the incidence surface of the discharge port is different from an area of the incidence surface so that the molten metal discharged from the discharge port swirls or rotates.
3. The method of claim 2,
Wherein a length of one side of the discharge port is less than half the length of the other side. 3. The method of claim 2,
Four discharge ports are provided along the side surface of the discharging portion in a cylindrical shape and at least one of the size, the position, and the oblique direction of the discharge port is changeable according to the type of the casting or the selection of the user. Immersion nozzle for casting. The method according to claim 1,
Wherein the discharge port extends to an end of the discharge portion and at least one side of the discharge port is opened toward the other side of the immersion nozzle. 6. The method of claim 5,
The discharge port may be tapered from the incident surface to the exit surface so that the molten metal discharged from the discharge port has a rotational force or the discharge surface may be provided in a parallelogram shape so that the discharge port has a rotation angle of 45 degrees from the vertical direction Features a dipping nozzle for casting. 3. The method of claim 2,
Wherein the casting immersion nozzle is used in a continuous casting apparatus for producing billets and blooms, and the casting face speed and the casting face temperature are controlled by providing the emission face area of the casting outlet at 1600 square millimeters or less.

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