WO2017060937A1

WO2017060937A1 - Bottom-blowing plug

Info

Publication number: WO2017060937A1
Application number: PCT/JP2015/005096
Authority: WO
Inventors: 邦博小出
Original assignee: 東京窯業株式会社
Priority date: 2015-10-07
Filing date: 2015-10-07
Publication date: 2017-04-13
Also published as: BR112016022757B1; KR101828140B1; BR112016022757A2; EP3231878A4; KR20170085616A; CN107075596B; EP3231878A1; CN107075596A; EP3231878B1

Abstract

Provided is a highly durable bottom-blowing plug to be installed in a large-sized top-and-bottom blown converter. This plug has multiple through-holes formed in the central part of a top face that intersects a gas-blowing direction of a plug body. When the area size of the top face is defined as Su, and when an area size of an opening part defined as an area surrounded by the centers of the openings of the through-holes situated on the outside of the top face is defined as So, So/Su≤0.25 and Su≥400 cm² are satisfied, and the value of total number of openings / area size So, i.e., the density of the openings forming an opening group, is 0.6-3.9.

Description

Bottom blow plug

The present invention relates to a bottom blowing plug that is provided at the bottom of an up-and-down blowing converter in which the treatment amount of molten iron is 150 tons or more and blows gas into the molten iron.

Conventionally, a bottom blowing plug for gas blowing provided with a plurality of through-holes through which gas passes is arranged at the bottom of a vessel such as a converter, and the inert gas (argon etc.) is supplied to the vessel through the bottom blowing plug. The molten metal was fed from the bottom of the slab. By this stirring, the temperature and components of the molten metal in the container are made uniform and cleaned. As such a bottom blow plug, there is a bottom blow plug including a through hole in which an opening opened on an upper surface of a plug in contact with a molten metal is positioned at the apex of an equilateral triangle (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 61-207505

In recent years, in order to obtain high-quality steel with high productivity, there is a demand for a large vertical blow converter with a molten iron treatment amount of 150 tons or more.

The present invention aims to provide a bottom blow plug suitable for such a large vertical blow converter.

In the conventional bottom blow plug, the through holes are located at the apex of the triangle, and the through holes are arranged more densely than those at the apex of the square. However, the number of through holes in one bottom blow plug is not large.

The inventors noticed that the durability of the bottom blowing plug is increased by increasing the number of through holes of one bottom blowing plug while keeping the gas amount from one opening appropriately, It is an object of the present invention to provide a bottom blowing plug with higher durability.

In order to solve this problem, the bottom blow plug of the present invention is equipped with an up-and-down converter having a processing amount of molten iron of 150 tons or more and each of at least 30 through holes on the upper surface in contact with the molten iron. A bottom-blown plug having a plug body for opening an opening group of openings and for injecting 20 to 60 Nl / min of inert gas from one opening during refining to blow a maximum amount of gas,
The opening group is located in the center of the upper surface of the plug body, and when the area of the upper surface is Sucm ² , the area Socm ² of the opening group portion where the opening group is located is So / Su ≦ 0.25. Su ≧ 400 cm ² , and the number of the openings, which is the density of the openings constituting the opening group / the area So of the opening group part, is 0.6 to 3.9.

The bottom blow plug of the present invention is installed in a large vertical blow converter with a molten iron treatment amount of 150 tons or more. The shape of the converter is a barrel type or a western type, with a shaft attached, and can freely rotate back and forth. Injecting hot metal and taking out molten steel are performed by tilting the furnace. During refining (reaction), with the furnace upright, high-pressure pure oxygen is blown upward, and at the same time, stirring gas such as argon or nitrogen is supplied from the bottom. Blow with the bottom blow plug.

As a large-sized up-and-down converter, one with a processing amount of molten iron of 150 tons or more at one time, and a processing amount of 250 to 350 tons at one time is usually used.

The bottom blow plug of the present invention has the first feature in that the upper surface Su of the plug body in contact with the molten metal is as large as 400 cm ² or more. The larger the upper surface Su, the more durable the bottom blow plug. Although the upper surface Su is at least 400 cm ^2, 800 cm ² or more, or high durability by increasing the 1200 cm ² or more. The shape of the upper surface of the bottom blowing plug can be the same as the shape of the upper surface of the conventional bottom blowing plug, such as a circle, square, rectangle, trapezoid or fan shape.

Next, the bottom blow plug of the present invention has a large number of openings opened on the upper surface thereof. The number of openings is at least 30, but is preferably 70 or more, more preferably 110 or more.

When the area of the upper surface of the bottom blow plug of the present invention is Su, the area So of the opening group portion where the opening group is located needs to be So / Su ≦ 0.25. Here, the area So of the opening group part means an area surrounded by a polygon formed by connecting the centers of adjacent openings of the openings located in the outermost outline of the opening group or a shape close thereto. The opening group portion So is 25% or less of the upper surface area Su, and the opening group portion is located at the center of the upper surface. This means that the opening group portion is located far away from the periphery of the upper surface and the upper surface. This means that the area between the peripheral edge of each of the openings and the opening group is as large as 75% or more of the upper surface area Su.

The number of the openings which is the density of the openings constituting the opening group / the area So of the opening group part is 0.6 to 3.9. The size of the opening is about 1 to 3 mm in diameter. When the density of the openings is small, that is, when the number of openings per unit area is small, an opening having a large opening area is employed, and when the opening density is large, an opening having a small opening area is employed.

The relative arrangement of the openings constituting the opening group is such that each opening is formed in the plug body in a positional relationship in which each opening is positioned on each vertex of an equilateral triangle having one side of Pmm on the upper surface of the plug body. Can do. More specifically, the central opening at the center of the opening group is located at the center of a regular hexagon having six openings at a distance of P mm from the central opening, and all the remaining openings are centered on the central opening. It can be located on the apex or side of a concentric regular hexagon.

The relative arrangement of the openings constituting the opening group is such that each opening is formed in the plug body in such a positional relationship that each opening is positioned on each top of a square having a side of Pmm on the upper surface of the plug body. be able to.

Further, the relative arrangement of the openings constituting the opening group is formed in the plug body in such a state that each opening is positioned on the upper surface of the plug body on the circumference of a concentric circle having a radius of Pmm intervals. Can be. In addition, although it is preferable that the space | interval of the opening which is on the same periphery and mutually adjoins is Pmm which is a space | interval of a radius, even if the space | interval between some openings leaves | separates from Pmm, it is permissible.

The relative arrangement of the openings is preferably one regularly arranged at intervals of the pitch P as described above, but one having no regularity in the arrangement is acceptable.

Here, the value of P can be 6 mm to 12 mm.

In addition, it is also preferable that the openings are concentrated at the center of the upper surface of the bottom blowing plug. In order to close the openings, it is preferable that all three adjacent openings be in the close-packed arrangement located at the apex of the equilateral triangle.

More specifically, each of the six openings that are separated by P mm in the centrifugal direction from the opening at the center of the opening group that opens on the upper surface of one bottom blowing plug (hereinafter referred to as the central opening) is the apex. A row of regular hexagons is formed. The first row of regular hexagons has one opening at each of the six vertices, and the first row of regular hexagons has a total of six openings. A regular hexagon in the second row is formed Pmm away from the regular hexagon in the first row in the centrifugal direction. One hexagon is formed in each of the six vertices of the regular hexagon in the second row and the six locations in the middle of the six sides. Openings are formed, and the second row of regular hexagons has a total of 12 openings. The second row of regular hexagons is a concentric regular hexagon that is 2 × Pmm away from the central opening and has the same central opening as the first row of regular hexagons. Similarly, the third row of concentric regular hexagons further Pmm apart in the centrifugal direction has 18 openings, the fourth row of concentric regular hexagons has 24 openings, and the fifth row of concentric regular hexagons has 30 openings. The sixth row of concentric regular hexagons has 36 openings, the seventh row of concentric regular hexagons has 42 openings, and the eighth row of concentric regular hexagons has 48 openings.

The total number of openings formed on the upper surface of the plug body is one center opening, six concentric regular hexagons in the first row, and twelve concentric regular hexagons in the second row up to the second row of concentric regular hexagons. The total is 19. 37 up to the third concentric regular hexagon, 61 up to the fourth concentric regular hexagon, 91 up to the fifth concentric regular hexagon, 127 up to the sixth concentric regular hexagon, seventh row Up to 169 numerical apertures up to concentric regular hexagons, and up to 217 numerical apertures up to the concentric regular hexagons in the eighth row.

The bottom blow plug of the present invention has excellent spalling resistance due to the opening group being considerably separated from the peripheral edge of the upper surface, and greatly contributes to the improvement of durability.

The opening located at the apex of the polygon of the opening group is the opening closest to the periphery of the upper surface of the bottom blowing plug. It is also possible not to provide the opening located at the outermost contour closest to the periphery of the opening group so that all the openings are located as far as possible from the periphery of the upper surface. Similarly, it is possible not to provide the outermost opening that is the second closest to the peripheral edge, or it is possible to prevent the third, fourth, etc. opening that is closer to the peripheral edge from being provided.

If the shape of the top surface of the bottom blow plug is square or trapezoidal, the opening at a specific vertex of the outermost contour or the opening at that specific vertex and the opening on the adjacent side are necessarily positioned above the other vertex. It may be closer to the upper edge than the opening. In such a case, it is also possible not to provide an opening at the specific vertex or an opening on the side adjacent to the opening at the specific vertex. Thus, by not providing an opening close to the peripheral edge, the distance from the required peripheral edge to the opening closest to the peripheral edge can be maintained, and more openings can be provided, and further higher spalling resistance. Can be maintained.

Also, it is preferable that the distance from the peripheral edge of the upper surface of the plug body to the nearest opening is longer than the distance from the nearest opening to the center opening. As a result, the distance from the peripheral edge of the upper surface to the nearest recent opening can be increased, and high spalling resistance can be obtained.

The amount of inert gas ejected from one opening of the bottom blow plug of the present invention is 20 to 60 Nl / min. By setting the amount of the inert gas to be ejected, the wear rate of the bottom blow plug worn by one molten iron treatment can be kept low, and the number of converter treatments can be increased.

The bottom blow plug of the present invention has a large area on the upper surface of the plug main body in contact with the molten metal and a large number of openings opened on the upper surface. Further, the opening group on the upper surface of the plug body is concentrated in the central portion of the upper surface, and the area So of the opening group portion where the opening group is formed is as narrow as 25% or less of the area Su of the opening. The distance to the surroundings is long. For this reason, this plug body has excellent spalling resistance and high durability. Further, since an inert gas of 20 to 60 Nl / min per one opening is ejected from the opening of the plug body, the wear of the plug body is suppressed and the durability is further enhanced.

Further, the area So of the opening group portion of the plug body is 25% or less of the area Su of the upper surface, and the distance from the nearest opening to the nearest opening is longer than the distance from the nearest opening to the center opening. By doing so, all the openings can be surely separated from the peripheral edge of the upper surface, and more reliable high spalling resistance can be expected.

Further, the bottom blow plug of the present invention is used for a large vertical blow converter, and the resulting steel has high productivity and high quality.

It is a longitudinal cross-sectional view of the bottom blow plug of Embodiment 1. It is a top view of the bottom blowing plug of Embodiment 1. It is a top view of the bottom blow plug of the modification of Embodiment 1. It is a top view of the bottom blow plug of Embodiment 2.

Embodiments of the present invention will be described below in detail with reference to the drawings.
(Embodiment 1)

The configuration of the bottom blow plug of this embodiment will be described with reference to FIGS. The bottom blowing plug of this embodiment has a plug body 2 having an upper surface 2a intersecting with a gas blowing direction (arrow A1 direction) and a pipe 1 having a through hole 1a regularly embedded in the plug body 2. .

The pipe 1 is disposed on the n (= 6) concentric regular hexagons Hn centered on the center O of the upper surface 2a of the plug body 2 at a pitch P. The length of the side of the innermost hexagon H1 corresponds to the pitch P. Here, “equal” means not strictly Pmm, but within a certain range.

In this embodiment, P is 12 mm, and the inner diameter of the pipe 1 is 2 mm. An opening group consisting of all openings is composed of a central opening of a central pipe, six concentric regular hexagonal vertices, and 127 openings on the sides thereof. The opening group is a hexagonal portion connecting the centers of the six pipes A, B, C, D, E, and F located at the apex of the outermost concentric regular hexagon H6. The area So of the opening group is 135 cm ² . The top surface of the bottom blow plug is trapezoidal, the top side W1 is 250 mm long, the bottom side W2 is 350 mm long, the height L is 300 mm, and the top surface area Su is 900 cm ² . Accordingly, the area So of the opening group portion of the bottom blow plug of this embodiment is 15% of the area Su of the upper surface, and the distance from the opening in the outermost surface of the opening group to the periphery of the upper surface is long. Therefore, the bottom blow plug of this embodiment has excellent spalling resistance and is excellent in durability.

Density of apertures constituting the aperture groups also, the area of the aperture group unit number of the opening is at 127 So. is because it is 135 cm ^2, it is 0.94 pieces / cm ^2.
(Modification of Embodiment 1)

The top view of the bottom blow plug of this modification is shown in FIG. The bottom blowing plug of this modification is obtained by removing six pipes from the pipes located on the apexes and sides of the outermost concentric regular hexagon of the bottom blowing plug of the first embodiment, and otherwise the bottom blowing plug of the first embodiment. Same as blow plug. The removed pipes are a total of six pipes, four pipes A, C, D, and E in FIG. 2, one right next to C and one right next to E in FIG. 2. .

As is clear from FIG. 3, since there are no six hexagonal pipes, the shape formed by connecting the outermost pipes is similar to a rounded trapezoid. In the bottom blow plug of this modification, the pipes that form the nearest opening closest to the peripheral edge of the upper surface are the two pipes indicated by the symbols J and K in FIG. The distance from these nearest openings to the peripheral edge of the upper surface is 84 mm, and the distance from the nearest opening to the central opening is 66 mm. Therefore, in the bottom blow plug of this modification, the distance from the nearest opening to the nearest opening is longer than the distance from the nearest opening to the center opening. Thereby, all the openings can be separated from the peripheral edge of the upper surface, and a more reliable high spalling resistance can be expected.

Density of apertures constituting the aperture groups also, the area of the aperture group unit number of the opening is at 121 So. is because it is 131 cm ^2, it is 0.92 pieces / cm ^2.
(Embodiment 2)

The configuration of the bottom blow plug of this embodiment will be described with reference to FIG. The bottom blow plug of the present embodiment is obtained by changing the shape of the upper surface 2a of the plug body 2 of the bottom blow plug of Embodiment 1 shown in FIG. 1 to a rectangle. Similarly to the bottom blowing plug of the first embodiment, the bottom blowing plug of the present embodiment also has an upper surface 2a intersecting with the gas blowing direction, and a pipe 1 having a through hole 1a regularly embedded in the center of the plug body 2. have.

The pipe group is composed of 100 pipes 1, and each pipe is arranged at four corners of a square with a side of 8 mm, 10 pieces vertically and horizontally at a pitch (P) of 8 mm. The center O of the upper surface 2a of the plug body 2 is located at the center of these pipe groups.

In this embodiment, P is 8 mm and the inner diameter of the pipe 1 is 2 mm. The area So of the opening group portion is 52 cm ² . Further, the upper surface 2a of the bottom blow plug is a rectangular circle having a vertical (W3) of 280 mm and a horizontal (W4) of 300 mm, and the area of the upper surface 2a is 840 cm ² . Therefore, the area So of the opening group part of the bottom blow plug of this embodiment is 6.2% of the area Su of the upper surface. Further, the shortest distance from the opening in the outermost outline of the opening group to the periphery of the upper surface is 104 mm, and the distance from the center of the upper surface 2a to the center of the farthest opening is 51 mm. Therefore, the shortest distance from the opening at the outermost contour of the opening group to the periphery of the upper surface is longer than the distance from the center of the upper surface 2a to the center of the furthest opening. Therefore, the bottom blow plug of this embodiment has excellent spalling resistance and is excellent in durability.

Density of apertures constituting the aperture groups also, the area of the number of openings opening group unit in 100 So is because it is 52cm ^2, it is 1.92 pieces / cm ^2.

The opening group of the first embodiment has concentric regular hexagonal vertices and openings on the sides thereof, and the opening group of the second embodiment has openings on the square vertices and the sides thereof. However, the arrangement of the openings does not necessarily have a strong regularity. In the description of the present invention, the opening group is described as being provided at the central portion of the upper surface of the plug body. However, the opening group may be a portion close to the center.

1a ... Through hole 2 ... Plug body 2a ... Top P ... Pitch

Claims

An opening group consisting of at least 30 through-holes is opened on the upper surface in contact with the molten iron installed in an up-and-down converter with a treatment amount of molten iron of 150 tons or more. A bottom-blown plug including a plug body that ejects an inert gas of 60 Nl / min,
The opening group is located in the center of the upper surface of the plug body, and when the area of the upper surface is Sucm ² , the area Socm ² of the opening group portion where the opening group is located is So / Su ≦ 0.25. Su ≧ 400 cm ² ,
The bottom blow plug, wherein the number of the openings, which is the density of the openings constituting the opening group / the area So of the opening group portion, is 0.6 to 3.9.

The bottom blow plug according to claim 1, wherein a pitch P of the adjacent openings is 6 mm to 12 mm.

The relative arrangement of the openings constituting the opening group is formed in the plug main body in a state in which each of the openings is positioned at each vertex of a regular triangle or a quadrangle having one side of Pmm on the upper surface. Item 3. A bottom blowing plug according to Item 1 or 2.

The bottom blow plug according to claim 1, 2, or 3, wherein a distance from the peripheral edge of the upper surface to the nearest opening that is the closest to the nearest opening is longer than a distance from the nearest opening to a center opening at the center of the opening group.