KR20230140142A - Bottom blowing nozzle and method for processing molten metal - Google Patents

Abstract

An embodiment of the present invention is a low-odor nozzle that can be installed at the bottom of a machine, a main body made of a material containing a refractory material, and a nozzle that can be installed to be inserted into the main body so as to be arranged in one direction and in another direction intersecting one direction. It includes a plurality of blowing pipes, and the separation distance (D) between the blowing pipe disposed at the outermost part of the plurality of blowing pipes and the end of the upper surface of the main body is 15 mm to 100 mm.
Therefore, according to embodiments of the present invention, by reducing the size of the main body made of a material containing a refractory material, the size of the difference in strength at each location can be reduced, and durability can be improved. As a result, damage such as breakage and erosion of the body due to thermal shock can be suppressed or prevented.

Description

BOTTOM BLOWING NOZZLE AND METHOD FOR PROCESSING MOLTEN METAL}

The present invention relates to a bottom odor nozzle and a method of treating molten iron, and more specifically, to a bottom odor nozzle and a method of treating molten iron that can suppress or prevent damage and clogging.

When molten iron is charged into the converter, oxygen is blown into the molten iron in the converter using a lance to perform dephosphorization and decarburization refining to remove phosphorus (P) and carbon (C) contained in the molten iron. At this time, in order to equalize the temperature and component content of the molten iron, inert gas is blown into the converter using a low-breathing nozzle installed at the bottom of the converter.

The low-odor nozzle includes a main body made of refractory material and a plurality of blowing pipes installed to be inserted into the main body. The inert gas flows into each of the plurality of blowing pipes and is then blown into the converter.

Meanwhile, the low blowing nozzle is prepared by inserting a plurality of blowing pipes into the mold, charging a refractory into the mold, and then compression molding the refractory. In addition, in the case of a conventional bottom blowing nozzle, the outer area of the plurality of blowing pipes, that is, the main body made of refractory material, is large. Accordingly, in the case of a main body made of refractory material, there is a problem of large differences in strength depending on the location.

This difference in strength depending on the position of the main body acts as a factor that promotes damage such as breakage and erosion when inert gas is sprayed from the bottom blowing nozzle. That is, when injecting an inert gas from a bottom odor nozzle, thermal shock due to molten iron is applied to the bottom odor nozzle. However, in this case, if the strength of the body made of refractory material is uneven at each location, damage or erosion is promoted starting from the location with relatively low strength.

In addition, in the middle stage of refining, where the decarburization reaction to remove carbon (C) during molten pig iron mainly occurs, the amount of inert gas blown from the bottom blowing nozzle is reduced compared to the early stage of refining. This is because the inert gas blown in from the low-odor nozzle may interfere with decarburization. However, when the blowing flow rate of the inert gas is reduced in this way, the pressure inside the blowing pipe provided in the bottom blowing nozzle is low, so molten iron may flow into the blowing pipe. And as a result, blockage may occur in the intake pipe.

Korean registered patent 10-2047122

The present invention provides a low odor nozzle and a treatment method for molten iron that can suppress or prevent damage and clogging.

The present invention provides a low odor nozzle with uniform intensity at each location.

An embodiment of the present invention is a low odor nozzle that can be installed at the bottom of a container, including a main body made of a material containing a refractory material; A plurality of blowing pipes that can be installed to be inserted into the interior of the main body so as to be arranged in one direction and another direction intersecting the one direction, and a blowing pipe disposed at the outermost part of the plurality of blowing pipes and the main body. The separation distance (D) from the end of the upper surface may be 15 mm to 100 mm.

The area (A _t ) of the upper surface of the main body may be less than 400 cm ² .

The main body has a polygonal cross-sectional shape including a plurality of sides, and the length (L) of each of the plurality of sides, which is the end of the upper surface of the main body, may be 100 mm to 200 mm.

On the upper surface of the main body, the shape of the blowing pipe area S _b formed by connecting the outer peripheral surfaces of the outermost blowing pipes may be circular or polygonal.

On the upper surface of the main body, the area (A _sb ) of the blowing pipe area (S _b ) formed by connecting the outer peripheral surfaces of the outermost blowing pipes is 20% to 40% of the upper surface area (A _t ) of the main body. It may be %.

On the upper surface of the main body, the blowing pipe is not installed in the central area of the blowing pipe area S _b formed by connecting the outer peripheral surfaces of the outermost blowing pipes, and the length B of the central area is It may be 5% to 30% of the length (L) of the side at the end of the upper surface of the main body.

The difference between the maximum compressive strength (CS _max ) and the compressive strength (CS _p ) of the plurality of different positions of the main body (CS _max - CS _p ) is 0% to 0% of the maximum compressive strength. It could be 20%.

A plurality of the blowing pipes may be arranged at equal intervals.

The number of blowing pipes may be 34 to 68.

The container may include a converter into which molten iron can be charged.

A method of processing molten iron according to an embodiment of the present invention includes the process of charging molten iron into a converter where a bottom odor nozzle is installed at the bottom; A process of blowing oxygen into the converter; and blowing inert gas into the converter using the bottom blowing nozzle so that the flow rate blown from each of the plurality of blowing pipes is 0.05 Nm ³ /min to 0.08 Nm ³ /min; may include.

According to embodiments of the present invention, by reducing the size of the main body made of a material containing a refractory material, the size of the difference in strength at each location can be reduced and durability can be improved. As a result, damage such as breakage and erosion of the body due to thermal shock can be suppressed or prevented.

Additionally, as the size of the main body of the bottom blowing nozzle is reduced, the number of blowing pipes is installed in a smaller number than before. Accordingly, the flow rate of the inert gas blown from each of the plurality of blowing pipes can be increased. Due to this, when blowing inert gas into molten iron using a bottom blowing nozzle, it is possible to suppress or prevent clogging of the blowing pipe due to the inflow of molten iron.

Figure 1 is a diagram showing a converter in which a low-odor nozzle is installed according to an embodiment of the present invention.
Figure 2 is a plan view of the upper surface of a bottom odor nozzle according to an embodiment of the present invention.
Figure 3 shows the blowing pipe area (S _b ) in addition to Figure 2 in order to explain the arrangement form of the plurality of blowing pipes and the area where the plurality of blowing pipes are installed in the bottom blowing nozzle according to the embodiment of the present invention. It is a drawing.
Figure 4 is a plan view of the upper surface of the bottom odor nozzle according to the first modification of the embodiment.
Figure 5 is a plan view of the upper surface of a bottom odor nozzle according to a second modification of the embodiment.
Figure 6 is a graph showing the pressure inside the blowing pipe relative to the blowing flow rate of the inert gas in the blowing pipe.
Figure 7 is a graph showing the erosion rate according to the flow rate of inert gas blown into the blowing pipe.
Figure 8 is a graph showing the compressive strength at each position of the main body according to the separation distance between the outermost blowing pipe and the end of the upper surface of the main body in the bottom blowing nozzles according to the first to sixth experimental examples.
Figure 9 is a conceptual diagram for explaining the compressive strength measurement position in the bottom blowing nozzle according to the first to sixth experimental examples.
Figure 10 is a graph showing the compressive strength at each position of the main body according to the length of the side, which is the end of the upper surface of the main body, in the bottom blowing nozzles according to experimental examples 7 to 12.
Figure 11 is a graph showing the erosion rate of the low odor nozzle when using the low odor nozzle according to experimental examples.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the attached drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. These embodiments only serve to ensure that the disclosure of the present invention is complete and to fully convey the scope of the invention to those skilled in the art. This is provided to inform you. The drawings may be exaggerated to explain embodiments of the present invention, and like symbols in the drawings refer to like elements.

Figure 1 is a diagram showing a converter in which a low-odor nozzle is installed according to an embodiment of the present invention.

Before explaining the low-odor nozzle according to an embodiment of the present invention, the converter in which the low-odor nozzle is installed will first be described.

The converter 100 is a vessel in which refining is performed by blowing oxygen into the molten iron (M) charged inside to remove impurities such as phosphorus (P) and carbon (C) contained in the molten iron (M). This converter 100 may include a body 110 having an internal space, a tapping port 120 that is an opening provided on a side of the body 110, and a furnace port 130 that is an opening provided in an upper portion of the body 110. .

The body 110 may include a steel shell 111 that forms the outer wall or exterior of the converter 100, and an inner wall 112 formed along the inner wall surface of the steel shell 111 and made of a material containing a refractory material. Here, the inner wall 112 may be made of a material containing, for example, refractory magnesium oxide (MgO) and graphite (C).

The tapping port 120 is a passage through which refining finished molten iron (M), that is, molten steel, is discharged to the outside. In addition, the furnace opening 130 is a passage through which molten iron, scrap, and iron alloy are introduced into the body 110. Additionally, a lance 300, which is a means of blowing or blowing oxygen, is introduced through the furnace hole 130.

When the molten iron (M) is charged into the converter 100 as described above, oxygen is blown or sprayed into the converter 100 using the lance 300. In other words, oxygen is blown into the molten iron (M) in the converter (100). Accordingly, converter refining such as dephosphorization and decarburization, in which blown oxygen reacts with phosphorus (P) and carbon (C) in molten iron, is performed. During such converter refining, an inert gas, such as Ar gas, is blown into the converter 100 from the bottom of the converter 100 to equalize the temperature and component content of the molten iron M contained within the converter 100. That is, the inert gas is blown or sprayed into the converter 100 using the low-odor nozzle 200 installed on the lower part of the converter 100 body 110. A plurality of low odor nozzles 200 are provided, and the plurality of low odor nozzles 200 are arranged to be spaced apart from each other at the lower part of the converter 100.

As described above, since the low odor nozzle 200 is installed on the body 110 of the converter 100, it can be explained that the low odor nozzle 200 is a component of the converter 100. In other words, the converter 100 can be described as including a body 110, a tapping port 120, a furnace port 130, and a bottom blowing nozzle 200.

When inert gas is blown into the converter 100 using the bottom odor nozzle 200, the bottom odor nozzle 200 may be damaged or eroded due to thermal shock due to the heat of the molten iron (M).

In addition, in the early stages of refining (early stage of oxygen blowing), a dephosphorization reaction to remove phosphorus (P) from molten iron mainly occurs, and from the middle stage of refining (middle stage of oxygen blowing), a decarburization reaction to remove carbon (C) from molten iron mainly occurs. At this time, since the inert gas blown in from the bottom blow nozzle 200 may interfere with decarburization from the middle stage of refining, when the decarburization reaction mainly occurs, the flow rate of the inert gas blown in during the middle stage of refining is adjusted to be small compared to the early stage of refining.

However, when the blowing flow rate of the inert gas is reduced in this way, the pressure inside the bottom blow nozzle 200 is low, so the molten iron (M) can flow into the bottom blow nozzle 200. And this may cause clogging of the low odor nozzle 200.

Accordingly, an embodiment of the present invention provides a low-odor nozzle 200 that can suppress or prevent damage and clogging.

Figure 2 is a plan view of the upper surface of a bottom odor nozzle according to an embodiment of the present invention. FIG. 3 is a diagram illustrating the blowing pipe area S _b in FIG. 2 to explain the arrangement of a plurality of blowing pipes and the area where the plurality of blowing pipes are installed in the bottom blowing nozzle according to an embodiment of the present invention. .

The bottom blowing nozzle 200 may be installed to penetrate the bottom or bottom of the converter 100 in the vertical direction, as shown in FIG. 1. More specifically, the bottom odor nozzle 200 is installed to be inserted through the lower part of the inner wall 112, which is made of a material including the iron shell 111 and refractory material constituting the body 110 of the converter 100, in the vertical direction. . At this time, the bottom blowing nozzle 200 may be installed at an angle so as to approach the center of the width direction of the lower portion of the converter 100 as it moves upward, as shown in FIG. 1 . Of course, the bottom odor nozzle 200 may be installed vertically rather than inclined.

A plurality of low odor nozzles 200 are provided, and a plurality of low odor nozzles 200 are installed to be spaced apart from each other in the lower part of the body 110 of the converter 100. At this time, the number of installed low-odor nozzles 200 is adjusted and installed according to the volume inside the converter 100. That is, as the volume inside the converter 100 increases, the number of installed low-odor nozzles 200 increases.

Referring to Figures 1 and 2, the bottom blowing nozzle 200 includes a main body 210 and a plurality of blowing pipes 220 installed inside the main body 210. In addition, the bottom blowing nozzle 200 may include a passage 230 provided inside the main body 210 to communicate with the inside of the plurality of blowing pipes 220.

The main body 210 is made of a material containing a refractory material. More specifically, the main body 210 may be made of a material containing a refractory material containing magnesium oxide (MgO). Additionally, the main body 210 may be made of a material containing a refractory material containing graphite (C) in addition to magnesium oxide (MgO).

The main body 210 may be provided in a shape extending in the vertical direction so that it can be installed to be inserted into the lower part of the body 110 of the converter 100, as shown in FIG. 1. Additionally, the upper part of the main body 210 may have a shape whose width decreases toward the top, for example, a trapezoidal shape, and the lower part of the main body 210 may have a shape that does not change its width in the vertical direction. Of course, the shape of the main body 210 is not limited to the above-described example and may be changed in various ways. For example, the entire body 210 may have a shape in which the width decreases toward the top, or the entire body 210 may have a shape in which the width does not change in the vertical direction.

When the main body 210 is installed at the lower part of the converter 100, the upper surface of the main body 210 may be installed to be exposed to the internal space of the converter 100. More specifically, the main body 210 may be installed so that its upper surface is positioned at the same height as the bottom surface of the inner wall 112. And the main body 210 may be installed so that its lower surface protrudes toward the lower side of the body 110 of the converter 100.

The main body 210 may have a polygonal shape in plane or cross section when viewed from above. That is, the upper surface of the main body 210 may be polygonal. More specifically, the main body 210 may have a cross-sectional shape extending in a first direction (X-axis direction) and a second direction (Y-axis direction) intersecting the first direction. Accordingly, the upper surface of the main body 210 may have a square shape as shown in FIG. 2. Of course, the shape of the main body 210 is not limited to the above-described square shape, and may be provided in various polygonal shapes such as triangles, pentagons, and hexagons.

Here, the first direction (X-axis direction) may be referred to as one direction, and the second direction (Y-axis direction) may be referred to as the other direction.

Hereinafter, in explaining the bottom blowing nozzle 200, the case where the main body 210 has a square shape will be described as an example.

Referring to FIG. 2, the main body 210 has first and second sides 211 and 212, each extending in a first direction (X-axis direction) and arranged in a second direction (Y-axis direction), and each It extends in two directions (Y-axis direction) and may include third and fourth sides 213 and 214 arranged in the first direction (X-axis direction). In addition, the main body 210 has a third side 213 connected between one end of the first side 211 and one end of the second side 212, and the other end of the first side 211 and the second side 212. ) may have a shape in which the fourth side 214 is connected between the other ends. That is, the main body 210 may have a roughly rectangular shape in which the first to fourth sides 211 to 214 are connected to each other. In other words, the main body 210 may have a quadrangular shape including first to fourth sides 211 to 214, which are the outermost sides.

Additionally, at least one of the first to fourth sides 211 to 214 may have a curvature, that is, a curved shape. That is, at least one of the first to fourth sides 211 to 224 may have a curved shape. Additionally, the lengths of the first to fourth sides 211 to 224 may all be the same, or at least one length may be different. For example, as shown in FIG. 2, the third and fourth sides 213 and 214 may have a curvature, that is, a curve, and the length (L ₃ ) of the third and fourth sides 213 and 214 may be curved. , L ₄ ) may be different. At this time, each of the first and second sides 211 and 212 may be a straight line without curvature, and the lengths (L ₁ and L ₂ ) of the first and second sides 211 and 212 may be the same.

Of course, the main body 210 may have a shape in which the first and second sides 211 and 212 are curved and the third and fourth sides 213 and 214 are straight. In addition, the length (L ₁ ) of the first side (211) and the length (L ₂ ) of the second side (212) are different from each other, and the length (L 3 ) of the third side (213) and the fourth side (L ₃ ) are different from each other. 214) may have the same length (L ₄ ). As another example, the length (L 1 ) of the first side ₂₁₁ and the length (L ₂ ) of the second side 212 are different from each other, and the length (L 3 ) of the third side 213 and the length of the fourth side (L ₃ ) are different from each other. The length (L ₄ ) of (214) may also be different. As another example, the length (L ₁ ) of the first side 211 and the length (L ₂ ) of the second side 212 are the same, the length (L 3 ) of the third side ₂₁₃ and the length of the fourth side 214 ) may be the same, and the lengths (L 1 to L ₄ ) of the first to fourth sides ₂₁₁ to ₂₁₄ may be the same.

At least one of the first to fourth sides 211 to 214 is provided as a curve because the lower surface of the body 110 of the converter 100 into which the bottom odor nozzle 200 is inserted is a curved surface having a curvature in the width direction. am. That is, in order to enable the bottom odor nozzle 200 to be easily installed in the lower part of the body 110 of the converter 100, which is curved, at least one of the first to fourth sides 211 to 214 is provided as a curve. It is desirable.

The blowing pipe 220 is a means for blowing or spraying an inert gas into the converter 100. This blowing pipe 220 extends in the direction in which the main body 210 extends, that is, in the vertical direction, and may be shaped like a pipe with openings at both ends in the direction of extension. The blowing pipe 220 is installed to be inserted into the main body 210 as shown in FIGS. 1 and 2, and one end facing the upper surface of the main body 210, that is, the upper end, is directed to the upper surface of the main body 210. It is installed exposed. At this time, it is preferable that the upper end of the blowing pipe 220 is installed at the same height as the upper surface of the main body 210. In addition, the lower end, which is the other end of the blowing pipe 220, communicates with the passage 230 provided inside the main body 210, and the passage 230 is connected to the inert gas supply pipe 10 installed outside the converter 100.

A plurality of blowing pipes 220 are provided, and each of the plurality of blowing pipes 220 is installed to be inserted into the main body 210 as shown in FIGS. 1 and 2. At this time, the plurality of blowing pipes 220 may be arranged in a first direction (X-axis direction) and a second direction (Y-axis direction) and spaced apart from each other, and may be arranged to be spaced apart from each other in the first and second directions (X-axis direction and Y-axis direction) can be arranged in multiple rows.

At this time, it is preferable that the intervals A between the plurality of blowing pipes 220 are arranged at equal intervals. In addition, the distance A between the adjacent blowing pipes 220 is arranged to be 10 mm to 30 mm, preferably 15 mm to 25 mm. Here, the distance A between the adjacent blowing pipes 220 may be the distance between the radial centers of the blowing pipes 220.

On the other hand, if the gap A between adjacent blowing pipes 220 is less than 10 mm or exceeds 30 mm, a problem may occur in which the amount of inert gas discharged from the plurality of blowing pipes 220 is non-uniform. there is.

In order to explain the arrangement of the plurality of blowing pipes 220 in other words, a set of the plurality of blowing pipes 220 arranged in the first direction (X-axis direction), that is, a group, is referred to as 'blowing pipe group (G _b )'. Reflecting this and explaining again the arrangement of the plurality of blowing pipes 220, the low blowing nozzle 200 is a blowing pipe group (G _b ) including a plurality of blowing pipes 220 arranged in the first direction (X-axis direction) ), wherein the blowing pipe group (G _b ) is provided in plural numbers, and the plurality of blowing pipe groups (G _b ) are arranged to be aligned in the second direction (Y-axis direction).

In this way, a plurality of blowing pipe groups G _b including a plurality of blowing pipes 220 arranged in the first direction (X-axis direction) are provided and arranged in the second direction (Y-axis direction), 220 may be described as being arranged in multiple rows in each of the first direction (X-axis direction) and the second direction (Y-axis direction).

In a more specific example with reference to FIG. 2 , the blowing pipe group G _b may include seven blowing pipes 220 arranged in a first direction (X-axis direction). Seven blowing pipe groups (G _b ) may be provided, and seven blowing pipe groups (G _b ) may be arranged to be aligned in the second direction (Y-axis direction). Accordingly, the blowing pipes 220 can be described as being arranged in 7 rows in the first direction (X-axis direction) and 7 rows in the second direction (Y-axis direction). At this time, the fourth blowing pipe group G _b arranged from one side to the other side based on the second direction may be provided to include six blowing pipes 220 . In addition, the blowing pipe group G _b may be provided with six blowing pipes 220 so that the blowing pipes 220 are not disposed at the center position in the first direction (X-axis direction).

When the plurality of blowing pipes 220 are arranged in a row, the arrangement shape may be arranged to have a predetermined shape. To explain this in more detail, the area formed by connecting the outer peripheral surfaces of the outermost blowing pipes 220 on the upper surface of the main body 210, as shown in FIG. 3, is referred to as the 'blowing pipe area (S _b )'. It is defined as That is, the blowing pipe area S _b means an area where a plurality of blowing pipes 220 are installed.

Reflecting this and explaining again the arrangement shape of the plurality of blowing pipes 220, the shape of the blowing pipe area S _b may be arranged to be, for example, more square than square, as shown in FIG. 3 . And, as shown in FIG. 3, the blowing pipe 220 may not be installed in the central area of the blowing pipe area S _b .

At this time, the length (B) of the central area where the blowing pipe 220 is not installed in the blowing pipe area (S _b ) is 5 of the length (L: L ₁ to L ₄ ) of the side at the end of the upper surface of the main body 210, which will be described later. It may be % to 30%, preferably 5% to 20%.

In addition, if the blowing pipe 220 is not installed in the central area of the blowing pipe area S _b , the gap A between the blowing pipes 220 arranged across the central area may exceed 30 mm. there is. That is, the spacing A between the adjacent blowing pipes 220 is set to 10 mm to 30 mm, which is the distance between the blowing pipes 220 other than the blowing pipe 220 arranged across the central region. It may mean.

And, when the blowing pipe 220 is not installed in the central area of the blowing pipe area S _b , the gap B between the blowing pipes 220 arranged across the central area is the remaining blowing pipe 220. ) may be different from the spacing (A) between them. In other words, arranging the distance A between the plurality of blowing pipes 220 at equal intervals means that, in addition to the blowing pipes 220 arranged across the central area, the spacing between the remaining blowing pipes 220 is equal. It could mean an interval.

In the above, it was explained that the blowing pipe 220 is not installed in the central area of the blowing pipe area S _b . However, it is not limited to this, and the blowing pipe 220 may be installed in the central area of the blowing pipe area S _b .

In providing the low odor nozzle 200, the total area of the upper surface of the low odor nozzle 200 exposed to the inside of the converter 100 (A _t ), the length (L) of the upper surface of the low odor nozzle 200, and the low odor nozzle (200) The ratio (R _a ) of the area (A _sb ) of the blowing pipe area (S _b ) to the total area of the upper surface (A _t ) and the upper surface of the blowing pipe (220) and the main body (210) disposed at the outermost edge. Prepare by adjusting the separation distance (D) from the end.

In addition, the difference (CS _{max -} CS p ) between the maximum compressive strength (CS max ) and the compressive strength (CS _p ) at a plurality of positions among the compressive strengths at a plurality of different positions of the main body _is 0% to 20% of the maximum compressive strength _. Arrange for %.

First, the total area (A _t ) of the upper surface of the bottom odor nozzle 200 will be described.

In providing the low-odor nozzle 200, the total area (A _t ) of the upper surface exposed to the inside of the converter 100, that is, the inside of the body 110, is less than 400 cm ² , preferably 100 cm ² or more and less than 400 cm ² . Prepare as much as possible. More preferably, it is set at 100 cm ² to 300 cm ² (100 cm ² or more and 300 cm ² or less).

Here, since the low-odor nozzle 200 includes the main body 210 and a plurality of blowing pipes 220 installed to be inserted into the main body 210, the upper surface of the low-odor nozzle 200 exposed to the inside of the body 110 ' is 'the upper surface of the main body 210 constituting the low-odor nozzle 200'. Accordingly, it can be explained that the total area (A _t ) of the upper surface of the main body 210 is less than 400 cm ² , preferably between 100 cm ² and less than 400 cm ² , and more preferably between 100 cm ² and 300 cm ² .

On the other hand, when the area (A _t ) of the upper surface of the main body 210 is 400 cm ² or more, the area of the main body 210 made of a material containing a refractory increases, and accordingly, the strength of the main body 210 at each position increases. It may not be uniform. To be more specific, the bottom blowing nozzle 200 is manufactured by injecting a plurality of blowing pipes 220 and materials for forming the main body 210 into the mold and then compressing them. At this time, it is realistically difficult to apply a uniform force to the entire inside of the mold. In addition, as the main body 210 is manufactured, the size of the mold becomes larger and the amount of raw materials charged into the mold increases, making it difficult to apply a uniform force to all of the raw materials charged into the mold. Accordingly, when the main body 210 is manufactured so that the upper surface area (A _t ) is 400 cm ² or more, the strength of the main body 210 may not be uniform at each position because the size of the main body 210 is too large. That is, the difference in strength depending on the position of the main body 210 may be large. And when injecting an inert gas from the bottom odor nozzle 200, thermal shock due to the molten iron M is applied to the bottom odor nozzle 200. However, if the difference in strength between positions of the main body 210 is large, damage may be promoted starting from a position with relatively low strength.

Conversely, when the main body 210 is manufactured so that the area (A _t ) of the upper surface is less than 100 cm ² , the number of installation pipes 220 is small. Accordingly, the blowing flow rate of the gas blown from each of the plurality of blowing pipes 220 increases. Therefore, the pressure inside the blowing pipe 220 is high, so the pressure for blowing or spraying gas from the blowing pipe 220 into the converter 100 may be high. This impacts the inner wall 112 of the converter 100 and the main body 210 of the low-odor nozzle 200, which are made of a material containing a refractory material, and thus the inner wall 112 of the converter 100 and the low-odor nozzle The main body 210 of 200 may be damaged or eroded.

Therefore, the area (A _t ) of the upper surface of the main body 210 is manufactured to be less than 400 cm ² , preferably 100 cm ² to 400 cm ² , and more preferably 100 cm ² to 300 cm ² .

Next, the length (L) of the upper surface of the bottom blowing nozzle 200 will be described. In preparing the bottom odor nozzle 200, it is prepared by adjusting the length (L) of the upper surface.

At this time, the edge of the upper surface of the bottom blowing nozzle 200, that is, the length (L) of each of the plurality of sides, which are the ends of the upper surface, is set to 100 mm to 200 mm (100 mm or more and 200 mm or less). Preferably, the length (L) of each of the plurality of sides at the end of the upper surface of the bottom blowing nozzle 200 is set to 130 mm to 190 mm (130 mm or more and 1900 mm or less).

At this time, since a plurality of blowing pipes 220 are installed to be inserted into the interior of the main body 210, the length (L) of the upper surface of the bottom blowing nozzle 200 may be the length (L) of the upper surface of the main body 210. And the plurality of sides that are the ends of the upper surface of the bottom blowing nozzle 200 refer to the plurality of sides that are the ends of the upper surface of the main body 210. Accordingly, it can be explained that the length of each of the plurality of sides, which are the ends of the upper surface of the main body 210, is 100 mm to 200 mm, preferably 130 mm to 190 mm.

2 as an example, if the shape of the main body 210 is a square shape with first to fourth sides 211 to 214, the first to fourth sides 211 to 214 of the upper surface of the main body 210 ) Each length (L ₁ to L ₄ ) is provided to be 100 mm to 200 mm, preferably 130 mm to 190 mm. In this way, providing the length (L) of each of the plurality of sides at the end of the upper surface of the main body 210 to 100 mm to 200 mm reduces the difference in strength at each position of the main body 210, preventing damage to the main body 210 due to uneven strength. This is to suppress or prevent the occurrence and to stably support the plurality of blowing pipes 220.

Meanwhile, when the length of at least one of the plurality of sides at the end of the upper surface of the main body 210 exceeds 200 mm, the size of the main body 210 is large, so the difference in strength at each position of the main body 210 may be large. As described above, this may be a factor that promotes damage when thermal shock due to the molten iron (M) is applied to the bottom blowing nozzle 200.

Conversely, when the length of at least one of the plurality of sides at the end of the upper surface of the main body 210 is less than 100 mm, the distance between the end of the main body 210 and the blowing pipe 220 is close, so that when manufacturing the bottom blowing nozzle 200 Problems may arise where the blowing pipe 220 is bent or broken. To be more specific, the bottom blowing nozzle 200 is manufactured by putting a body forming material including a plurality of blowing pipes 220 and a refractory material into a mold and then compression molding it. However, when manufacturing the body 210 so that the length of at least one of the plurality of sides at the end of the upper surface is less than 100 mm, manufacturing defects may occur in which the blowing pipe 220 is bent or broken due to the force caused by compression molding. You can.

Next, with reference to FIG. 3 , the ratio (R _a ) of the area (A _sb ) of the blowing pipe area (S _b ) to the total area (A _t ) of the upper surface of the main body 210 will be described.

In preparing the bottom blowing nozzle 200, it is prepared by adjusting the ratio (R _a ) of the area (Asb) of the blowing pipe area (S _b ) where the plurality of blowing pipes (220) are installed on the upper surface of the main body 210. That is, the ratio (R _a ) of the area (A _sb ) of the blowing pipe area (S _b ) on the upper surface to the total area (A _t ) of the upper surface of the main body 210 is 20% to 40%, preferably Arrange for it to be between 25% and 35% (see Formula 1).

[Formula 1]

By setting the ratio of the area of the blowing pipe area (A _sb ) to the area of the upper surface (A _t ) of the main body 210 to 20% to 40%, the difference in strength at each position of the main body 210 can be reduced. In other words, it is possible to provide a low-odor nozzle with uniform strength at each position of the main body 210. Additionally, the plurality of blowing pipes 220 inserted into the main body 210 can be stably supported.

On the other hand, when the ratio of the area (A _sb ) of the blowing pipe area to the upper surface area (A _t ) of the main body 210 is less than 20%, the area occupied by the main body 210 is large, so the strength of the main body 210 at each position is increased. It is not uniform, and the difference in intensity may be large. As described above, when inert gas is blown into the molten iron M using the bottom blowing nozzle 200, this may be a factor that promotes damage or erosion.

Conversely, when the ratio of the area (A _sb ) of the blowing pipe area to the upper surface area (A _t ) of the main body 210 exceeds 40%, the area of the main body 210 supporting the plurality of blowing pipes 220 Because this is small, the strength of the main body 210 to support the plurality of blowing pipes 220 is weak and the plurality of blowing pipes 220 cannot be stably supported. And this may be a factor that weakens the strength of the entire low odor nozzle 200.

Next, with reference to FIG. 2 , the separation distance D between the outermost blowing pipe 220 of the plurality of blowing pipes 220 and the end of the upper surface of the main body 210 will be described.

In preparing the bottom blowing nozzle 200, the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 is set to 15 mm to 100 mm (15 mm or more and 100 m or less). More preferably, the separation distance (G) is set to be 15 mm to 60 mm (15 mm or more and 60 m or less).

Here, the end of the upper surface of the main body 210 may mean an edge or a plurality of outermost sides of the upper surface of the main body 210. For example, when the upper surface of the main body 210 has a shape including first to fourth sides 211 to 214 as shown in FIG. 2, both ends of the upper surface of the main body 210 in the second direction are It can be described as the first and second sides (211, 212), and both ends in the first direction are the third and fourth sides (213, 214). In addition, it can be explained that the upper surface of the main body 210 has first to fourth ends, and the first to fourth ends mean first to fourth sides 211 to 214. Accordingly, the ends of the upper surface of the main body 210 may represent the first to fourth sides 211 to 214.

And, the outermost blowing pipe 220 among the plurality of blowing pipes 220 may mean the outermost blowing pipe 220 among the blowing pipes 220 arranged in a plurality of rows. That is, when a plurality of blowing pipes 220 are arranged in a plurality of rows in the first direction (X-axis direction) and the second direction (Y-axis direction) as shown in FIG. 2, the blowing pipe 220 disposed at the outermost position may mean the blowing pipes 220 located at both ends of the first direction (X-axis direction) and the blowing pipes 220 located at both ends of the second direction (Y-axis direction). And the outermost blowing pipe 220 as described above can be explained as blowing pipes (15 mm or more and 100 m or less) arranged at the outermost part of the blowing pipe area S _b as shown in FIG. 3.

In addition, in the distance D between the outermost blowing pipe 220 and the end of the upper surface of the main body 210, the location of the blowing pipe 220, which is the standard for the distance D, may be its outer peripheral surface. More specifically, it may be the distance (D) between the outer peripheral surface of the blowing pipe 220, which faces the end of the upper surface of the main body 210 without passing through the other blowing pipe 220, and the end of the upper surface of the main body 210. there is.

Each of the outermost blowing pipes is arranged to face the end, that is, the side, of the upper surface of the main body 210. For example, each of the blowing pipes 220 arranged at the outermost side of one side in the first direction (X-axis direction) faces the third side 213 without other blowing pipes in between, and is disposed at the outermost side of the other side in the first direction. Each of the blowing pipes 220 arranged in faces the fourth side 214 without any other blowing pipe in between. In addition, each of the blowing pipes 220 arranged on the outermost side of the second direction (Y-axis direction) faces the first side 211 without other blowing pipes in between, and is disposed on the outermost side of the other side in the second direction. Each of the blowing pipes 220 arranged in faces the second side 212 of the main body without another blowing pipe in between. In addition, among the blowing pipes arranged on the outermost side, the blowing pipe facing the corner between two sides faces the two sides without any other blowing pipe in between.

In the embodiment, the bottom blow nozzle 200 is provided so that the separation distance (D) between the outermost blowing pipe 220 and the end of the main body 210 is 15 mm to 100 mm, preferably 15 mm to 60 mm.

At this time, the separation distances (D) between the outermost blowing pipes 220 and the ends of the main body 210 may be the same within the range of 15 mm to 100 mm, or may be different in at least one. That is, the shape of the main body 210, the length of each side of the main body 210, the shape of the blowing pipe area (S _b ), the size of the blowing pipe area (S _b ), and the size of the blowing pipe area (S _b ) on the main body 210. Depending on at least one of the positions, the separation distances D between the outermost blowing pipes 220 and the ends of the main body 210 may all be the same, or at least one may be different. Accordingly, if the separation distance (D) between the outermost blowing pipes 220 and the end of the main body 210 is 15 mm to 100 mm, the blowing pipe area S _b is the upper surface of the main body 210 as shown in FIG. It may be located in the center of or tilted to one side.

In this way, by setting the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 to 15 mm to 100 mm, the difference in strength at each position of the main body 210 can be reduced. In other words, the difference in strength at each position of the main body 210 can be made more uniform compared to the prior art. In addition, it is possible to prevent the blowing pipe 220 from breaking or bending when compression molding is performed to manufacture the low blowing nozzle 200.

On the other hand, when manufacturing so that the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 is less than 15 mm, when manufacturing the bottom blowing nozzle 200, the blowing pipe 220 is Problems with bending or breaking may occur. That is, manufacturing defects may occur in which the blowing pipe 220 is bent or broken due to the force caused by compression molding.

Conversely, when the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 exceeds 100 mm, the area of the main body 210 is too large and the location of the main body 210 is different. The difference in intensity can be large. And this can act as a factor promoting damage or erosion when thermal shock caused by molten iron is applied to the bottom odor nozzle.

Accordingly, the low blowing nozzle is provided so that the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 is 15 mm to 100 mm.

In this way, by providing the bottom blowing nozzle 200, the difference in strength at each position of the main body 210, that is, compressive strength, can be reduced as described above. To be more specific, the difference (CS _{max - CS p ) between the maximum compressive strength (CS max )} and the compressive strength (CS _p ) at a plurality of positions among the compressive strengths at a _plurality of different positions of the main body 210 is the maximum. It can be set to 0% to 20% (0% or more and 20% or less) of the compressive strength, more preferably 0% to 15% (0% or more and 15% or less).

To be described in more detail with reference to FIG. 9, the maximum compression strength (CS _p : CS _p1 , CS _p2 , CS _p3 , CS _p4 , CS _p5 ) at the first to fifth positions (P ₁ to P ₅ ). Strength (CS _max ) and the difference (CS max - CS p: CS _{max -} CS p1, CS _max - _{CS p2} ) between the compressive strengths (CS _p1 , CS _p2 , CS _p3 , CS _p4 , _{CS p5} ) for each position. , CS _max - CS _p3 , CS _max - CS _p4 , CS _max - CS _p5 ) is 0% to 20% (0% to 20%) of the maximum compressive strength (CS _max ), more preferably 0% to 20%. It can be arranged to be 15% (0% or more and 15% or less) (see Equation 2).

[Formula 2]

Figure 4 is a plan view of the upper surface of the bottom odor nozzle according to the first modification of the embodiment. Figure 5 is a plan view of the upper surface of a bottom odor nozzle according to a second modification of the embodiment.

In the above, the case in which a plurality of blowing pipes 220 are arranged as shown in FIG. 2, that is, the shape of the blowing pipe area S _b is rectangular has been described as an example. However, the form in which the plurality of blowing pipes 220 are arranged, that is, the shape of the blowing pipe area S _b , is not limited to the above-described example, and may be changed to various polygonal shapes. For example, as in the first modification shown in FIG. 4, the blowing pipe area (S _b ) may be triangular, or as in the second modification shown in FIG. 5, the blowing pipe area (S _b ) may be hexagonal. Additionally, the shape of the blowing pipe area S _b is not limited to a polygon and may be provided to be circular (not shown).

In this way, in providing the bottom odor nozzle 200, the area (A _t ) of the upper surface of the main body 210 exposed to the inside of the converter 100 as described above, the edge at the end of the upper surface of the main body 210 Length (L), ratio (R _a ) of the area (A _sb ) of the blowing pipe area (S _b ) to the area (A _t ) of the upper surface of the main body (210), the blowing pipe (220) disposed on the outermost side and the main body By adjusting the separation distance (D) between the ends of the upper surface of 210, the size of the main body 210 can be reduced compared to the prior art. By reducing the size of the main body 210 made of a material containing a refractory material compared to the prior art, the size of the difference in strength at each location can be reduced, thereby improving durability. In addition, this can suppress or prevent damage such as breakage and erosion of the main body 210 due to thermal shock.

Additionally, as the size of the main body 210 is reduced compared to the prior art, the number of blowing pipes 220 installed inside the main body 210 is installed in a smaller number than before. That is, conventionally, the number of blowing pipes 220 installed in the main body 210 was 100 or more, but in the embodiment, 34 to 68 blowing pipes 220 are installed in the main body 210. At this time, depending on the volume of the converter 100 where the bottom blow nozzle 200 is installed, the number of blowing pipes 220 provided in each bottom blow nozzle 200 can be adjusted within the range of 34 to 68.

As the number of blowing pipes 220 installed in the main body 210 decreases, the flow rate of the inert gas blown from each of the plurality of blowing pipes 220 increases. That is, since the target flow rate of the inert gas that must be blown from the plurality of bottom blowing nozzles 200 for converter refining is fixed, if the number of blowing pipes 220 installed in the main body 210 decreases, the plurality of blowing pipes ( 220) The flow rate of inert gas blown from each is increased. Accordingly, the pressure of each of the plurality of blowing pipes 220 may increase, thereby preventing the problem of the molten iron M penetrating into the blowing pipe 220 and clogging it.

In blowing inert gas into the interior of the converter 100 using the bottom blowing nozzle 200 according to the embodiment, the flow rate of the gas blown in from each of the plurality of blowing pipes 220 is 0.05Nm ³ /min to 0.08Nm ³ /min (more than 0.05Nm ³ /min and less than 0.08Nm ³ /min). More preferably, it is adjusted to 0.06Nm ³ /min to 0.08Nm ³ /min.

Meanwhile, when the flow rate of gas blown from each of the plurality of blowing pipes 220 is less than 0.05 Nm ³ /min, the pressure inside each blowing pipe 220 may be low. Accordingly, the molten iron (M) of the converter 100 may flow into the blowing pipe and block the blowing pipe 220. Also, when the flow rate of gas blown from each of the plurality of blowing pipes 220 exceeds 0.08 Nm ³ /min, the pressure inside each blowing pipe 220 may be high. Accordingly, the pressure of the gas blown into the converter 100 from each blowing pipe 220, that is, the injection pressure, is large, and as a result, the inner wall 112 of the converter 100 and the main body 210 of the low blowing nozzle 200 are damaged. Damage such as breakage or erosion may occur.

Figure 6 is a graph showing the pressure inside the blowing pipe relative to the blowing flow rate of the inert gas in the blowing pipe.

For the experiment, the low odor nozzle 200 according to the example was installed in the converter 100. Then, molten iron (M) was charged into the converter 100, oxygen was blown using the lance 300, and Ar gas was blown using the bottom blow nozzle 200. At this time, the blowing flow rate blown from each of the plurality of blowing pipes 220 included in the bottom blowing nozzle 200 was varied from 0.03 Nm ³ /min to 0.09 Nm ³ /min.

In addition, when molten iron flows into the blowing pipe 220 and becomes clogged, a predetermined pressure is reached, and this pressure is set as a 'blockage pressure' through which it can be confirmed whether a blockage has occurred. And, when the pressure of the blowing pipe 220 became more than the clogging pressure, it was determined that the blowing pipe 220 was clogged.

Referring to FIG. 6, when the flow rate of the inert gas blown in from the blowing pipe 220 or passing through the blowing pipe 220 is less than 0.05 Nm ³ /min, the pressure of the blowing pipe 220 became more than the clogging pressure. . That is, when the flow rate of the inert gas passing through the blowing pipe 220 was less than 0.05 Nm ³ /min, the blowing pipe 220 was clogged due to molten iron flowing into the blowing pipe 220. However, when the flow rate of the inert gas passing through the blowing pipe 220 was 0.05 Nm ³ /min or more, the pressure inside the blowing pipe 220 was less than the clogging pressure, and no clogging occurred.

From this, it can be seen that when blowing inert gas using the bottom blowing nozzle 200, it is desirable to adjust the flow rate of the inert gas passing through each of the plurality of blowing pipes 220 to 0.05 Nm ³ /min or more. there is.

Figure 7 is a graph showing the erosion rate according to the flow rate of inert gas blown into the blowing pipe.

For the experiment, two converters 100 having the same volume were prepared, and a bottom odor nozzle 200 different from the example was installed in each converter 100. Then, molten iron (M) was charged into the converter 100, oxygen was blown using the lance 300, and Ar gas was blown using the bottom blow nozzle 200. At this time, the blowing flow rate of the inert gas blown from each of the plurality of blowing pipes 220 in the bottom blowing nozzle 200 installed in one converter 100 was set to 0.08 Nm ³ /min or less. And in the bottom blowing nozzle 200 installed in the other converter 100, the blowing flow rate of the inert gas blown from each of the plurality of blowing pipes 220 was adjusted to exceed 0.08 Nm ³ /min.

Then, the erosion rate of the bottom odor nozzle 200 was calculated. The erosion rate of the low odor nozzle 200 varies from the size of the low odor nozzle 200 before spraying Ar gas using the low odor nozzle 200 to the size of the low odor nozzle 200 after the injection of Ar gas using the low odor nozzle 200 is completed. It can be calculated by subtracting the size and dividing this deduction by the number of uses (Ch) of the converter in the current operation.

2 as an example, from the length (L ₁ ) of the first side 211 of the upper surface of the bottom odor nozzle 200 before spraying Ar gas to the upper part of the bottom odor nozzle 200 after the injection of Ar gas is completed. It can be calculated by subtracting the length (L _1b ) of the first side 211 of the surface and dividing this deduction by the number of uses (Ch) of the converter in the current operation (see Equation 3).

[Formula 3]

In the above, the erosion rate was calculated based on the first side 211 of the upper surface of the bottom blowing nozzle 200, but it may be calculated using the change in length of any side.

Here, the usage cycle (Ch) of the converter 100 refers to the cycle in which molten iron (M) was charged into the converter 100 used in the experiment and converter refining was performed. For example, for an experiment, molten iron is charged into the converter 100 and converter refining is performed. If the converter refining cycle of the converter 100 is the 50th, the number of uses (Ch) of the converter is '50'.

Referring to FIG. 7, when the inert gas blowing flow rate from the blowing pipe 220 is less than 0.08 Nm ³ /min compared to when it exceeds 0.08 Nm ³ /min, the erosion rate of the bottom blowing nozzle 200 is low. From this, it can be seen that when blowing inert gas using the bottom blowing nozzle 200, it is desirable to adjust the flow rate of the inert gas passing through each of the plurality of blowing pipes 220 to 0.08 Nm ³ /min or less. there is.

In addition, when combining the experimental results of FIGS. 6 and 7, when blowing inert gas using the bottom blow nozzle 200, the flow rate of the inert gas passing through each of the plurality of blowing pipes 220 is 0.05 Nm ³ /min. It can be seen that it is desirable to adjust it to 0.08 Nm ³ /min.

Figure 8 is a graph showing the compressive strength at each position of the main body according to the separation distance between the outermost blowing pipe and the end of the upper surface of the main body in the bottom blowing nozzles according to the first to sixth experimental examples. Figure 9 is a conceptual diagram for explaining the compressive strength measurement position in the bottom blowing nozzle according to the first to sixth experimental examples.

For the experiment, bottom blowing nozzles 200 with different separation distances (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 were prepared. That is, the bottom blow according to the first to sixth experimental examples in which the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 is 120mm, 100mm, 80mm, 60mm, 40mm, and 20mm. A nozzle 200 was provided. At this time, the main bodies 210 according to the first to sixth experimental examples were prepared in the same shape, and only the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 was manufactured differently. .

Then, the compressive strength of the main body 210 of the low-odor nozzle 200 according to the first to sixth experimental examples was measured. At this time, the compressive strength was measured at five different first to fifth positions (P ₁ to P ₅ ) in each main body 210 of the first to sixth experimental examples. Here, the first to fifth positions (P ₁ to P ₅ ) are the positions of the area between the end of the upper surface of the main body 210 and the blowing pipe 220, as shown in FIG. 9. In addition, from the end of the upper surface of the main body 210 toward the blowing pipe 220, the first position (P ₁ ), the second position (P 2 ), the third position (P ₃ ), the fourth position (P 4 ), and the first position (P 1 ), the second position (P 2 ), the third position (P ₃ ), and the fourth position (P ₄ ) It was set in order of 5 positions (P ₅ ).

The compressive strength was obtained by separating the first to fifth positions (P ₁ to P ₅ ) from each of the manufactured bottom blowing nozzles 200 to prepare first to fifth specimens, and applying a load to the first to fifth specimens. Compressive strength was measured. That is, by applying a load to each of the first to fifth specimens and detecting the load at which they break, the compressive strength (kgf/cm ² ) is detected. The compressive strength of each of the first to fifth specimens detected in this way is the compressive strength of the first to fifth positions (P ₁ to P ₅ ).

Referring to FIG. 8, as the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 decreases, the compression of the first to fifth positions (P ₁ to P ₅ ) It can be seen that the difference in intensity is small and gradually becomes uniform. In addition, as the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 decreases, the compressive strength of the first to fifth positions (P ₁ to P ₅ ) increases. shows a tendency

At this time, in the case of the first experimental example in which the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 exceeds 100 mm, the first to fifth positions (P ₁ to P ₅ ) ) The difference in compressive strength between the two is large, and the compressive strength is small. On the other hand, in the case of the second to sixth experimental examples in which the separation distance (D) between the outermost blowing pipe 220 and the upper surface end of the main body 210 is 100 mm or less, compared to the first experimental example, the first to fifth experimental examples The difference in compressive strength between positions (P ₁ to P ₅ ) is small, and the compressive strength is large.

From this, it can be seen that it is desirable to set the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 to 100 mm or less. In addition, when looking at the difference in compressive strength and the size of the relative compressive strength at the first to fifth positions shown in FIG. 8, the distance between the upper surface end of the outermost blowing pipe 220 and the main body 210 It can be seen that it is more preferable to set the distance (D) to 60 mm or less.

On the other hand, when the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 is less than 15 mm, the distance between the end of the main body 210 and the blowing pipe 220 is close, When compression molding is performed to manufacture a low-odor nozzle, a problem may occur in which the blowing pipe 220 is bent or broken.

Therefore, it is preferable that the separation distance (D) between the outermost blowing pipe 220 and the end of the upper surface of the main body 210 is set to 15 mm to 100 mm, and the separation distance (D) is set to 15 mm to 60 mm. desirable.

Figure 10 is a graph showing the compressive strength at each position of the main body according to the length of the side, which is the end of the upper surface of the main body, in the bottom blowing nozzles according to experimental examples 7 to 12.

For the experiment, bottom odor nozzles with different side lengths were prepared on the upper surface of the bottom odor nozzle 200. More specifically, as shown in FIG. 2, the upper surface has first to fourth sides 211 to 214, the cross section is square in shape, and the third and fourth sides 213 and 214 are curved. A bottom odor nozzle (200) equipped with was prepared.

At this time, the bottom odor nozzles 200 according to the 7th to 12th experimental examples have different lengths of the first and second sides 211 and 212. That is, the bottom odor nozzle 200 according to the 7th to 12th experimental examples has the lengths of the first and second sides 211 and 212 of 240mm (7th experimental example), 220mm (8th experimental example), and 200mm (7th experimental example). 9 Experimental Example), 180mm (10th Experimental Example), 160mm (11th Experimental Example), and 140mm (13th Experimental Example).

Then, the compressive strength of the main body 210 was measured for the low-odor nozzle 200 according to the 7th to 12th experimental examples. At this time, the compressive strength was measured at five different first to fifth positions (P ₁ to P ₅ ) in each main body 210 in experimental examples 7 to 12 (see FIG. 9). The method for measuring compressive strength is the same as the method described previously, so description thereof is omitted.

After measuring the compressive strength at the first to fifth positions (P ₁ to P ₅ ) in the bottom blowing nozzle 200 according to the 7th to 12th experimental examples, it was organized into a box plot as shown in FIG. 10. indicated. That is, for each of the 7th to 12th experimental examples, the compressive strength at the first to fifth positions (P ₁ to P ₅ ) was measured, and 25% to 75% in the range between the minimum compressive strength and the maximum compressive strength. Compressive strength with a size of was derived. At this time, the size difference between the compressive strength corresponding to 25% and the compressive strength corresponding to 75% is referred to as the 'compressive strength deviation'. And, the median compressive strength is the intermediate value between the minimum compressive strength and the maximum compressive strength, and the average compressive strength is the average value of the compressive strengths measured at each of the first to fifth positions (P ₁ to P ₅ ).

Comparing the compressive strength deviation in FIG. 10, the 7th and 8th experiments in which the lengths (L ₁ and L ₂ ) of the first and second sides 211 and 212 on the upper surface of the bottom blowing nozzle 200 exceed 200 mm. Compared to the compressive strength deviation of the example, the compressive strength deviation of the 9th to 12th experimental examples in which the lengths (L ₁ , L ₂ ) of the first and second sides 211 and 212 on the upper surface of the bottom blowing nozzle 200 are 200 mm or less is small.

From this, it can be seen that the length of the upper surface side (L) of the bottom blowing nozzle 200, that is, the length (L) of the upper surface side of the main body 210, is preferably 200 mm or less. In addition, when the length (L) of the upper surface side of the main body 210 is less than 100 mm, the distance between the end of the main body 210 and the blowing pipe 220 is close, so that the blowing pipe 220 is used when manufacturing the bottom blowing nozzle 200. Problems with bending or breaking may occur. Therefore, when providing the bottom odor nozzle 200, it is desirable to set the length of the upper surface side of the main body 210 to 100 mm to 200 mm.

Figure 11 is a graph showing the erosion rate of the low odor nozzle when using the low odor nozzle according to experimental examples.

For the experiment, four converters (first to fourth converters) were prepared, and bottom odor nozzles 200 according to experimental examples were installed in the first to fourth converters. That is, low odor nozzles according to the 13th and 14th experimental examples in the first converter, low odor nozzles according to the 15th and 16th experimental examples in the second converter, low odor nozzles according to the 17th and 18th experimental examples in the third converter, The low odor nozzles according to the 19th and 20th experimental examples were installed in the fourth converter.

Here, the 14th Experimental Example, the 16th Experimental Example, the 18th Experimental Example, and the 20th Experimental Example are the low odor nozzle 200 manufactured by the method according to the embodiment of the present invention. That is, the upper surface area (A _t ) of the main body 210 is less than 400 cm ² , the length (L) of the plurality of sides at the ends of the upper surface of the main body 210 is 100 mm to 200 mm, and the upper surface area of the main body 210 ( The ratio (R _a ) of the area (A _{s b} ) of the blowing pipe area (S b ) to A _t ) is 20% to 40%, and the upper surface end of the blowing pipe 220 and the main body 210 disposed at the outermost end It is a low-odor nozzle with a separation distance (D) of 15 mm to 100 mm.

And, the low odor nozzle 200 according to the 13th experimental example, the 15th experimental example, the 17th experimental example, and the 19th experimental example is a conventional low odor nozzle. That is, the upper surface area (A _t ) of the main body 210 is 400 cm ² or more, the length (L) of a plurality of sides at the ends of the upper surface of the main body 210 exceeds 200 mm, and the upper surface area of the main body 210 ( The ratio (R _a ) of the area (A _{s b} ) of the blowing pipe area (S b) to A _t ) is less than 20%, and the gap between the upper surface end of the blowing pipe 220 and the main body 210 disposed on the outermost side. It is a low-odor nozzle with a distance (D) exceeding 100 mm.

After installing the bottom odor nozzles according to the 13th to 20th experimental examples at the bottom of the first to fourth converters, molten iron (M) was charged into the first to fourth converters. At this time, different steel types of molten iron (M) were charged into each of the first to fourth converters.

In addition, the lance 300 was inserted into each of the first to fourth converters to blow oxygen, and an inert gas, that is, Ar gas, was injected into the converter using the bottom blow nozzle 200 installed at the bottom.

At this time, the flow rate of Ar gas blown from the bottom blowing nozzle installed in the same converter was adjusted to be the same. That is, the flow rate of Ar gas blown using the low-odor nozzles 200 according to the 13th and 14th experimental examples installed in the first converter are the same, and the low-odor nozzles 200 according to the 15th and 16th experimental examples installed in the second converter are set to the same level. The flow rate of Ar gas blown in using the nozzle 200 was made the same, and the flow rate of Ar gas blown in using the bottom blowing nozzles according to the 17th and 18th experimental examples installed in the third converter was made the same, and the The flow rate of Ar gas blown in using the bottom blowing nozzles according to the 19th and 20th experimental examples installed in the converter was the same.

In addition, since the steel types of the molten iron (M) charged to each of the first to fourth converters were different, at least one of the flow rate and blowing time of Ar gas blown into the first to fourth converters was changed. That is, the low odor nozzles 200 according to the 13th and 14th experimental examples installed in the first converter, the low odor nozzles 200 according to the 15th and 16th experimental examples installed in the second converter, and the 15th and 16th odor nozzles installed in the third converter. When injecting Ar gas from the low-odor nozzle 200 according to the 16th experimental example and the low-odor nozzle 200 according to the 15th and 16th experimental examples installed in the fourth converter, among the blowing flow rate and blowing time of the injected Ar gas At least one of them was adjusted differently.

The method for obtaining the erosion rate of the bottom odor nozzle is the same as the method described previously, so description thereof is omitted.

Figure 11 shows the erosion rate of the conventional low odor nozzles of the 13th Experimental Example, the 15th Experimental Example, the 17th Experimental Example, and the 19th Experimental Example, and the 14th Experimental Example and the 16th Experimental Example of the low odor nozzle according to the embodiment. , The ratio of the erosion rate of the bottom odor nozzle of the 18th experimental example and the 20th experimental example is calculated and shown.

Referring to FIG. 11, the erosion rates of Experimental Examples 14, 16, 18, and 20 are lower than those of Experimental Examples 13, 15, 17, and 19. . To be more specific, if the erosion rates of the 13th Experimental Example, the 15th Experimental Example, the 17th Experimental Example, and the 19th Experimental Example are a, b, c, and d, respectively, the 14th Experimental Example, the 16th Experimental Example, The erosion rates of Experiment 18 and Experiment 20 were low at 0.82a, 0.86b, 0.86c, and 0.81d. That is, the erosion rate of the bottom odor nozzle 200 according to the 14th Experimental Example is 82% (0.82a) of the erosion rate (a) of the bottom odor nozzle 200 according to the 13th Experimental Example, and the bottom odor nozzle according to the 16th Experimental Example ( The erosion rate of 200) is 86% (0.86b) of the erosion rate (b) of the bottom odor nozzle 200 according to the 15th Experimental Example, and the erosion rate of the bottom odor nozzle 200 according to the 18th Experimental Example is the erosion rate (b) of the bottom odor nozzle 200 according to the 17th Experimental Example. It is 86% (0.86c) of the erosion rate (c) of the bottom odor nozzle 200, and the erosion rate of the bottom odor nozzle 200 according to the 20th Experimental Example is the erosion rate (d) of the bottom odor nozzle 200 according to the 19th Experimental Example. It is 81% (0.81d).

In this way, the erosion rates of the 14th Experimental Example, 16th Experimental Example, 18th Experimental Example, and 20th Experimental Example, which are the low odor nozzle 200 according to the embodiment, are compared to those of the conventional low odor nozzle, the 13th Experimental Example, the 15th Experimental Example, and the 17th Experimental Example. Experimental example, the erosion rate is as low as 81% to 86% of the 19th experimental example. From this, it can be seen that erosion can be suppressed by using the bottom odor nozzle 200 according to the embodiments.

In this way, the low odor nozzle 200 according to embodiments reduces the size of the main body 210 made of a material containing a refractory material compared to the prior art, thereby reducing the size of the difference in strength at each location, thereby improving durability. It can be improved. In addition, this can suppress or prevent damage such as breakage and erosion of the main body 210 made of a material containing a refractory material.

Additionally, as the size of the main body 210 is reduced compared to the prior art, the number of blowing pipes 220 installed inside the main body 210 is installed in a smaller number than before. The flow rate of the inert gas blown from each of the plurality of blowing pipes 220 may increase. Therefore, it is possible to suppress or prevent the blowing pipe 220 provided in the bottom blowing nozzle 200 from clogging in a section where a relatively low flow rate of inert gas is blown during converter refining, such as a decarburization section. That is, during converter refining, the flow rate of inert gas blown into the decarburization section is reduced compared to other sections, and the target flow rate to be blown in at this time is fixed. Accordingly, as the number of blowing pipes 220 provided in the bottom blowing nozzle 200 decreases, the blowing flow rate in each blowing pipe 220 increases, and accordingly, the pressure inside the blowing pipe 220 increases. Therefore, it is possible to suppress or prevent molten iron from flowing into the blowing pipe 220 and clogging it. That is, even if the total blowing flow rate of the inert gas is reduced in the decarburization section, the pressure inside the blowing pipe 220 is higher than before, and thus clogging of the blowing pipe 220 can be suppressed or prevented.

100: Converter 200: Low odor nozzle
210: main body 220: blowing pipe

Claims (11)

A low odor nozzle that can be installed at the bottom of the container,
A body made of a material containing a refractory material;
It includes a plurality of blowing pipes that can be installed to be inserted into the main body so as to be arranged in one direction and in another direction intersecting the one direction,
A low-odor nozzle in which the separation distance (D) between the outermost blowing pipe of the plurality of blowing pipes and the end of the upper surface of the main body is 15 mm to 100 mm. In claim 1,
A low-odor nozzle whose area (A _t ) of the upper surface of the body is less than 400 cm ² . In claim 2,
The main body has a cross-sectional shape of a polygon including a plurality of sides,
A bottom odor nozzle where the length (L) of each of the plurality of sides at the end of the upper surface of the main body is 100 mm to 200 mm. In claim 2,
In the upper surface of the main body, the shape of the blowing pipe area (S _b ) formed by connecting the outer peripheral surfaces of the outermost blowing pipes is circular or polygonal. In claim 2,
On the upper surface of the main body, the area (A _sb ) of the blowing pipe area (S _b ) formed by connecting the outer peripheral surfaces of the outermost blowing pipes is 20% to 40% of the upper surface area (A _t ) of the main body. % low odor nozzle. In claim 2,
On the upper surface of the main body, the blowing pipe is not installed in the central area of the blowing pipe area S _b formed by connecting the outer peripheral surfaces of the outermost blowing pipes,
The length (B) of the central area is 5% to 30% of the length (L) of the side at the end of the upper surface of the main body. In claim 1,
The difference (CS max - CS _p ) between the maximum compressive strength ₍ CS _{max )} and the compressive strength (CS _{p ) at a plurality of different positions (CS p} ) of the main body is the maximum compressive strength. A low odor nozzle that is 0% to 20% of . In claim 2,
A low-odor nozzle in which a plurality of the blowing pipes are arranged at equal intervals. In claim 2,
A low-odor nozzle in which the number of blowing pipes is 34 to 68. In claim 1,
The container is a bottom odor nozzle including a converter into which molten iron can be charged. A process of charging molten iron into the converter where the bottom blowing nozzle of any one of claims 1 to 10 is installed at the bottom;
A process of blowing oxygen into the converter; and
A process of blowing inert gas into the converter using the bottom blowing nozzle so that the flow rate blown from each of the plurality of blowing pipes is 0.05 Nm ³ /min to 0.08 Nm ³ /min; A method of handling chartered ships, including:

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