JP2004285475A - Switching method and replacing method of bottom-blown tuyere in converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a switching method of a bottom-blown tuyere in a converter capable of forming a grinding hole by punching the central part of the brick for punching along a prescribed punching direction in a short time when the bottom-blown tuyere is switched by inserting a bottom-blown tuyere installed at the bottom part of the converter. <P>SOLUTION: When the bottom-blown tuyere is switched by forming a new bottom-blown tuyere at the brick 6 for punching previously installed at a part other than an installation part of the bottom-blown tuyere in a refractory layer covering the bottom part of the converter, either one of the surface of a steel shell 9 covering the outside of the converter or the flange surface 10a attached to the steel shell is used as a reference surface, and the brick 6 for punching is previously installed at a place different from a previous tuyere in the refractory layer in such a way that the reference surface is perpendicular to the punching direction of the brick 6 for punching, and the brick 6 for punching is punched in the direction perpendicular to the reference surface by a punching machine, and the new bottom-blown tuyere 1a in the converter is inserted in the grinding hole 7 formed by penetrating a punching hole of the brick 6 for punching. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method of switching a bottom blow tuyere for switching a bottom blow tuyere for injecting gas into a steel bath from the bottom of the converter to stir and refine the steel bath, and a converter for replacing the bottom blow tuyere. The present invention relates to a method of replacing a tuyere.

In a converter that refines a steel bath by oxygen blowing from an upper blowing lance, it is necessary to increase the reaction interface area between the slag and the steel bath existing in the converter, or to segregate components and temperature distribution of the steel bath itself. In order to increase the efficiency of the refining reaction by reducing the dispersion of the steel, it has been widely practiced to blow the stirring gas into the steel bath from the bottom blowing tuyere provided at the bottom of the converter to strongly stir the steel bath. . Also, not only a stirring gas but also a refining O ₂ gas is blown from a bottom blowing tuyere provided at the bottom of the converter.

  However, in converter refining using bottom-blow tuyeres, the refractories around the bottom-blow tuyeres are more likely to be eroded than refractories in other parts, so the thickness of the bricks other than the bottom-blow tuyeres is sufficient. Despite this, the furnace operation has to be stopped. Therefore, various proposals have conventionally been made to extend the life of the bottom blowing tuyere.

  For example, in Patent Literature 1, a brick for perforation serving as a tuyere receiving brick is previously installed in a place other than the bottom blown tuyere, and the tuyere used during use becomes large and cannot be used. At this point, a technique is disclosed in which the previously installed perforated brick is perforated from outside the converter steel shell, a new tuyere is inserted into a grinding hole formed through the perforated hole, and the converter operation is continued. I have. In this case, the bottom blowing tuyere that can no longer withstand use is closed by a suitable refractory material such as a cast refractory material, a sprayed refractory material or a sprayed refractory material. The tuyere receiving brick is a brick that is installed around the tuyere to support and protect the tuyere.

Further, Patent Document 2 discloses that a worn tuyere is extracted, a refractory is filled in the extracted gap by a flame spraying method, a tuyere insertion hole is newly formed in the filled portion, and a new feather is formed in the formed hole. A technique of inserting a mouth to replace a tuyere is disclosed.
JP-A-9-176720 JP-A-59-41414

  However, in the case of perforating a perforated brick or tuyere receiving brick by a perforator from outside the converter as in Patent Literature 1 and Patent Literature 2, the perforation is performed to perforate from outside the converter. It is difficult to match the drilling direction of the brick to be drilled (usually the axial direction of the longitudinal direction) with the drilling direction of the drilling machine, so that the grinding hole by the drilling machine does not stay in the brick to be drilled, Drilling to the surrounding bricks may damage the surrounding bricks, and may cause problems such as an unnecessarily large grinding hole. In this case, the replacement of the tuyere is promoted, and the service period of the bottom-blow tuyere is greatly reduced as compared with the assumed period. Further, in setting the drilling machine, it takes time to determine the drilling direction, and there is a problem that the drilling time becomes longer than necessary.

The present invention has been made in view of the above circumstances, and an object thereof is to use a drilling machine from the outside of a converter to drill a perforating brick previously installed in a portion other than the installation portion of a bottom blowing tuyere of a converter bottom. When switching the bottom blow tuyere by inserting a new bottom blow tuyere into the cut hole formed by drilling, the center of the perforated brick is perforated in a short time along the predetermined perforation direction. It is an object of the present invention to provide a method of switching the tuyere of a converter bottom blow, which makes it possible to form a grinding hole.
Another object of the present invention is to pierce the center of a tuyere receiving brick of a conventional tuyere along a predetermined piercing direction in a short time when replacing a bottom blow tuyere of a converter bottom. It is an object of the present invention to provide a method for exchanging a tuyere of a converter bottom, which makes it possible to form a grinding hole.

  According to the first aspect of the present invention, a new bottom-blowing tuyere is formed in a perforated brick previously installed in a portion other than the installation portion of the bottom-blowing tuyere in the refractory layer covering the bottom of the converter. A method of switching a bottom-blowing tuyere that switches the bottom-blowing tuyere, wherein either one of a steel surface covering the outside of the converter or a flange surface attached to the steel shell is used as a reference surface, Pre-installing a perforated brick at a position different from the conventional tuyere in the refractory layer so that the surface and the perforated direction of the perforated brick are perpendicular to each other; and A step of piercing from the outside of the skin in a direction perpendicular to the reference plane by a piercing machine, and a step of inserting a new converter bottom blowing tuyere into a grinding hole formed by piercing a hole of the brick for piercing. The method for switching the converter bottom blowing tuyere is provided.

  According to the second aspect of the present invention, the tuyere comprising the refractory and the gas injection tube provided in the refractory layer covering the bottom of the converter has melted down and the remaining thickness has reached a predetermined value. A method of replacing a tuyere bottom blowing tuyere that sometimes replaces the tuyere, wherein one of a steel surface covering the outside of the converter and a flange surface attached to the steel shell is used as a reference surface, and A step of installing the tuyere receiving brick such that the reference surface and the perforation direction of the tuyere receiving brick on which the tuyere is installed are perpendicular, and a tuyere receiving brick in which the conventional tuyere is installed Drilling a hole perpendicular to the reference plane by a drilling machine from the outside of the steel shell, and a new converter bottom blowing tuyere in a grinding hole formed through the drilling hole of the tuyere receiving brick. And a step of inserting the tuyere of the converter bottom.

  ADVANTAGE OF THE INVENTION According to this invention, when switching a converter bottom-blow tuyere, the brick for integral perforation used as a tuyere receiving brick is either one of the iron surface of a converter, or the flange surface attached to the iron skin. One of them is set as a reference plane, and the brick for perforation is installed so as to be perpendicular to the reference plane, and the brick is drilled perpendicular to the reference plane. Also, when replacing the tuyere tuyere of the converter bottom, the tuyere receiving brick to be pierced is used as one of the steel surface of the converter or the flange surface attached to the steel shell as a reference surface. The tuyere receiving brick is installed so that the drilling direction of the tuyere receiving brick is vertical, and the tuyere receiving brick is drilled perpendicular to this reference plane. For this reason, in any case, it is possible to form a grinding hole along a target drilling direction substantially at the center of the drilling brick and the tuyere receiving brick without damaging the surrounding bricks at the time of drilling. It becomes possible. As a result, the life of the inserted tuyere is stabilized, and gas can be blown for a long time.

  Further, the drilling machine only has to drill a hole perpendicularly to the above-mentioned reference plane, and can perform the drilling in a short time without positioning the brick for drilling and the tuyere receiving brick to be drilled. The brick for perforation and the tuyere receiving brick to be perforated are provided with an extension line in the perforating direction of the drilling machine and a converter iron shell for the perforating brick and the tuyere receiving brick so that a grinding hole is provided at the center thereof. It is installed in advance so that the center of the side end face substantially matches.

  ADVANTAGE OF THE INVENTION According to this invention, the brick for perforation and the tuyere receiver can be used without damaging the work brick in the peripheral part of the perforation brick and tuyere receiving brick, and without generating troubles such as an unnecessarily large grinding hole. In a short period of time, a ground hole can be drilled in the center of the brick along a predetermined drilling direction, and the bottom tuyere can be switched / replaced.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, the structure of a converter having a bottom tuyere will be described. FIG. 1 is a sectional view showing a part of a converter having a tuyere.

  As shown in FIG. 1, the converter includes a steel shell 9 that forms an outer shell, a permanent brick 14 lined inside a part of the steel shell 9 that contacts the steel shell 9, and a liner that is lined inside the permanent brick 14. And a work brick 13 as a consumable member. In the figure, the work brick 13 is made up of one layer, but may be made of two or more layers.

At the bottom of the converter, a plurality of bottom-blowing tuyeres 1 are provided through the work brick 13 and the permanent brick 14. Through these bottom-blowing tuyeres 1, Ar gas is introduced into a steel bath in the converter. A stirring gas such as N ₂ gas or carbon dioxide gas, and further an O ₂ gas for refining are blown, so that the steel bath is stirred or refined.

  The bottom blowing tuyere 1 covers a metal wind box 4 provided at the bottom, a plurality of gas blowing pipes 2 extending upward from the wind box and having an inner diameter of 5 mm or less, and the gas blowing pipe 2. It has a provided refractory 3 and a gas introduction pipe 5 inserted into the bottom of the wind box 4 for supplying the above-described stirring gas or refining gas. The agitating gas or the refining gas introduced into the wind box 4 through the gas inlet pipe 5 is equalized in the wind box 4, and then uniformly in the steel bath through the plurality of gas injection pipes 2. Is blown into The plurality of gas injection pipes 2 and the refractory 3 are integrally formed. The bottom tuyere is not limited to the one having such a structure, and may be appropriately selected according to the purpose. For example, there is no problem even if one gas introduction pipe and a coated refractory covering the same are provided.

  The bottom blow tuyere 1 is fitted into a part of the brick of the work brick 13, and the brick functions as a tuyere receiving brick 13a.

  On the outside of the tuyere receiving brick 13a where the bottom blow tuyere 1 exists, a flange 10 that is continuous with the steel shell 9 is provided. A plurality of the flanges 10 are arranged at appropriate positions on the steel shell as communication paths with the gas blowing device. A flange lid 11 is bolted to the flange 10. The base brick 8 is interposed between the permanent brick 14 and the flange lid 11.

  By the way, the work brick 13 provided around the bottom blowing tuyere 1 receives severe erosion from the steel bath which is vigorously stirred by the blowing gas, and has a higher erosion rate and a faster remaining thickness than other parts. Decrease. Along with this, the tip of the bottom blowing tuyere 1 is also melted down, the remaining thickness of the bottom blowing tuyere 1 reaches a predetermined value, and it becomes necessary to switch or replace the bottom blowing tuyere.

Hereinafter, a method of switching and replacing a bottom-blow tuyere according to an embodiment of the present invention will be described.
First, a first brick is drilled in a different place from the conventional bottom blow tuyere, and a new bottom blow tuyere is installed in a grinding hole of the brick for drilling to switch the bottom blow tuyere. An embodiment will be described with reference to FIG. FIG. 2 is a cross-sectional view for explaining the steps of the method for switching the bottom blowing tuyere according to the first embodiment of the present invention.

  In the tuyere forming portion for switching, a brick 6 made of an integrally molded refractory is previously arranged when the work brick 13 and the permanent brick 14 are installed in the converter. In this case, in order to facilitate connection with the gas injection device outside the converter, the perforation brick 6 is usually provided with a flange 10 serving as a communication path with the gas injection device attached to the steel shell 9. Placed at

  In the present embodiment, first, as shown in FIG. 2A, the inner surface 9a or the outer surface 9b (iron surface) of the iron shell 9 is set as a reference surface, and the perforating brick 6 whose perforating direction is the longitudinal direction is used. It is arranged in advance so that its longitudinal direction, that is, the perforation direction is perpendicular to the reference plane (first step). In the present embodiment, since the flange 10 is disposed so that the flange surface 10a is parallel to the steel skin surface, the longitudinal direction of the perforating brick 6 is also perpendicular to the flange surface 10a. The same applies to the reference plane. When the iron skin surfaces 9a, 9b and the flange surface 10a are not parallel, any of the iron skin surfaces 9a, 9b and the flange surface 10a may be used as the reference surface.

  Usually, the work bricks 13 of the converter are arranged in a direction in which the longitudinal direction thereof is perpendicular to the steel shell 9 as shown in these figures, and are installed between the work bricks 13. The drilling brick 6 is also installed so that its longitudinal direction is perpendicular to the steel shell 9. However, when the work brick and the drilling brick are not installed vertically to the steel shell 9, the flange is not provided. It is necessary to install 10 in advance in a direction in which the flange surface is perpendicular to the work brick and the perforation brick. In this case, of course, the flange surface and the steel surface are not parallel.

  The concrete construction method of the perforated brick 6 is as follows. First, the flange 10 and the flange lid 11 are fixed by bolts (not shown), and the base brick 8 whose upper and lower surfaces are smooth and parallel planes. Is placed on the flange lid 11. In the figure, two base bricks 8 are installed, but it is determined by the relationship with the installation thickness of the permanent bricks 14. If the tip of the perforated brick 6 is arranged inside the receiving brick 15, If so, the number of installations may be any. In the center of the flange lid 11, a hole 11a that is large enough to pass through the bottom blowing tuyere 1 is provided.

  Next, the perforated brick 6 is arranged on the base brick 8 so that its longitudinal axis is perpendicular to the base brick 8. In this case, the receiving brick 15 is arranged at the position where the perforated brick 6 is disposed so as to surround the perimeter of the perforated brick 6. The thickness of the receiving brick 15 is equivalent to that of the permanent brick 14, and the receiving brick 15 may be a combination brick or an integral brick. Since the perforation brick 6 is surrounded by the receiving brick 15, even if the perforation brick 6 is melted and shortened, it does not easily come out inside the furnace. Thereafter, the work bricks 13 are arranged around the perforated bricks 6 to form the lining of the converter.

  In the state where the drilling direction of the drilling brick 6 is set in advance in such a manner as to be perpendicular to the reference plane in this way, as shown in FIG. Punching is performed by a punch in a direction perpendicular to the reference plane (second step). This step is performed when the used bottom tuyere is worn and it is necessary to switch the bottom tuyere.

  In this step, first, molten steel and slag in the converter are discharged, and the converter is maintained in a state where the converter is tilted at an appropriate angle (usually tilted so that the drilling direction is horizontal), and the flange 10 or The flange lid 11 is connected to a mounting flange (not shown) of a drilling machine (not shown) to which a drill 16 is mounted at the tip. This automatically aligns the drill 16 of the drilling machine with the center of the flange lid 11. The drilling accuracy is improved by connecting the drilling machine to the flange 10 or the flange lid 11, but when the drilling machine cannot be connected, the drilling machine may be left on the converter work floor.

  Then, drilling is performed while rotating the drill 16 in the direction perpendicular to the flange surface, that is, the flange lid 11, and toward the center of the flange lid 11 to form the grinding hole 7. In this case, a plurality of drills 16 having different outer diameters are prepared, and the drills are sequentially drilled from the smaller-sized drill 16. Further, in order to make the perforation work easy and reliable, a guide hole having a small diameter may be formed in advance at the perforated portion of the base brick 8 and the perforation brick 6, and the base brick 8 has a predetermined size. May be used in which holes are provided in advance. The guide hole of the perforated brick 6 is not penetrated, but is set halfway.

  At the time when the predetermined drilling process is completed, the state of the drilling hole is checked, and as shown in FIG. 2C, if the drilling hole has penetrated and the grinding hole 7 has been formed, the drilling machine is connected to the flange 10 or As shown in FIG. 2D, a new bottom blow tuyere 1a in which the gas injection pipe 2 and the coated refractory 3 covering the outer circumference of the pipe are integrally formed is inserted into the grinding hole 7 as shown in FIG. (Third step).

  After inserting the new bottom blowing tuyere 1a, as shown in FIG. 1, the gas introduction pipe 5 of the bottom blowing tuyere 1 is passed through a hole provided at the center thereof, and the convex portion of the flange lid 11 is formed. The tuyere holding lid 12 for entering the hole 11a and holding the bottom blowing tuyere 1a and the flange lid 11 are fixed with bolts (not shown). In addition, the gap between the bottom blowing tuyere 1a and the brick 6 for perforation is filled with mortar previously applied to the outer surface of the bottom blowing tuyere 1a. Further, it is preferable that a repair material is poured into the gap between the bottom blowing tuyere 1a and the perforated brick 6 from the inside of the converter so that the gap is minimized.

  By switching the bottom tuyere in this way, the work brick 13 around the perforation brick 6 is not damaged, and the trouble such as the grinding hole 7 becoming unnecessarily large does not occur. It is possible to drill the grinding hole 7 in the center along a predetermined drilling direction in a short time, and to switch the bottom blowing tuyere. As a result, not only is the productivity of the converter improved, but also the rate of wear of the new bottom blow tuyere is equal to the rate of wear of the bottom blow tuyere used during the operation of the converter. However, it is possible to operate the bottom blowing tuyere 1a until the end of the furnace body life. As a result, the refining reaction of the converter is made more efficient until the end of the life of the furnace body, so that an improvement in iron yield and a reduction in iron alloy consumption per unit are achieved.

  Next, when the conventional bottom tuyere is melted and cannot be used, the tuyere receiving brick on which the conventional tuyere was installed is pierced, and a new bottom blown tuyere is formed in the formed grinding hole. A second embodiment in which a mouth is installed and the bottom blow tuyere is replaced will be described with reference to FIG. FIG. 3 is a cross-sectional view for explaining the steps of the method for replacing a bottom-blowing tuyere according to the second embodiment of the present invention.

  In the present embodiment, the above-mentioned stirring gas or refining gas is blown through the bottom blowing tuyere 1 to agitate or refine the steel bath in the converter. When the remaining thickness of the tuyere 1 reaches a predetermined value, the tuyere 1 is replaced.

  First, as shown in FIG. 3A, the inner surface 9a or the outer surface 9b (steel surface) of the steel shell 9 is set as a reference surface, and the tuyere receiving brick 13a whose longitudinal direction is the drilling direction is previously set in its longitudinal direction. It is arranged so that the direction, that is, the perforation direction is perpendicular to the reference plane (first step). Similarly to the first embodiment, in the present embodiment, the flange 10 is also arranged so that the flange surface 10a is parallel to the steel skin surface. Vertical. When the steel surfaces 9a and 9b are not parallel to the flange surface 10a, the flange surface 10a may be used as the reference surface as in the first embodiment.

  With the tuyere receiving brick 13a thus set in advance so that the perforation direction is perpendicular to the reference plane, as shown in FIG. Punching is performed from the outside by a punch in a direction perpendicular to the reference plane (second step). This step is performed when the bottom blowing tuyere 1 in use is melted and the remaining thickness of the bottom blowing tuyere 1 reaches a predetermined value.

  At this time, first, the molten steel and slag in the converter are discharged, and the converter is tilted at an appropriate angle (usually tilted so that the perforation direction is horizontal) and maintained. 12 is removed from the flange lid 11. Then, the metal wind box 4 of the bottom blowing tuyere 1 is removed so as not to hinder the perforation. Next, similarly to the first embodiment, the flange 10 or the flange lid 11 and a mounting flange (not shown) of a drilling machine (not shown) having a drill (not shown) attached to the tip thereof are attached. connect. As a result, the drill of the drilling machine is automatically aligned with the center of the flange lid 11.

  Then, while rotating the drill in the direction perpendicular to the flange surface, that is, the flange lid 11 and toward the center of the flange lid 11, the center position of the conventional bottom blowing tuyere 1 is set to the center position of the newly formed grinding hole. The bottom blow tuyere 1 and the tuyere receiving brick 13a are perforated so that they substantially coincide with each other.

  In this case, the conventional bottom-blowing tuyere 1 is perforated while being installed, and the newly formed grinding hole in the tuyere receiving brick 13a has its inner diameter larger than the outer diameter of the conventional bottom-blowing tuyere 1. Increase it slightly. This is because the inner surface of the tuyere receiving brick 13a that has been in contact with the conventional bottom blow tuyere 1 may have reduced properties as a refractory, and cracks or peeling may occur before or during perforation. The state of fitting with the bottom blowing tuyere 1 to be used next is impaired, which may lead to a decrease in the number of times of use, etc., to prevent this from happening. Accordingly, the bottom blow tuyere used next has a slightly larger outer diameter than the conventional bottom blow tuyere 1.

  At the time when the predetermined drilling process is completed, the state of the drilling hole is checked, and as shown in FIG. 3C, if the drilling hole has penetrated and the grinding hole 7 has been formed, the drilling machine is connected to the flange 10 or After being removed from the flange lid 11, as shown in FIG. 3D, a new bottom blowing tuyere 1 b integrally formed with a gas injection pipe and a coated refractory covering the outer periphery of the pipe is inserted into the grinding hole 7 ( Third step).

  After the insertion of the new tuyere tuyere 1b, the tuyere holding lid is attached to the flange lid 11 to prevent the tuyere tuyere 1b from falling off. The gap between the bottom blow tuyere 1b and the tuyere receiving brick 13a is filled with mortar previously applied to the outer surface of the bottom blow tuyere 1b. Further, a repair material is poured into the gap between the bottom blow tuyere 1b and the tuyere receiving brick 13a from the inside of the converter to minimize this gap.

  By exchanging the tuyere tuyere in this way, the tuyere receiving brick can be formed without causing any trouble such as damaging the work brick 13 around the tuyere receiving brick or making the grinding hole 7 unnecessarily large. The grinding hole 7 can be pierced in a short time along the predetermined piercing direction at the center of the center 13a, and the bottom blowing tuyere can be replaced. As a result, not only is the productivity of the converter improved, but also the wear rate of the exchanged bottom blow tuyere 1b becomes equal to the wear rate of the bottom blow tuyere used during the operation of the converter. However, it is possible to operate the bottom-blowing tuyere 1b until the end of the furnace body life, so that the refining reaction of the converter is made more efficient until the end of the furnace body life, thereby improving the iron yield and reducing the unit iron alloy consumption. Achieved.

  The present invention is not limited to the above description, and various changes can be made. For example, although the base brick 8 is installed, the base brick 8 is not installed, and the perforated brick 6 serving as a tuyere receiving brick may be arranged so as to be in contact with the flange lid 11, or a plurality of layers may be provided. The work brick 13 may be arranged.

  ADVANTAGE OF THE INVENTION According to this invention, the brick for perforation and the tuyere receiver can be used without damaging the work brick in the peripheral part of the perforation brick and tuyere receiving brick, and without generating troubles such as an unnecessarily large grinding hole. In a short period of time, a ground hole can be drilled in the center of the brick along a predetermined drilling direction, and the bottom tuyere can be switched / replaced. As a result, industrial utility value is high, such as improvement of converter productivity and improvement of iron yield.

Sectional drawing which shows some converters which have a tuyere. FIG. 4 is a cross-sectional view for explaining steps of a method for switching the bottom blowing tuyere according to the first embodiment of the present invention. Sectional drawing for demonstrating the process of the replacement | exchange method of the bottom blowing tuyere which concerns on 2nd Embodiment of this invention.

Claims (4)

A new bottom-blowing tuyere is formed in a brick for drilling that has been previously installed in a portion of the refractory layer covering the bottom of the converter other than the portion where the bottom-blowing tuyere is installed. A method of switching tuyeres,
Either the steel surface covering the outside of the converter or the flange surface attached to the steel surface is used as a reference surface, and the refractory layer is placed so that the reference surface is perpendicular to the drilling direction of the perforating brick. A step of pre-installing a perforating brick at a position different from the previous tuyere in the
Perforating the perforated brick in a direction perpendicular to the reference plane by a perforator from the outside of the steel shell,
Inserting a new converter bottom blowing tuyere into a grinding hole formed through the drilling hole of the drilling brick.   2. The method of switching a tuyere according to claim 1, wherein the tuyere is formed by integrally molding a plurality of gas injection tubes and a refractory covering these gas injection tubes. A method of switching the bottom tuyere of a converter. A converter bottom for exchanging the tuyere when the tuyere comprising the refractory provided in the refractory layer covering the bottom of the converter and the gas injection pipe is melted and the remaining thickness reaches a predetermined value. How to replace the tuyere
Either the steel surface covering the outside of the converter or the flange surface attached to the steel surface is used as a reference surface, and the reference surface is perpendicular to the perforation direction of the tuyere receiving brick in which the tuyere is installed. So that the tuyere receiving brick is installed,
A step of perforating a tuyere receiving brick in which a conventional tuyere is installed in a direction perpendicular to the reference plane by a perforator from outside the steel skin;
Inserting a new converter bottom blowing tuyere into a grinding hole formed through the perforation hole of the tuyere receiving brick.   4. The method of replacing a bottom blown tuyere according to claim 3, wherein the tuyere is formed by integrally molding a plurality of gas blowing tubes and a refractory covering these gas blowing tubes. A method of replacing the tuyere of the converter bottom.

Images