JP5225635B2 - Gas injection plug - Google Patents

Description

  The present invention relates to a gas blowing plug used for blowing gas into molten metal in a steelmaking process.

  In the steelmaking process, a gas injection plug using a gas-permeable refractory is attached to the bottom of the pan, etc. to agitate the molten metal, adjust the temperature, and accelerate the removal reaction of nonmetallic components. A process of blowing a gas such as the above into the molten metal is performed. This gas blowing plug is roughly divided into a porous plug composed of a porous regular refractory layer and a slit plug in which a slit-like void is formed in a dense amorphous refractory layer. The continuous air holes and the slit-shaped voids in the dense layer serve as a path through which the gas flows. On the other hand, such a gas flow path is also a path through which the molten metal enters, so that the intruded metal is blocked by cooling and solidifying, and gas permeability may be impaired.

  Therefore, oxygen cleaning is performed in which oxygen is blown to the gas blowing plug at a high temperature after the molten metal is discharged. This is because oxygen is blown to forcibly oxidize the metal that has penetrated into the refractory layer, and the surface layer of the refractory layer is altered by the large heat generated by the oxidation reaction. By blowing oxygen from the outside of the plug while blowing a gas such as argon through the gas flow path, the oxide layer and the altered layer are blown away, the new refractory layer surface is exposed, and the gas permeability is restored.

  In order to facilitate such oxygen cleaning, conventionally, as shown in FIG. 8, a concave portion 101 is formed on the end surface in contact with the molten metal, and the molten metal is stored in the concave portion 101 so as to generate a fire type for oxygen cleaning. A gas blowing plug 100 is proposed (see, for example, Patent Document 1).

No. 7-21561

  However, in the conventional gas blowing plug 100 intended to facilitate the oxygen cleaning, the molten metal collected in the recess 101 easily enters the refractory layer 102, and the degree of oxygen cleaning is increased. There was a risk that the gas blowing plug would be worn out with time.

  In addition, in the oxygen cleaning of the gas blowing plug, normally, after the molten metal is discharged from the ladle, as shown in FIG. This is done by bringing the tip of the pipe P close to the vicinity of the blowing plug 110 and ejecting oxygen. At this time, since the ladle F is still in a very high temperature state of 1400 to 1700 ° C., the operator performs the operation of blowing oxygen from a position away from the ladle F using the long pipe P. Therefore, the long pipe P is bent, it is difficult to concentrate oxygen on the gas blowing plug 110, and oxygen is blown to the tuyere bricks 111 and the like disposed around the gas blowing plug 110, There was a problem that the tuyere brick 111 and the like were worn out. In addition, it is an excessive burden on the operator to hold the pipe P in a state where the gas blowing plug 110 is focused during the work.

  Therefore, in view of the above circumstances, an object of the present invention is to provide a gas blowing plug that facilitates oxygen cleaning.

  In order to solve the above problems, a gas blowing plug according to the present invention is a gas blowing plug for blowing gas into a molten metal in a steelmaking process, and includes a plug body including at least a gas permeable refractory layer; Three or more gas pipes that supply gas to the gas permeable refractory layer and three or more non-linearly spaced apart from each other on a plug end surface that is an end surface of the plug body that is in contact with the molten metal And a protrusion.

  The “plug body” can be composed of only a gas-permeable refractory layer. In addition, the “plug body” shall include a refractory layer with poor gas permeability or a layer that protects the gas-permeable refractory layer. You can also. In addition, the “plug end face” is not limited to the end face of the gas permeable refractory layer, and when the plug body includes a configuration other than the gas permeable refractory layer, in the entire plug body including those configurations, The end surface on the side that comes into contact with the molten metal.

  The “gas permeable refractory layer” includes a porous refractory layer, a dense refractory layer formed using an amorphous refractory material, and a refractory layer in which slit-like voids are formed as gas flow paths. And the refractory layer which compounded both can be illustrated.

  Here, the kind of the refractory material constituting the gas permeable refractory layer is not particularly limited. For example, alumina, spinel, alumina-silica, alumina-spinel, alumina-magnesia, alumina-carbon, Refractory materials such as magnesia-carbonaceous, alumina-chromic, and magnesia-chromic can be used.

  The shape of the “projection” is not particularly limited, and may be a columnar shape, a quadrangular columnar shape, a columnar shape with a curved side surface, or the like. Moreover, since the protrusion provided on the plug end face comes into contact with the molten metal, it is desirable that the protrusion be formed of a refractory material. The protrusion may be integrated with the refractory layer constituting the plug body after the formation of the refractory layer constituting the plug body, such as a gas permeable refractory layer. If the part is formed integrally, it is preferable that it becomes a stable protrusion that does not easily fall off. For example, it is possible to use a mold having irregularities corresponding to the shape of the protrusions, compression-molding the refractory material, and then firing it to form a regular refractory layer with protrusions formed. Alternatively, a castable refractory material mud is cast into a similar mold and formed into an amorphous refractory layer having protrusions. Alternatively, the protrusion can be formed by cutting or the like after the formation of the regular refractory layer or the irregular refractory layer.

  According to the present invention, with the configuration described above, three or more protrusions are provided in a non-linear manner on the plug end surface, so that a space is formed inside the protrusions. Then, by operating the pipe to supply oxygen to perform oxygen cleaning (hereinafter simply referred to as “oxygen pipe”) in the space, the tip of the pipe can be supported by the protrusion. . Thereby, even if a long oxygen pipe is operated from a remote position, it becomes easy to blast oxygen gas intensively to the gas blowing plug. Moreover, since the tip of the oxygen pipe is supported by the protrusion, it is easy to apply oxygen to the gas blowing plug even if the long pipe is bent, and to maintain the state in which oxygen gas is blown toward the gas blowing plug. Become.

  Here, in order to support the front-end | tip of an oxygen pipe with a gas blowing plug, it can also assume forming a recessed part in a plug end surface. However, in this case, as described above, the molten metal accumulates in the recess, and the metal easily enters the gas blowing plug. On the other hand, in the present invention, since three or more protrusions are provided “separated from each other”, the molten metal can flow through the gap between the protrusions, and the molten metal is formed on the plug end surface. It can prevent staying.

  In the gas blowing plug according to the present invention, “the projections are arranged at substantially equal angular intervals on a substantially single circumference”.

  With the above configuration, according to the present invention, three or more protrusions are located substantially on a single circumference, so that it is more suitable for supporting an oxygen pipe that is usually a circular pipe. It becomes. In addition, since three or more protrusions are provided at substantially equal angular intervals, the protrusions do not depend on the direction in which the gas blowing plug is attached to the ladle or the direction in which the ladle is tilted during oxygen cleaning. It becomes easy to support the tip of the pipe.

  In the gas blowing plug according to the present invention, “the protrusion has at least an inner surface formed in a substantially arc shape in a plan view of the plug end surface”.

  The “inner side surface” refers to a side surface facing the center side of the plug end surface in each of the three or more protrusions arranged in a non-linear manner. In addition, it is preferable that the “substantially arcuate” arc is an arc centered on the center of the plug end face. If the inner surface is arcuate in plan view, the shape of the outer surface is not particularly limited. For example, the outer surface is also concentric with the inner surface, and the projection is formed in a fan-like column shape in plan view. be able to.

  With the above configuration, according to the present invention, the arc-shaped inner surface of the protrusion is likely to be along the outer peripheral surface of the oxygen pipe, which is usually a circular tube. Therefore, the tip of the oxygen pipe can be stably supported by the protrusion.

  The gas blowing plug according to the present invention is as follows: "The plug body further includes a sleeve layer that covers a side peripheral surface of the gas-permeable refractory layer, and the protrusion includes at least the plug end surface of the sleeve layer. It is possible to be “disposed in”.

  The “sleeve layer” can be composed of an irregular refractory layer, a dense regular refractory layer, or a porous regular refractory layer. Normally, when a gas blowing plug is attached to a ladle, the gas blowing plug is fitted into a hole provided in a tuyere brick (receiving brick) at the bottom of the ladle. While being able to fix to a tuyere brick, protecting a permeable refractory layer, damage to the hole part of a tuyere brick is suppressed.

  Further, since the sleeve layer is configured to cover the “side peripheral surface” of the gas permeable refractory layer, the end surface on the molten metal side in the gas permeable refractory layer (hereinafter simply referred to as “gas permeable layer end surface”). ) And the end surface on the molten metal side in the sleeve layer (hereinafter simply referred to as “sleeve layer end surface”), that is, the plug end surface includes the gas permeable layer end surface and the sleeve layer end surface. Here, as the case where the protrusions are provided “at least on the plug end face in the sleeve layer”, when all the protrusions are provided on the sleeve layer end face, the protrusion provided on the sleeve layer end face and the gas permeable layer When both of the protrusions provided on the end face exist, a case where the single protrusion is positioned so as to straddle both the sleeve layer end face and the gas permeable layer end face can be exemplified.

  According to the above configuration, according to the present invention, since the protrusion is mainly provided on the end face of the sleeve layer, the area occupied by the protrusion on the end face of the gas permeable layer is not or is small. Thereby, it becomes easy to ensure the area of the gas permeable layer end surface which has the effect | action which blows gas in molten metal. In addition, by providing the protrusion mainly on the end face of the sleeve layer, the gas ejected from the oxygen pipe supported by the protrusion can be easily applied to a wide area of the end face of the gas permeable layer, and the gas permeable refractory layer is sufficiently provided. It becomes easy to clean oxygen.

  Further, when the protrusions are provided only on the end face of the sleeve layer, the respective protrusions are provided near the outer periphery on the plug end face. Therefore, in this case, the inner space formed by the protrusion becomes wide, and the operation of supporting the tip of the oxygen pipe from the distant position can be more easily performed.

  As described above, as an effect of the present invention, it is possible to provide a gas blowing plug that facilitates oxygen cleaning.

  Hereinafter, the gas blowing plug which is 1st embodiment of this invention is demonstrated based on FIG. 1 thru | or FIG. Here, FIG. 1 is a plan view and a longitudinal sectional view showing the configuration of the gas blowing plug of the first embodiment, and FIG. 2 is an explanatory view for explaining a state in which the oxygen pipe is supported by the protrusion. 3 is a plan view showing another example of the gas blowing plug of the first embodiment. 1B is a cross-sectional view taken along line AA in FIG. 1A, and FIG. 1D is a cross-sectional view taken along line BB in FIG. 1C. Moreover, each figure is schematic and does not display the shape and dimensional ratio of a gas blowing plug correctly.

  The gas blowing plug 1 of the first embodiment is a gas blowing plug for blowing gas into molten metal in a steelmaking process, and includes a plug body 4 including at least a gas permeable refractory layer 10, and a gas permeable refractory. Three or more protrusions 5 that are arranged away from each other in a non-linear manner on a gas supply pipe 9 that supplies gas to the material layer 10 and a plug end surface 30 that is an end surface of the plug body 4 on the side in contact with the molten metal. It is equipped with.

  If it demonstrates in detail, the plug main body 4 of 1st embodiment will be comprised only by the gas-permeable refractory layer 10, and the gas-permeable refractory layer 10 is formed in the substantially cone shape. In addition, the bottom end 6, which is the end opposite to the plug end face 30 in the gas permeable refractory layer 10, is connected to the gas supply pipe 9 via the gas pool 7. Further, the side peripheral surface of the gas permeable refractory layer 10 is covered with an iron skin 8, and this iron skin 8 also covers the bottom end portion 6 through the gas pool portion 7 and supports the gas supply pipe 9, The gas supply pipe 9 is kept in communication with the gas pool section 7.

  As shown in FIGS. 1A and 1B, three protrusions 5 are formed in a columnar shape, and are provided at substantially equal angular intervals on a single circumference concentric with the center of the plug end face 30. . Thus, when performing oxygen cleaning with the ladle lying down, the tip of the oxygen pipe P (shown in the figure, two-dot chain line) between the protrusions 5 is formed as schematically illustrated in FIG. And can be supported by the protrusion 5. In addition, the height of a protrusion can be 5-20 mm, for example.

  Further, as shown in FIGS. 1 (c) and 1 (d), the protrusion 5 can also be formed in a fan-like columnar shape in plan view in which both the inner side surface 5 a and the outer side surface 5 b are formed in an arc shape. . Also in this example, the protrusions 5 are provided on the single circumference concentric with the center of the plug end surface 30 at substantially equal angular intervals, and the inner side surface 5 a and the outer side surface 5 b are the center of the plug end surface 30. The center point is an arc. When performing oxygen cleaning, as illustrated in FIG. 2B, the arc-shaped inner surface 5 a of the protrusion 5 is easily along the outer peripheral surface of the oxygen pipe P, and therefore, the oxygen pipe P is stably formed by the protrusion 5. Can be supported.

  Furthermore, the number of the protrusions 5 is not limited to three, and for example, four may be provided as shown in FIG. Further, the position of the protrusion 5 on the plug end face 30 is not limited to the above example. For example, as shown in FIG. 3B, the protrusion 5 may be provided along the outer periphery of the plug end face 30. it can. As a result, the space inside the protrusion 5 is widened, and the operation of inserting the tip of the oxygen pipe into the space and supporting the protrusion 5 is facilitated. Moreover, it can respond also when the diameter of an oxygen pipe is large.

  Next, the gas blowing plug 2 which is 2nd embodiment of this invention is demonstrated using FIG. 4 thru | or FIG. 4 is a plan view and a longitudinal sectional view showing the configuration of the gas blowing plug 2 of the second embodiment, and FIG. 5 is a plan view showing another example of the gas blowing plug 2 of the second embodiment. FIG. 6 is a plan view and a longitudinal sectional view showing still another example of the gas blowing plug 2 of the second embodiment, and FIG. 7 is an explanation for explaining a manufacturing method of the gas blowing plug 2 of FIG. FIG. 4B is a cross-sectional view taken along line XX in FIG. 4A, and FIG. 6B is a cross-sectional view taken along line YY in FIG. 6A. Detailed description of the same configuration as that of the first embodiment will be omitted, and description will be made using the same reference numerals.

  The difference of the second embodiment from the first embodiment is that the plug body 4 includes a sleeve layer 20 that covers the side peripheral surface of the gas permeable refractory layer 10 in addition to the gas permeable refractory layer 10. Is a point. More specifically, as shown in FIGS. 4A and 4B, the sleeve layer 20 covers the side peripheral surface of the gas permeable refractory layer 10 through the iron skin 8, and the gas permeable refractory The bottom end 6 of the material layer 10 is also covered with the sleeve layer 20 via the gas pool portion 7 and the iron skin 8. FIG. 4 illustrates a case where the gas blowing plug 1 described with reference to FIGS. 1C and 1D is a gas blowing plug 2 further including a sleeve layer 20. Even when the sleeve layer 20 is provided, the protrusion 5 can be provided on the end face 31 of the gas permeable layer.

  On the other hand, as shown in the plan views of FIGS. 5A and 5B, the protrusion 5 may be provided only on the end surface 32 of the sleeve layer. Here, FIG. 5A illustrates a case where five columnar protrusions 5 are provided, and FIG. 5B illustrates a case where three fan-shaped protrusions 5 are provided in plan view. Thus, by providing the protrusion 5 only on the sleeve layer end face 32, the space inside the protrusion 5 becomes wider, and the operation of inserting the tip of the oxygen pipe into this space and supporting the protrusion 5 is performed. It will be easier. In addition, the oxygen ejected from the oxygen pipe supported by the protrusion 5 is likely to hit almost the entire surface of the gas permeable layer end face 31, and the gas permeable refractory layer 10 can be sufficiently cleaned with oxygen.

  Furthermore, as shown in FIGS. 6A and 6B, the protrusions 5 can be provided so as to be located on both the gas permeable layer end surface 31 and the sleeve layer end surface 32. By doing in this way, the thickness of the protrusion 5 can be set large, and even if the tip of the oxygen pipe collides during oxygen cleaning, it is possible to achieve a strong configuration that is difficult to damage. .

  Thus, the gas blowing plug 2 provided with the protrusions 5 so as to be located on both the gas permeable layer end face 31 and the sleeve layer end face 32 can be manufactured as follows, for example. First, a castable refractory material slurry C is poured into a mold M having irregularities corresponding to the shape of the protrusion 5 to a depth corresponding to the height of the protrusion 5 (see FIGS. 7A and 7B). . Next, the gas permeable refractory layer 10 to which the gas supply pipe 9 and the iron skin 8 are attached is set in the molding die M (see FIG. 7C), and the mud C is poured (FIG. 7D). )reference). Thereafter, by drying and removing from the mold, the gas blowing plug 2 shown in FIG. 6 is obtained (see FIG. 7E).

  As described above, according to the gas blowing plug 1 of the first embodiment and the gas blowing plug 2 of the second embodiment, since the tip of the oxygen pipe can be supported by the protrusion 5, the long pipe is bent. However, it is easy to concentrate oxygen on the gas blowing plugs 1 and 2, and the state can be easily maintained.

  Further, since the molten metal can freely flow through the gaps between the protrusions 5 that are separated from each other, the molten metal stays on the plug end surface 30 and does not cause the molten metal to enter the plug end surface 30. The structure which supports the front-end | tip of an oxygen pipe can be provided.

  Further, in any of the embodiments, since the plurality of protrusions 5 are provided on the single circumference at substantially equal angular intervals, the support of the oxygen pipe by the protrusions 5 has no directivity. .

  Further, when the protrusion 5 is formed in a sector shape in plan view, the oxygen pipe is stably supported on the inner surface 5 a of the protrusion 5.

  In addition, when the protrusion 5 is provided only on the sleeve layer end face 32, the operation of supporting the tip of the oxygen pipe from the distant position to the protrusion 5 is easy, and the gas permeable end face 32 is entirely exposed. Oxygen can be sprayed on the gas-permeable refractory layer 10 and the oxygen permeable refractory layer 10 can be sufficiently cleaned with oxygen.

  The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements can be made without departing from the scope of the present invention as described below. And design changes are possible.

  For example, although the case where the gas permeable refractory layer is a single layer is illustrated in any of the embodiments, the present invention is not limited to this and may be a composite layer of a plurality of gas permeable refractory layers having different gas permeability. .

  In the second embodiment, the case where the sleeve layer is cast and formed using a castable refractory material is exemplified. However, the present invention is not limited to this, and the sleeve layer may be composed of a porous or dense shaped refractory layer. it can.

  Furthermore, in the second embodiment, the case where the iron skin is interposed between the gas permeable refractory layer and the sleeve layer is exemplified, but the present invention is not limited to this, and the gas permeable refractory layer is directly covered with the sleeve layer. In addition, the outside can be covered with an iron skin.

It is the top view and longitudinal cross-sectional view which show the structure of the gas blowing plug of 1st embodiment. It is explanatory drawing explaining the state which made the protrusion support the oxygen pipe. It is a top view which shows the other example of the gas blowing plug of 1st embodiment. It is the top view and longitudinal cross-sectional view which show the structure of the gas blowing plug of 2nd embodiment. It is a top view which shows the other example of the gas blowing plug of 2nd embodiment. It is the top view and longitudinal cross-sectional view which show another example of the gas blowing plug of 2nd embodiment. It is explanatory drawing explaining the manufacturing method of the gas blowing plug of FIG. It is a side view which shows the structure of the conventional gas blowing plug intended to make it easy to perform oxygen cleaning. It is explanatory drawing explaining oxygen cleaning.

Explanation of symbols

1, 2 Gas blowing plug 4 Plug body 5 Projection 7 Gas pool part 8 Iron skin 9 Gas supply pipe 10 Gas permeable refractory layer (plug body)
20 Sleeve layer (plug body)
30 Plug end face 31 Gas permeable layer end face (plug end face)
32 Sleeve layer end face (plug end face)

Claims (4)

A gas blowing plug for blowing gas into molten metal in a steelmaking process,
A plug body comprising at least a gas permeable refractory layer;
A gas supply pipe for supplying gas to the gas permeable refractory layer;
3. A gas blowing plug comprising: a plug end surface, which is an end surface of the plug body on the side in contact with molten metal, and three or more protrusions that are spaced apart from each other and arranged non-linearly.   The gas blowing plug according to claim 1, wherein the protrusions are disposed at substantially equal angular intervals on a substantially single circumference.   The gas blowing plug according to claim 1 or 2, wherein at least an inner surface of the protrusion is formed in a substantially arc shape in a plan view of the plug end surface. The plug body further comprises a sleeve layer covering a side peripheral surface of the gas permeable refractory layer,
The gas blowing plug according to any one of claims 1 to 3, wherein the protrusion is disposed at least on the plug end surface of the sleeve layer.

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