JP2008231554A - Method for manufacturing gas injection plug and gas injection plug - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a gas injection plug by which the judgement of an end-point using a refractory for judging the end-point can be performed and the possibility of molten steel leakage through a joint part at the boundary between the refractory for judging the end-point and a plug base body, can be reduced, and to provided the gas injection plug manufactured by the above method. <P>SOLUTION: The gas injection plug 11 is provided with the plug base body 2 constituted of a gas-permeable refractory and an end-point judging body 3 constituted of a refractory different in the gas-permeability or/and heat-conductivity from the plug base body 2 and is integrated without leaving the joint part at the boundary between the plug base body 2 and the end-point judging body 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a gas blowing plug manufacturing method and a gas blowing plug, and in particular, a gas blowing plug that is attached to a container such as a ladle in a steelmaking process and used to blow gas into molten steel. And a gas blowing plug manufactured by the method.

  In the steelmaking process, a gas blowing plug using a gas-permeable refractory is attached to the bottom of a vessel such as a pan to agitate the molten steel, adjust the temperature, remove non-metallic components, and so on. The process of blowing various gases is performed. Since the molten steel permeates into the gas flow passage inside the refractory, the gas blowing plug is more worn out by the molten steel than the refractory on the lining of a container such as a ladle. Therefore, in order to avoid a serious accident of molten steel leakage, it is necessary to replace with a new gas blowing plug before the wear progresses remarkably. However, it is wasteful in terms of resources, labor, and economy if the gas blowing plug is replaced too early to fear leakage of molten steel.

  Therefore, conventionally, as illustrated in FIG. 8A, an end point determination refractory 103 for detecting the arrival of the replacement time is embedded in the plug base body 102 made of a refractory having gas permeability. A gas blowing plug 100 is used. More specifically, in the gas blowing plug 100, a gas supply pipe 108 for supplying gas is attached to one end which is outside a container such as a ladle in use. And the inner edge part which becomes the molten steel side in use is set so that the end part 103b of the refractory 103 for end point determination is outside (container side) from the end part 102b of the plug base body 102. Thereby, when the plug base body 102 is worn away from the inner end portion 102b side and the end portion 103b of the end point determination refractory 103 is exposed, it is possible to know that the replacement time has arrived by detecting this. . Here, the detection that the end portion 103b of the end-point determination refractory 103 is exposed is performed by, for example, forming the plug base body 102 and the end-point determination refractory 103 with refractory materials having different thermal conductivities, thereby causing molten steel. This can be done by utilizing the difference in color depending on the degree of red heat at the time of discharge (for example, Patent Documents 1 and 2).

JP-A-7-229686 JP-A-10-219338

  However, as shown in FIGS. 8B and 8C, the conventional gas blowing plug 100 includes a plug base body 102 that is pre-fired into a shape having a recess 104 corresponding to the shape of the refractory 103 for end point determination, Alternatively, it is manufactured by inserting a fired refractory material 103 for end-point determination, which has been fired in advance, and bonding it with a mortar 105 into a plug base body 102 obtained by drying a cast molded body. Therefore, with the gas blowing process into the molten steel by the gas blowing plug 100, the mortar 105 having low fire resistance comes into contact with the molten steel at the stage where the plug base body 102 is worn out and the refractory material for end point determination 103 is exposed. There is a risk that the molten steel may be melted in advance and the molten steel may enter the joint portion at the boundary between the plug base body 102 and the refractory material 103 for determining the end point, resulting in leakage of molten steel.

  Further, the filling of the mortar 105 into the joint portion may be insufficient, so that a so-called empty joint may be formed. In this case, the risk of molten steel leakage is larger than that in the above case. In particular, when the end point determination refractory 103 has a shape such as a prismatic shape, a rubbing operation is performed when the end point determination refractory 103 is inserted into the recess 104 of the plug base 102 via the mortar 105. Since it is difficult, there is a higher possibility that a portion that becomes a void is formed, and the risk of leakage of molten steel is even greater.

  Therefore, in view of the above situation, the present invention is capable of end point determination using the end point determination refractory, and there is a risk of molten steel leakage through the joint portion of the boundary between the end point determination refractory and the plug base. It is an object of the present invention to provide a gas blowing plug manufacturing method that can be reduced and a gas blowing plug manufactured by the method.

  In order to solve the above-mentioned problems, a method for producing a gas blowing plug according to the present invention is described as follows: “In a plug base made of a gas-permeable refractory, the plug base is gas permeable or / and thermal conductivity. A method for producing a gas injection plug in which an end point determination body composed of different refractories is embedded, and a step of forming a raw material refractory material of the end point determination body to obtain a fixed shape, and forming the fixed shape body In a state of being held inside the mold, pouring the slurry of the raw material refractory material of the plug base into the mold, and forming an amorphous refractory layer in which at least a part of the fixed shape is embedded; A step of drying or / and firing the amorphous refractory layer in which the fixed form is embedded.

  The “end point determination” in the “end point determination body” is to know that it is time to replace the gas injection plug with a new one by detecting that the gas injection plug has been worn out over a predetermined length. It is used as intended. Further, in the gas blowing plug in which the end point determination body is embedded in the plug base body, the end portion of the end point determination body is outside the end portion of the plug base body (container side) at the inner end portion on the molten steel side in use. It is attached to a container such as a ladle. As a result, when the inner end of the plug base is worn and the inner end of the end determination body is exposed, the end can be determined by detecting this.

  Examples of the “gas permeable refractory” include a dense refractory having a slit as a gas flow passage and a porous refractory.

  The plug matrix and the end-point determination body are composed of refractories having different gas permeability and / or thermal conductivity. For example, the plug base is a dense refractory with slits and the end-point determination body is porous. In the case of high quality refractories, if the plug base is a porous refractory and the end point determination body is a dense refractory, the plug base body and the end point determination body are both porous refractories, and the thermal conductivity differs due to the difference in the composition of both. In this case, the case where both the plug base body and the end point determination body are porous refractories and the gas permeability is different due to the difference in porosity can be mentioned. Here, when the gas permeability of the plug base body and the end-point determination body is different, when the molten steel is discharged from a container such as a ladle, the one with the higher gas permeability exhibits a dark color due to the cooling action by the ejected gas. Using this, it is possible to determine the end point. Further, when the thermal conductivity of the plug base body and the end point determination body are different, the end point determination can be performed using the difference in color depending on the degree of red heat.

  The kind of “raw material refractory material” of the plug base and the end-point determination body is not particularly limited. For example, alumina, spinel, alumina-silica, alumina-spinel, alumina-magnesia, alumina-carbon, magnesia Refractory materials such as carbonaceous, alumina-chromic, magnesia-chromic can be used.

  “Standardized products” made from raw material refractory materials are widely used to include those in which refractory materials can be maintained in a certain shape, and are sintered and calcined after molding. Examples thereof include a calcined body, a pressure-molded molded body, and a dried body dried after casting.

  “Mudow” can be prepared by mixing the raw refractory material with water and adjusting agents such as a binder, a curing agent, and a dispersant. In addition, the configuration in which the shaped object is “at least partially embedded” in the amorphous refractory layer is a configuration in which the end-point determination body is partially embedded in the plug matrix as the final gas blowing plug configuration. Even if it exists, the structure by which the whole end-point determination body was embed | buried inside the plug base body may be sufficient.

  After the step of pouring the slurry to form the amorphous refractory layer, the “drying and / or firing step” is performed as a mode in which only the step of drying the cast molded body into which the slurry is poured is cast. When performing the step of firing after passing through the step of drying the molded body, after solidifying the cast molded body with a curing agent or the like and demolding, then performing drying and firing in a single step by controlling the temperature rise conditions, etc. Etc. can be illustrated. Moreover, it can also be comprised by adding another process to said process, for example, the process of demolding, the process of calcination, etc. can be provided. Furthermore, when the plug base is made of a dense refractory having slits, a process for forming the slits can be provided. For example, a process in which a flammable material burned down by firing is placed in an amorphous refractory layer, or a wire rod arranged so as to penetrate through the amorphous refractory layer is solidified to some extent by the amorphous refractory layer A step of pulling out can be provided.

  According to the present invention, according to the present invention, the raw material refractory material of the end point determination body of the plug base body and the end point determination body is preliminarily shaped, and the slurry of the plug base material refractory material is poured around the plug base body and the end point determination body. By forming a regular refractory layer and then drying or / and firing, a gas blowing plug in which the plug base body and the end point determination body are integrated is manufactured. Thereby, since the joint part is not formed at the boundary between the end point determination body and the plug base body, it is possible to solve the conventional problem that the molten steel may leak through the joint part.

  In addition, in the conventional manufacturing method, when the end point determination body is bonded to the recess of the plug base body with mortar, the end point determination body can be inserted while being rubbed against the inner peripheral surface of the recess so that the mortar is sufficiently filled. It was done. Therefore, the shape of the end-point determination body is easily limited to a shape such as a columnar shape that facilitates the rubbing operation. On the other hand, in the present invention, the plug base and the end point determination body can be integrated without using a mortar, and it is not necessary to perform the rubbing operation as described above. The shape of the end point determination body including the shape is highly flexible.

  Moreover, in the conventional manufacturing method, it was necessary to shape | mold the plug base body beforehand in the shape which has a recessed part corresponding to the shape of an end point determination body. In general, since it is difficult to form a complicated shape by using a punching die, the shape of the recess that can be formed in the plug base, that is, the shape of the end point determination body is limited to a simple shape to some extent. On the other hand, in the present invention, since it is a method of forming an irregular refractory layer that becomes a plug base by pouring mud around a standardized end-point determining body, the end-point determining body is used by using a split mold or the like. Even if the shape is complicated, a plug matrix corresponding to the shape can be formed.

  In addition, the method for producing a gas blowing plug according to the present invention is described as follows. “A plug base made of a gas permeable refractory is made of a refractory having a gas permeability or / and a thermal conductivity different from that of the plug base. A method for producing a gas blowing plug in which an end-point determination body embedded is embedded, wherein the raw material refractory material of the plug base body is shaped to obtain a shaped product having a recess in a part of the outer surface, and the end-point determination Pouring the slurry of the raw material refractory material into the recess to form an amorphous refractory layer, and drying or / and firing the shaped product on which the amorphous refractory layer is formed. is doing.

  The “part of the outer surface recesses” of the shaped product can be formed by setting the mold when performing pressure molding or casting. Alternatively, by arranging a plurality of regular refractories having a predetermined shape, it is possible to form a regular shape having a recess on a part of the outer surface while forming slits between the regular refractories.

  With the above configuration, according to the present invention, of the plug base body and the end point determination body, the raw material refractory material of the plug base body is preliminarily shaped, and the raw material refractory material of the end point determination body is formed in the recess formed on the outer surface thereof. A gas blowing plug in which the plug base body and the end-point determination body are integrated is manufactured by pouring mud to form an amorphous refractory layer and then performing drying or / and firing. Thereby, since the joint part is not formed at the boundary between the end point determination body and the plug base body, it is possible to solve the conventional problem that the molten steel may leak through the joint part. Further, since it is not necessary to perform a mortar rubbing operation, the shape of the concave portion, that is, the shape of the end-point determination body, has a high degree of freedom including a shape having a corner such as a prismatic shape.

  Further, the gas blowing plug according to the present invention is composed of “a plug base made of a gas permeable refractory, and the plug base made of a refractory having different gas permeability and / or thermal conductivity, And an end point determination body integrated without having a joint between the plug base body ”.

  The gas blowing plug having such a configuration can be manufactured by the above-described manufacturing method. According to the present invention, the end point determination body and the plug base body are integrated with each other without having a “joint portion”, that is, a void layer called a mortar layer or a so-called empty joint. Therefore, the conventional problem that there is a possibility of molten steel leakage through the joint portion can be solved.

  Further, the gas blowing plug according to the present invention can be assumed that “the end point determination body is entirely embedded in the plug base”.

  The gas blowing plug having such a configuration is, for example, that the raw material refractory material of the end point determination body is preliminarily shaped, and the shaped product is partially partially held in a mold with a holder such as a wire. Pour the raw material refractory material mud of the plug base into the mold so as to be buried, form an amorphous refractory layer, remove the retainer at the stage where the amorphous refractory layer is solidified to some extent, It can be manufactured by pouring mud so that it is completely buried.

  With the above configuration, according to the present invention, the boundary between the end point determination body and the plug base does not reach any end of the gas blowing plug. As a result, due to the difference in thermal expansion coefficient between the end point determination body and the plug base body made of refractories having different gas permeability and / or thermal conductivity, the boundary between the end point determination body and the plug base body should be avoided. Even if a crack occurs, the risk of the crack reaching the outer end of the gas blowing plug is small, so that it is possible to more reliably prevent molten steel leakage.

  Furthermore, the gas blowing plug according to the present invention is such that “the end-point determination body is made of a porous refractory, and the plug base is made of a dense refractory having a slit”. it can.

  With the above configuration, during normal use, gas is blown into the molten steel through the slit of the plug base. When the end of the plug base body on the molten steel side (inner end) progresses and the end-point determination body is exposed, a large amount of gas is ejected through the end-point determination body made of a porous refractory. Thereby, when the molten steel is discharged from a container such as a ladle, the plug base body made of a dense refractory is red hot, whereas the end point determination body cooled by the jetting gas exhibits a dark color, It is possible to easily detect that the end-point determination body has been exposed and to know that the replacement timing of the gas blowing plug has arrived.

  Further, even if the plug base is a porous refractory and the end point determination body is a dense refractory, it is possible to detect that the end point determination body is exposed due to the difference in color, but in the present invention, By making the structure in contact with the molten steel during normal use a dense refractory having a higher resistance to the molten steel than the porous refractory, the service life of the gas blowing plug can be extended.

  As described above, as an effect of the present invention, the end point determination using the end point determination refractory is possible, and the risk of leakage of molten steel through the joint at the boundary between the end point determination refractory and the plug base is reduced. It is possible to provide a method for producing a gas blowing plug that can be produced, and a gas blowing plug produced by the method.

  A gas blowing plug manufacturing method (hereinafter simply referred to as “manufacturing method”) and a gas blowing plug manufactured by the manufacturing method according to the best embodiment of the present invention will be described below with reference to FIGS. This will be explained based on. Here, FIG. 1 is a process diagram of a manufacturing method according to an embodiment of the present invention, FIG. 2 is an explanatory diagram for explaining the manufacturing method of FIG. 1, and FIG. 3 is a process diagram of a manufacturing method according to another embodiment. 4 is an explanatory view for explaining the manufacturing method of FIG. 3, FIG. 5 is a cross-sectional view showing the structure of the gas blowing plug manufactured by the manufacturing method of FIGS. 1 and 3, and FIG. FIG. 7 is a cross-sectional view showing a configuration of a gas blowing plug according to still another embodiment, and FIG. 7 is an explanatory view for explaining a method for manufacturing the gas blowing plug of FIG. 1 to 7 are schematic views, and do not accurately indicate the shape and dimensional ratio of the gas blowing plug.

  As shown in FIG. 5, the gas blowing plug 11 according to the present embodiment includes a plug base 2 made of a gas permeable refractory, and the plug base 2 has a fire resistance different in gas permeability and / or thermal conductivity. And an end point determination body 3 integrated with the plug base body 2 without having a joint portion.

  More specifically, the plug base body 2 is formed in a substantially truncated cone shape, and the end point determination body 3 is formed in a substantially truncated quadrangular pyramid shape. In addition, the end point determination body 3 is embedded in the plug base body 2, and the end point determination body 3 is provided at an outer end portion that is an outer side when the gas blowing plug 11 is attached to a container such as a ladle. The outer end 3a and the outer end 2a of the plug base 2 are substantially flush with each other. Both outer end portions 2 a and 3 a are connected to the gas supply pipe 8 through the gas pool portion 9. Further, the inner end portion 3 a of the end point determination body 3 is set to be positioned outside the inner end portion 2 b of the plug base body 2. The disposed gas supply pipe 8 is supported by an iron skin 10 that covers the outer surface of the plug base 2 and the gas pool portion 9.

  Next, a method for manufacturing the gas blowing plug 11 having the above-described configuration will be described with reference to FIGS. In the manufacturing method of the present embodiment, the plug base body 2 made of a gas permeable refractory has an end point determination body 3 made of a refractory having a gas permeability or / and a thermal conductivity different from that of the plug base body 2. In the method of manufacturing the buried gas blowing plug 11, the step S <b> 1 for obtaining the shaped product 31 by shaping the raw material refractory material 300 of the end-point determination body 3, and holding the shaped product 31 inside the mold 18. In the state, the slurry of the raw material refractory material 200 of the plug base body 2 is poured into the molding die 18 to form the irregular refractory layer 22 in which at least a part of the fixed shape 31 is embedded, and the fixed shape 31 includes a step S5 for drying the amorphous refractory layer 22 in which 31 is embedded, a step S5 for demolding, and a step S6 for firing.

  More specifically, first, the raw material refractory material 300 of the end point determination body 3 is shaped by a method such as firing after molding, calcining after molding, pressure molding, drying after casting, or the like to obtain a shaped product 31 (step) S1) (see FIG. 2A). Next, the fixed object 31 is suspended and held inside the forming die 18 by using a holder 19 such as a wire (step S2), and the slurry of the raw material refractory material 200 of the plug base 2 is formed in this state. Pour into the mold 18 (step S3) (see FIG. 2B). In the present embodiment, the pouring of the mud is performed so that the upper surface of the mud is substantially flush with the upper end of the shaped object 31 in the mold 18. Thereby, the amorphous refractory layer 22 in which the fixed object 31 is embedded except for one end is formed. In addition, the holding method of the fixed form 31 and the holding position in the shaping | molding die 18 are not limited to what was demonstrated using illustration in this embodiment.

  Next, the amorphous refractory layer 22 is dried (step S4) (see FIG. 2C), and the holder 19 is removed from the fixed shape 31 and demolded (step S5). Then, the amorphous refractory layer 22 in which the fixed object 31 is embedded is fired (firing step S6). Thereby, the gas blowing plug 11 in which the end point determination body 3 and the plug base body 2 are sintered is manufactured (see FIG. 2D).

  According to the gas blowing plug 11 of this embodiment manufactured by the above manufacturing method, since the joint portion is formed without forming a joint portion at the boundary between the end point determination body 3 and the plug base body 2, The conventional problem that there is a risk of molten steel leaking through the portion can be solved. Further, in the present embodiment, since the baking step S6 is performed after the drying step S4, the integrated end-point determination body 3 and the plug base body 2 are further firmly bonded by sintering, and molten steel leaks. Fear can be further reduced.

  In addition, unlike the conventional manufacturing method, there is no need to insert the end-point determination body into the recess of the plug base body through a mortar, so that the end-point determination body 3 can also be a truncated quadrangular pyramid shape having a corner. There are no obstacles. In the present embodiment, the end point determination body 3 is exemplified as a headed quadrangular pyramid shape, but is not limited thereto. For example, in this embodiment, since the plug base is formed by pouring mud around the end point determination body, even if the end point determination body has a complicated shape such as a polygonal column by using a split mold, the shape corresponds to the shape. A plug matrix can be formed.

  Next, the gas blowing plug 11 can be manufactured by a manufacturing method of another embodiment as shown in FIGS. 3 and 4. In the manufacturing method of the present embodiment, the plug base body 2 made of a gas permeable refractory has an end point determination body 3 made of a refractory having a gas permeability or / and a thermal conductivity different from that of the plug base body 2. A method of manufacturing the buried gas blowing plug 11, the step P1 for obtaining the shaped product 21 having the concave portion 24 on a part of the outer surface by shaping the raw material refractory material 200 of the plug base body 2, and the end-point determination body 3 Pour the mud of the raw material refractory material 300 into the recess 24 to form the amorphous refractory layer 32, the step P3 to dry the shaped product 21 on which the amorphous refractory layer 32 is formed, and the step P4 to calcinate. It is equipped with.

  More specifically, first, the raw material refractory material 200 of the plug base 2 is shaped to obtain a shaped product 21 (step P1) (see FIG. 4A). At this time, the concave portion 24 corresponding to the desired shape as the shape of the end point determination body 3 is formed on the outer surface of the shaped object 21 by setting the shape of the molding die or the like.

  Next, the slurry of the raw material refractory material 300 of the end point determination body 3 is poured into the recess 24 (step P2) (see FIG. 4B). As a result, an irregular refractory layer 32 is formed in the recess 24, and a regular article 21 is formed in which the irregular refractory layer 32 is embedded except for one end (see FIG. 4C).

  Thereafter, the amorphous refractory layer 32 is dried (process P3) and further baked (firing process P4). Thereby, the end point determination body 3 and the plug base body 2 are firmly integrated by sintering, and the gas blowing plug 11 in which the joint portion is not formed at the boundary between the end point determination body 3 and the plug base body 2 is manufactured (FIG. 4 (d)).

  Furthermore, the gas blowing plug 12 of other embodiment is demonstrated. As shown in FIG. 6, the gas blowing plug 12 of the present embodiment includes a plug base 2 ′ made of a gas permeable refractory and the plug base 2 ′ having gas permeability or / and thermal conductivity. An end-point determination body 3 ′ composed of different refractories and integrated with the plug base body 2 ′ without having a joint portion is provided. The end-point determination body 3 ′ is entirely inside the plug base body 2 ′. It is buried in. In addition, below, while using the same code | symbol about the structure similar to the gas blowing plug 11, detailed description is abbreviate | omitted.

  A method of manufacturing the gas blowing plug 12 having such a configuration will be illustrated with reference to FIG. In the manufacturing method of the present embodiment, an end point determination body made of a refractory having a gas permeability or / and a thermal conductivity different from that of the plug base 2 ′ is used for the plug base 2 ′ made of a gas permeable refractory. 3 ′ is a method for manufacturing the gas blowing plug 12 embedded, the step of forming the raw material refractory material 300 of the end-point determination body 3 ′ to obtain a shaped product 31 ′; A process of pouring the slurry of the raw material refractory material 200 of the plug base 2 ′ into the molding die 18 while holding the plug inwardly to form an amorphous refractory layer 22 ′ in which the fixed shape 31 ′ is embedded, It includes a step of drying and firing a non-standard refractory layer 22 'in which an object 31' is embedded.

  More specifically, first, the raw material refractory material 300 of the end point determination body 3 ′ is shaped to obtain a shaped product 31 ′, and then the shaped product 31 ′ is placed inside the mold 18 using the holder 19. In this state, the slurry of the raw material refractory material 200 of the plug base body 2 ′ is poured into the mold 18 (see FIG. 7A).

  At this time, mud is poured into the mold 18 so that the shaped article 31 'is partially buried, thereby forming an irregular refractory layer 22' (see FIG. 7B). Then, the amorphous refractory layer 22 'is solidified to some extent and the holder 19 is removed (see FIG. 7 (c)), and further, mud is poured so that the entire fixed shape 31' is buried (FIG. 7 (d). )reference). As a result, an irregular refractory layer 22 ′ in which the entire shaped article 31 ′ is embedded is formed (see FIG. 7E).

  Thereafter, similarly to the above embodiment, drying and demolding are performed, and the amorphous refractory layer 22 ′ in which the entire fixed shape 31 ′ is embedded is fired. As a result, the entire end-point determination body 3 ′ is embedded in the plug base body 2 ′, and the gas blowing plug 12 in which both are firmly integrated by sintering is manufactured (see FIG. 7 (f)).

  According to the gas blowing plug 12 of the present embodiment, the boundary between the end point determination body 3 ′ and the plug base body 2 ′ does not reach any end of the gas blowing plug 12. Therefore, due to the difference in thermal expansion coefficient between the end point determination body 3 ′ and the plug base body 2 ′, which is made of refractories having different gas permeability and / or thermal conductivity, the end point determination body 3 ′ Even if a crack occurs at the boundary between the plug body 2 ′ and the plug base 2 ′, the crack does not easily reach the outer end of the gas blowing plug 12. Thereby, molten steel leak can be prevented more reliably.

  In the gas blowing plugs 11 and 12, the plug bodies 2 and 2 'can be made of a dense refractory having slits, and the end point determination bodies 3 and 3' can be made of a porous refractory. With this configuration, when the gas is blown into the molten steel through the slits of the plug body 2, 2 'during normal use, and the end point determination body 3, 3' is exposed due to wear, the end point determination is a porous refractory. A large amount of gas is ejected through the bodies 3 and 3 '. As a result, when the molten steel is discharged from a container such as a ladle, an end point determination that exhibits a dark color due to the cooling action of the plug bases 2 and 2 ′ that are red hot because they are dense refractories and the gas that is ejected in large quantities It is possible to easily detect that the end point determination bodies 3 and 3 ′ are exposed based on the color difference from the bodies 3 and 3 ′.

  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, in the above embodiment, the case where the plug base is made of a dense refractory having a slit and the end point determination body is made of a porous refractory is exemplified, but the present invention is not limited to this. For example, the plug matrix can be made of a porous refractory, and the end point determination body can be made of a dense refractory. In this case, the end point can be determined by visually recognizing the red hot end point determining body in the plug base body which exhibits a dark color by cooling with the jetting gas.

  Alternatively, even if the plug base and the end-point determination body have the same degree of gas permeability, by using both refractories with different thermal conductivities, utilizing the color difference due to the degree of red heat, End point determination can be performed.

  Moreover, although the case where a baking process was performed through a drying process was illustrated in said embodiment, it is not limited to this, It can also be used as a gas blowing plug in the stage which finished the drying process. Alternatively, after the cast molded body is solidified with a curing agent or the like and demolded, drying and firing can be performed in a single step by controlling the temperature rise conditions and the like.

It is process drawing of the manufacturing method of one Embodiment of this invention. It is explanatory drawing explaining the manufacturing method of FIG. It is process drawing of the manufacturing method of other embodiment. It is explanatory drawing explaining the manufacturing method of FIG. It is sectional drawing which shows the structure of the gas blowing plug manufactured by the manufacturing method of FIG.1 and FIG.3. It is sectional drawing which shows the structure of the gas blowing plug of other embodiment. It is explanatory drawing explaining the manufacturing method of the gas blowing plug of FIG. (A) is sectional drawing which shows schematic structure of the conventional gas blowing plug, (b) And (c) is explanatory drawing explaining the manufacturing method of the gas blowing plug of (a).

Explanation of symbols

2, 2 'plug base body 3, 3' end point determination body 8 gas supply pipe 9 gas pool section 10 iron skin 11, 12 gas blowing plugs 21, 31 shaped article 22, 32 amorphous refractory layer 24 recess 200, 300 raw material Refractory material

Claims (5)

Manufacturing method of gas blowing plug in which plug body made of gas permeable refractory is embedded with end point judging body made of refractory having gas permeability or / and thermal conductivity different from that of plug body Because
A step of stiffening the raw material refractory material of the end-point determination body to obtain a shaped product;
While holding the fixed shape inside the molding die, the slurry of the raw material refractory material of the plug base is poured into the molding die, and an amorphous refractory layer in which at least a part of the fixed shape is embedded is formed. Forming, and
And a step of drying or / and baking the amorphous refractory layer in which the fixed form is embedded. Manufacturing method of gas blowing plug in which plug body made of gas permeable refractory is embedded with end point judging body made of refractory having gas permeability or / and thermal conductivity different from that of plug body Because
A step of forming a raw material refractory material of the plug base to obtain a shaped product having a recess in a part of the outer surface;
Pouring the slurry of the raw material refractory material of the end-point determination body into the recess, and forming an amorphous refractory layer;
And a step of drying or / and firing the shaped article on which the amorphous refractory layer is formed. A plug base made of a gas permeable refractory;
The plug base is composed of refractories having different gas permeability and / or thermal conductivity, and includes an end point determination body integrated with the plug base without having a joint portion. Gas blowing plug to do.   The gas blowing plug according to claim 3, wherein the end point determination body is entirely embedded in the plug base body.   5. The gas blowing plug according to claim 3, wherein the end-point determination body is made of a porous refractory, and the plug base is made of a dense refractory having slits formed therein. .

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