JPH0430887B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for manufacturing a sliding nozzle installed in a molten metal storage container such as a ladle or tundish.

Prior Art It is known that a sliding nozzle is provided with a gas introduction hole for inert gas bubbling in order to prevent non-metallic inclusions from adhering to the molten steel and to prevent oxidation of the molten steel. This gas introduction hole has a hole extending radially from the nozzle hole, so that the sliding plate, the fixed plate,
It is provided on one of the lower nozzles or on two or more members. Conventionally, this gas introduction hole has been formed by drilling. Therefore, as shown in FIG. 5, in order to drill holes 30 extending radially, it is necessary to manufacture the member 1 by dividing it into a member body 2 and an insert ring 3. It was necessary to accurately drill the hole 20 for receiving the ring. Further, it takes time and skill to provide the radial holes 30 and the grooves 31 that communicate these in the insert ring 3, and when the insert ring 3 is made of gas-permeable porous brick, it is difficult to provide the holes and grooves. There was a problem in that it took even more time and effort. Furthermore, the obtained parts had variations in air permeability between the parts due to poor processing accuracy and non-uniformity of the joint mortar 32 between the part body and the insert ring, and air inflow from the joint between the part body and the insert ring. It is very difficult to prevent this, and there is a problem in that the molten steel passing through the nozzle is likely to be oxidized.

Purpose of the Invention The present invention solves the problems of the prior art, allows gas introduction holes to be easily provided in a member without dividing the member, and eliminates variations in air permeability and air permeability in the resulting member. It is an object of the present invention to provide a method for manufacturing a sliding nozzle that can reduce inflow to an extent that does not pose a problem.

Structure of the Invention The object of the present invention is to provide an annular portion that extends so as to surround a portion corresponding to the nozzle hole when molding a member provided with a gas introduction hole in a sliding nozzle with clay; a radial portion extending from the annular portion toward the center thereof to be longer than a portion corresponding to the gas introduction hole;
In addition, a molded body that is burnt out, volatilized, softened, flowed out, or shrunk when the member is fired is buried and molded at the gas introduction hole formation position in the clay, and after firing the molded body, a nozzle hole is bored. This is achieved by a method for manufacturing a sliding nozzle characterized by the following.

Firing at 800℃~1800℃, preferably 1000℃~
The process is carried out at 1500°C, which provides a strong bond between the refractory raw materials in the clay and makes the component rigid.

Substances that are burned off, volatilized, softened, flowed out, or contracted during firing include, for example, vinyl chloride resin, thermoplastic resins such as polyethylene, polyester, and polypropylene, thermosetting resins such as phenolic resin, styrene resin, and epoxy resin, paper, bamboo, Examples include organic fibers, inorganic fibers, or those impregnated with resin, and metals such as lead, brass, tin, aluminum, and wood metal.

Embodiments The method of the present invention will be described below with reference to the accompanying drawings, taking as an example the case where the method is applied to a sliding plate of a sliding nozzle.

1 and 2 show a sliding plate material 4 formed from clay 6 in which a forming body 5 is embedded. As shown in FIG. 3, the forming body 5 has a radial portion 5 corresponding to the shape of the gas introduction hole to be obtained.
0. It has an annular portion 51 that connects this and a guide hole 52 that reaches the side wall of the plate material, and is integrally molded. As shown in FIG. 3, the radial portion 50 is formed to extend from the annular portion 51 toward its center longer than the desired radial shape (90 in FIG. 4). The forming body 5 is made of a substance that disappears, volatilizes, softens, flows out, or shrinks at the firing temperature of the sliding plate material 4 as described above, but materials that easily disappear and leave no residue, such as vinyl chloride resin, polyethylene, and polypropylene, are used. It is preferable to use a thermoplastic resin that does not leave residue. The forming body 5 is buried at the position where the gas introduction hole is to be formed, and this embedding is done so that the annular portion of the forming body 5 is concentric with the circular protrusion 60 that will serve as a reference for later drilling of the nozzle hole. It is desirable to do so. If these centers shift, the gas discharge from the gas introduction holes may become uneven as a result. When the sliding plate material 4 thus obtained is fired at a normal firing temperature, the formed body 5 disappears, softens and flows out, and a space is created in the area where the formed body 5 was placed. When a nozzle hole 8 is bored in the obtained fired body with reference to the circular protrusion 60, a sliding plate 7 having a gas introduction hole 9 opened on the inner surface of the nozzle hole is formed, as shown in FIG. can get. This gas introduction hole 9 corresponds to the shape of the forming body 5, and includes a radial hole 90 extending outward from the inner surface of the nozzle hole 8, an annular hole 91 communicating with the hole 90, and a conductor leading from the annular hole 91 to the side surface of the plate 7. It has a hole 92. In this way, the gas introduction holes can be obtained without dividing the plate 7 as in the prior art, so that the problem of air flowing in from the joints of the disassembly members does not occur. Furthermore, since the gas introduction holes can be obtained without drilling, manufacturing is easy, and variations in air permeability between the obtained plates can be reduced to a non-problematic level.

The annular portion of the molded body may have various shapes such as a circular shape, a rectangular shape, and a fan shape, and the number of radial portions can be determined as necessary. Since the nozzle hole diameter is selected by drilling a hole of a predetermined diameter in the member, it is much easier than manufacturing the insert ring by changing the diameter as in the past. Furthermore, if a nozzle hole is formed at the same time as embedding the formed body during clay molding, the nozzle hole drilling step during firing can be omitted or simplified.

The above explanation took the sliding plate as an example, but
The present invention can be similarly applied to other members such as the fixed plate of the sliding nozzle or the lower nozzle.

Next, an experimental example of the present invention will be shown.

Experimental Example 1 In manufacturing an alumina-carbon sliding plate, gas introduction hole forming bodies each made of vinyl chloride resin, polyethylene, phenol resin, and synthetic rubber were embedded and molded into the clay. This was calcined for 5 hours in a reducing atmosphere in a coke plea at 1300°C.

The forming body has an annular part with a diameter of 100 mm and a wire diameter of 3 mm.
A wire consisting of 30 wires each having a radial portion with a wire diameter of 0.5 mm and a guide hole portion with a wire diameter of 3 mm was used.

Products made of vinyl chloride resin, phenolic resin, and polyethylene do not show any cracks during the molding and firing process, and there are no visible burnt residues in the fired products except for the phenolic resin, and there are no formed bodies. A space was created at the position where the In the case of the phenolic resin product, the residual carbon content of the phenolic resin was approximately 40%, and adhesion of resin carbide was observed in the spaces. After firing, a sliding plate having gas introduction holes was easily obtained by drilling nozzle holes of a predetermined size. There was almost no variation in air permeability between the sliding plates obtained, and no air flowed into the molten steel during use.

Experimental Example 2 In manufacturing an alumina sliding plate, the same molding bodies as those in Experimental Example 1 were respectively injected into the clay and molded. This was fired at 1500°C for 5 hours in an oxidizing atmosphere.

No cracking was observed in vinyl chloride, polyethylene, and phenolic resin. There was no burnt residue left in any of the fired products, and a space was formed at the position where the formed body had been placed, and by drilling with the nozzle hole, a sliding plate with gas introduction holes was easily obtained. .

There was almost no variation in air permeability between the sliding plates obtained, and no air inflow occurred during use.

Effects of the Invention As explained above, according to the present invention, it is possible to provide a method for manufacturing a sliding nozzle that has the following effects. That is, when molding a member with a gas introduction hole in a sliding nozzle using clay, an annular portion extending to surround a portion corresponding to the nozzle hole, a guide hole portion for communicating the annular portion with the outside of the member, and A formed body having a radial part extending from the annular part toward the center thereof, and which is burnt out, volatilized, softened, flowed out, or shrunk when the member is fired, is buried in the clay at the position where the gas introduction hole is formed, and molded. do. Therefore, at the same time as the molded body is fired, an annular hole, a guiding hole, and a radial hole are formed in the member corresponding to the annular portion, guiding hole portion, and radial portion. That is, the member provided with the holes can be manufactured easily and accurately without separately preparing an insert ring in which the holes and grooves are formed as in the conventional method. Furthermore, since the radial portion is formed to extend longer than the portion corresponding to the radial hole in the gas introduction hole, by firing the molded body in which it is embedded, a hole extending longer than the portion corresponding to the radial hole is formed in the member. . Therefore, when subsequently drilling a nozzle hole, the member is drilled including the part extending beyond the portion corresponding to the radial hole, and as a result, the nozzle hole and the radial hole are connected together with the nozzle hole drilling. communication can be easily and reliably obtained.

[Brief explanation of drawings]

Figures 1 to 4 are diagrams for explaining one embodiment of the present invention, in which Figure 1 is a plan view of clay molded into a sliding plate shape with a forming body embedded therein, and Figure 2 is a plan view of clay molded into a sliding plate shape. 1
FIG. 3 is a plan view of the formed body, FIG. 4 is a cross-sectional view of the obtained sliding plate, and FIG. 5 is a cross-sectional view taken along line A-A in the figure. FIG. 3 is a longitudinal sectional front view of the sliding plate. 4... Sliding plate material, 5... Forming body, 6...
Clay, 7... Sliding plate, 8... Nozzle hole, 9
...Gas introduction hole.

Claims (1)

[Claims] 1. In a sliding nozzle, when molding a member provided with a gas introduction hole with clay, an annular portion extending to surround a portion corresponding to the nozzle hole, and a guide hole portion for communicating the annular portion with the outside of the member. corresponds to the gas introduction hole, and further has a radial portion extending from the annular portion toward the center to be longer than a portion corresponding to the gas introduction hole, and is not burned out, volatilized, softened, outflowed, or evaporated during firing of the member. A method for producing a sliding nozzle, which comprises: embedding a shrinkable molded body in the clay at the position where the gas introduction hole is to be formed, molding the molded body, firing the molded body, and then drilling a nozzle hole.