JPS62203663A - Nozzle for pouring molten metal provided with net-like fine pore for gas blowing - Google Patents

Abstract

PURPOSE:To prevent the sticking of nonmetallic inclusions to a fine pore aperture and to permit the extension of a nozzle life and smoother pouring operation by providing net-like fine pore communicating with a hollow chamber for blowing which surrounds the inside of a nozzle body and section to be immersed into a molten metal. CONSTITUTION:The inert gas blown from a socket 4 for gas blowing of an immersion nozzle for pouring passes the hollow chamber 3 surrounding the inside of the body and is ejected from near a discharge port 6 after passing the net-like fine pore part 6. The sticking of the nonmetallic inclusions in the molten metal poured therein near said part is thus prevented by which the nozzle life is extended and the trouble such as defective pouring is eliminated. The net-like fine pores 6 are formed by distributing an org. material into a molten of a refractory raw material for the nozzle, heating the same to carbonize, evaporate and shrink the org. material, etc.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a nozzle for pouring molten metal, such as a casting dipping nozzle or a long nozzle, which has a gas blowing structure to prevent clogging caused by non-metallic inclusions. Regarding.

(Prior art) Molten metal injection nozzles used in continuous casting of -8 molten metals such as steel are prone to non-metallic inclusions such as alumina on the nozzle spouting hole wall, which tends to clog the nozzle. Therefore, in order to prevent this clogging, casting nozzles that carry out casting while blowing an inert gas or the like into the molten metal through the cylindrical part of the casting nozzle have come into widespread use.

An example of a casting nozzle having this gas blowing structure is a submerged nozzle described in Japanese Patent Application Laid-Open No. 102357/1983. This immersion nozzle has a gas blowing hollow chamber with an annular cross section formed in the axial direction of the nozzle body.
The structure is such that an inert gas or the like is blown into the molten metal flowing through the pouring hole of the immersion nozzle from this hollow chamber. In this submerged nozzle, the gas blown from the hollow chamber forms a gas film on the inner wall of the submerged nozzle, thereby preventing nonmetallic inclusions such as alumina from adhering to the inner wall of the submerged nozzle.

[Problem that the invention seeks to solve]

In this gas-blown casting nozzle, the non-occupied gas is blown from the hollow chamber into the spout hole through the pores of the nozzle material. Therefore, in order to prevent non-metallic inclusions from adhering to the discharge port where non-metallic inclusions tend to adhere, it is necessary to provide a hollow chamber around the discharge port.

but,? When actually manufacturing a nozzle for injection of molten metal, it was difficult to arrange the hollow chamber in this way. Furthermore, since this region is strongly affected by the heat of the molten metal, the size of the pores tends to change, making it difficult to obtain stable gas ejection. As described above, it cannot be said that the aforementioned gas blowing casting nozzle °ζ has sufficient measures to prevent the adhesion of metal inclusions.

Therefore, the molten metal injection nozzle of the present invention was developed with the aim of eliminating such unstable gas injection.

[Means for solving problems]

In order to achieve this purpose, the casting nozzle of the present invention has mesh-like pores partially formed along the circumferential direction inside the main body, and the mesh-like pores connect the hollow chamber for gas blowing and the melting hole. It is characterized by being in communication with the gas jet [1] provided at the part to be immersed in the metal.

〔Example〕

Hereinafter, features of the present invention will be specifically explained with reference to embodiments shown in the drawings.

FIG. 1 is a sectional view showing the internal structure of the molten metal injection nozzle in this example.

The molten metal injection nozzle is an inner wall member that defines the pouring hole A! and an outer wall member 2 forming the outer surface of the nozzle body. A hollow chamber 3 is provided between the inner wall member 1 and the outer wall member 2. A hole connected to the hollow chamber 3 for blowing gas is provided in the outer wall member 2, and a socket 4 for blowing gas is embedded in this hole.

In such a molten metal injection nozzle, a discharge hole 5 is provided at the bottom of the nozzle body, and the molten metal that has flowed into the spout hole A is discharged to the outside of the molten metal injection nozzle through this discharge hole 5. , continuous casting, etc. At this time, the hollow chamber 3 and the discharge hole 5 are communicated with each other by a reticular pore. The spout hole A is also opened on the inner wall.

FIG. 2 shows the distribution of the network pores 6.

In this example, the mesh pores 6 are provided at two symmetrical positions in the circumferential direction of the molten metal injection nozzle. That is, if
The mesh pores 6 are opened not over the entire inner and outer surfaces of the molten metal injection nozzle, but only in areas where non-metallic inclusions are heavily adhered, such as the discharge hole 5 and its surroundings, the inner bottom wall of the nozzle, or the outside of the nozzle. It can be specified to the surface etc.

Therefore, the gas is supplied to the required area over the shortest distance, and it is possible to prevent the pressure of the gas from decreasing until it reaches the opening, which would be caused by the gas escaping through the pores of the brick. In addition, such a network pore (the arrangement of i is
This method does not cause a decrease in the strength of the molten metal injection nozzle itself (in addition, it is possible to effectively prevent non-metallic inclusions from being deposited by blowing a relatively small amount of gas).

Note that the reference number 7 in FIG. 1 indicates a protective layer provided on the outer wall member 2 of the nozzle for injecting molten metal at a position corresponding to the slag level SL. This is effective in preventing erosion.

The gas blown into the molten metal injection nozzle having such a structure from the gas injection socket 4 passes through the hollow chamber 3, the mesh pores 6, and flows into the molten metal as fine bubbles from the inner wall of the spouting hole A and its surroundings. It is squirted. At this time, since the openings of the mesh pores 6 are provided at locations where nonmetallic inclusions are frequently attached, it is possible to efficiently prevent the attachment of nonmetallic inclusions with a relatively small amount of gas. It becomes possible.

That is, when this casting nozzle is used, gas is blown finely and uniformly to the necessary locations, making prevention of blockages more effective and efficient.

The network pores 6 described in the above example may have a pore structure that expands two-dimensionally or three-dimensionally. Such network pores 6 are carbonized by heating.

An organic material that undergoes changes such as volatilization and shrinkage is incorporated in a predetermined distribution in a molded body of refractory raw material for nozzle construction, and when the refractory raw material is heated by reduction firing, low-temperature heat treatment, etc. It can be easily formed by undergoing changes such as carbonization, volatilization, and shrinkage.

If the organic material used at this time is a planar mesh,
The created network pores 6 have a two-dimensional expansion. Furthermore, if the material is sponge-like, the created net-like pores 6 will have a three-dimensional expansion. As this arousal material, for example, natural fibers, organic fibers, polyethylene, PVA, organic chemicals such as vinyl chloride, wires such as phenol resins, furan resins, etc. are used.

〔Effect of the invention〕

As explained above, in the molten metal injection nozzle of the present invention, network pores are selectively opened on the inner wall of the discharge hole and its surroundings. Therefore, the adhesion of non-metallic inclusions can be effectively prevented with a relatively small amount of gas, and a decrease in strength can also be avoided due to the built-in network pores. In addition, these porous pores can cause carbonization of organic materials,
Because it is formed as a result of volatilization, contraction, etc.
It has a two-dimensional or three-dimensional structure with a high degree of freedom and exhibits excellent gas distribution. As a result, the life of the molten metal injection nozzle is extended, and the pouring operation can be carried out smoothly, and many other effects can be achieved.

[Brief explanation of drawings]

FIG. 1 shows a molten metal injection nozzle according to an embodiment of the present invention,
FIG. 2 shows the distribution of network pores in the layered metal injection nozzle.

Claims (1)

[Claims] 1. Reticulated pores partially formed along the circumferential direction are provided inside the main body, and the reticulated pores communicate the hollow chamber for gas blowing with the gas outlet provided at the part immersed in the molten metal. A molten metal injection nozzle characterized by: