JP4246348B2 - Gas seal structure of molten metal injection nozzle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gas seal structure used in a molten metal processing apparatus (for example, a continuous casting apparatus).
[0002]
[Prior art]
Generally, refractory materials such as intermediate nozzles and sliding plates used in continuous casting apparatuses are formed by combining various refractory materials. This is to facilitate handling of the refractory and to allow only the damaged part to be replaced.
[0003]
A fire-resistant mortar, a fire-resistant sheet, or the like is used at the joint portion (also referred to as a fitting portion) between the refractory and the immersion nozzle in order to prevent the molten metal from flowing out and to suppress the inflow of outside air to the molten metal. .
[0004]
However, prevention of inflow of outside air to the molten metal cannot be sufficiently achieved with conventional refractory mortars and refractory sheets. Conventional refractory mortars and refractory sheets shrink due to heat from the molten metal, thereby causing cracks (cracks) from which the outside air enters. Alternatively, the outside air flows into the molten metal through the refractory mortar or the refractory sheet itself.
[0005]
At the joint portion of the immersion nozzle, particularly the long nozzle, the atmosphere of the joint portion is adjusted by ejecting an inert gas from the outside toward the joint portion.
[0006]
In the conventional method of adjusting the atmosphere around the joint, a pipe having a large number of holes is wound around the joint surface of the lower plate or the intermediate nozzle and the joint surface of the immersion nozzle, so that the inert gas is directly directed toward the refractory mortar. There is known a method of ejecting the liquid.
[0007]
FIG. 4 is an example of a conventional atmosphere adjustment method around the joint.
[0008]
As shown in FIG. 4, a method is also known in which an immersion gas 3 is ejected from the side of a metal case 13 with an inert gas N. In this case, the inert gas N is introduced from a gas inlet 15 provided on the outer peripheral surface of the metal case 13, and the inert gas N is ejected from an inert gas outlet provided at one end of the metal case 13. Gas ejection is performed from 14 toward the joint 6.
[0009]
[Problems to be solved by the invention]
The biggest problem with the prior art is the inefficiency of adjusting the atmosphere around the joint. In order to eject an inert gas from the outside of the joint and adjust the atmosphere around the joint, a large amount of gas is required, and generally 10 to 50 liters of gas is used per minute.
[0010]
In addition, when a large amount of gas is ejected, the joint portion of the refractory such as the intermediate nozzle or the plate is locally cooled, and there is a possibility that spalling is induced in that portion.
[0011]
An object of the present invention is to provide a gas seal structure of a molten metal injection nozzle that can prevent air from flowing into an immersion nozzle easily and at low cost.
[0012]
[Means for Solving the Problems]
The present invention provides a storage container for storing molten metal, a flow control device for molten metal attached to the bottom of the storage container, a refractory provided below the flow control device, and provided below the refractory. In the molten metal processing apparatus having the immersion nozzle formed and the joining surface of the refractory and the joining surface of the immersion nozzle are joined, an annular slit is formed concentrically with the molten metal passage hole on the joining surface of the immersion nozzle. The slit has an opening toward the joining surface of the immersion nozzle and is connected to a gas supply hole from the outside of the immersion nozzle. The opening of the slit in the joining surface of the immersion nozzle is made of a fireproof sheet that allows gas to pass through. In a molten metal processing apparatus that is closed and the joining surface of the immersion nozzle and the joining surface of the refractory are joined via a joint material, a refractory sheet with the slit opening closed. By passing the inert gas, and a gas seal structure of the molten metal pouring nozzle, characterized in that as Okurikomeru the inert gas directly to the joint surface as the gist.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is an improvement in the gas seal structure of the nozzle joint for molten metal injection.
[0014]
In the present invention, the opening of the annular slit formed inside the joining surface of the immersion nozzle is closed with a refractory sheet, and the inert gas for sealing is a joined portion of the refractory and the immersion nozzle through the refractory sheet. The air is prevented from flowing into the immersion nozzle by spraying on the joint material.
[0015]
It is important that the refractory sheet prevents the slits from being clogged with mortar and has air permeability, and in general porous bricks, the air permeability decreases because it becomes dense and softens during use. Absent.
[0016]
Various types of immersion nozzles (including not only narrow immersion nozzles but also long nozzles) can be used.
[0017]
【Example】
Hereinafter, one embodiment of the present invention will be described with reference to FIGS.
[0018]
FIG. 1A is an enlarged cross-sectional view schematically showing a main part of a gas seal structure for a molten metal processing apparatus according to the present invention, in particular, a submerged nozzle for injecting molten metal. FIG. 1B is a top view of FIG. FIG. 2 is a cross-sectional view showing a gas seal structure for a molten metal processing apparatus according to the present invention, particularly a molten metal injection submerged nozzle and its joint. FIG. 3 is a diagram showing a processing example of the molten metal injection nozzle shown in FIG.
[0019]
1 and 2, the immersion nozzle 3 has a molten metal passage hole 12 along the central axis, and the slit 8 is arranged concentrically with the molten metal passage hole 12 of the immersion nozzle 3. On the joint surface 10 of the immersion nozzle 3, the opening of the slit 8 is opened concentrically with the molten metal passage hole 12 of the immersion nozzle 3, and has an annular shape.
[0020]
A gas supply hole 7 leading to the slit 8 is provided on the outer peripheral side surface of the immersion nozzle 3. The inert gas N is supplied to the slit 8 through the gas supply hole 7.
[0021]
The width W of the slit 8 can be set arbitrarily. In consideration of clogging of the slit 8 and the strength of the joint, the width W of the slit 8 is preferably 2 to 3 mm. The depth D of the slit 8 can be arbitrarily set according to the diameter of the gas supply hole 7 and the contact around the joint. In consideration of the strength of the joint, the depth D of the slit 8 is desirably 30 mm or less. The slit 8 is configured to be closed by the fireproof sheet 9 on the joint surface 10, for example, to be covered.
[0022]
The refractory sheet 9 is generally inferior in corrosion resistance to molten metal as compared to the refractory mortar. Therefore, it is desirable to install the refractory sheet 9 at a position not in direct contact with the molten metal.
[0023]
The thickness of the refractory sheet 9 is desirably 0.5 mm or less or compressed to 0.5 mm or less when the immersion nozzle is set. This is because if the refractory sheet 9 is thicker than this, the molten metal erodes the joint material 4 and the molten metal may flow out to the outside.
[0024]
As the fireproof sheet 9, for example, a mullite ceramic fiber sheet can be used.
[0025]
For example, a ceramic fiber sheet of alumina: silica = 30-50%: 50-70% can be used. It is preferable to use a fiber sheet of 70% alumina or more and 30% silica or less.
[0026]
Since the ceramic fiber sheet is generally formed of an organic binder, the binder is decomposed by heat from the molten metal, so that the sheet becomes porous and air permeability is improved, which is suitable for the present invention. .
[0027]
In this invention, since an inert gas is introduce | transduced into a joint part via a fireproof sheet, cooling can be eased.
[0028]
This ceramic fiber sheet can also be applied when using highly plastic mortar as the joint material, but when using a hard and poorly plastic joint material, for example, a metal plate with fine pores or a dense fireproof material. Materials can also be used. In these cases, it is necessary to consider the air permeability during use. If a metal plate is used, it should not be in direct contact with the molten metal.
[0029]
FIG. 2 shows an example in which the molten metal injection immersion nozzle 1 shown in FIG. 1 is attached to the lower plate 2 (an example of a refractory). A joint material 4 is filled between the lower plate 2 and the immersion nozzle 1 for injecting molten metal. Conventional refractory mortar or the like can be used as the joint material 4.
[0030]
As shown in FIG. 3, the slit 8 can be formed without lowering the strength of the joint 6 by installing the reinforcing iron plate 11 on the upper outer peripheral surface of the immersion nozzle 1 for molten metal injection.
[0031]
【The invention's effect】
According to the gas seal structure of the present invention, the slit formed inside the immersion nozzle is closed by the refractory sheet, and the inert gas can be ejected to the joint through the refractory sheet. Cooling can be mitigated.
[0032]
Since processing into the immersion nozzle is easy, the manufacturing cost can be kept low. Further, according to the present invention, since an inert gas can be directly fed into joint refractories and cracks and cracks generated in the joint refractories, it is possible to cast molten metal at a gas ejection amount of about 5 liters per minute. Is possible.
[0033]
Furthermore, since the slit forming method and the like are simple, the manufacturing cost can be reduced as compared with the conventional method.
[0034]
The slit may be formed by cutting or burning of wax or the like conventionally performed.
[Brief description of the drawings]
FIG. 1A is an enlarged sectional view showing a main part of a nozzle for pouring molten metal according to the present invention. (B) is a top view of (A).
FIG. 2 is a view for explaining a gas seal structure of a nozzle joint surface for molten metal injection according to the present invention.
FIG. 3 is a view showing a processing example of a molten metal injection nozzle shown in FIG. 3;
FIG. 4 is an enlarged cross-sectional view illustrating an example of a gas sealing method in a conventional metal injection nozzle joint.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Molten metal injection nozzle 2 Lower plate 3 Immersion nozzle 4 Joint material 6 Joint part 7 Gas supply hole 8 Slit 9 Refractory sheet 10 Joint surface 11 Reinforced iron plate 12 Molten metal passage hole 13 Metal case 14 Inert gas ejection hole 15 Gas introduction Mouth N inert gas

Claims (4)

A storage container for storing molten metal, a flow control device for molten metal attached to the bottom of the storage container, a refractory provided below the flow control device, and an immersion nozzle provided below the refractory In the molten metal processing apparatus in which the joining surface of the refractory and the joining surface of the immersion nozzle are joined, an annular slit is formed concentrically with the molten metal passage hole on the joining surface of the immersion nozzle. Has an opening toward the joining surface of the immersion nozzle and is connected to a gas supply hole from the outside of the immersion nozzle, and the opening of the slit in the joining surface of the immersion nozzle is closed by a refractory sheet that allows gas to pass through. In addition, in the molten metal processing apparatus in which the joining surface of the immersion nozzle and the joining surface of the refractory are joined via a joint material, an inert gas is applied to the refractory sheet with the slit opening closed. Umbrella so, the gas seal structure of the molten metal pouring nozzle, characterized in that as Okurikomeru direct inert gas to the bonding surface. The gas seal structure for a molten metal injection nozzle according to claim 1, wherein the refractory sheet is made of a material having air permeability. The joint material is interposed between the joint surface of the refractory and the joint surface of the immersion nozzle, and the fireproof sheet is interposed between the joint material of the joint material and the immersion nozzle. Item 3. A gas seal structure for a molten metal injection nozzle according to Item 1 or 2. The gas seal structure for a molten metal injection nozzle according to any one of claims 1 to 3, wherein a reinforcing iron plate is installed on an upper outer peripheral side surface of the immersion nozzle.

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