JPS644872B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sliding nozzle device installed in various types of molten steel containers to adjust the flow rate of molten steel.

[Conventional technology]

In recent years, sliding nozzle devices have been widely used because they can accurately control the flow rate of molten steel flowing out from a molten steel container or the like.

However, compared to a method using a stopper head, this method has the disadvantage that it is more likely to cause air to be inserted, which can cause inclusions and _N2 pick-up.

For example, in the case of continuous casting, it is possible to prevent air from entering the immersion pipe that forms the molten steel flow path from the molten steel storage container such as a ladle or tundish to the mold; In the riding nozzle device, air is inserted into the molten steel flow, and the components of the molten steel, Al,
This oxidizes Si and Ti, generates nonmetallic inclusions, and causes _N2 absorption in the molten steel, resulting in a deterioration in steel quality.

Such air insertion often occurs along the sliding surface between the sliding plate and the upper and lower fixed plates, and along the joint between the lower fixed plate and the casting nozzle.

To solve this problem, conventional methods for preventing insertion have been proposed, such as Japanese Patent Publication No. 55903/1983 and Japanese Patent Application Laid-open No. 56-559.
No. 141961, Utility Model Publication No. 165555, Japanese Patent Application Publication No. 1987-
There is one described in each publication of No. 52564, and another that prevents air from being inserted by spraying an inert gas such as argon onto the sliding plate, the upper and lower fixed plates, and the periphery of the immersion nozzle.

[Problem that the invention seeks to solve]

However, what is described in Utility Model Publication No. 55-55903 is
This is an example of open casting, which is simply provided with a shielding cover, which is very large and inconvenient, taking up space.

The method described in JP-A No. 56-141961 aims to prevent oxidation of carbon-containing refractory bricks, and although it can prevent air from getting into the molten steel, it requires a large-scale hood, so its airtightness cannot be ensured. cannot be said to be sufficient.

Also, the method described in Japanese Patent Application Laid-Open No. 57-52564 cannot fully achieve its purpose, as in the two cases mentioned above.

Further, the technique described in Japanese Utility Model Application Publication No. 56-165555 only relates to a sealing device for a submerged nozzle connection portion, and does not take into consideration the sealing for the sliding surface of a sliding nozzle device.

The present invention solves the problems of the prior art, and is designed to completely prevent air from entering from the nozzle in a sliding nozzle device.
The purpose of the sliding nozzle device of the present invention is to improve the quality of steel [Means for solving the problem] In order to achieve the purpose, the sliding nozzle device of the present invention supports the upper surface of the upper fixed plate and supports the lower sliding A fixed metal frame with an open bottom end that surrounds the moving plate and the lower fixed plate, a sealing metal frame that forms a circular opening and is removably attached to the lower part of the fixed metal frame, and an opening in the sealing metal frame. a circular lower fixing plate holding fitting that is configured to be insertable into the lower fixing plate and press-supports the lower surface around the spout hole of the lower fixing plate; A groove is formed on either side of the inner circumferential end surface, and an O-ring is placed in the groove, and the O-ring seals between the outer circumferential edge surface of the lower fixing plate holding fitting and the inner circumferential edge surface of the sealing frame opening. A sealing part for joining and sealing around the upper end of the immersion nozzle at the bottom of the lower fixed plate is connected to the lower fixed plate holding fitting, and the inside of the fixed metal frame including the upper part of the immersion nozzle is made into a sealed chamber. It is characterized in that an inert gas supply pipe is connected in communication within the sealed chamber.

〔Example〕

The present invention will be described below based on embodiments shown in the drawings.

FIG. 1A is a longitudinal cross-sectional view of the sliding nozzle device according to the present invention, FIG. It is a sectional view taken along the line arrow.

In the figure, 1 is placed at the bottom of the tundish and has an open bottom end cross-sectional shape that is concave toward the bottom. 2 is removable from the fixed frame 1 with a connecting bolt 19 via a gasket 11 for sealing. It is a seal metal frame connected to.

This sealing metal frame 2 is provided with a circular opening 2a, and an annular sealing wall 2b that projects inside the fixed metal frame 1 is formed in this opening 2a.

Reference numeral 3 denotes a lower fixing plate holding fitting having a circular planar shape with a concave groove 3a formed in the outer peripheral wall and an O-ring 12 fitted into the concave groove 3a, and is configured to be insertable into the opening 2a of the seal metal frame 2. When installed, the O-ring 12 is in close contact with the seal wall 2b, creating a sealed chamber C in which the inside of the fixed metal frame 1 is isolated from the outside.

Reference numeral 4 designates a nozzle seal ring fitted into the upper end of the immersion nozzle 10, and 5 represents an immersion nozzle holder located below the seal ring 4.

This immersion nozzle holder 5 is composed of a pair of semicircular arc-shaped members connected to each other by a hinge 30 so as to be openable and closable, and is held by sandwiching the periphery of the immersion nozzle 10 and using bolts and nuts 31 and 32 for fastening. do.

A heat-resistant gasket 13 is arranged on the outer periphery of the upper end of the nozzle seal ring 4 to seal between it and the opening 3b of the lower fixed plate holding fitting 3, and furthermore, the lower end of the nozzle seal ring 4 and the upper end of the immersion nozzle holder 5 are arranged. A heat-resistant packing 14 that closely contacts the peripheral wall of the immersion nozzle 10 is provided between them. The pair of gaskets 13 and 14 function as a sealing portion D that isolates the space between the upper side of the immersion nozzle 10 and the immersion nozzle holder 5 from the outside, and the gasket 13 allows the same portion to be placed in the sealed chamber C. It has a sealed connection configuration.

Furthermore, 6 is a sliding metal frame that moves forward and backward by a cylinder device, 7 is an upper fixed plate whose upper surface is supported by the fixed metal frame 1 and connected to the upper nozzle 20 in the furnace, and 8
is a sliding plate connected to the sliding metal frame 6, and 9 is a lower fixed plate.

The lower fixing plate 9 is attached to the lower fixing plate holding fitting 3
The lower surface is supported by the compression coil spring 1.
The contact pressure of the sliding surface A between each plate 7, 8 and 8, 9 is maintained in a state where the urging force by 8 is applied.

The sliding surface A between each of these plates 7 to 9 and the joint B between the lower surface of the lower fixed plate 9 and the upper surface of the immersion nozzle 10 are both located within the sealed chamber C, and can be maintained in a state insulated from the outside.

Further, 15 is a supply pipe for supplying an inert gas such as argon into the sealed chamber C. An auxiliary supply pipe 16 is connected to the piping system of this supply pipe 15 so that gas can also be supplied to the opening 3b of the lower fixed plate holding fitting 3 and the upper end portion of the immersion nozzle 10. Furthermore, a cooling gas supply pipe 17 for cooling the box 18a of the compression coil spring 18 and other metal frame devices (not shown) is connected.

The auxiliary supply pipe 16 is connected to the lower surface of the lower fixed plate holding fitting 3 as shown in FIG. A flow path 3c for supplying into the seal ring 4 is formed.

Note that the total amount of inert gas supplied from these piping systems can be kept at 100 N/min or less.

In the above configuration, inside the sealed chamber C is the seal metal frame 2.
The sealing joint between the immersion nozzle 10 and the lower fixed plate 9 and the seal portion D at the upper end of the immersion nozzle 10 isolates it from the outside air. Intrusion of outside air from part B can be prevented.

In addition to preventing outside air from entering, inert gas is supplied into the sealed chamber C from the supply pipe 15 and the auxiliary supply pipe 16, so even if a seal failure occurs on the sliding surface A or the joint B, This inert gas atmosphere does not cause oxidation of the molten steel or absorption of N ₂ , making it possible to reliably improve the quality of the steel.

In addition, since the sealing frame 2 and the lower fixed plate holding fitting 3 are sealed by the O-ring 12 and the sealing wall 2b located in the vertical direction, the upper and lower positions of the plates 7, 8, and 9 may vary due to slight dimensional differences. It can be reliably sealed against fluctuations. Similarly, since the sealing wall 3d of the lower fixed plate holding fitting 3 is located in the vertical direction, it can be reliably sealed even if its position changes in the vertical direction when the immersion nozzle 10 is attached.

Furthermore, since the lower fixing plate holding fitting 3 is formed into a circular shape, the distortion is equalized by thermal stress, the amount of deformation is reduced, and the sealing performance is improved and the surface pressure on the sliding surface A of each plate 7 to 9 is reduced. This ensures that suitable operating conditions can be obtained.

Incidentally, when replacing each of the plates 7 to 9, there is no need to remove the seal metal frame 2 from the fixed metal frame 1, and this can be easily done by pulling out the lower fixed plate holding fitting 3 downward.

Further, in this embodiment, the O-ring 12 is attached to the lower fixed plate holding fitting 3 side, but a groove may be provided in the seal wall 2b of the seal metal frame 2 and the O-ring may be disposed in this groove.

Further, the configuration of the present invention is not limited to a nozzle device for a tundish, but can also be applied to a ladle sliding nozzle device and a rotary type nozzle device other than a reciprocating type (reciprocating type).

〔Effect of the invention〕

In the present invention, since the space including the sliding surface of the nozzle plate and the joint between the immersion nozzle and the plate is formed as a sealed chamber that is isolated from the outside air, it is possible to completely prevent air from entering the molten steel flow. This has the effect of improving steel quality.

[Brief explanation of the drawing]

Fig. 1A is a vertical sectional view of the sliding nozzle device according to the present invention, Fig. 1B is an explanatory diagram of the installation of each metal frame and metal fittings, Fig. 2 is a bottom view of the sliding nozzle device, and Fig. 3 is a FIG. 1A is a sectional view taken along the - line in FIG. 1A, and FIG. 4 is an enlarged sectional view of a seal portion provided in the immersion nozzle portion. 1: Fixed metal frame, 2: Seal metal frame, 2a: Opening, 2b: Seal wall, 3: Lower fixed plate holding fitting, 3a: Concave groove, 3b: Opening, 3c: Channel, 3
d: Seal wall, 4: Nozzle seal ring, 5:
Immersion nozzle holder, 7: Upper fixing plate, 8:
Sliding plate, 9: Lower fixed plate, 10: Immersion nozzle, 11: Gasket, 12: O-ring, 1
3, 14: packing, 15: supply pipe, 16: auxiliary supply pipe, 17: cooling gas supply pipe, 20: upper nozzle, A: sliding surface, B: joint, C: sealed chamber,
D: Seal part.

Claims (1)

[Scope of Claims] 1. A fixed metal frame with an open bottom end that supports the upper surface of the upper fixed plate and surrounds the lower sliding plate and the lower fixed plate, and a circular opening formed in the fixed metal frame. a seal metal frame removably attached to the lower part of the seal metal frame, and a circular lower fixing plate holding metal fitting configured to be insertable into the opening of the seal metal frame and supporting the lower surface of the lower fixing plate in pressure contact around the spout hole. A groove is formed in either the outer circumferential end surface of the lower fixing plate holding fitting or the inner circumferential edge surface of the opening of the seal metal frame, and an O-ring is arranged in the groove, and the O-ring A seal portion for sealing the outer circumferential end surface of the lower fixed plate holding fitting and the inner circumferential end surface of the seal metal frame opening and sealing around the upper end of the immersion nozzle at the bottom of the lower fixed plate is connected to the lower fixed plate holding fitting. A sliding nozzle device having a sealing mechanism characterized in that a fixed metal frame including the upper part of the immersion nozzle is a sealed chamber, and an inert gas supply pipe is connected in communication with the sealed chamber. 2. The sealing section includes a nozzle section seal ring into which the upper part of the immersion nozzle is inserted and a sealing material arranged between the lower fixing plate holding fitting and the nozzle section seal ring which holds the immersion nozzle in pressure contact with the lower surface of the lower fixing plate and the nozzle section sealing ring. 2. A sliding nozzle device having a sealing mechanism according to claim 1, comprising a ring and a submerged nozzle holder for sealing the outer periphery of the submerged nozzle. 3. The sealing mechanism according to claim 1, characterized in that a gas supply pipe for supplying inert gas into the sealed chamber is connected to the fixed metal frame and/or the lower fixed plate holding fitting. Sliding nozzle device.