JPS6310051A - Submerged nozzle for continuous casting - Google Patents

Abstract

PURPOSE:To improve cooling and oxidizing prevention effects for power part and to improve the service life by forming a gap between the powder part and a nozzle body and forming gas curtain by passing through gas in this gap. CONSTITUTION:Inert gas is blown from a gas blow-in part 15 and passed in a slit-like pressure equalizing zone 14 to downward. Then, as the distance between the inner wall face of nozzle body 10 and the slit-like pressure equalizing zone 14 is kept to almost constant, the prescribed gas curtain is formed on the inner wall face of the body 10. After that, the gas is gone to the lower end part of slit-like pressure equalizing zone 14 and discharged from a gas discharging hole 16 to the lower end part of circular gap 18 between the nozzle body 10 and the powder part 17. The gas is further flowed to upward in the gap 18 to form the gas curtain. Then, the gas is flowed out from the upper end of gap 18 to outside as shown by the arrow mark.

Description

[Detailed description of the invention] Part 1: This invention is continuous! l! This invention relates to an improvement of a submerged nozzle for F construction.

Conventional immersion nozzles for continuous casting are provided with a powder portion for the purpose of preventing oxidation and heat retention of the molten steel surface within the mold and lubricating the mold surface. Generally, Zr02-C10 is mainly used for the powder part. This is because if the nozzle body is made of AQ203-C quality, the corrosion resistance will be poor.

Known methods for attaching the powder portion to the nozzle body include, for example, those in which the powder portion is crimped at the same time as molding, and those in which the powder portion is fixed with mortar or the like after processing the nozzle body.

An example of the material of such a powder part is Zr.
02-cvtr, which has a ZrO2 component of 85% and a C component of 15%, is widely used.

-, is about to be L Φ In the immersion nozzles for continuous and II construction which are being used more and more recently, the material of the powder part as mentioned above has become an obstacle to extending the service life.

It should be noted that increasing the thickness of the powder portion mentioned above imposes considerable restrictions in terms of mold size and spalling resistance.

An object of the present invention is to provide a continuous casting immersion nozzle that can overcome the drawbacks of the prior art as described above and have a longer service life.

In order to achieve the above-mentioned object, the present invention includes a nozzle body having a molten steel inlet at the upper end and a molten steel outlet at the lower end; Immersion nozzle for continuous casting, comprising a nozzle hole formed from the molten steel inlet at the upper end of the nozzle body to the molten steel outlet at the lower end of the nozzle body, and a powder part provided near the gas discharge part. The powder portion is formed as an outer ring, the powder portion is provided along the outer periphery of the nozzle body, a gap is formed between the nozzle body and the powder portion, and the gas discharged from the gas discharge portion is The gist of the present invention is a submerged nozzle for continuous casting, characterized in that the gas flows upward in the gap and then flows out.

In the immersion nozzle for continuous casting according to the present invention, referring to Embodiment 1, the powder portion 17 is formed as an outer ring, and the powder portion 17 is formed along the outer periphery of the nozzle body 10. establish. At this time, an annular gap 18 is formed between the powder portion 17 and the nozzle body 10. For example, it is desirable to set the size of the void within a range of 0.5 to 5. This is because the gas curtain has the best cooling effect when the temperature is within this range.

A slit-shaped pressure equalizing zone 14 formed within the nozzle body 10
When a gas such as an inert gas discharged from a gas discharge part (for example, the gas discharge port 16 or the porous part 20) connected to the lower end part flows upward through the gap 18, the cooling gas is form curtains. A gas curtain is formed on the inner surface of the nozzle body 1o, and is also formed in the gap 18 between the powder portion 17 and the nozzle body 10. Thereby, the cooling effect and oxidation prevention of the powder portion 17 become remarkable. Further, it becomes easy to arbitrarily select the wall thickness and material of the powder portion 17.

Friend 11 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

The nozzle body 10 has a molten steel inlet 1 formed at the upper end of the nozzle body 10 in the longitudinal direction of the nozzle body 10.
It has a nozzle hole 13 formed from 1 to a molten steel discharge port 12 formed at the lower end. The nozzle body 10 and the nozzle hole 13 are concentric. In the embodiment shown in FIG. 1, the molten steel discharge port 12 is oriented slightly above the radial direction of the nozzle body 10. A slit-shaped pressure equalizing zone 14 is formed along the nozzle hole 13 and around the nozzle body 1.
It is formed within a wall thickness of 0. This slit-shaped pressure equalizing zone 14 is concentric with the nozzle body 1o. A gas blowing part 15 is formed at the upper part of the slit-shaped pressure equalizing zone 14 so as to be connected thereto. The gas blowing part 1
5 extends in the radial direction of the nozzle body 10 and is open to the outer surface of the nozzle body 10. On the other hand, a hole-shaped gas discharge port 16 is formed at the lower end of the slit-shaped pressure equalizing zone 14 as a gas discharge section.

A powder portion 17 is formed as an outer ring at the gas discharge port 16. This powder portion 17 is made of, for example, Zr 02 -C and has a predetermined length.

An annular gap 18 is formed between the powder portion 17 and the outer surface of the nozzle body 10. This void 18 has approximately constant dimensions throughout. For example, the radial dimension of the void 18 is preferably 0.5 to 5 mm. This is because with such dimensions, a good gas curtain for cooling is likely to be formed within the cavity 18.

The powder part 17 is attached to the nozzle body 10 at its lower end. For example, a female threaded portion 17a may be formed inside the lower end of the powder portion 17, and the nozzle body 1 may be formed in a corresponding manner.
The powder part 17 is fixed to the nozzle body 10 by forming a male screw part 11a on the outer surface of the nozzle o and screwing them together.

To explain the operation of the above embodiment, inert gas is blown from the gas blowing section 15 and passed downward through the slit-shaped pressure equalizing zone 14. At this time, since the distance between the inner wall surface of the nozzle body 10 and the slit-shaped pressure equalizing zone 14 is kept substantially constant, a predetermined gas curtain is formed on the inner wall surface of the nozzle body 10. Thereafter, the gas reaches the lower end of the slit-shaped pressure equalizing zone 14 and is discharged from the gas discharge port 16 into the lower end of the annular gap 18 between the nozzle body 10 and the powder section 17. The gas further flows upwardly through the gap 18, forming a regas curtain therein. Thereafter, it flows outward from the upper end of the gap 18 (that is, from between the upper end of the powder portion 17 and the outer surface of the nozzle body 10) as shown by the arrow.

FIG. 2 shows another embodiment according to the invention. Second
Shown in the figure are a nozzle body 10, a molten steel inlet 11, a molten steel outlet 12, a nozzle hole 13, and a slit-shaped pressure equalizing zone 14.
, the configurations of the gas blowing section 15 and the powder section 17 are substantially the same as those in the embodiment shown in FIG. 1, so detailed explanation thereof will be omitted.

In the embodiment shown in FIG. 2 as well, the lower end of the powder portion 17 is connected to the nozzle body 10 by a screw method. An annular gap 18 is formed between the nozzle body 10 and the powder portion 17.

The differences between the embodiment of FIG. 1 and the embodiment of FIG. 2 are as follows. That is, in the embodiment shown in FIG. 1, the gas discharge 016 is formed at the lower end of the slit-shaped pressure equalizing zone 14, but in the embodiment shown in FIG. A porous portion 20 is connected to the lower end of the slit-shaped pressure equalizing zone 14. The porous portion 20 is disposed in the intermediate region of the powder portion over a length of about 1/2 to 1/3 of the length of the powder portion 17, and has a ring shape as a whole. A gap 18 having the same size as the gap 18 between the nozzle body 1o and the powder part 17 is also formed between the porous part 2o and the powder part 17.

The operation of the embodiment of FIG. 2 is substantially the same as that of the embodiment of FIG. The inert gas flows from the slit-shaped pressure equalizing zone 14 through the porous portion 20 into the air gap gA18, further passes upward through the air gap 18, and then flows out to the outside.

3 to 5 show other embodiments of the invention. The nozzle body 110 shown in FIG. 3 is not provided with a pressure equalization zone. Therefore, the nozzle body 110 has high strength. The nozzle body 110 has a molten steel inlet 111, a molten steel outlet 112, a nozzle hole 113, and a powder portion 17, which are substantially the same as in the previous embodiment.

Also in the embodiments shown in FIGS. 3 to 5, the lower end of the powder part 17 is connected to the nozzle body 110 by a screw method. Thus, an annular gap 18 is formed between the nozzle body 110 and the powder portion 17.

A pipe 120 is provided outside the nozzle body 110.

The lower end of the pipe 120 is connected to a gas discharge ring 130 as shown in FIG. This gas discharge ring 13
0 is located at the bottom of the cavity 18 and along the outer periphery of the nozzle body 110. A plurality of gas discharge ports 131 are formed in the gas discharge ring 130 at equal intervals.

In the embodiment of FIGS. 3 to 5, the inert gas is supplied to the pipe 12.
0, the gas is passed through the pipe 120 and the gas discharge ring 130, and is discharged from the gas discharge port 131. This causes the gas to flow upwardly through the gap 18 and out to the outside.

Uαj-1 In this invention, the powder part 17 and the nozzle body 10
Since a gap 18 is formed between the powder part 17 and the powder part 17, a gas curtain is formed in the gap 18 by passing gas through the gap 18, so that the cooling effect and the oxidation prevention effect of the powder part 17 are excellent.

As a result, the useful life of the powder portion 17 is dramatically improved. Furthermore, the thickness and material of the powder portion 17 can be selected to suit the number of consecutive uses, and a desired service life can be efficiently obtained.

Further, with the configuration of the present invention, it is extremely easy to attach the powder portion 17 after processing the nozzle body 10, and the service life of the powder portion 17 can be easily extended. For example, the powder part 17 can be attached to the nozzle body 10 using a screw method or a cotter method, and the workability thereof is extremely excellent.

Furthermore, the gas such as inert gas flowing out from the nozzle body 10 can also form a gas curtain on the mold surface.
It is possible to effectively prevent oxidation of the surface of molten steel.

Moreover, the strength of the nozzle body can be increased by discharging the gas from the precipitation portion through an external pipe without providing a pressure equalization zone in the nozzle body.

In addition, in the above-mentioned embodiment, the powder portion 17 is made of Zr.
Although a material made of 02-C has been described, the present invention is not limited to such a material. For example, the powder part 17 is made of dense Zr02-C quality or Zr0z-
It can also be formed from A2203 quality, Zr 02 gl, etc. In that case, the useful life of the powder portion 17 becomes even longer.

[Brief explanation of the drawing]

Figure 1 shows [11] the immersion nozzle for continuous casting according to the present invention.
2 is a schematic vertical sectional view showing another continuous casting immersion nozzle according to the present invention, FIG. 3 is a schematic longitudinal sectional view showing another continuous casting immersion nozzle according to the present invention, and FIG. 4 is a schematic longitudinal sectional view showing another continuous casting immersion nozzle according to the present invention. FIG. 5 is an enlarged perspective view of the pipe and gas blowing ring. 10.110. ,,,/Zuru L body 11.111. ,,, Molten steel inlet 12.112. ,,, Molten steel discharge port 13.113. , , Nozzle hole 14 , , , Slit-shaped pressure equalizing zone 15 , , ,
, , , Gas blowing part 16 , , , Gas discharge port 1'7. , , , , , Powder part ia , , , , Gap 20 , , , Porous part 17a , , , Female threaded part 10a , , , Male Threaded portion 120 Pipe 130 Gas discharge ring 131 Gas discharge port Fig. 3 II 10 It 10 Fig. 2 Fig. 4 Fig. 5

Claims (7)

[Claims] (1) A nozzle body having a molten steel inlet at the upper end and a molten steel outlet at the lower end, and extending from the molten steel inlet at the upper end of the nozzle body in the longitudinal direction of the nozzle body to the lower end of the nozzle body. In the immersion nozzle for continuous casting, which has a nozzle hole formed up to the molten steel discharge port, and a powder part provided near the gas discharge part, the powder part is formed as an outer ring, and the powder part is formed as an outer ring, and the outer periphery of the nozzle body is The powder part is provided along the nozzle body, a gap is formed between the nozzle body and the powder part, and the gas discharged from the gas discharge part flows upward in the gap and then flows out. Features: Immersion nozzle for continuous casting. (2) A patent in which a pressure equalization zone for passing gas is formed along the nozzle hole within the wall thickness of the nozzle body, and the gas discharge part is connected to the lower end of the pressure equalization zone. An immersion nozzle for continuous casting as set forth in claim 1. (3) The immersion nozzle for continuous casting according to claim 2, wherein the gas discharge portion is a hole-shaped gas discharge port formed in a lower portion of the pressure equalization zone. (4) The immersion nozzle for continuous casting according to claim 2, wherein the gas discharge section is a porous section for discharging gas arranged below the pressure equalization zone. (5) The immersion nozzle for continuous casting according to any one of claims 1 to 4, wherein the powder part is attached to the nozzle body by a screw method. (6) The immersion nozzle for continuous casting according to any one of claims 1 to 4, wherein the powder part is attached to the nozzle body by a cotter method. (7) The immersion nozzle for continuous casting according to claim 1, wherein a pipe is provided outside the nozzle body, and gas passes through the pipe and is discharged from the gas discharge portion.