JPH0372014A - How to switch converter bottom blowing nozzle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a bottom-blowing nozzle for stirring the molten metal by blowing gas into the molten metal from the bottom of a converter, and more specifically, a method for switching the bottom-blowing nozzle. Regarding.

[Prior Art] In a converter blowing method using a bottom blowing nozzle, the refractory around the bottom blowing nozzle is selectively eroded at a much faster rate than other parts. Therefore, even if the remaining thickness of the surrounding refractory layer approaches its limit, the remaining thickness of the refractory layer in other parts generally has a considerable margin.

Based on this viewpoint, the applicant filed the patent application Sho G1-244.
588 (Japanese Unexamined Patent Publication No. 63-100117) proposes a method of switching the converter bottom blowing nozzle without replacing it. In this method, when the refractory layer around the previously used nozzle reaches a predetermined residual thickness, a through hole is drilled at the bottom of the converter sufficiently distant from the previously used nozzle and a pipe is inserted.
The blowing of gas from the previously used nozzle is stopped, and the pipe is used as a new bottom blowing nozzle.

[Problems to be Solved by the Invention] In the above switching method, however, since the refractory layer in which the through holes are formed is made of bricks stacked in blocks (permanent bricks and work bricks), A problem arose in that the pipe for the new nozzle that was inserted was corroded by the molten metal that entered through the joints between the bricks and did not last long.

Therefore, it is an object of the present invention to solve the problem of corrosion of the new nozzle pipe. Another object of the present invention is to increase the reliability and simplicity of the switching operation.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, in the previously proposed switching method, a predetermined length is provided along the penetration direction of the portion where the through hole is bored. A perforating brick made of an integrally molded refractory having an angle of 6° is placed in the refractory layer prior to use of the previously used nozzle. The tip of the drilling brick is located at a position within the work brick layer corresponding to the erosion of the refractory layer of the through-hole forming portion at the time when the erosion of the refractory layer around the previously used nozzle reaches the predetermined value. It extends to the inside of the converter. Further, the rear end extends closer to the permanent brick layer than the boundary between the permanent brick layer and the work brick layer.

Desirably, prior to use of the previously used nozzle, a flange for drilling is arranged in the converter shell at a portion where the through hole is to be bored, in alignment with the through hole.

Desirably, prior to use of the pre-use nozzle, a guide hole is bored in the perforation brick along the axis of the through hole,
The guide hole is filled with a plug brick that is softer than the drilling brick.

[Function] With the above configuration, in the present invention, the new nozzle pipe is disposed within the integrally molded refractory brick, so there are no brick joints around the pipe in the vicinity of the furnace atmosphere.

The above-mentioned flange for drilling work is used for mounting a drilling device, etc.

The guide hole assists the drilling drill to advance in the desired direction.

[Example] Fig. 2 is a schematic cross-sectional view showing the entire converter according to the present invention, in which a permanent brick layer 14 is formed inside the class 10 at a portion in contact with the steel shell 12, and further on top of the permanent brick layer 14. Work brick layers 16 are stacked, which are updated every time the furnace is repaired. At the bottom of the converter, a number of bottom blowing nozzles 24 (only one of which is shown in FIG. 2) are arranged for blowing stirring gas into the molten toothpick in the converter. is referred to in the present invention as a "previously used bottom blowing nozzle". As described above, in the converter blowing method using the bottom blowing nozzle, the refractory layer 14, 16 around the bottom blowing nozzle is selectively eroded at several times the rate of other parts.

At the bottom of the converter sufficiently far away from the previously used nozzle 24,
A portion 26 forming a switching nozzle is provided. The planar positional relationship between the previously used nozzle 24 and the switching nozzle forming portion 26 is as shown in FIG. 3, for example. As shown in the figure, the switching nozzle forming portion 26 is a portion that is hardly affected by the selective melting around the previously used nozzle 24, and is a portion that is not affected by selective melting around the previously used nozzle 24, and is a portion that applies stirring gas evenly to the molten metal in the converter. Selected so that it can be infused.

Details of the switching nozzle forming portion 26 are shown in an enlarged view in FIG. In the same figure, all of the upper layer leH of the work brick layer 16 and a part of the lower layer 1 [ib] have already been lost due to melting (the lost part is shown by a broken line and the remaining part is shown by a solid line), and the exposed surface inside the furnace A state in which the line has retreated to line 22 is shown. At this point, the work brick layer 16 around the previously used nozzle 24 is almost lost due to selective erosion;
The thickness of the refractory layer in this area will now be substantially similar to the thickness of the permanent brick layer 14.

In the switching nozzle forming portion 2G, prior to use of the previously used nozzle 24, a perforating brick 30 made of an integrally molded refractory is disposed within the refractory layer 14.16.

Furthermore, three brick layers 32 are disposed between the bricks 30 and the steel shell 12 (outer flange 38 in the illustrated embodiment). The brick 30 has the following predetermined length, and its longitudinal direction is arranged along the axial direction of the through hole formed for the switching nozzle.

The tip of the perforating brick 30 (already melted in FIG. 1) is aligned with the tip of the lower layer 16b of the work brick layer at the time of installation. The position of the tip of this brick 30 is such that the melting loss of 1 m of refractory material around the previously used nozzle 24 is a predetermined value (for example, the residual thickness is 1 m of the permanent brick layer 1 as described above).
It is determined based on the point in time when the wall thickness reaches 4). The tip of the brick 30 is located at a position within the work brick layer corresponding to the erosion of the refractory layer of the switching nozzle forming portion 2G at the point 03 (i.e., line 22 in this embodiment).
It is set so that it extends further inside the converter.

On the other hand, the rear end of the perforating brick 30 is aligned with the lower surface of the upper layer 14a of the permanent brick layer 14 in this embodiment. The rear end position of the bricks 30 is selected so as to make it difficult for the molten metal to enter the side of the switching nozzle pipe 44 through the joints between the bricks.

That is, it is effective for the rear end of the brick 30 to extend beyond the boundary 18 between the permanent brick layer 14 and the work brick layer I6 and toward the permanent brick layer side.

If possible after considering other factors, it is desirable that the rear end is placed so as to penetrate into the permanent brick layer 14 as much as possible.

A guide hole 34 is formed in the center of the switching nozzle forming portion 2G prior to use of the previously used nozzle 24 in order to facilitate and ensure the drilling operation. The guide hole 34 extends along the edge of the pipe 44 to be installed, penetrates the three brick layers 32, and terminates at the middle of the perforating brick 30. Further, the guide hole 34 is filled with a plug brick that is softer than the drilling brick 30.

An inner flange 36 for drilling is attached to the steel shell 12 with its axis aligned with the guide hole 34, and the flange 36 is closed by an outer flange 38 before drilling. The outer flange 38 has a hole 42 in the center, and after installing the nozzle pipe 44, the flange 38 and the pipe 44 are connected to each other.
Kaede is used to connect the two.

The procedure for switching the bottom blowing nozzle in the converter will be described below.

First, when the refractory layer around the previously used nozzle reaches a predetermined residual thickness due to selective erosion, the inside of the converter is emptied and the converter is tilted so that its center axis is approximately aligned with the water V. do. The outer flange 38 is then removed and a flange 54 of a drilling device 50 as shown in FIG. 4 is attached to the inner flange 36. At this time, the drill 58 of the device 50 is used to drill the drilling brick 3.
It automatically becomes aligned with the guide hole 34 of 0. The drilling device 50 is movable along a rack 56 in which a drive body 52 supporting a drill 58 is connected to a flange 54 .

The drill 58 used is preferably an air-cooled type with a shaft hole formed in the center. The diameter of the drill 58 depends on the dimensions of the pipe 44 of the switching nozzle, but in this embodiment it is somewhat larger than the diameter of the guide hole 34 (
For example, for a guide hole 34 with a diameter of 245 m, the diameter is 29 I.
I11 drill 58). Drilling is performed from the rear end of the brick 32 to the melted line 22 of the brick 30, that is, the exposed surface inside the furnace, while changing drills with lengths of, for example, 500 mm, 800 mm, and 1000 mm in order. The drill 58 is driven by the driver 52
In addition to the engagement with the rack 5B, the aid of the guide hole 34 makes it possible to reliably advance in a predetermined direction.

After drilling, it is confirmed that the hole has penetrated, the drill device 50 is removed, and the flange 38 is restored. Then, a nozzle pipe 44 is inserted into the formed through hole through the center hole 42 of the flange 38.
to be divine. The length of the pipe 44 is preferably the through-hole length plus the furnace inside length 150111 and the furnace outside length 100++v. The outside portion of the pipe 44 is seal-welded to the center hole 42 of the flange 38, and a stirring gas piping is connected thereto.

Generally, it takes about 100 hours to completely replace a bottom blow nozzle, but the time required for the above changeover is about 1 hour assuming that all nozzles are worked in parallel. Become. For this reason, the converter does not cool down completely when switching the nozzle, and preheating energy and time can be reduced when restoring the converter to a working state. Furthermore, the equipment and labor required for switching are simplified as described above.

[Effects of the Invention] According to the present invention, brick joints are no longer present around the new nozzle pipe in the vicinity of the furnace atmosphere, and the pipe is no longer corroded by molten metal entering through the joints. . Furthermore, if the flange for the above-mentioned drilling work is provided, it becomes possible to attach a drilling device thereto and perform the work quickly. Also, if the above guide hole is provided,
Through-holes can be reliably drilled in a desired direction.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view showing the switching nozzle forming part of the converter according to the present invention, FIG. 2 is a schematic sectional view showing the entire converter, and FIG. 3 is a previously used nozzle and a switching nozzle. FIG. 4 is a diagram showing an example of the positional relationship with the forming part. FIG. 4 is a diagram showing a state in which the perforating drill device is attached to the flange of the switching nozzle forming part.

Claims (3)

[Claims] (1) When the refractory layer around the previously used nozzle reaches a predetermined residual thickness, a through hole is drilled at the bottom of the converter sufficiently far away from the previously used nozzle, and a pipe is inserted into the bottom of the converter. Switching of the bottom blowing nozzle of a converter lined with a refractory layer consisting of a permanent brick layer and a work brick layer, by stopping gas blowing from the used nozzle and using the above pipe as a new bottom blowing nozzle. In the method, along the penetrating direction of the portion where the through hole is formed, the tip is formed of a refractory layer of the through hole forming portion at the time when the melting loss of the refractory layer around the previously used nozzle reaches a predetermined value. Extends to the inside of the converter from the position within the work brick layer corresponding to melting of the material layer, and the rear end extends toward the permanent brick layer side from the boundary between the permanent brick layer and the work brick layer. A perforation brick consisting of an integrally formed refractory having a length,
A method for switching a bottom blowing nozzle in a converter, characterized in that the previously used nozzle is placed in a refractory layer prior to use. (2) A claim in which, prior to use of the previously used nozzle, a flange for drilling is arranged in the converter shell at the portion where the through hole is to be drilled, in alignment with the through hole. (1
) method described. (3) Prior to using the previously used nozzle, drill a guide hole along the axis of the through hole in the perforation brick, and fill the guide hole with a plug brick that is softer than the perforation brick. The method according to claim (1).