JP2000063931A - Immersion tube for molten iron or molten steel treating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve an immersion tube for molten steel treating equipment which can reduce the frequency of repair or exchange to an upper portion of a cap part in the immersion tube by dissolving such problem that the upper portion of the cap part is not directly dipped into the molten steel but the lower portion thereof is easily damaged caused by the reception of the heat, etc., and then, the repair is frequently needed. SOLUTION: In the immersion tube for molten iron or molten steel treating equipment provided with a duct part 20 held with an elevating/lowering device and the cap part 41 connected with the tip part of the duct part, and constituting the cap part 41 with the upper portion 29 and the lower portion 25 connected so as to be freely attached/detached, the length C of the lower portion 25 is longer than or the same as the length B of the upper portion 29.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dip pipe for hot metal or molten steel (hereinafter, these may be collectively referred to as molten steel) treatment equipment.

[0002]

2. Description of the Related Art The composition of steel and the cleaning of molten steel are performed using molten steel processing equipment. Among these methods, for example, the CAS type simple ladle refining method The slag floating on the surface is removed and separated by a dip pipe (closed tank), and an inert gas is sent from the bottom of the ladle toward the dip pipe,
An alloy is added to the surface of the molten steel exposed in the immersion pipe. Since the alloy to be added is introduced into the exposed molten steel surface through the dip pipe filled with the inert gas, it is not oxidized by slag or air, and therefore, the variation of the molten steel composition is small. . In addition, the molten steel is agitated by bubbling the above-mentioned inert gas to homogenize the components, and a lance that opens in the immersion pipe is provided and high-pressure oxygen is jetted from the lance toward the molten steel to oxidize impurities such as carbon It is burned and removed.

Since the lower part of the immersion pipe is immersed in the molten steel as described above, the lower part has a structure in which the front and back of the core iron skin is covered with a refractory material such as bricks, and further, inside the immersion pipe. Since it is exposed to the radiant heat from, the entire inner wall of the immersion pipe is covered with refractory, not only the lower part that is immersed in molten steel.

Although the dip pipe is covered with the refractory material as described above, the refractory material itself is damaged by the molten steel, so that the dip tube often needs to be replaced. Therefore, there has been proposed an immersion pipe having a structure in which a damaged lower part can be separated by immersing it in molten steel and only the lower part is appropriately replaced.

FIG. 3 is a vertical sectional view showing the immersion tube. The immersion pipe 10 is composed of a duct portion 20 gripped by an elevating device (not shown) and a cup portion 41 connected to the tip of the duct portion 20. The cup portion 41 is a lower portion (hereinafter referred to as a cup) immersed in molten steel. It is divided into a lower part (sometimes referred to as a lower part) 15 and an upper part (hereinafter, also referred to as a cup upper part) 19 connected to the duct portion 20. These cup upper part 19 and cup lower part 15 are flanges. It is detachably connected by 19a and 15a. AA shown in the figure
The molten steel surface reaches the line, and the dipping pipe 1 goes below this line A.
Since 0 will be immersed in molten steel, the length B of the cup upper part: the length C of the cup lower part is about 1 in accordance with this.
It is 0: 7.

As described above, the lower cup portion 15 is covered with the refractory materials 12 and 13 on the outer side, the inner side and the lower side of the iron shell 11 serving as a core, and the cup upper portion 19 and the duct portion 20 are the iron shell 1.
The inside of 7 is covered with refractory material 14.

A flange 20b for detachably connecting to an exhaust / alloy charging duct (not shown) is provided at the upper end of the duct portion 20. Further, the duct portion 20 is provided with a temporary placement arm 18, and the temporary placement arm 18 is hooked on a support base and stored when the dipping tube 10 is not used for a ladle.

[0008]

As described above, in the conventional dip pipe, only the cup lower portion 15 which is immersed in molten steel and suffers melting damage is replaced to reduce the maintenance cost, but the cup upper portion 19 is required. Although it is not directly immersed in the molten steel, it is apt to be damaged by heat or the like especially in the lower portion (in the vicinity of the connection portion with the cup lower portion 15), and the cup upper portion 19 needs to be repaired. This repair frequently occurs, and since the lower cup portion 15 is replaced every time, the work efficiency of replacement / repair deteriorates.
There is a problem that the operation efficiency of the molten steel processing equipment deteriorates due to the suspension of operation during repair.

Further, when the melting of the refractory material below the upper portion 19 of the cup progresses, the lower iron shell 11 is red-heated and damaged, and in severe cases, the studs for fixing the refractory material are thermally deformed and come off. , Refractories fall out. Therefore, it is necessary to replace the entire cup upper portion 19 and the entire duct portion 20 without repairing only by repairing.

Therefore, it is an object of the present invention to provide an immersion pipe for molten steel processing equipment, which can reduce the frequency of repair and replacement of the upper portion of the cup of the immersion pipe.

[0011]

A submerged pipe for hot metal or molten steel processing equipment according to the present invention comprises a duct part to be gripped by an elevating device and a cup part connected to the tip of the duct part. In a dip pipe for a hot metal or molten steel treatment facility, which is composed of an upper portion and a lower portion that are freely connected, the gist is that the lower portion is longer than or equal to the upper portion.

By thus making the length of the lower portion of the cup of the dip tube relatively long, the portion corresponding to the lower portion of the upper portion of the conventional cup becomes the lower portion of the cup, and therefore the damage to the upper portion of the cup is reduced. Therefore, the frequency of repair and replacement of the upper part of the cup is reduced.

Further, in the present invention, it is preferable to provide an air cooling device in which a plurality of air ejection holes are annularly arranged toward the outer shell of the immersion pipe.

By thus cooling the outer iron shell of the dip tube with the air cooling device, it is possible to prevent red heat of the iron shell and also to prevent the refractory from falling off when the studs come off.

In addition, as described above, in the case where a plurality of air jets are widely and finely air-conditioned, the iron shell can be cooled more efficiently than in the case where a large fan blows a large amount of air at once to perform air cooling. Therefore, even if the amount of ejected air is small, it can be sufficiently cooled.

[0016] For example, Japanese Patent Publication No. 3-50804 discloses that a cooling pipe is provided on an iron plate which is the core of the immersion pipe to cool the immersion pipe. However, such an immersion pipe has a structure. However, since the manufacturing cost is high and the life of the dipping tube is long, the replacement cost is high.

On the other hand, in the present invention, air cooling is performed from the outside of the immersion pipe by the air cooling device provided separately from the immersion pipe, that is, the structure of the immersion pipe itself is not changed.
The cost of replacing the dip tube is not high, and the life of the dip tube is long.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION FIG. 1 is a vertical sectional view showing a dip pipe for molten steel treatment equipment according to an embodiment of the present invention.
The same components as those in FIG. 3 are designated by the same reference numerals to avoid redundant description.

The ratio (C: B) of the length C of the lower portion 25 of the cup portion 41 and the length B of the upper portion 29 of the dipping pipe 23 is 2.5: 1, and the lower portion 25 of the cup and the cup The connecting portion of the upper portion 29 is located at a position considerably higher than the molten steel surface height A, and the length of the cup upper portion 29 is shortened by the length of the cup lower portion 25. As in the conventional case, the lower cup portion 25 and the upper cup portion 29 are formed of
It is detachably connected by 19a.

The upper cup portion 29 and the duct portion 20 have a structure in which the insides of the steel skins 27 and 28 are covered with a refractory material 24, while the lower cup portion 25 is a steel skin for the lower side immersed in molten steel. The outer side, the inner side, and the lower side of 21 are covered with the refractory material 22, and the upper portion of the cup lower portion 25 is structured such that only the inner side of the iron shell is covered with the refractory material 22. As described above, the outer side of the iron shell in the upper portions of the duct portion 20, the cup upper portion 29 and the cup lower portion 25 is not covered with the refractory, but the radiant heat from the molten steel does not hit the outer side of the iron shell, and This is because it will not be soaked.

The damage of the immersion pipe is caused by the portion (A-A
Not only (below the line) but also the portion close to the molten steel surface is damaged, but in the dip pipe 23 according to the present embodiment, such damage remains only in the cup lower portion 25 and almost in the cup upper portion 29. Since it is not damaged, only the lower cup portion 25 needs to be replaced, and the upper cup portion 29 does not need to be replaced or repaired much.

The immersion pipe 23 is provided with a cooling device 30 so that air is jetted toward the upper part of the iron shell 21 of the lower cup portion 25 and the iron skin 27 of the upper cup portion 29. There is.

2A is an enlarged cross-sectional view showing the cooling device 30 portion, and FIG. 2B is a front view of the cooling device 30 as seen from the air ejection hole 31a side.

The cooling device 30 includes a ventilation pipe 32 and a wind blast panel 3.
1 and the wind panel 31 includes the cup lower portion 25.
At a position extending from the upper side portion to the cup upper portion 29, the cup lower portion 25 and the cup upper portion 29 are annularly arranged so as to surround the outer periphery. Further, the air blast panel 31 is provided with air ejection holes 31a directed toward the dipping pipe 23 over the entire surface of the panel.

The air supplied to the ventilation pipe 32 reaches the blast panel 31 and is ejected from the air ejection holes 31a (see arrow E). Although the diameter of the air ejection holes 31a is small and the total amount of air to be ejected is not so large, since the air is ejected from the plurality of air ejection holes 31a over the entire surface of the blast panel 31, the immersion pipe is The iron skins 21 and 27 of 23 are widely air-cooled and are efficiently cooled. In addition, the blast panel 31 and the iron skins 21 and 27
The distance D is preferably 60 to 100 mm.

By thus cooling with air, the iron shells 21 and 27 are heated to, for example, 400 ° C. or less, and do not glow red, so that the refractory material does not fall off and the immersion pipe 23 is prevented from being damaged.

Further, since the upper cup portion 29 is not only separated from the molten steel surface as described above but also is air-cooled in this manner, it is more difficult to be damaged and has a long life.

As described above, with respect to the immersion pipe according to the present invention,
Although it has been specifically described with reference to the drawings showing one embodiment,
The present invention is not limited to the illustrated examples as a matter of course, and it is also possible to make appropriate modifications and implement them within a range that is compatible with the above gist, and they are all included in the technical scope of the present invention. It

[0029]

According to the present invention, the severely damaged portion is contained only in the lower portion of the cup portion of the dip tube.
The life of the upper part of the cup part is extended and the cycle of repair and replacement can be extended. Further, in the case where the air cooling device is provided, the frequency of repair and replacement of the upper portion of the cup portion is further reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an immersion pipe for molten steel processing equipment according to an embodiment of the present invention.

FIG. 2A is an enlarged cross-sectional view showing a cooling device 30 portion,
(b) is a front view of the cooling device as seen from the air ejection hole side.

FIG. 3 is a vertical sectional view showing a conventional immersion pipe.

[Explanation of symbols] 10,23 Immersion tube 11, 17, 21, 27, 28 Iron skin 12, 13, 14, 22, 24 Refractory 15,25 cup lower part 15a, 19a, 20b Flange 18 Temporary arm 19,29 cup upper part 20 Duct part 30 cooling system 31 Wind panel 31a Air ejection hole 32 ventilation pipe 41 cup

Claims (2)

[Claims] 1. A molten pig iron or molten steel comprising a duct portion gripped by an elevating device and a cup portion continuously provided at a tip thereof, the cup portion being detachably connected to the upper portion and the lower portion. A dip tube for processing equipment, wherein the lower part is longer than or the same as the upper part. 2. The immersion pipe for hot metal or molten steel treatment equipment according to claim 1, wherein an air cooling device having a plurality of air ejection holes arranged in an annular shape is provided toward the outer shell of the immersion pipe.