JPH0881711A - Circulating flow tube for vacuum-degassing apparatus - Google Patents

Abstract

PURPOSE: To provide a circulating flow tube for vacuum-degassing apparatus having a long service life of a wall structure. CONSTITUTION: A dowel 5 extending in the vertical direction so that the upper end part inclines to the working surface side, is arranged in a single brick 4 for tuyere, and a contacting surface between the single brick 4 for tuyere and a lower brick 3 is formed as inclining upward from the back surface side to the working surface side. The wall brick 1 composed of the single brick 4 for tuyere and the lower bricks 2, 3 is arranged as ring-state to form the circulating flow tube.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflux pipe for a vacuum degassing device provided below a degassing tank of a vacuum degassing device for refining molten steel produced in a converter or the like by the RH method.

[0002]

2. Description of the Related Art Two reflux pipes are provided between an upper degassing tank and a lower molten steel ladle to suck molten steel from the molten steel ladle into the degassing tank while returning the molten steel to the molten steel ladle. . This reflux pipe is a part where the frictional force due to the flow of molten steel is very strong, and after treatment it becomes a cold air passage whose temperature is significantly lower than the molten steel flow, and it is susceptible to spalling damage due to thermal fluctuations and mainly peeled off. Wear is severe.

[0003]

FIG. 4 (a) shows a cross section of an example of a brick which constitutes the wall of a conventional reflux pipe.
In this way, the tuyere bricks 102 are stacked on the lower bricks 100 and 101 to form the wall of the recirculation pipe, and as the working surface side is used, the wear as shown by the chain double-dashed line 103 is shown. To show the line. Further, the tuyere brick 102 is affected by the molten steel flow, and as shown in FIG. 4 (b), a horizontal crack (indicated by a broken line in the drawing) 104 also occurs at the same time as the wear, and this crack causes the crack. Tuyere brick 1
The 02 pieces may be fragmented and swept along with the molten stream. In addition, the lower brick 101 and the tuyere brick 1
Due to the large wear of the joint portion 105 between No. 02 and No. 02, the life of the reflux pipe tends to be shortened.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a reflux tube for a vacuum degassing apparatus having a wall structure having a long life.

[0005]

As a result of intensive studies, the inventors of the present invention have found that the aforementioned problems can be achieved by adopting a structure in which fragments are less likely to flow even after cracks have occurred, and the present invention Has been completed.

That is, according to the present invention, a lower set brick formed by arranging a plurality of single bricks in a ring shape is arranged below a tuyere set brick formed by a plurality of single tuyere bricks arranged in a ring shape. A vacuum degassing recirculation pipe comprising: a tuyere single brick that is adjacent to one of the tuyere single bricks. The present invention relates to a reflux tube for a vacuum degassing device, characterized in that a concave line that engages with the convex line is provided on the surface.

[0007]

According to the vacuum degassing recirculation pipe of the present invention, the tuyere single brick having the ridges and the tuyere single brick having the ridges are formed by the engagement of the ridges and the ridges. The close contact state of the two is enhanced, and it becomes difficult for the two to come off from each other even when an external force is applied. Even if cracks occur in the single tuyere bricks and become fragments that are usually easily flown, the fragments do not flow due to the presence of the ridges and grooves, so the life of the reflux pipe is greatly extended.

Further, if the convex and concave lines extending in the vertical direction are provided so that the upper end side thereof is inclined toward the inner wall surface of the ring, the catch becomes strong and the fragments of the single tuyere brick are more difficult to flow. . Furthermore, if the contact surface between the tuyere set brick and the lower set brick is made to be an uphill from the outer wall surface side of the ring toward the inner wall surface side, this contact surface,
That is, since the joint faces upward toward the inner surface of the ring and follows the upward flow of the molten steel flow, the degree of wear of the joint decreases. Further, since the contact surface is slanted, the area of the contact surface is increased and the tuyere set brick is less likely to come off the lower set brick.

[0009]

EXAMPLES Next, specific examples of the reflux tube for a vacuum degassing apparatus according to the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1A shows a wall brick 1 constituting a wall of a vacuum degassing reflux pipe according to an embodiment of the present invention.
A side view of is shown. As described above, the wall brick 1 forming the wall of the reflux pipe is formed by stacking the tuyere single bricks 4 on the lower single bricks 2 and 3. The left side of the wall bricks 1 is the working surface (inside the ring), and the right side is the back side (outside of the ring).
The reflux pipe is formed by arranging in a ring shape so that When this reflux pipe is used as an ascending pipe, a molten steel flow flows as shown by an outlined arrow in Fig. 1 (a).

A dowel 5 as a ridge (or a dowel hole as a ridge) is provided on the single tuyere brick 4 so as to extend in the vertical direction. Between two wall bricks 1 adjacent to each other in a ring shape, when one wall brick 1 is provided with a dowel hole 5, the other wall brick 1 is provided with a dowel hole, and the dowel hole 5 and the dowel hole are engaged with each other. It is supposed to do. Also,
The dowel 5 is provided so that its upper end portion is inclined toward the inner wall surface side (operating surface side) of the ring.

When the reflux pipe is used, the wall brick 1 is worn as shown in FIG. 1 (b). That is, the upper end portion of the tuyere brick 4 on the working surface side is mainly worn,
Horizontal cracks 6 are also created in the remaining portion of the tuyere brick 4 as indicated by the broken lines 6. As a result of this wear, the molten steel flow flows along the surface of the worn tuyere brick 4 as indicated by the white arrow in FIG. 1 (b), and the thermal stress due to the high heat of this molten steel flow and the molten steel flow. Due to the impact of the crack, the tuyere brick 4 cracks 7 at the position indicated by the chain double-dashed line and fragments tend to detach. However, since the dowels 5 are provided as described above, the fragments are prevented from being detached from the cracks 7 or 6 and flowing. Even so, the wear due to the wear of the molten steel flow progresses, and eventually the tuyere brick 4 is cut into the shape shown by the crack 7, but the dowel 5 is provided so that the upper end portion thereof is inclined toward the working surface side. Therefore, the effect of preventing detachment of fragments by the dowels 5 is maintained even if the wear progresses.
This is because the dowels 5 are arranged so that the dowels 5 always exist in the portions where cracks are likely to occur. Also,
The flow direction of the molten steel flow indicated by the white arrow is the dowel 5.
It can be said that the effect of preventing the fragment desorption is great because it is in the direction of traversing (the fragment can easily come off if the molten steel flow flows along the dowel).

The arrangement of the dowels 5 is x in FIG. 1 (a).
It is preferable that the upper end portion of the dowel is located on the working surface side and the lower end portion is located on the rear surface side with respect to the center line, and in this embodiment, an angle of 6.5 ° is formed with respect to the center line x. The cross-sectional shape of the dowel is not particularly limited, but a semicircular shape, a trapezoidal shape, or a similar shape is preferable in terms of manufacturing and construction (brickwork).

Further, in this wall brick 1, the contact surface (joint) 4a between the single tuyere brick 4 for the tuyere and the lower brick 3 is an upward slope from the back surface to the working surface. By adopting such a structure, the molten steel flow flowing upward on the working surface side is joint 4
It is possible to reduce the extent to which the joint a collides with and invades to damage the joint peripheral portion. That is, this structure is suitable for the reflux pipe on the side where molten steel rises. Such a structure is useful because the rise of molten steel has a high flow velocity due to gas injection. Further, even if the wear progresses to some extent, the joint 4a has a large area because it is slanted, that is, the contact area between the tuyere single brick 4 and the lower single brick 3 is large, so that the tuyere single brick 4 is the lower single brick 3 It becomes difficult to come off.

The angle formed by the joint (contact surface) with the horizontal plane is preferably 10 to 45 °. If it is less than 10 °, the effect is not so good, and if it is more than 45 °, the lower single brick 3
This is because the corners of are too sharp and brick breakage is likely to occur.

FIG. 2 is a sectional view showing a state in which the wall bricks 1 are arranged in a ring shape below the degassing tank 8 to form reflux tubes 9 and 10. A sectional view taken along the line AA is shown in FIG. Thus, the tuyere single bricks 4 and the lower bricks 2 and 3 each constitute a ring-shaped set brick, and these set bricks are stacked to form the reflux pipes 9 and 1.
0 is formed. During operation, one of the return pipes 9 and 10 is used as an ascending side and the other is used as a descending side.
The descending side is replaced. As described above, since the flow velocity on the rising side is high and wear is likely to occur, the wall brick 1 having the above-described structure suitable for the rising side is arranged in a ring shape in each of the circulation tubes 9 and 10. In addition, the bricks 4'on the outer peripheral side of the degassing tank 8
4'is not provided with dowels at all, because heat dissipation is good on the outer peripheral side and the degree of wear of the bricks 4 ', 4'is small. Needless to say, a dowel may be provided in this portion.

In the above structure, the dowel has a substantially trapezoidal cross section with an upper bottom of 30 mm, a lower bottom of 50 mm, and a height of 11 mm as shown in FIG. The angle formed with the center line x of (a)) is 6.5 °, and the angle between the contact surface between the tuyere simple brick 4 and the lower brick 3 and the horizontal plane is 20 ° to form a reflux pipe. Was used to operate the vacuum degasser. At the same time, the vacuum degassing device using a conventional reflux pipe in which the contact surface between the single tuyere brick and the lower brick was arranged horizontally without the dowel was operated under other conditions in the same manner. . As a result, in the conventional reflux pipe, the tuyere bricks remained after 250 times use and had to be discarded. However, in the reflux pipe of the present embodiment, the tuyere single brick 4 remained after 320 times use. 45 left
It could be used up to 0 times.

[0018]

According to the reflux tube for vacuum degassing of the present invention,
Since the convex strips and the concave strips are caught with each other, the fragments of the single tuyere bricks are prevented from flowing, and the life of the reflux pipe is greatly extended. Further, if the ridges and the ridges are provided so as to incline toward the inner side of the ring, the catch becomes stronger and the fragments of the single tuyere brick become more difficult to flow. Furthermore, by making the contact surface between the tuyere set brick and the lower set brick uphill from the outside of the ring to the inside, the damage of this contact surface is reduced and the contact area is increased to increase the tuyere set brick. Is hard to come off from the lower set brick.

[Brief description of drawings]

FIG. 1 is a view showing a brick constituting a wall of a vacuum degassing reflux pipe according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a degassing tank in which a vacuum degassing reflux pipe of the present invention is arranged below.

FIG. 3 is a sectional view taken along line AA of FIG.

FIG. 4 is a side view showing a worn state of a wall of a conventional reflux pipe.

[Explanation of symbols]

 1 Wall brick 2,3 Lower single brick 4,4 'Single tuyere brick for tuyere 5 Dowel 8 Degassing tank 9,10 Reflux pipe

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kuniaki Taguchi Kuniaki Taguchi 5-3 Tokai-cho, Tokai-shi, Aichi Pref.Nippon Steel Works Ltd. (72) Inventor Michio Fukuoka 1-chome, Niihama, Arai-cho, Takasago, Hyogo 3-1 In Harima Ceramic Co., Ltd. (72) Inventor Manabu Kimura 1-3-1 Niihama, Niihama, Arai Town, Takasago City, Hyogo Prefecture Harima Ceramic Co., Ltd.

Claims (3)

[Claims] 1. A vacuum desorber in which a lower set brick in which a plurality of single bricks are arranged in a ring shape is arranged below a tuyere set brick in which a plurality of single tuyere bricks are arranged in a ring shape. A reflux pipe for a gas device, in which a ridge extending vertically is provided on the adjoining surface of one of the adjoining single tuyere bricks and the projection on the adjoining surface of the other tuyere simple brick. A reflux tube for a vacuum degassing device, characterized in that a recessed line that engages with the line is provided. 2. The recirculation pipe for a vacuum degassing apparatus according to claim 1, wherein the ridges and the ridges are provided so that the upper end side is inclined toward the inner wall surface of the ring. 3. The vacuum degassing apparatus according to claim 1, wherein a contact surface between the tuyere set brick and the lower set brick is an upward slope from an outer wall surface side of the ring toward an inner wall surface side thereof. Return pipe.