JPH11315317A - Immersion tube in vacuum degassing furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability even in the case that a crack generates on a monolithic refractory and to enable the use for a long time by providing a separating zone for separating into partially a centrifugal side and a centripetal side extending, along a core metal at the base end side from the tip parts of anchors at an interval from the core metal, in the inner part of the monolithic refractory in which the tip parts of plural anchors fixed to the core metal at the base end parts are embedded. SOLUTION: An immersion tube 1 in a vacuum degassing furnace is provided with a cylindrical monolithic refractory 5 which is integrally formed on the lower end surface 4c of a cylindrical regular shaped refractory 4 arranged and fixed at the inside of a cylindrical core metal 2 and at the outside and on the lower end surface 2c of the cylindrical core metal 2 and plural anchors 3 fixed to the cylindrical core metal 3 at the base ends and embedded in the monolithic refractory 5 at the tip parts. The monolithic refractory 5 is provided with a separating zone 6A for separating into a least partially a centrifugal side and a centripetal side extending along the cylindrical core metal 2 at the base end side from the tip parts of the anchors 3A at an interval from the cylindrical core metal 2 to the inner part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a dip tube for a vacuum degassing furnace.

[0002]

2. Description of the Related Art As shown in FIG. 11, a dip tube 1D of a vacuum degassing furnace, which is one of the conventional examples, has a cylindrical cored bar 2 and a cylindrical fixed refractory arranged and fixed inside the cored bar 2. Object 4 and core 2
, A lower end face 2c and an irregular refractory 5 integrally formed on the lower end face 4c of the fixed refractory 4.

[0003] As shown in Fig. 10 of an embodiment shown with the help of this, the immersion pipe 1D is provided between a lower molten metal furnace (a molten steel pot) 7a and an upper degassing tank 7c constituting a vacuum degassing furnace 7. Are connected in parallel at the vertical position, and one is used as a riser pipe passage 7b of the molten metal circulation system, and the other is used as a descending pipe passage 7d of the molten metal circulation system.

[0004]

The conventional dip tube 1D described above
Is a constant liquid level h1 of the molten metal in the lower molten metal furnace 7a when used.
Cracks 9 are likely to occur in the outer peripheral surface 53 and the lower end surface 52 of the region of the irregularly shaped refractory 5 arranged below that contacts the molten metal 8. The crack 9 is generated due to the temperature difference between the heating and the standby cooling, which are alternately repeated during the operation cycle of the vacuum degassing furnace 7.

[0005] Once the crack 9 is generated, it grows toward each region of the amorphous refractory 5, and propagates and spreads. Then, the molten metal 8 penetrates into the propagation area of the crack 9 and the enlarged area, and the amorphous metal refractory 5, the metal core 2, and the fixed metal refractory 4 are melted and damaged.
The durable life of the immersion pipe 1D is shortened in order to cause problems such as melting of the anchor 3 and collapse of the lower end portion 50 of the irregular-shaped refractory 5.

For example, as disclosed in Japanese Utility Model Laid-Open Publication No. 58-135457, a slag line (contact area with slag) of a tubular irregular-shaped refractory is provided with a durable specification. Even when using a provided dip tube, if the crack propagates and expands in the area below the reinforcement area,
Since the above-mentioned erosion, anchor erosion, and collapse of the lower end of the irregular-shaped refractory occur, it is inevitable to dispose it while largely maintaining its original durable life, which is disadvantageous in terms of cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an immersion pipe of a vacuum degassing furnace which can improve durability even if a crack occurs in an amorphous refractory and can withstand long-term use. The task is to provide.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a dip tube for a vacuum degassing furnace comprises a cylindrical core, a cylindrical fixed refractory arranged and fixed inside the core, and an outside of the core. An immersion having an irregular refractory integrally formed on a lower end surface and a lower end surface of the refractory, and a plurality of solid anchors having a base fixed to the core bar and a distal end embedded in the irregular refractory. A tube, wherein the amorphous refractory extends therein at a distance from the core bar and extends along the core bar proximal to the distal end of the anchor and at least partially toward the distal side and the centripetal side. It is characterized by having a dividing zone for separation.

[0009] According to the immersion tube having the above-described configuration, for a predetermined period,
When a crack is generated from the outer peripheral surface side or the lower end surface side of the irregular-shaped refractory due to thermal fatigue during use, the crack is interrupted by a dividing band in the middle of growing from the source to the core metal. Therefore, even if a crack occurs, the irregular-shaped refractory can be prevented from propagating and expanding toward another region. On the other hand, in the amorphous refractory, the centrifugal side and the centripetal side separated by the dividing band are fixed and held by the anchor and reinforced.

Therefore, according to the dip tube of the present invention, the durability of the amorphous refractory can be improved, it can be used for a long time without collapsing, and can be used up to the limit of the preset durability life without waste. Excellent in cost.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The dividing band formed on the irregular-shaped refractory includes a slit-shaped member, a cylindrical member surrounding a metal core, and a lower end face of the metal core from the slit-shaped member and the cylindrical member. One having a surrounding flange-shaped portion extending in the radial direction can be used. The dividing band is formed by embedding a non-refractory at the time of molding a tubular amorphous refractory.

[0012] For example, prior to the formation of an amorphous refractory, the non-refractory is formed into a desired shape (slit, tube, or core metal) in an inner space of a mold frame arranged around the core. After being arranged in a radially extending flange shape surrounding the lower end surface), the raw material of the amorphous refractory is poured into the internal space,
By splitting, burning, and melting during high-temperature drying for hardening the raw material, it is possible to form a split zone having gaps (spaces) of the above-described shapes.

The non-refractory material may be any material that can form a gap by being heated, carbonized, burned out, and melted. For example, a resin film such as polyethylene or polyvinyl chloride or a resin sheet, paper, cloth, etc. Can be used. The dividing band has a width of 0.01 mm to 5.0 mm.
It is preferable that The reason for this is 0.01 m
If the width is less than m, the interval between the cracks generated in the centrifugal region and the detour around the dividing zone and reaching the centripetal region is shortened, and the effect of preventing the propagation and expansion of the cracks is reduced. If the width exceeds 0 mm, it becomes a passage through which the molten steel enters through the crack.

The width of the dividing band can be fixed or changed within the above range according to the purpose. As the formation position of the split band (position extending along the core bar at a distance from the core bar and proximal to the distal end of the anchor), the distance in the centrifugal direction (radial direction) from the outer peripheral surface of the core bar is not appropriate. The thickness is preferably set to 10% to 50% of the thickness of the fixed refractory.

[0015] The reason for this is that if the interval is less than 10% of the thickness of the amorphous refractory, the propagation of cracks is difficult to be divided, and if it exceeds 50%, erosion of the outer peripheral slag line is reduced. This is because it may promote it. A plurality of slit-shaped dividing bands are formed at predetermined intervals in a wide area surrounding the cylindrical irregular-shaped refractory along the circumferential direction. The number and the intervals of the slit-shaped dividing bands can be variously set.

The irregular refractory separated into the centrifugal side and the centripetal side by the slit-shaped dividing band can be strengthened by the anchor, and furthermore, the interval between the slit-shaped dividing bands (regions not separated). Can be connected together and strengthened. The tubular dividing band surrounding the cored bar can cope with a crack generated in a wide area surrounding the tubular irregular-shaped refractory along the circumferential direction.

In addition to the reinforcement by the anchor, a connecting region for connecting the centrifugal side and the centripetal side can be provided in the tubular dividing band as means for further strengthening. In order to provide the connection region, a predetermined number of communication holes of various shapes penetrating in the radial direction are provided in the peripheral wall of a cylindrical non-refractory which is buried therein when the raw material is poured to form an amorphous refractory. By filling the communication hole, the distal side and the centripetal side are connected via the communication hole.

The split band having a flange-like portion extending in the radial direction surrounding the lower end surface of the cored bar from the slit-like or cylindrical shape can cope with a crack generated at the lower end of the irregular-shaped refractory. In addition, a non-refractory having at least one surface formed with a predetermined number of protrusions or depressions or unevenness is used, and an opposing surface between the centrifugal side and the centripetal side separated by the dividing band (the dividing band and the centrifugal side or The shape can also be transferred to a boundary surface with the centripetal side).

In this case, depending on each transferred shape,
As the area of the facing surface increases, cracks split from the distal side
Lengthen the distance before reaching the centripetal side by bypassing
Can be. Because of this, the crack is interrupted by the split zone
In addition to the action, it propagates and expands from
The effect of making it difficult to obtain is obtained. The material of the refractory
For example, for example, MgO-Cr_TwoO_ThreeQuality, MgO-Al
_TwoO_Three-C, MgO-Spinel-C, Al_TwoO
_Three-C, MgO-C, Al_TwoO_ThreeUse quality
Can be.

The anchor has a base end connected to the outer peripheral surface of the metal core by welding, and extends from the base end toward the centripetal side, the dividing band, and the distal side of the irregular-shaped refractory, and the distal end extends toward the distal side. It has a function of connecting and fixing and holding the distal side and the centripetal side via the dividing band. It is preferable that the anchor portion has a shape that can increase the contact area with the irregular-shaped refractory in order to enhance the anchoring effect. For example, an inverted Y-shape in which the tip portion is branched into a plurality,
An inverted T-shape, a trifurcated shape, a substantially inverted V-shape, a substantially inverted U-shape, a trumpet shape, or a coil shape can be used.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a dip tube of a vacuum degassing furnace (hereinafter referred to as a dip tube) according to the present invention will be described with reference to FIGS. FIG. 1 is a plan view, and FIG. 2 is a sectional view taken along the line AA of FIG. 1 and partially shows an outer periphery of a main part. The anchor 3 used to reinforce the normal anchor 3 connected to the end face 2c and the area where the cutting zone 6A of the fixed refractory 5 is formed.
A, a cylindrical fixed refractory 4 arranged on the inner peripheral surface 2a side of the core 2 with a cylindrical gap e (see FIGS. 1 and 2) therebetween, and a core 2 filled in the gap e. Inner peripheral surface 2a and fixed refractory 4
Refractory 5a integrally formed on outer peripheral surface 4b of
And an irregular refractory 5 integrally formed on the outer peripheral surface 2b and the lower end surface 2c of the cored bar 2 and the lower end surface 4c of the fixed refractory 4
A dividing band 6A formed inside the refractory 5;
Consists of

The core 2 is made of a metal plate (SS40) having a thickness of 9 mm.
It is formed into a cylindrical shape having the desired diameter by using (0). On the other hand, a ring-shaped flange 23 having rigidity is connected to the upper end portion on the outer peripheral surface 2b side of the metal core 2 by welding. A predetermined number of ribs 24 for mounting and holding the lower end surface 4c of the fixed refractory 4 at a predetermined interval along the circumferential direction S are welded to a lower end portion on the inner peripheral surface 2a side of the cored bar 2 by welding. . Also, a ring 25 having a circular cross section is connected to each rib 24 by welding to also secure a space for reinforcing the ribs and adding the anchor 3.

It is preferable that the ribs 24 place and hold at least three or more end faces 4c of the plurality of fixed refractories 4 arranged along the circumferential direction S. Anchor 3
The desired number is connected to the outer peripheral surface 2b and the lower end surface 2c of the cored bar 2 by welding. The desired number of the anchors 3 are also connected to the ribs 24, the rings 25, and the like by welding (not shown in FIG. 2 due to space limitations).

The anchor 3A has a proximal end 3a (see FIG. 4) connected to the outer peripheral surface 2b and the lower end surface 2c of the metal core 2 by welding, and a centripetal region inside the irregular refractory 5 from the proximal end 3a. r1, a dividing band 6A, and an anchor portion 3b (see FIG. 4) protruding and extending to the distal-side region r2.
A centripetal region r1 and a distal region r2 separated by A
Are connected and fixedly held, so that even if the split band 6A is formed inside the irregular-shaped refractory 5, it can be strengthened.

The fixed refractory 4 is a brick made of MgO—Cr ₂ O ₃ and manufactured in advance in a desired shape. The refractory 4 is made up and down of two steps along the circumferential direction S on the inner peripheral surface 2 a side of the cored bar 2. To form a cylindrical body. Next, the case where the immersion tube 1 of the embodiment is manufactured using the core metal 2, the fixed refractory 4, the irregular refractories 5a, 5 and the non-refractory 6a (see FIG. 7) as a material for forming the dividing band 6A. Will be described.

First, the centripetal region r1 and the centrifugal region r2 are connected in advance via the ribs 24, the ring 25, the commonly used ordinary anchor 3, and the dividing band 6A formed on the irregular refractory 5. The metal core 2 (see FIG. 2) integrally connected to the anchor 3A and the like by welding is installed on a horizontal base (not shown) with the flange 23 downward. Thereafter, a plurality of fixed refractories 4 are arranged along the circumferential direction S at a distance e of about 30 mm in the centripetal direction at a position on the inner peripheral surface 2a side of the metal core 2, and are stacked vertically in two stages. Raised, inside diameter 300m
m is formed as a cylindrical body.

At this time, the fixed refractory 4 has one surface 40 thereof.
And the height of the flange 23 is adjusted to a position where the one surface 230 coincides (becomes a surface). Each gap (joint) e1 of the monolithic refractories 4 arranged as described above, the bonding material of interest [MgO protein or MgO-Cr ₂ O ₃ Quality of mortar (not shown)] is filled . It is to be noted that the mortar may not be filled and the vacant joint construction may be performed.

Next, in a cylindrical space e formed between the inner peripheral surface 2a of the cored bar 2 and the outer peripheral surface 4b of the fixed refractory 4,
Using the raw material of the irregular refractory 5a [powder refractory (a mixture of refractory powder and refractory hydraulic cement)
With water added at the time of use]. As the raw material dries and hardens in the space e, it is formed as an irregular shaped refractory 5a for joining, integrating and fixing the cored bar 2 and the fixed refractory 4.

Thereafter, the metal core 2 integrated with the fixed refractory 4 on the horizontal base is concentrically spaced apart from the outer peripheral surface 2b by a predetermined distance in the centrifugal direction from the other surface 231 of the flange 23. An unillustrated outer formwork extending in a cylindrical shape to a predetermined length along the direction of the axis P is arranged. The outer formwork is formed by the other surface 231 of the flange 23, the outer peripheral surface 2 b and the lower end surface 2 c of the metal core 2, and the lower end surface 4 c of the fixed refractory 4. Form a space.

In this space, a non-refractory material 6a (see FIG. 7) made of a paper cylinder having a width W set to 3 mm is provided.
30 mm (interval of 30% of the thickness t of the amorphous refractory 5) in the centrifugal direction [radial direction (see arrow R1)] from the outer peripheral surface 2b. The non-refractory 6a used in this embodiment includes a cylindrical portion 60a and a cylindrical portion 60a.
And a flange-like portion 61a formed at the lower end. The flange-shaped portion 61a includes a ring-shaped horizontal portion 62a extending horizontally from the lower end of the cylindrical portion 60a toward the centripetal side (radially inward side), and a small-diameter tube rising from the ring-shaped horizontal portion 62a along the axis P. It is composed of a shaped portion 63a.

The non-refractory 6a can be fixed and held in place by penetrating the distal end portion 300 of the anchor portion 3b of the anchor 3A. Further, the fixed refractory 4 has an outer peripheral surface on the inner peripheral surface 4a side, which is in contact with the inner peripheral surface 4a, and has a predetermined length along the same axial center line P as the outer formwork. An inner formwork is arranged.

Then, a raw material of the amorphous refractory 5 (the same as the raw material of the amorphous refractory 5a) is poured into a cylindrical space formed by the outer mold and the inner mold. Then
The raw material fills the outer peripheral surface 2b and the lower end surface 2c of the cored bar 2, the other surface 230 of the flange 23, the rib 24, the ring 25, the anchors 3, 3A, the non-refractory 6a, and the lower end surface 4c of the fixed refractory 4 further. Fill and cure by high heat drying.

As the raw material is hardened by high-temperature drying, the non-refractory 6a is extinguished, the shape of the raw material is left as a space to form a dividing band 6A, and the outer peripheral surface 2b, lower end surface 2c, and Flange 23, rib 24, ring 25, anchor 3, 3A, lower end surface 4 of fixed refractory 4
c and the like are integrally formed and formed as an irregular-shaped refractory 5.

In the immersion tube 1 manufactured as described above, the dividing zone 6A formed inside the irregular-shaped refractory 5 has a shape similar to the non-refractory 6a, and has a cylindrical shape surrounding the metal core 2. And has a flange shape extending in the radial direction surrounding the lower end surface 2 c of the cored bar 2. The dividing band 6A is spaced apart from the core 2 and closer to the base 3a than the distal end 300 of the anchor 3A.
And separates the centrifugal side region r2 and the centripetal side region r1. The interval (thickness) L1 of the centripetal region r1 and the interval (thickness) L2 of the centrifugal region r2 can be variously set.

The centrifugal region r2 and the centripetal region r1 separated by the dividing band 6A are connected and fixedly held by a plurality of solid anchors 3A whose tips 300 are embedded in the irregular refractory 5. That is, even if the amorphous refractory 5 is separated into the centrifugal side region r2 and the centripetal side region r1 by the separation zone 6A, the refractory 5 is connected, fixed and held by the anchor 3A,
And can be strengthened.

As shown in FIG. 10, the immersion pipe 1 of this embodiment has a pair of two immersion pipes arranged in parallel at a vertical position between the lower melting furnace 7a and the upper degassing tank 7c of the vacuum degassing furnace 7. One of them is a riser passage (inlet passage) 7 of the molten metal circulation system.
b, and the other is used by forming a downcomer passage (outlet passage) 7b of the molten metal circulation system. In addition, the rising pipe passage 7b
And the downcomer passage 7d have lower end side openings 70b, 70d
Is arranged and held so as to be located below the prescribed liquid level h1 of the molten metal in the lower molten metal furnace 7a. The immersion pipe 1 on the side where the riser pipe passage 7b is formed is provided with a lift gas injection pipe 71b which opens on the inner peripheral surface 4a of the fixed refractory 4 above the molten metal specified liquid level h1. The lift gas injection pipe 71
b has a lift gas supply source (not shown), a gas pressure adjusting unit, and a control unit for controlling gas supply control and stop control on the upstream side.

In use of the immersion tube 1, even if cracks 9 are formed on the outer peripheral surface 53 and the lower end surface 52 of the amorphous refractory 5, its growth is blocked by the dividing band 6A (FIG. 2, FIG. 4). Therefore, the crack 9 is difficult to propagate and expand from the centrifugal side region r2 to the centripetal side region r1, and the molten metal 8 penetrates to the propagation and expansion region of the crack 9 to form the irregular refractory 5, the metal core 2, and the standard refractory. The occurrence of problems such as erosion of the object 4, erosion of the anchor 3, and collapse of the lower end portion 50 of the amorphous refractory 5 can be reduced.

For this reason, the refractory of irregular shape 5 can extend the durability life as compared with the conventional case. For example, the durable life of the lower end portion 50 is about 118 times in terms of the number of cycles in which heating and cooling during standby of the vacuum degassing furnace 7 are alternately repeated, which is about 70 times in the conventional case. The durability can be improved by about 170%.

(Modification 1) The cylindrical dividing band 6A of Modification 1 shown in FIG. 5 has an irregular shape instead of forming the cylindrical dividing band 6 of the above embodiment inside the irregular refractory 5. The structure is the same as that of the above embodiment except that a plurality of connection regions r3 for connecting the centripetal region r1 and the centrifugal region r2 in the radial direction inside the refractory 5 are formed.

In order to form the tubular dividing band 6A inside the irregular-shaped refractory 5, the non-refractory 6a (see FIG. 6) is used.
Instead of a plurality of holes 60 penetrating radially through the peripheral wall
A non-refractory 6a1 having 0 (see FIG. 8) is used. The number, shape, size, etc. of the plurality of holes 600 are as follows:
Various settings can be made in advance according to the purpose.

The plurality of holes 600 of the non-refractory 6a1 are filled when the raw material is poured and the irregular refractory 5 is formed, and a cylindrical dividing zone 6A is formed, while the centripetal region r1 and the centrifugal region are formed. A plurality of connection regions r3 connecting r2 with r2 can be formed. The irregular-shaped refractory 5 having the tubular dividing band 6A is capable of reducing the trouble caused by the crack 9 according to the above-described embodiment, and also connects and fixes and holds the centripetal region r1 and the centrifugal region r2 by the anchor 3A. And the connection region r3.

(Modification 2) The slit-shaped dividing band 6B of Modification 2 shown in FIG. 6 is formed by forming a cylindrical dividing band 6A inside the irregular-shaped refractory 5, instead of forming 30 in the circumferential direction S.
The configuration is the same as that of the above-described embodiment except that four are formed in a 60-degree arc region with an interval S1 of.

In order to form the slit-shaped dividing band 6B inside the irregular-shaped refractory 5, the non-refractory 6a (FIG.
3) in the circumferential direction S surrounding the cored bar 2
Four non-refractory materials 6b (see FIG. 9) arranged in an arc region of 60 ° with an interval S1 of 0 ° are used. The non-refractory 6b is made of paper having a width W set to 3 mm, and includes an arc-shaped vertical portion 60b and a flange-shaped portion 61b formed at a lower end of the arc-shaped vertical portion 60b. Flange 61
b is an arcuate horizontal portion 62b extending horizontally from the lower end of the arcuate vertical portion 60b toward the centripetal side (radially inward)
And a small-diameter circular vertical portion 63b rising from the circular horizontal portion 62b along the axis P.

The irregular-shaped refractory 5 formed with each of the divided zones 6B of the modified example is, in addition to the centripetal region r1 and the centrifugal region r2, centrifugally separated from the centripetal region r1 at an interval S1 of 30 ° in the circumferential direction S. Four connection regions r4 connecting the side regions r2 are formed. For this reason, in the irregular-shaped refractory 5, the same effect as the effect of the dividing band 6A of the embodiment can be obtained by the respective dividing bands 6B, and the centripetal region r1 and the distal-side region r2 are connected by the anchor 3A. In addition to the above, the connection action of the four connection regions r4 can further strengthen the connection region as compared with the case of the above-described embodiment.

The operation of the vacuum degassing furnace 7 (see FIG. 10) using the immersion tube 1 of the above embodiment will be described below. The vacuum degassing furnace 7 is configured such that after the molten metal 8 is introduced to the prescribed molten metal level h1 of the lower molten metal furnace (molten steel pot) 7a, the upper degassing tank 7
The internal space 70c of c is controlled to a predetermined reduced pressure state.

A part of the molten metal 8 of the lower molten metal furnace 7a is
Due to the pressure difference between the atmospheric pressure acting on the prescribed liquid level h1 of the molten metal and the internal space 70c of the upper degassing tank 7c in a depressurized state, it moves to the upper degassing tank 7c via the rising pipe passage 7b and the descending pipe passage 7d. I do. Here, the lift gas injection pipe 71b
From above, a lift gas having a predetermined pressure is injected into the riser pipe passage 7b and rises toward the upper degassing tank 7c.

Then, the molten metal 8 in the riser pipe passage 7b moves to the upper degassing tank 7c due to the lifting action of the lift gas, and riser pipe passage 7b-upper degassing tank 7c-downcomer passage 7d-lower part. It circulates and moves repeatedly in the order of the melt furnace 7a and the riser passage 7b. Note that the injection state of the lift gas is maintained for a target time. On the other hand, the molten metal 8 moved to the degassing upper degassing tank 7c is degassed (discharges gas such as H ₂ , O ₂ and N ₂ contained in the molten metal 8) and decarburized under the reduced pressure conditions. It acts to homogenize components and temperature by stirring, and to float and separate nonmetallic inclusions.

The internal space 70c of the upper degassing tank 7c
The gas degassed to the outside together with the lift gas is discharged to the outside or collected from a reduced-pressure exhaust passage 71c opened above the upper degassing tank 7c.

[0049]

According to the present invention, according to the immersion pipe of the vacuum degassing furnace, the irregular-shaped refractory extends along the core at a distance from the core and at the base end side from the distal end of the anchor. It is characterized by having a dividing zone that separates the centrifugal side and the centripetal side. For this reason, cracks generated from the region in contact with the molten metal on the outer peripheral portion (the outer peripheral surface and the lower end surface) of the irregular-shaped refractory are blocked and prevented by the above-mentioned dividing band even if they are going to grow.

That is, unlike the conventional refractory, the crack does not grow from the generation region and propagates to other regions and does not expand. Refractory, core metal,
Melting loss of fixed refractories can be reduced. Furthermore, the amorphous refractory can maintain a predetermined strength because the region separated into the centrifugal side and the centripetal side by the dividing band is connected and strengthened by the anchor.

Therefore, in the present invention, in the case of the immersion tube of the vacuum degassing furnace, the durability of the amorphous refractory can be improved and the durability life can be extended.

[Brief description of the drawings]

FIG. 1 is a plan view showing a plane of a dip tube of an embodiment.

FIG. 2 is a cross-sectional view partially showing the cross section taken along line AA in FIG. 1 and the outer periphery of a main part.

FIG. 3 is a sectional view taken along line BB in FIG. 2;

FIG. 4 is a partially enlarged view showing a part of a main part of FIG. 3 in an enlarged manner.

FIG. 5 is a cross-sectional view showing a first modification of the dividing band formed on the irregular-shaped refractory at a position taken along a line BB in FIG. 2 (a position in FIG. 3).

FIG. 6 is a cross-sectional view showing a modified example 2 of the dividing band formed on the irregular-shaped refractory at a position taken along a line BB in FIG. 2 (a position in FIG. 3).

FIG. 7 is a perspective view showing a non-refractory used for forming a dividing band in the dip tube of the embodiment.

FIG. 8 is a perspective view showing a first modification of the non-refractory in FIG. 7;

FIG. 9 is a perspective view showing a second modification of the non-refractory in FIG. 7;

FIG. 10 is a schematic view showing an example of use of the dip tube of the embodiment.

FIG. 11 is a cross-sectional view showing a dip tube as one of the conventional examples at a position corresponding to a cross section taken along line AA in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Immersion pipe of a vacuum degassing furnace 2 ... Cylindrical core metal 2c ... Lower end surface 23 ... Flange 24
... Rib 25 ... Ring 3,3A ... Anchor 4 ... Cylindrical refractory 4c ... Lower end face 5,5a ... Unshaped refractory 50 ... Lower end 51 ... Inner peripheral surface 52 ... Lower end surface 53 ... Outer peripheral surface 6,6A ... Cylindrical dividing band 6B Slit-shaped dividing band r1. Centripetal region r2.
4 Connection area 7 Vacuum degassing furnace 7a Lower melting furnace 7b Ascending pipe passage 7c Upper degassing tank 7d Downcoming pipe passage 8 Molten metal 9 Crack

Claims (5)

[Claims] 1. A cylindrical core, a cylindrical fixed refractory disposed inside and fixed to the core, and an outer and lower end face of the core and a lower end face of the fixed refractory. A dip tube having an irregular refractory and a plurality of solid anchors having a base end fixed to the core bar and a distal end embedded in the irregular refractory, wherein the irregular refractory is provided therein. A vacuum degassing furnace characterized in that it has a dividing zone extending along the core bar at a distance from the core bar and on the proximal side from the distal end of the anchor and at least partially separating the centrifugal side and the centripetal side. Immersion tube. 2. The device according to claim 1, wherein said dividing band has a slit shape.
A dip tube for the vacuum degassing furnace described. 3. The immersion pipe of a vacuum degassing furnace according to claim 1, wherein said dividing zone is formed of a non-refractory. 4. The immersion pipe of a vacuum degassing furnace according to claim 1, wherein said dividing band has a cylindrical shape surrounding said cored bar. 5. The immersion pipe of a vacuum degassing furnace according to claim 1, wherein said dividing band has a radially extending flange-like portion surrounding a lower end surface of said cored bar.