JP2694494B2 - Tuyere bullion lifting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tuyere care device for exchanging a dipping nozzle (hereinafter abbreviated as IN) of a steel tundish, and particularly for pushing up a metal layer remaining on the upper surface of the tuyere after leaving IN. The present invention relates to a tuyere metal pushing up device for peeling and removing.

[0002]

2. Description of the Related Art In general, molten steel carried by a pot from a converter in a continuous casting facility is once stored in a tundish and then injected into a mold through a submerged nozzle attached to the bottom tuyere. The service life of the tundish is 100 charges or more, while the service life of the immersion nozzle is as short as 5 to 10 charges. Therefore, the replacement of the immersion nozzle is indispensable in the continuous casting operation.

When the types of immersion nozzles are broadly classified, there are an integrated type in which the flow rate of molten steel is adjusted by raising and lowering a stopper, and a divided type in which the flow rate is adjusted by a horizontal sliding nozzle.

The former integrated dipping nozzle is usually an insertion type that is installed from the inside of the tundish. When replacing it, the bricks corresponding to the tuyere are damaged and removed after the temperature of the tundish bricks has dropped. It is common to insert a new immersion nozzle by replacing it with a new one. However, since tuyere bricks are constructed after the temperature drops, continuous use of tundishes becomes impossible, and there is a disadvantage that material costs and labor costs for replacing bricks increase.

On the other hand, in the latter split type immersion nozzle, although the immersion nozzle can be easily replaced, a drift is likely to occur in the immersion nozzle portion when the molten steel is injected into the mold, and the molten steel flow state in the mold is compared with that of the integrated type. It has the disadvantage of being easily changed. Therefore, in the hot rolling of the tundish, the integral type immersion nozzle, which is advantageous in terms of quality, is used as an external insertion type to be mounted from the outside of the tundish.

By the way, in the replacement of the immersion nozzle of the internal insertion type or the external insertion type, it is necessary to remove the metal layer remaining on the upper surface of the tuyere after the IN is removed from the upper surface or the lower surface of the tundish. Yes, conventionally, (1) manually remove the metal layer from the opening on the upper surface of the tundish or the opening on the lower surface of the tuyere by using a tool such as a crowbar or breaker, or (2) supply pure oxygen to the iron pipe. By spraying on the ingot layer, the ingot layer is fluidized at a high temperature to eliminate the outflow from the tuyere. These are manual bullion removal operations using tools. On the other hand, (3) there is also a treatment method in which a dedicated offline bullion lifting device driven by a hydraulic cylinder is used to separate the bare metal remaining in the tundish from the refractory bricks in the tundish, and remove the bare metal. .

[0007]

However, the above (1)
The method (2) is a so-called 3K work that is dangerous and dangerous under a high temperature and harsh environment, and requires a long time because the work efficiency is low. Further, since the removed metal adheres to the inner surface of the tuyere, it takes a long time in addition to the removal of the metal remaining on the upper part of the tuyere, and the adhered metal cannot be completely removed manually.

Further, in the above method (3) using the dedicated offline bullion lifting device, time is required for handling and transporting to the bullion lifting device, and the brick layer must be cooled to a certain extent and cooled down. Not separated from. However, when the temperature is lowered, it takes a cooling time, and unless the temperature is raised again, the recasting work cannot be started.

An object of the present invention is to solve the above-mentioned drawbacks and to provide a compact tuyere metal pushing-up device capable of peeling and removing a metal layer without manual work or an off-line dedicated metal lifting device. To do.

[0010]

In order to achieve the above object, a tuyere base pushing-up device of the present invention is provided with an elevating body to be inserted into a tuyere after a dipping nozzle is detached and attached to an upper portion thereof. And a cylindrical pushing head made of a combustible and sublimable material that pushes up and removes the bare metal layer remaining on the upper surface of the tuyere (claim 1).

In the present invention, the above-mentioned push-up head has a diameter that does not cause it to hit the inner surface of the tuyere when it is inserted, and its thickness has such a capacity that the combustion disappears to the extent that it is not caught when the head is extracted. The thickness should be set so as to have an insertion allowance for pushing up to a position where the metal layer does not hang down below the tuyere upper end by the time when a new immersion nozzle is inserted afterward, and it is suitable for the working condition (claim 2). .

A particularly preferred form is a tuyere care device body in which the elevating body has a cutting tool that can be expanded and contracted by a rotating centrifugal force, and the push-up head does not interfere with the turning motion of the care device body. It is attached to the head hole of the tuyere care device body in such a state (claim 3).

The push-up head is made of wood (claim 4), and a plurality of streaks are formed on the outer circumferential surface of the push-up head for foreign matter such as mortar remaining on the inner surface of the upper end of the tuyere when it is inserted into the tuyere. It can be equipped with a number of nails (claim 5).

[0014]

The pushing head is inserted into the tuyere after the immersion nozzle is removed together with the lifting body, and pushes up and removes the bare metal layer remaining on the upper surface of the tuyere (claim 1). Therefore, it is possible to avoid the work by man and the work by the off-line dedicated metal pushing-up device, and the processing can be performed without the need for cooling and cooling and re-heating.

Further, since the push-up head is simply attached to the upper part of the lifting body, it becomes a compact device. Since the push-up head is made of a material capable of burning and sublimating and has a property of extinguishing the burning, the lifting body does not become stuck when the head is extracted.

In particular, when the head size and shape suitable for the working condition are selected as claimed in claim 2, not only does it not hit the inner surface of the tuyere when the head is inserted, but also the metal layer forms the upper end of the tuyere. It is pushed up to a position where it does not droop below, and burns off to the extent that it is not caught when the head is extracted (claim 2).

According to the third aspect, which is a particularly preferable form, since the tuyere care device main body having a blade capable of expanding and contracting due to the centrifugal force is moved up and down, the metal layer is pushed up simultaneously with the tuyere care. Is performed, and there is no overlap in work time when performing each independently, and processing can be performed in a short time (claim 3).

It is economical to use a wooden push-up head (Claim 4). A nail is provided on the outer circumferential surface of the push-up head to prevent foreign matter such as mortar remaining on the inner surface of the upper end of the tuyere when it is inserted into the tuyere. By performing the processing for the streak, it is possible to supplement the care by the tuyere care device main body (Claim 5).

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to one embodiment shown in the drawings. 1 to 3, an IN (immersion nozzle) exchange truck 3 for a tuyere 2 of a tundish 1 is provided so as to be able to travel on a truck traveling rail 5 by wheels 4, and the IN exchange truck 3 has an IN recovery device A , Tuyere care device B, IN
The insertion device C is mounted in this order.
A portion of the IN / mortar switching trolley 3b connected to the frame 3a of the N exchange trolley 3 has an IN adjacent to the IN insertion device C.
A preheating furnace D, a mortar stand E, and an IN-mortar transfer device F are installed.

The IN replacement work is IN collection → repair of tuyere → I
Follow the procedure of N transfer → mortar transfer → IN insertion. At this time, the trolley 3 moves on the rail 5 (1) First, the recovery device A has the tuyere 2
(2) After the collecting operation, the care device B advances to the cleaning position facing the tuyere 2, and (3)
After cleaning the inner surface of the tuyere, I prepared by then and set in the IN insertion device C by the IN-mortar transfer device F
In order to insert N into the tuyere 2, the IN insertion device C advances to the collection position facing the tuyere 2, and (4) after the IN insertion (supply) work, retracts on the rail 5 to the standby position. In these operations, the recovery device A, the care device B, and the IN insertion device C advance from the standby position indicated by the solid line in FIG. 1 to the operation position indicated by the dotted line.

Of these, the present invention is particularly directed to the tuyere inner surface care device B for performing tuyere cleaning work, and the construction thereof is shown in FIGS. 4 to 6. This tuyere care device B
A tuyere care device body 6 composed of a phase-saw blade and a flat blade or a dresser that can be expanded / contracted by a centrifugal force, and a combustion attached to the top of the tuyere care device body to push up the upper metal layer of the tuyere, It has a bullion pushing head 7 made of a sublimable material (eg, wood).

(A) Tuyere Care Device Main Body FIG. 4 shows the appearance of the tuyere care device main body 6, and FIG. 5 shows a sectional structure. 4 and 5, the rotary cylinder 13 fitted on the upper part of the rotary shaft 11 and fixed to the rotary shaft 11 by screws 12 is substantially triangular as a whole as shown in FIG. Three turning bases 14 are extended so as to form a shape. A base 16a of a cutting tool holder 16 is swingably mounted on each of the triangular tops of the revolving base 14 by a shaft 15, and a cutting tool 17 is pivotally mounted on the holder 16 by a shaft 18. .

That is, when the rotary shaft 11 rotates, the rotating centrifugal force causes the holder 16 to rotate about the shaft 15 and the blade 17 to rotate about the shaft 18, and the length up to the tip of the blade is increased. It constitutes a link mechanism that expands and contracts. 3 above
The swivel bases 14 of the book are provided in a plurality of stages in the vertical direction of the rotating shaft, and the swivel bases 1 of the adjacent upper and lower stages are provided.
As shown in FIG. 6, the positions of the upper and lower tiers 4 are circumferentially displaced so as to project from the center between the open legs of the adjacent swivel base 14 as shown in FIG.

Cutting tool 1 attached to each cutting tool holder 16
7, three types of cutting tools 17a, 17b, 17c shown in FIG.
And a dresser 17d shown in the lower part of FIG. FIG.
The cutting tool 17a shown in FIG. 8A is composed of a saw blade having two straight blades a protruding radially outward in a mountain-shaped cross section at positions spaced apart in the axial direction. The cutting tool 17b shown in FIG. 17a comprises a saw blade having two straight blades b out of phase with each other.

The cutting tool 17c shown in FIG. 8 (c) is composed of a flat blade c having an axial width which covers the areas of these saw blades 17a and 17b. The dresser 17d is formed by forming a thin metal wire into a cylindrical brush shape. These cutting tools 17
For the material of, a material having a slightly lower strength than the tuyere surface is selected in order to prevent damage due to excessive maintenance of the tuyere surface.

These cutting tools 17 are provided in the order of cutting tools 17a, 17b, 17c in the circumferential direction on the top of the swivel base 14 which constitutes the above-mentioned one step and is located in the circumferential direction. However,
A dresser 17d is provided for all of the lowermost stage and the previous stage. However, each of the blades 17 can be configured by combining a plurality of saw blades, phase shift saw blades, and flat blades for each stage including two stages from the bottom.

The shaft 15 pivotally supporting the base 16a of the cutting tool holder 16 is parallel to the rotary shaft 11, while the shaft 18 pivotally supporting the cutting tool 17 to the holder 16 is flared with respect to the rotary shaft 11. The angle of inclination is substantially the same as the angle of inclination of the inner surface of the tuyere to be treated, that is, the apex angle of the immersion nozzle. That is, the blades 17 are arranged so that the envelope of the whole blades forms a frustoconical shape following the inner surface of the tuyere, and the shaft 18 restricts each blade 17 from falling in the turning direction with respect to the inner surface of the tuyere 2. ing.

Due to the above-mentioned structure, when the caring apparatus main body 6 is inserted into the tuyere 2 by the elevating mechanism and the rotary shaft 11 is rotated by the turning drive mechanism, the caring apparatus main body 6 is arranged in the above-mentioned conical shape. Due to the centrifugal force of the turning, the entire cutting tool 17 is always expanded and contracted following the shape of the inner surface of the tuyere.

That is, each cutting tool 17 turns while being pressed against the inner surface of the tuyere 2 as shown in FIG. Due to this turning pressure contact force, the mortar 28 which is the adhered foreign matter on the tuyere surface (see FIG. 11)
First, two types of saw blade-shaped cutting tools 17a, 17 with different phases are used.
b is crushed into a groove shape by b, and the remaining portion other than the groove is crushed by the flat bladed cutter 17c, and finally the dresser 17
The surface is finished with d. Therefore, the tuyere surface is efficiently cleaned.

The turning drive mechanism and the elevating mechanism may have any structure, but in this embodiment, the structure is shown in FIG. In FIG. 9, the right side of the central axis shows the case where the care device main body 6 is in the lowered position, and the left side shows the case where it is in the raised position. The lower portion of the rotary shaft 11 is disposed in a bottomed cylindrical movable frame 19, and is supported by a seat frame member 20, a double row conical roller bearing 21 and a cylindrical roller bearing 22 at the opening edge of the movable frame 19. Have been.

In the movable frame 19, a hydraulic motor 23 as a swing drive means is coaxially attached to the lower end of the rotary shaft 11, and the rotary shaft 11 is rotated by the hydraulic motor 23. The movable frame 19 is disposed in a cylindrical fixed frame 26, and the bottom lower surface of the movable frame 19 is supported by a lifting hydraulic cylinder 25 provided between the movable frame 19 and the bottom of the fixed frame 26. 25 makes it possible to move up and down. Reference numeral 27 denotes a guide mechanism 27 provided between the movable frame 19 and the fixed frame 26 to guide the movable frame 19 in the vertical direction during the elevating operation.

As described above, the entire cutting tool 17 arranged in the above-described frustoconical shape is always expanded / contracted in accordance with the shape of the tuyere inner surface by the turning centrifugal force, as shown in FIG. Therefore, by controlling the turning speed, the maintenance ability by the centrifugal force can be controlled.

At this time, (1) the care ability can be amplified by slightly moving the turn, not turning at a uniform rotation speed. (2) Further, by adjusting the turning speed, it is possible to prevent the stop of the cutting tool and the damage to the tuyere, and it is possible to realize safe and stable hot maintenance. In addition, as the turning drive means, a known power source capable of performing a rotary motion such as an electric motor, a hydraulic motor, and an air motor can be used.

FIG. 10 shows an example of control in the tuyere maintenance work. Here, as the exercise load measuring means, an ammeter is provided in the case of the swing drive by an electric motor, and a pressure gauge or the like is provided in the case of the swing drive by a hydraulic motor, an air motor, or the like.
It is assumed that the turning load is monitored.

(1) First, the maintenance device body 6 is raised by the lifting hydraulic cylinder 25, and the maintenance device body 6 is inserted into the tuyere 2.

(2) Next, a high-speed inching swivel motion is started by the swivel drive means. In this high-speed jogging movement, the blade 17 contracts due to the inertia at the time of starting rotation, collides with the tuyere surface due to the centrifugal force generated by the rotation, and the blade 17 is pressed against the tuyere surface due to the inertia at the time of stopping rotation. Therefore, the foreign matter adhering to the tuyere surface such as mortar can be crushed by the force obtained by amplifying the centrifugal force due to the continuous turning motion at a uniform speed. It should be noted that this high-speed inching and swiveling step can be omitted if the deposit is light.

(3) Following the high-speed inching turning motion, the high-speed continuous turning motion is entered this time. In the continuous swirling motion, the crushed foreign matter is finely pulverized and dropped by the pressing force of the blade tool 17 against the tuyere surface by the swirling centrifugal force. This crushing is performed in a groove-like crushing process using saw blade-shaped cutting tools 17a and 17b having different phases, and the remaining portion other than the grooves is flat-bladed cutting tool 1.
The process is efficiently performed by repeating the step of pulverizing in step 7c.

(4) When the turning load monitored by the exercise load measuring means falls below a predetermined value, the high speed continuous turning motion is started to the low speed continuous turning motion. This means that the turning speed is reduced to avoid damage to the tuyere surface, and the process proceeds to the finishing care process. At this stage, dresser 17
d is located on the outside of the tuyere and the surface finish is executed.

(5) When the load is further reduced, the maintenance work is completed. That is, the maintenance device main body 6 is lowered by the hydraulic cylinder 25, and the turning by the hydraulic motor 23 is stopped.

The effects obtained by the configuration of the above-mentioned care device body are as follows. (1) By expanding and contracting the cutting tool by rotating centrifugal force,
Fine adjustment of the cutting depth of the cutting tool is not required, and unstable phenomena such as turning stop during maintenance can be avoided. Further, since the centrifugal force is used, the turning power can be set small, and the structure, strength, and the like can be simplified.

(2) By slewing the swivel movement and combining a saw blade and a flat blade with different phases, the maintenance ability is dramatically improved, and maintenance can be performed at light load and in a short time.

(3) The care ability can be controlled by adjusting the turning speed, and the turning load can be monitored to avoid damage to the tuyere surface due to excessive care. Also, the selection of the material reduces the damage to the tuyere.

(B) Bullion push-up head As shown by the solid line in FIG. 11, the bullion push-up head 7 manually removes the bullion layer 27 remaining on the upper surface of the tuyere 2 after the IN is removed. The above-mentioned tuyere care device as an elevating body to be inserted into the tuyere 2 for pushing up and peeling off as shown by the dotted line in FIG. It is attached to the top of the body 6.

4 and 5, the metal pushing head 7 is made of a material capable of burning and subliming, and is made of wood in this example. The metal lifting head 7 is formed in a columnar shape, and is provided with a mounting leg 7a at the center of the lower surface thereof. The metal lifting head 7 is attached to the tuyere maintenance device main body 6.
, A hole 13a provided in the head of the rotary cylinder 13
It is performed by inserting the leg 7a into the inside.

That is, the rotary cylinder 13 of the tuyere maintenance device main body 6 described above is a support cylinder for the bullion pushing head 7, and the lifting mechanism using the hydraulic cylinder 25 described in FIG. It becomes an elevating mechanism, and the "bulb pushing up device" is constituted by the bullion pushing head 7, the rotary cylinder 13, the rotary shaft 11, and the elevating mechanism.

The head 7 for pushing up the bullion is set.
Is inserted into the tuyere 2 at the same time as the tuyere care device body 6 in the tuyere care work immediately after the IN is removed and collected by the IN collection device A. The metal push-up head 7 is a consumable that is burned and sublimated in the tundish. Although the head 7 is described as having a columnar shape, it is sufficient that the function of the head 7 described later can be achieved. Therefore, the term “cylindrical” here means a polygonal column shape in addition to a literal column shape. It is used as a broad concept that includes

FIG. 12 shows the procedure for pushing up the metal. First, the head 7 before insertion is sufficiently moistened with water or the like, and the head 7 is loaded on the upper end of the tuyere care device main body 6. At this time, the leg 7a of the head 7 is merely inserted into the head hole 13 of the rotary cylinder 13, and the rotation is not stopped, so that the head 7 has a free structure. This is to prevent the operation of the care device main body 6 such as a turning motion from being disturbed.

In the tuyere maintenance work immediately after the IN is removed and collected by the IN collecting device A, the bullion lifting device is raised to its upper limit, that is, the upper limit of the operation stroke of the hydraulic cylinder 25, and the bullion pushing head 7 is winged. Insert in mouth 2. In this process, the bullion lifting head 7 is moved to
The metal layer 27 remaining on the upper surface of the tuyere at around 1350 ° C. is pushed up as shown by the dotted line in FIG. 11 to be removed by peeling. Then, the metal lifting device is lowered.

The insertion time of the bullion pushing head 7 during this period is, for example, 60 seconds, and the time from the start of head extraction until a new IN is inserted is, for example, 90 seconds. Therefore, if the metal pushing-up head 7 is completely burned or sublimated during the former insertion time of 60 sec, the push-up and peeling action is not sufficiently exerted, and the latter 90 sec.
If the metal layer 27 hangs down again during c and falls below the upper end of the tuyere, the push-up and peeling work ends in failure.

Therefore, the material and shape of the head 7 are determined in consideration of the following points. First, the temperature inside and above the tuyere is 1
The temperature is about 000 to 1400 ° C., and it is necessary that the head 7 has almost the original shape when the metal is pushed up and inserted and has a strength capable of pushing up the metal layer 27 existing at the upper end of the tuyere.
Also, after the insertion is completed, it burns or sublimes in this temperature range, and the strength decreases or disappears partially or entirely,
It is necessary that the material is such that the head 7 is not hooked on the tuyere 2 at the time of extraction when the push-up is completed, or disappears even if it is hooked. In this example, the head is a wooden head, and the above conditions are sufficiently satisfied by being sufficiently wetted with water or the like before insertion.

Next, the inner surface of the tuyere 2 is generally circular in shape, and the sealing mortar 28 remains as an adhering foreign matter on the inner surface of the tuyere in a substantially uniform thickness. Therefore, the outer diameter of the head 7 is configured to be the diameter obtained by subtracting the remaining mortar thickness from the inner diameter of the tuyere 2, thereby avoiding the stoppage of the tuyere 2 and the mortar 28 during insertion.

The thickness of the head 7 has such a capacity that it burns and disappears without being caught at the time of extraction from the start of head extraction after the time from the completion of insertion of the head 7 to the start of extraction. The size is set such that the amount of metal layer 27 is raised to a position where the metal layer 27 does not drop and falls below the upper end of the tuyere before the start of new IN insertion.

In this example, the tuyere inner diameter is 186 mm, the mortar thickness is 3 mm, the head outer diameter is 180 mm, the head initial thickness is 30 mm, and the extraction thickness is 20 mm and the extraction outer diameter is 170 mm when the insertion time is 60 sec. A good result was obtained by using a wooden head with a head insertion margin of 50 mm for 90 seconds from the start of head extraction to the start of new IN insertion.

By the way, in this embodiment, as shown in FIGS. 4 and 5, nails 7b are driven to appropriate height positions at appropriate positions in the circumferential direction on the outer peripheral surface of the head 7. When the head 7 is lifted, the nail 7b cracks or grooves the foreign matter 28 such as mortar remaining on the inner surface of the upper end of the tuyere, thereby facilitating removal by the tuyere maintenance device body 6. do. For this reason, the protrusion of the driving nail 7b is adjusted according to the damage of the upper end due to the continuous use of the tuyere. Instead, the head 7 having a different outer diameter is changed according to the damage of the upper end of the tuyere. Several types may be prepared in advance and corresponded.

In any of the bullion pushing heads 7 of this embodiment, the bullion pushing head 7 is loaded on the upper end of the tuyere care device main body 6 as a consumable item, so that the work of pushing up the bullion and the tuyere care can be performed. It is possible to proceed at the same time and work time can be shortened. Moreover, a compact metal lifting device can be obtained. And
At the time of pushing up, the necessary dimension may be pushed up so that the metal may not interfere during the time until the maintenance work + IN insertion work is completed, and it is possible to carry out the processing in a short time, so that there is no need for cooling and cooling.

In the above embodiment, the push-up head 7 is attached to the tuyere care device main body 6, but the push-up head 7 is attached to an elevating body different from the tuyere care device main body to independently push up the metal. The device or the device having the function of the lifting body can also be used.

[0057]

As described above, according to the present invention, the following excellent effects can be obtained. (1) According to the constitutions of claims 1 to 5, an elevating body having a lifting head is inserted into the tuyere after the immersion nozzle is detached, and the metal layer remaining on the upper surface of the tuyere is pushed up to remove it. Therefore, it is possible to avoid the manual work and the work by the offline dedicated metal pushing-up device, and to push up the metal layer in a short time without the need for cooling and cooling and re-heating. Further, since the push-up head is simply attached to the upper part of the lifting body, it is a compact device.

(2) Especially, in the structure of claim 3, since the lifting head is moved up and down together with the tuyere care device main body, the work of pushing up the metal and the tuyere care can be carried out simultaneously, and the work time is shortened. it can.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an IN exchange bogie equipped with a tuyere care device according to one embodiment of the present invention.

FIG. 2 is a plan view of the IN exchange bogie of FIG. 1;

FIG. 3 is a side view showing the IN exchange bogie of FIG. 1 in a partial cross section.

FIG. 4 is an external view showing a bullion lifting head and a tuyere maintenance device body that constitute a bullion lifting device according to an embodiment of the present invention.

FIG. 5 is a side view showing the bullion lifting device of FIG. 4 in a partial cross section.

6 is a plan view showing a tuyere care device main body of the bullion pushing device of FIG. 5;

FIG. 7 is a diagram for explaining the operation of the blade of the tuyere care device body of FIG.

FIG. 8 is a diagram showing types of cutting tools of the tuyere care device main body of FIG. 4;

9 is a view showing a lifting / lowering mechanism of the bullion lifting device of FIG. 4, in which the right side is in a lowered position and the left side is in a raised position.

FIG. 10 is a flowchart showing an example of control of the tuyere care device body of FIG.

11 is an explanatory view of the operation of the bullion pushing head of the bullion lifting device of FIG. 4. FIG.

FIG. 12 is a diagram showing a procedure of pushing up the metal.

[Explanation of symbols]

 2 tuyere 6 tuyere care device main body 7 bullion pushing head 11 rotating shaft 13 rotating cylinder 13a head hole 25 hydraulic cylinder 27 ingot layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Setsu Matsui 1 Fuji-machi, Hirohata-ku, Himeji-shi, Hyogo Nippon Steel Corporation Hirohata Works (56) References )

Claims (5)

(57) [Claims] 1. An elevating body to be inserted into a tuyere after the immersion nozzle is removed, and a combustible and sublimable material that is attached to an upper part of the body and pushes up and removes a bare metal layer remaining on the upper surface of the tuyere. A tuyere base pushing-up device, comprising: 2. The push-up head has a diameter that prevents it from being caught on the inner surface of the tuyere when it is inserted, and its thickness has a capacity to burn and disappear to the extent that it is not caught when the head is extracted,
2. The thickness is set so as to have an insertion allowance for pushing up to a position where the metal layer does not hang down below the upper end of the tuyere after the head is extracted and before a new immersion nozzle is inserted.
The tuyere bar push-up device described. 3. The tuyere maintenance device main body in which the elevating body has a blade capable of expanding and contracting by swirling centrifugal force, and the push-up head is a wing in a rotation-free state that does not hinder the swiveling motion of the maintenance device main body. 3. The blade metal pushing-up device according to claim 1, which is attached to a head hole of a mouth care device body. 4. The tuyere base pushing-up device according to claim 1, wherein the lifting head is made of wood. 5. The push-up head is provided with a plurality of nails on the outer peripheral surface for performing streaking on foreign matter such as mortar remaining on the inner surface of the upper end of the tuyere when the head is pushed into the tuyere. The tuyere metal pushing up device according to claim 4.