JP4535594B2 - Immersion nozzle changer for continuous casting machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an immersion nozzle changing device and a method of using the same in a continuous casting machine. In particular, the present invention relates to a submerged nozzle changing device and a method of using the same, which can easily and safely replace a submerged nozzle at the bottom of a tundish during casting operation of a continuous casting machine.
[0002]
[Prior art]
Conventionally, it is generally known to use a slide gate at the outlet of a molten steel metal container to control the flow rate. The slide gate is mainly composed of a pair of refractory plates that make up the gate and a mechanical device that holds and drives it. The gate is adjusted by driving one of the refractory plates to control the discharge rate. It is a device to do. The refractory plate is used to control the flow rate by overcoming the static pressure of the molten metal and blocking or restricting the outflow of the metal, so if the surface pressure is not applied with a constant force, the molten metal will flow out from between the plates. There is a risk of accidents.
[0003]
For this reason, in a general melting container slide gate, the surface pressure between the plates is 0.00 per unit flat area of the refractory plate. A pressure of several MPa is applied, and the force applied to the entire refractory usually ranges from 2.3 to 10 tons. On the other hand, since the refractory material of the slide gate is exposed to a high-temperature molten metal, it is severely worn out and is replaced every several hours of use. In each exchange, it is necessary to release the surface pressure, open the slide gate hardware, replace the refractory by operating a push bolt or cotter, and apply the surface pressure again. Also, if the surface pressure is set too low, steel leaks from between the plates, and if it is too high, the sliding resistance of the slide gate becomes too large to operate, leading to serious accidents such as the inability to take out molten steel in the container. This is an extremely important task.
[0004]
In the continuous casting machine, the simplest method for controlling the amount of molten steel injected from the tundish into the mold is to direct the molten steel to the mold without using a conduit such as a submerged nozzle from an opening with a constant area provided in the tundish bottom plate. A so-called open nozzle system that drops air (or atmospheric gas) is widely used in billet continuous casting machines, bloom continuous casting machines, beam blank continuous casting machines, and the like. In an open nozzle, the flow rate of molten steel per unit time is proportional to the product of the square area of the nozzle opening area and the molten steel depth in the tundish. The amount is constant and the flow rate can be easily controlled. The conventional open nozzle is made of a refractory material having a certain opening and is fixed in the refractory material at the bottom of the tundish, and cannot be easily replaced during casting. For this reason, when performing so-called continuous casting operations in accordance with operations such as electric furnaces and converters on the molten steel supply side, the casting speed is controlled by adjusting the depth of molten steel in the tundish. If the molten steel depth becomes too shallow, the slab quality is deteriorated. Also, the molten steel stream from the ladle leads to damage to the bricks per hot water, so in multi-strand casting, the nozzle of a specific strand is plugged with a risk from the bottom of the tundish, or the nozzle hole is plugged from the inside of the tundish. Depending on the situation, the outflow of molten steel is stopped and synchronized with the molten metal supply. Similarly, when performing immersion nozzle casting without using a slide gate, it is necessary to control the casting speed by adjusting the molten steel depth of the tundish. When using a submersible nozzle of the type, it is necessary to plug a wedge from the inside of the tundish, and in the case of the exterior type, a nozzle without a hole after being plugged from the inside of the tundish or equipped with an immersion nozzle changer Need to be replaced.
[0005]
[Problems to be solved by the invention]
The open nozzle uses a high-strength refractory such as zirconia. However, it receives a scientific and mechanical attack from molten steel, and the diameter of the open nozzle usually increases in about 10 to 20 hours, making it unusable. Also, the immersion nozzle is usually eroded in several hours to several tens of hours, and the molten steel surface contact portion is eroded and cannot be used. On the other hand, tundish lining refractories are durable for several tens of hours, but for the life of the open nozzle and immersion nozzle, the casting is stopped and cooled, and the open nozzle and immersion nozzle are replaced and repaired or replaced. Is going.
[0006]
If the open nozzle and the immersion nozzle can be easily replaced during casting, the tundish can be used continuously and for a long time, and the preparation work can be reduced by continuous casting work. Benefits such as reduction of basic unit, reduction of energy loss of cooling and reheating are great. Conventionally, as a means for replacing the tundish open nozzle, for example, as disclosed in Japanese Patent Publication No. 49-31411 or Japanese Patent Publication No. 51-4187, the open nozzle is slidably mounted on a rail provided outside the tundish. What is replaceable is known. In the above-mentioned Japanese Patent Publication No. 51-4187, if the blank gate is a plate with an opening similar to the orifice gate corresponding to the open nozzle, the erosion nozzle can be replaced with a new nozzle. Casting can be stopped, and dangerous work such as stopping with a stopper is not necessary.
[0007]
In the above-described conventional method, the orifice plate for controlling the flow rate is usually composed of a refractory and a metal casing for the purpose of preventing cracking of the refractory, and includes two orifice plates or orifice plates, When replacing the blank plate during casting, the metal casing also passes through the opening of the upper nozzle, so that the metal casing is exposed to the molten steel. If the metal casing is configured to be flush with the upper sliding surface of the orifice plate and is sufficiently in close contact with the metal casing of the subsequent plate, leakage of molten steel will occur even when the orifice plate is replaced. However, for example, an orifice plate manufacturing means using an economical metal case that has been pressed does not necessarily provide sufficient flatness and adhesion.
[0008]
The present invention eliminates the above-mentioned conventional problems, and externally attaches a refractory plate and an immersion nozzle to the tundish bottom so that it can be exchanged safely and easily even during casting operation, and is balanced with the tundish refractory. It is an object of the present invention to provide an immersion nozzle exchange device for a continuous casting machine that enables a flexible operation and a flexible operation.
[0009]
[Means for Solving the Problems]
Immersion nozzle exchanging apparatus of the first invention, a base plate fixed to the bottom surface of the tundish (8), a nozzle (4) on a refractory which is fixed to the base plate (8), the hinge pin on the lower surface of the base plate (8) A frame (9) supported and swingable by (16) , and a pair attached to the frame (9) , supporting the refractory plate (5) and guiding the loading operation. An upper guide rail (11) , a lower guide rail (10) which is attached to the lower surface of the frame (9) , supports the immersion nozzle (6) and guides the charging operation, and the upper guide rail ( 11) The refractory plate (5) held on the entry side of the lower guide rail (10) and the immersion nozzle (6) held on the entry side of the lower guide rail (10) are moved to the opening position leading to the opening of the tundish. Previous exchange And a sheet Linda be pushed out to completion position (18), the upper guide rail (11) is mounted side by side two refractory plates (5), extrude one component of the refractory plate (5) long The lower guide rail (10) has a length that allows two immersion nozzles (6) to be mounted side by side, and can push out one of the immersion nozzles (6). An upper stopper (20a) that restrains the object plate (5) from moving in the direction of the replacement position is provided so as to be able to be inserted and removed, and the immersion nozzle (6) in the opening position is restrained from moving in the direction of the replacement position. The lower stopper (20b) is provided so that it can be inserted and removed .
Immersion nozzle exchanging apparatus of the second invention, removable in the first invention, the pre-alkoxy Linda (18) has a trunnion (18 d), the Frame (9), before Symbol trunnion to (18 d) A hook (9c) that can be freely fitted and detached is formed.
The immersion nozzle exchanging device according to a third aspect of the present invention is the submerged nozzle replacement device according to the first aspect , wherein the lower guide rail (10) includes an entry-side lower rail (10a) that supports the immersion nozzle (6) in the standby position and an immersion position in the open position nozzle and movable rails for supporting the (6) (10c), becomes from the exit-side lower rails for supporting the immersion nozzle (6) in the replacement position (10b), said movable rail (10c), said frame (9) Is supported by a spherical seat (13) attached to the outer periphery, and a coil spring (17) is interposed between the outer end and the frame (9), and an immersion nozzle (6) is placed thereon. The inner end is pushed up.
[0010]
The method of using the immersion nozzle changer according to the fourth aspect of the invention is the immersion nozzle changer according to claim 1 , wherein the upper stopper (20a) and the lower stopper (20b) are removed, the refractory plate (5) and the immersion nozzle are removed. The nozzles (6) are exchanged together.
The method of using the immersion nozzle changer of the fifth invention uses the immersion nozzle changer according to claim 1 , removes the upper stopper (20a) and attaches only the lower stopper (20b) , and the refractory plate (5). It is characterized by exchanging only.
The method of using the immersion nozzle changer according to the sixth aspect of the invention is the immersion nozzle changer according to claim 1 , wherein the lower stopper (20b) is removed and only the upper stopper (20a) is attached, and only the immersion nozzle (6). It is characterized by exchanging.
[0011]
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Next, preferred embodiments of the present invention will be described with reference to the drawings. 1 is a side sectional view of an immersion nozzle changing device according to the present invention, FIG. 2 is a bottom view of the immersion nozzle changing device as viewed from the direction of arrow A in FIG. 1, and FIG. 3 is a sectional view taken along line CC in FIG. FIG. 5 is a schematic view for explaining a casting operation in a continuous casting machine when an open nozzle 22 is used in the tundish 2a.
[0013]
First, molten steel flow control when an open nozzle is used in a continuous casting machine will be described with reference to FIG. If the molten steel flow supplied to the tundish 2a from the ladle 2c is turned on and off by the slide gate 21 provided at the bottom of the ladle 2c, and the molten steel depth H in the tundish 2a is controlled within a certain range, the tundish The amount of molten steel Q per unit time flowing into the mold 23 from the open nozzle 22 at the bottom of 2a is represented by Q∝A√ (H), where A is the opening area of the open nozzle 22. If the opening area A is constant, even if the molten steel depth H fluctuates by about 10%, the molten steel amount Q is suppressed to a fluctuation of about 5%, and sufficient practicality is ensured. Widely used in casting machines and beam blank continuous casting machines.
[0014]
The open nozzle 22 is a refractory member having a predetermined opening area. However, since the open nozzle 22 is exposed to molten steel at a high temperature and a high flow velocity, it gradually melts and increases the opening area A. Within the limit that can be secured, it becomes impossible to control to a predetermined Q. When the function of the open nozzle 22 is impaired by melting damage, casting is stopped, the tundish 2a is cooled, and replaced with the lining refractory. The casting stop operation is generally done by inserting a conical stopper into the lower part of the nozzle while there is some remaining steel and residue in the tundish 2a and the spill still continues, and there is a risk of burns. Is expensive. The same casting stop operation is also performed in an emergency such as a breakout or overflow, and there is a greater danger that the molten steel scatters as the molten steel depth is deeper.
[0015]
With reference to FIGS. 1-4, the immersion nozzle replacement | exchange apparatus 1 is demonstrated. The immersion nozzle changer 1 has a base plate 8 attached to the bottom of the tundish, and the base plate 8 has a recess for accommodating the upper nozzle 4.
[0016]
The frame 9 is coupled to the base plate 8 by a hinge pin 16 so that the frame 9 can be opened and closed. The frame 9 can be opened and closed around the hinge pin 16 in a door shape. The frame 9 has a recess for accommodating the upper nozzle 4, and a cylinder 18 for driving the refractory plate 5 and the immersion nozzle 6 is attached to one end. In other words, the refractory plate 5 and the immersion nozzle 6 are exchanged in accordance with the movement of the cylinder 18 and the metal fitting 19 attached to the end of the cylinder rod 18 b of the cylinder 18. Sliding surfaces are formed on the upper and lower surfaces of the refractory plate 5 .
[0017]
The entire immersion nozzle exchanging device 1 is attached to a base plate 8 integrated with a tundish iron skin 2b with four fixing bolts 14. The frame 9 of the immersion nozzle changing device 1 is a metal member having a generally square shape in plan as a whole, an opening for attaching the upper nozzle 4 at a substantially central portion thereof, a hook 9c for attaching a cylinder 18 at one end, An entry side lower rail 10a for guiding the immersion nozzle 6 in the horizontal direction is provided substantially on the extension line of the hook 9c.
[0018]
Next, the surface pressure load device will be described. The surface pressure load device is provided on the side surface of the frame 9. That is, a spring receiver 15 is provided on the side surface of the frame 9, and a coil spring 17 is incorporated in the spring receiver 15. As shown in FIG. 3, a stud 12 for attaching the movable rail 10 c is attached to the frame 9 across the opening for attaching the upper nozzle 4.
[0019]
The movable rail 10c is swingably supported by a spherical seat 13 assembled to the stud 12, and a coil spring 17 is attached to the outer end portion, whereby the inner end portion supporting the refractory plate 5 and the immersion nozzle 6 is the upper portion. It pushes up toward the nozzle 4. The refractory plate 5 has a predetermined opening 5 c for controlling the flow rate therein and is supported by the upper guide rail 11, the movable rail 10 c and the immersion nozzle 6 . Then, it is fed and driven from right to left in FIG. 1 by a metal fitting 19 attached to the tip of the rod 18b of the cylinder 18.
[0020]
The upper nozzle 4 is a refractory nozzle fixed by being sandwiched between the base plate 8 and the frame 9 of the immersion nozzle exchanging device 1, and the lower surface has a horizontal flat surface.
[0021]
The cylinder 18 has a trunnion 18d having a shape in which the tip end of the rectangular flange portion 18c on the rod side is cut into a square shape, and is positioned by fitting the trunnion 18d into a square groove 9d provided in the hook 9c of the frame 9. When lifted upward, the tundish can be removed from the gap between the iron skin 2b and the upper end of the hook 9c.
[0022]
The lower guide rail 10 referred to in the claims is constituted by the lower entrance rail 10a, the lower exit rail 10b, and the movable rail 10c. The upper surfaces of the entry-side lower rail 10a and the exit-side lower rail 10b are slightly lower than the upper surface of the movable rail 10c when the immersion nozzle 6 is set, for example, by 1 to 2 mm, thereby dimensional tolerance of the refractory plate 5 and the immersion nozzle 6 Even if there is, there is a consideration so as not to hit the corners of the upper nozzle 4 and the refractory plate 5. The movable rail 10c is moved to the entrance side so that the immersion nozzle 6 is surely transferred from the entry side lower rail 10a and the upper corner of the preceding side of the immersion nozzle 6 is reliably guided to the lower part of the refractory plate 5. A large slope 10d is formed.
[0023]
The lower guide rail 10 b of the upper guide rail 11 and the lower guide rail 10 temporarily holds the fireproof plate 5 and the immersion nozzle 6 pushed out by the cylinder 18 and prevents them from falling into the mold 23.
[0024]
Next, the assembling operation of the apparatus of the above embodiment and the immersion nozzle replacement apparatus 1 during operation will be described. In FIG. 1, the upper nozzle 4 is set in a frame 9, and a mortar 3b is attached to the upper nozzle 4 and fixed to the bottom of the refractory brick 3a via the frame 9. In mounting the refractory plate 5 and the immersion nozzle 6 on the immersion nozzle exchanging device 1, the refractory plate 5 and the immersion nozzle 6 are first inserted into the upper guide rail 11 and the lower guide rail 10 with the cylinder 18 removed. The square trunnion 18d of the cylinder 18 is mounted on the lower rail 10a so as to drop into the square groove 9d of the hook 9c. At this time, since the trunnion 18d of the cylinder 18 has a rectangular shape, the trunnion 18d does not tilt or fall even though its center of gravity is overhanging.
[0025]
Next, the stroke end of the cylinder 18 is determined so that the positions of the refractory plate 5 and the immersion nozzle 6 are accurately determined, and the frame 9, the cylinder 18, the push fitting 19, the stopper holes 9a and 9b, the upper stopper 20a, and the lower stopper 20b. Therefore, when pressure oil is sent from a hydraulic source (not shown) to the head side of 18, the cylinder rod 18 b protrudes to the left side of FIGS. 1 and 2, and is pushed by the metal fitting 19 at the tip, The refractory plate 5 and the immersion nozzle 6 move directly below the upper nozzle 4.
[0026]
Thereafter, the tundish 2a is preheated, and after the preheating is finished, the upper stopper 20a inserted in the stopper hole 9a is removed, the blank plate 7 is set in the cylinder 18 instead of the refractory plate 5, and the refractory brick 3a The filling is completed by filling the inside. In this case, since the immersion nozzle 6 is not replaced, the lower stopper 20b inserted in the stopper hole 9b is not removed.
[0027]
For casting, the tundish 2a is guided onto the mold 23, the molten steel is poured into the tundish 2a, and then the blank plate 7 is pushed out by the refractory plate 5 so that the molten steel has an upper nozzle opening 4c and a refractory plate opening 5c. Then, the immersion nozzle opening 6c is flowed down to start casting.
[0028]
If the upper stopper 20a and the lower stopper 20b inserted in the stopper holes 9a and 9b are removed from the state of FIG. 1 and the rod 18b of the cylinder 18 is pushed out, the refractory plate 5 is placed immediately below the upper nozzle 4 and the immersion nozzle 6 Moves directly under the refractory plate 5 and the refractories after use are pushed out and moved onto the upper guide rail 11 and the lower exit rail 10b to be replaced with new refractories.
[0029]
When only the flow rate control is performed , the nozzle diameter is different from the preceding refractory plate 5 currently in use with the lower stopper 20b inserted in the stopper hole 9b and the cylinder 18 removed in order not to move the immersion nozzle 6. If the subsequent refractory plate 5 is put on the upper guide rail 11, the cylinder 18 is attached, and the rod 18b of the cylinder 18 is pushed out, the exchange is completed.
[0030]
Here, instead of the refractory plate 5, a blank plate 7 (refractory plate without holes) is formed, and casting is stopped.
[0031]
When only the immersion nozzle 6 is to be replaced, the upper stopper 20a is inserted into the stopper hole 9a so as not to move the refractory plate 5, and the cylinder 18 is removed and the following is different from the preceding immersion nozzle 6a currently in use. When the immersion nozzle 6b is put on the lower rail 10a on the entry side of the lower guide rail 10 , the cylinder 18 is attached, and the rod 18b of the cylinder 18 is pushed out, the exchange is completed.
[0032]
During normal casting, the upper stopper 20a inserted in the stopper hole 9a is removed in order to cope with an instantaneous emergency stop, the blank plate 7 is placed on the upper guide rail 11, and the cylinder 18 is also refractory plate 5 Set it so that it can be replaced. In this case, the lower stopper 20b is always inserted into the stopper hole 9b so that the immersion nozzle 6 does not move.
The upper stopper 20a can be inserted into the stopper hole 9a, and can be changed between a set state and a removed state, and the lower stopper 20b is inserted into the stopper hole 9b, and the set state can be removed. It is possible to change to a state where only one of the upper stopper 20a and the lower stopper 20b is inserted and set, and a state where both are removed.
[0033]
During this replacement operation, the movable rail 10c can be swung up and down and left and right even if there is a slight error in the assembly height dimensions of the two sets of refractories that follow each other, and the refractory plate 5 and the immersion nozzle 6 are Close contact with the upper nozzle 4 and the refractory plate 5. The extruded refractory plate 5 and the immersion nozzle 6 are carried out of the system from the exit side lower rail 10b by a squeezing metal fitting.
[0034]
Here, when the refractory assembly pair of the refractory plate 5 is passed under the upper nozzle 4 in a progressive manner, if the upper surface of the refractory plate 5 is completely in close contact with the upper nozzle 4, Even in the filled tundish 2a, the molten steel flow is moved from the preceding refractory (refractory plate 5) to the subsequent refractory (refractory plate 5) while being completely cut off. According to this exchange device, the refractory plates 5 and 5 can be used repeatedly many times until the life of the plates.
[0035]
As described above, according to the present embodiment, replacement of the immersion nozzle can be performed by one-touch operation by cylinder operation during casting, and the casting operation can be continuously performed until the full life of the refractory lining the tundish. The unit price is reduced. Since the refractory plate can be replaced at the start of preheating or during casting, the nozzle diameter can be freely selected and changed, and the slab size can be changed flexibly and the casting speed can be changed. Moreover, the casting stop at the time of emergency etc. can be performed safely and reliably, and an extremely economical immersion nozzle replacement device can be obtained. Since the removal and attachment of the immersion nozzle can be performed quickly and easily, there are many effects such as flexibility in changing the casting conditions. In addition, both the equipment cost and the refractory cost are significantly lower than those of so-called slide gates that have been used conventionally.
[0036]
【The invention's effect】
According to the first aspect of the invention, extruded refractory prior to use with refractory plate in use (5) in the upper guide rail (11) the plate (5) in sheet cylinder (18), replacement even during casting and forward can, it is possible to push the immersion nozzle (6) before use and the immersion nozzle in use under the guide rail (10) (6) in Shi cylinder (18), is also exchanged pouring in and forward. Moreover, if the upper stopper (20a) and the lower stopper (20b) are removed, the refractory plate (5) and the immersion nozzle (6) can be replaced, and the upper stopper (20a) is inserted and the lower stopper (20b) is attached . If it is removed, the immersion nozzle can be replaced. If the upper stopper (20a) is removed and the lower stopper (20b) is inserted, the refractory plate (5) can be replaced.
According to the second invention, by disengaging fitting trunnion of shea cylinder (18) to (18 d) to the hooks (9c) of the frame (9) can be freely removable for sheet cylinder (18).
According to the third invention, the movable rail of the lower guide rail (10) (10c), since the inner end have put the immersion nozzle by a coil spring (17) (6) is pushed up, the immersion nozzle (6 ) Adheres to the refractory plate (5) .
According to the fourth invention, the refractory plate (5) and the immersion nozzle (6) can be exchanged by removing the upper stopper (20a) and the lower stopper (20b) .
According to the fifth invention, if the upper stopper (20a) is removed, only the refractory plate (5) can be replaced.
According to the sixth invention, if the lower stopper (20b) is removed, only the immersion nozzle (6) can be replaced.
[Brief description of the drawings]
FIG. 1 is a side cross-sectional view of a tundish immersion nozzle exchange device for a continuous casting machine according to an embodiment of the present invention.
FIG. 2 is a bottom view of the immersion nozzle exchanging device as seen from the direction of arrow A in FIG.
3 is a cross-sectional view taken along the line CC of FIG.
4 is a view taken in the direction of arrows BB in FIG. 1;
FIG. 5 is a schematic view for explaining a casting operation in a continuous casting machine using a refractory nozzle.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Immersion nozzle exchange device 4 Upper nozzle 5 Refractory plate 6 Immersion nozzle 7 Blank plate 8 Base plate 9 Frame 9c Hook 11 Upper guide rail
DESCRIPTION OF SYMBOLS 10 Lower guide rail 10a Entry side lower rail 10b Outlet side lower rail 10c Movable rail 12 Stud 13 Spherical seat 16 Hinge pin 17 Coil spring 18 Cylinder 19 Push metal 20a Upper stopper 20b Lower stopper

Claims (6)

A base plate (8) fixed to the bottom of the tundish;
A fire-resistant upper nozzle (4) fixed to the base plate (8) ;
A frame (9) provided on the lower surface of the base plate (8) by a hinge pin (16) so as to be swingable and openable;
A pair of upper guide rails (11) attached to the frame (9) , supporting the refractory plate (5) and guiding the charging operation;
A lower guide rail (10) attached to the lower surface of the frame (9) , supporting the immersion nozzle (6) and guiding the charging operation;
An opening through which the refractory plate (5) held on the entry side of the upper guide rail (11) and the immersion nozzle (6) held on the entry side of the lower guide rail (10) communicate with the opening of the tundish position until, also a sheet Linda (18) to be pushed out until the completion of the exchange position of the previous,
The upper guide rail (11) has a length that allows two refractory plates (5) to be placed side by side and pushes out one refractory plate (5), and the lower guide rail (10) is immersed. Two nozzles (6) are placed side by side and have a length that allows one of the immersion nozzles (6) to be extruded.
An upper stopper (20a) for restraining the refractory plate (5) at the opening position so as not to move in the direction of the replacement position is provided so that it can be inserted and removed.
An immersion nozzle exchanging apparatus, wherein a lower stopper (20b) for restraining the immersion nozzle (6) in the opening position so as not to move in the direction of the exchange position is detachably provided . Before carboxymethyl Linda (18), has a trunnion (18d),
Wherein the frame (9) is pre-Symbol trunnion (18 d) a removably fitted disengaged immersion nozzle exchanging apparatus according to claim 1, wherein the forming a hook (9c). The lower guide rail (10) is replaced with an entry-side lower rail (10a) that supports the immersion nozzle (6) in the standby position, and a movable rail (10c) that supports the immersion nozzle (6) in the open position. The lower exit rail (10b) supporting the immersion nozzle (6) in position,
Said movable rail (10c), said frame (9) is supported swingably with attached spherical seat (13), the outer end coil spring (17) through between the frame (9) are instrumentation, immersion nozzle exchanging apparatus according to claim 1, wherein the inner end portion that is mounted to the immersion nozzle (6) is pushed up. Using the immersion nozzle exchanging device according to claim 1 , the upper stopper (20a) and the lower stopper (20b) are removed, and the refractory plate (5) and the immersion nozzle (6) are exchanged together. How to use the immersion nozzle changer. An immersion nozzle changing device according to claim 1 , wherein the upper stopper (20a) is removed and only the lower stopper (20b) is attached, and only the refractory plate (5) is changed. How to use. An immersion nozzle changing device according to claim 1 , wherein the lower stopper (20b) is removed and only the upper stopper (20a) is attached, and only the immersion nozzle (6) is changed. how to use.

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