JPH1110293A - Operation of tundish nozzle in continuous caster and tundish nozzle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate the treatment of a tundish nozzle, to prevent the complication of a work, to simply execute safety countermeasure preparing work in short time and to further improve the safety of the operation in a continuous caster using a tundish changing device. SOLUTION: This tundish nozzle is constituted of an upper nozzle 6 arranged at the lower part of the tundish, a lower nozzle 8 slidably in the side direction while contacting with the lower surface of this upper nozzle 6 and arranged so as to be possible to be taken out to the front part in the sliding direction from the lower part of the tundish and a lower nozzle pushing means 7 arranged at the lower part position of the tundish at the rear part in the sliding direction of this lower nozzle 8 and pushing the lower nozzle 8 to the front part in the sliding direction. The length in the sliding direction from the nozzle center on the upper surface of the lower nozzle 8 to the front edge and the rear edge is made to be >= about 1.8 times of the inner diameter of the upper nozzle 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for operating a tundish nozzle and a tundish nozzle device in a continuous casting machine, and more particularly to a tundish nozzle that can be easily handled at the start and stop of casting. The present invention relates to a tundish nozzle operating method and a tundish nozzle device that can be easily replaced and safety measures can be easily and quickly performed.

[0002]

2. Description of the Related Art Various methods have been proposed for controlling the flow rate of molten steel from a tundish to a mold in a continuous steel casting machine. Among them, the simplest method is an open nozzle provided at the bottom of a tundish. There is an open nozzle system for obtaining a constant flow rate with the opening area A and the molten steel depth H in the tundish. The flow control tundish nozzle used in this open nozzle casting method uses a high-strength refractory such as zirconia to extend its life, but it cannot be said to be sufficient compared to the tundish lining refractory, This is an obstacle to long-term continuous casting machine operation. For this reason, for example, using a device shown in Japanese Patent Application Laid-Open No. Hei 8-224645 or Japanese Patent Application No. Hei 9-111950 and drawings, the flow control tundish nozzle is replaced to perform continuous casting for a long time. .

[0003] The casting situation of a continuous casting machine using a tundish nozzle exchanging apparatus will be described with reference to FIG. One or a plurality of upper nozzles 6 are provided in the bottom refractory 2b of the tundish 2 in accordance with casting conditions, and a lower nozzle 8 having a predetermined opening area A is supported on the lower surface of the upper nozzle 6 by pressure bonding. The next replacement nozzle (the position of a blind nozzle 21 described later) and a linear drive device such as a hydraulic cylinder 7 are disposed on the side of the lower nozzle during casting, and the next nozzle is pushed out by the hydraulic cylinder 7. During the casting, the lower nozzle 8 is pushed out of the casting position and is replaced with a new nozzle. As described above, the tundish nozzle includes the upper nozzle 6 and the lower nozzle 8 at the bottom of the tundish. In the flow control method with a constant opening area, if the opening area of the lower nozzle 8 is A and the steel bath depth of the tundish 2 is H, the amount of molten steel Q per unit time flowing from the tundish 2 to the mold 22 is: Q = kA√H (where k is a constant)
By opening and closing the slide gate 24 at the molten steel outlet of the ladle 23 upstream of the tundish 2 to control the flow rate within a certain range (for example, ± 10%), practically sufficient constant speed flow rate control can be obtained. It is widely used in casting machines and beam blank continuous casting machines.

[0004] Incidentally, the opening area A of the lower nozzle is eroded and expanded with the lapse of time of the continuous casting, and deposits are formed and clogging occurs. Is replaced with a new one as appropriate, but in a normal casting state, a blind nozzle 21 is provided at the next nozzle position so that casting can be stopped immediately in an emergency such as a breakout.

[0005] As a method of starting casting in a continuous casting machine using a tundish nozzle exchanging apparatus, usually, a method shown in FIG.
Or the method shown in FIG. 9 to 14
In order to facilitate understanding, the mechanical part of the tundish nozzle replacement device is omitted, and only the main refractory, the hydraulic cylinder 7 as a nozzle replacement drive device, and the metal fitting 14 are illustrated.
First, FIGS. 9 and 10 show a typical casting start method. When preheating of the tundish is completed,
A rope 20 made of a heat-resistant material such as glass wool is packed into a lower nozzle opening 8a from a lower portion of an open casting nozzle (hereinafter, referred to as a lower nozzle) 8 placed directly below the upper nozzle 6, and one end thereof is dropped downward. Keep it.

Next, a granular refractory filling 19 such as silica sand is filled into the upper nozzle opening 6a from the inside of the tundish.
In the casting, the molten steel is caused to flow down from the ladle 23 to the tundish 2, and when a certain amount of the molten steel has accumulated in the tundish 2, the heat-resistant rope 20 is pulled out by hand as shown by an arrow in FIG. 19 flows down, then the molten steel 25 flows out, and the casting starts. At this time, the blind nozzle 21 is placed at the next nozzle position to prepare for an emergency stop that is rarely needed immediately after the start of casting.

FIGS. 11 to 14 show a casting start method utilizing the function of the tundish nozzle changing device. First, when the preheating of the tundish 2 is completed, FIGS.
In place of the lower casting nozzle 8 at 0, the blind nozzle 21 is moved below the upper nozzle 6, and then the granular refractory filling 19 is filled into the upper nozzle opening 6a. An open nozzle (lower nozzle) 8 having 8a is set. At the start of casting, when the molten steel in the tundish reaches a predetermined amount, the next nozzle is pushed directly below the upper nozzle 6 by the hydraulic cylinder 7 and replaced with the blind nozzle 21. As a result, the granular filler 19 is removed from the opening 8 of the lower nozzle 8.
a, and the casting is started in the same manner as in the method using the heat-resistant rope 20. The blind nozzle 21 pushed out by the lower nozzle for casting is recovered, and the blind nozzle 21 is set again at the next nozzle position in preparation for an unexpected casting accident.

[0008]

By the way, in the method using the heat-resistant rope 20, since the rope filling operation is usually performed after or immediately before the end of the preheating of the tundish, the vicinity of the nozzle opening is heated to several hundred degrees Celsius. In addition to the risk of burns, it is necessary to carry out the casting in a short time until the start of casting, and the burden on the operator is large. Also, at the start of casting, as in the blind nozzle start method described below, it is possible to eliminate the trouble of collecting and resetting the blind nozzle, but it is necessary to extract the rope for each strand, and it is difficult to start casting by remote operation or automatic operation. is there.

On the other hand, in the blind nozzle start method using the blind nozzle 21 shown in FIGS.
The work of reducing the number of zeros is unnecessary, and if the hydraulic cylinder 7 is driven using a push button or an automatically operated hydraulic unit,
It is possible to start casting by remote operation or automatic operation, but in consideration of an unexpected accident immediately after the start, it is necessary to collect the blind nozzle 21 as soon as possible and set it to the next nozzle position. Although the labor of the person can be greatly reduced, the congestion of the work immediately after the start of the pouring cannot be sufficiently solved.

The present invention has been made in view of the above-mentioned problems of the conventional method, and when a continuous casting machine is operated using a tundish nozzle exchanging apparatus, handling of a tundish nozzle is facilitated and work congestion is prevented. A tundish nozzle operating method and a tundish nozzle device that further enhance the safety of the operation of a continuous casting machine using a tundish nozzle replacement device by enabling safety measure preparation work to be performed more easily and in a shorter time. Is to provide.

[0011]

According to the method of operating a tundish nozzle of a continuous casting machine according to the present invention, a lower nozzle is extruded laterally in contact with a lower surface of an upper nozzle of a lower portion of a tundish, and the lower nozzle is pushed before starting casting. Close the opening of the upper nozzle at the front upper surface in the extrusion direction ahead of the nozzle opening, hold the particulate refractory filler in the opening of the upper nozzle at the front upper surface, and then press the lower nozzle Is extruded to the center of the upper nozzle to discharge the filler through the opening of the lower nozzle, and to start casting.

Further, the method for operating a tundish nozzle of a continuous casting machine according to the present invention is characterized in that the lower nozzle is extruded laterally in contact with the lower surface of the upper nozzle of the lower part of the tundish, and when the casting is stopped, the lower nozzle is pushed backward from the opening of the lower nozzle. At the rear upper surface, the opening of the upper nozzle is closed to stop casting.

[0013] The tundish nozzle device of the continuous casting machine according to the present invention comprises an upper nozzle disposed at a lower portion of the tundish, and slidable in a lateral direction in contact with a lower surface of the upper nozzle. A lower nozzle provided so as to be able to be taken out in the front in the sliding direction, and a lower nozzle pushing means provided in the lower part of the tundish behind the lower nozzle in the sliding direction and for pushing the lower nozzle forward in the sliding direction. Wherein the length in the sliding direction from the center of the upper surface of the lower nozzle to the front edge and the rear edge is approximately 1.8 times or more the diameter of the upper nozzle.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, preferred embodiments of the present invention will be described with reference to the drawings. Referring to FIGS. 1 to 4, a tundish nozzle replacement device 1 includes a base plate 3 integrated with a bottom steel shell 2 a of a tundish 2.
The device 1 is attached with four bolts 4 via a frame 5 of the device 1. 2b is a bottom refractory of the tundish 2 to which the upper nozzle 6 is attached. The frame 5 of the tundish nozzle changing device 1 has a mounting opening 5a for the upper nozzle 6 at substantially the center, a hook 5b for mounting the hydraulic cylinder 7 at one end, and a hook 5b.
Side frame 5 for guiding the lower nozzle 8 in the horizontal direction on the extension of
c. Further, as shown in FIG. 4, a mounting stud 11 for the movable rail 10 is mounted on the frame 5 with the mounting opening 5a interposed therebetween.

The movable rail 10 has a spherical concave portion 10a, is swingably supported by a spherical seat 12 attached to a stud 11, and connects the lower nozzle 8 to the upper nozzle 6 by a compression coil spring 13 provided at one end. Pushing up. The lower nozzle 8 is made of a refractory having a rectangular flange-like upper part and a cylindrical lower part, and has a flow control opening 8a in the center part. The outer periphery is not shown so as to withstand continuous use for a long time. The upper rectangular flange portion 8b is provided with a reinforcing steel skin and the movable rail 10 and the guide rails 9, 9
1 and is driven from right to left in FIG. 1 by a press fitting 14 attached to the tip of the rod 7a of the hydraulic cylinder 7.

A circular hole 5d is formed in the side frame 5c toward the front of the lower nozzle 8 in the traveling direction, so that the stopper 16 can be positioned by the pin 15.
A spacer 17 is mounted on the hook 5b. The mounting position of the hydraulic cylinder 7 can be changed depending on whether the mounting position of the spacer 17 is closer to the center of the nozzle or opposite to the flange 7b of the hydraulic cylinder 7. I have. The hydraulic cylinder 7 has a trunnion 7c in which the tip of a rectangular flange 7b on the rod 7a side is cut into a square shape, and a square groove 5e provided in a hook 5b of the frame 5 and a square recess 18 formed by a spacer 17. If it is lifted upward, the tundish bottom iron shell 2c and hook 5b
It can be removed from the gap at the upper end of the.

When the lower nozzle 8 is set, the upper surface of the entrance-side guide rail 9 ′ is 2-3 m from the upper surface of the movable rail 10.
m, so that even if there is some manufacturing error in the thickness of the square flange portion 8b of the lower nozzle 8, care is taken not to hit the corner portion of the upper nozzle 6 and the movable rail 10
A large slope 10b is formed on the entry side of the lower nozzle 8 so that the lower nozzle 8 can be reliably transferred from the entry side guide rail 9 'and the upper end of the lower nozzle 8 can surely enter the lower portion of the upper nozzle 6. ing. The movable rail 10 also swings back and forth and left and right about the spherical seat 12 so that the upper nozzle 6
Even if there is a slight dimensional error of the lower nozzle 8, the lower nozzle 8 is in close contact with the lower surface of the upper nozzle. The exit side guide rail 9 is provided to temporarily hold the lower nozzle 8 pushed out by the hydraulic cylinder 7 and to prevent the lower nozzle 8 from dropping into the mold. It is easy to remove the lower nozzle 8 from this holding position. As described above, the upper surface is provided several mm lower than the upper surface of the movable rail 10.

Hydraulic cylinder 7, its cylinder rod 7a
The dimensional relationship between the metal fitting 14, the hook 5b of the frame 5, and the upper rectangular flange 8b of the lower nozzle 8 is such that the metal fitting 14 moves the lower nozzle 8 to the center of the lower nozzle opening 8a at the end of the extrusion stroke of the cylinder rod 7a. It is pushed out until it coincides with the center of the upper nozzle opening 6a. The lower nozzle 8 used in the tundish nozzle changing device 1 has a dimension in the traveling direction when extruding and replacing the upper rectangular flange portion 8b from the center of the lower nozzle opening to the leading edge in the traveling direction and the trailing edge in the traveling direction. To 1.8 times or more the upper nozzle opening diameter, so that the filler or the molten steel can be stopped.

Next, the preparatory work for casting will be described. In FIG. 1, the upper nozzle 6 is fixed at a predetermined height to the bottom of the tundish 2 with a mortar 2c using a jig (not shown) or the like. Next, the stopper 16 is passed through the hole 5d of the side frame 5c near the exit guide rail 9 and attached as shown. In mounting the lower nozzle 8, the lower nozzle 8 is first mounted on the inlet side guide rail 9 'with the hydraulic cylinder 7 removed, and then the hydraulic cylinder 7 is connected to the square trunnion 7c by the square groove of the hook. 5
e and a spacer 17 so as to be dropped into a rectangular recess 18. At this time, the hydraulic cylinder 7 is
Since c is square, it does not tilt or drop regardless of its center of gravity.

Next, when pressure oil is sent from a hydraulic source (not shown) to the head side of the hydraulic cylinder 7, the cylinder rod 7 a protrudes to the left, and is pushed by the metal fitting 14 at the tip, so that the lower nozzle 8
Is pressed against the stopper 16. At this time, the dimensional relationship between the stopper 16 and the lower nozzle 8 is determined by the upper flange portion 8 of the lower nozzle 8.
The flat portion on the leading side of b (far side from the hydraulic cylinder 7) is determined so as to just close the opening 6a of the upper nozzle 6. Thereafter, the opening 6a of the upper nozzle 6 is filled with a granular refractory filling 19 such as silica sand.

The operation of starting casting in a continuous casting machine using the tundish nozzle exchanging apparatus 1 according to the above embodiment will be described. After the preparatory steps described above, first, the pin 15 is pulled out, the stopper 16 is removed, and then the tundish 2 is guided onto the mold 22 by using a transporting means such as a tundish car, and then the slide gate 24 is removed from the ladle 23. When the molten steel 25 is opened, the molten steel 25 is supplied into the tundish 2, and when a predetermined amount of molten steel is reached, the lower nozzle 8 is moved directly below the upper nozzle 6 by pushing out the hydraulic cylinder 7 to the rod stroke end. Casting is started when the granular filler 19 falls and then the molten steel flows out. At this time, the preheating of the tundish 2 is performed in the same manner as ordinary casting.

When the casting is started, a preparation is made so that the casting can be stopped immediately when an accident such as a breakout or an overflow occurs during the casting. That is, the cylinder rod 7a extruded at the start of casting is retracted, the hydraulic cylinder 7 is removed, the blind nozzle 21 is set on the entry-side guide rail 9 ', and the hydraulic cylinder 7 is attached again to enable an emergency stop. To

Alternatively, after the cylinder rod of the hydraulic cylinder 7 is retracted, as shown in FIG.
Of the hydraulic cylinder 7 with respect to the trunnion 7c so as to be on the opposite side to FIG. By this rearrangement, the mounting position of the hydraulic cylinder 7 moves toward the center of the frame 5, and when the cylinder rod 7a is pushed out to the stroke end, the flat portion on the rear side of the upper flange portion 8b of the lower nozzle 8 becomes the upper nozzle opening 6a. Is closed. In order to stop the casting at the rear side of the upper flange portion of the lower nozzle 8, a flat area on the rear side is required to be a predetermined amount or more. In connection with this, if the casting continues for a long time and the temperature of the molten steel flowing through the refractory and the opening rises, a large area is required.
The size of the upper flange 8b must be large, so it is not necessarily economical. However, in the rare case of an accident immediately after the start of casting, the refractory temperature is not high, so a large area is required. It is effective in this respect.

FIG. 6 shows another embodiment of the hook 5b of the frame 5 in which a groove 5g for receiving a square trunnion 7c of the hydraulic cylinder 7 is provided.
1 and 5 can be set by selecting the grooves 5g and 5h in which the hydraulic cylinder 7 is mounted. Alternatively, a third groove (not shown) is provided further outside (far from the center of the nozzle) of the two grooves 5g and 5h shown in FIG. 6, and the lower nozzle 8 is positioned using the stopper 16 described with reference to FIG. Instead, the position of the lower nozzle 8 before the start of casting can be set as the pushing end of the rod 7a of the hydraulic cylinder 7 by the position of the third groove. In addition, since the position of the lower nozzle 8 positioned by the stopper 16 in FIG. 1 before the start of casting only stops the fall of the granular refractory filling, the positional accuracy is not important, Even if the hydraulic cylinder 7 is slowly operated and positioned while checking the position where the filling is stopped by looking through the opening 8a, there is no problem.

FIG. 7 is a side view of a hydraulic cylinder according to another embodiment in which the pushing stroke end of the lower nozzle 8 is changed. Attachment 14a is attached to the tip of press fitting 14 by magnet 14b provided inside. As in the case where the dimension of the spacer 17 is selected to determine the stroke end of the hydraulic cylinder 7, the attachment 14a
If the length is appropriately selected, the position of the lower nozzle 8 or the blind nozzle 21 at the stroke end of the hydraulic cylinder 7 can be appropriately determined. Further, by using the attachment 14a of this embodiment and the spacer 17 together, or by using a plurality of hydraulic cylinder mounting grooves 5g and 5h, multi-stage positioning is possible. Also, since the attachment 14a is attached to the metal fitting 14 by the magnet 14b, no time is required for attachment and detachment. As means for attaching the attachment 14a,
There is no particular limitation on the magnet, as long as the thrust of the hydraulic cylinder 7 can be transmitted to the lower nozzle or the blind nozzle by a simple device such as dropping or insertion.

By shifting the mounting position of the hydraulic cylinder 7 or by attaching or detaching the attachment 14a to or from the metal fitting 14 at the tip of the rod of the hydraulic cylinder, the lower nozzle 8 for controlling the casting flow rate is adjusted. It can be moved to a fully open or fully closed position to perform pouring or pouring stop. Alternatively, the stopper 16
By setting the lower nozzle 8 to a position before the start of casting by another means, and then operating the cylinder 7 to the stroke end, casting can be started easily and quickly.

The hydraulic cylinder used in the present invention determines the position of the lower nozzle, which is the driven body, only at the rod pushing end, so that position detection and positioning in the middle of the stroke are not required, and the hydraulic device has a very simple hydraulic circuit. Can be configured.

During the normal casting operation, if the lower nozzle opening 8a is melted and enlarged, and the amount of molten steel passing per hour becomes too large or becomes too tight, the amount of molten steel passing becomes too small. In 3, a new lower nozzle is placed on the entrance guide rail 9 ′ instead of the blind nozzle 21, and the old lower nozzle that has failed in the hydraulic cylinder 7 is replaced by pushing it to the left with the new lower nozzle. When casting is continued for a long time and the temperature of the refractory rises, in order to stop casting reliably and safely, the blind nozzle 21 is pushed to the left by the hydraulic cylinder 7 from the state of FIG. Replace with nozzle.

The lower nozzle used in the present invention is more economical if the dimension from the center of the lower nozzle opening 8a to the front edge of the upper square flange is as small as possible. In theory, the opening 6a of the upper nozzle 6 is ideal. Assuming that the diameter of the upper nozzle is equal to the diameter of the opening 8a of the lower nozzle, the function can be achieved if it is approximately 1.5 times the diameter of the upper nozzle. It is desirable. Similarly, the dimension from the center of the opening 8a of the lower nozzle 8 to the rear edge is preferably as large as possible in consideration of the safe closing of the molten steel, but it is preferable to make it symmetrical with the front edge side.

[0030]

As described above, according to the present invention, there is no need to pack a rope-shaped filling material into a preheated tundish, so there is no danger of burns, the operation is easy, and automatic operation and remote operation are possible. Casting can be started and stopped by operation. The risk of dropping and damaging the blind nozzle during handling is small and economical. When the work immediately after the start of continuous casting is congested, the work of collecting the upper nozzle is not required. In addition, the filling can be held at the start of casting and the casting can be stopped by one lower nozzle. There are many effects such as being able to quickly position the position of the lower nozzle at the required position in stages using inexpensive devices and means.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view along a longitudinal direction showing a state before starting casting in a continuous casting machine employing a tundish nozzle replacement device according to an embodiment of the present invention.

FIG. 2 is a plan view as viewed from an arrow A in FIG.

FIG. 3 is a longitudinal sectional view showing a state during casting in the tundish nozzle replacement device of FIG. 1;

FIG. 4 is a cross-sectional view near the center of the nozzle in FIG. 3;

5 is a cross-sectional view showing a state at the time of completion of pouring by the tundish nozzle exchanging device of FIG. 1;

FIG. 6 is a side view showing another embodiment of the hydraulic cylinder mounting portion in FIG.

FIG. 7 is a side view of a hydraulic cylinder showing another embodiment of the present invention in a case where the pushing stroke end of the lower nozzle is changed.

FIG. 8 is a schematic side view of a general continuous casting facility in which casting is performed using a tundish nozzle replacement device.

FIG. 9 is a schematic view showing a state in which a granular filler is closed in a nozzle using a conventional heat-resistant rope as a stopper to prepare for the start of casting.

10 is a schematic view showing a state in which a heat-resistant rope is pulled out from the state of FIG. 9, a granular filling is removed, and casting is started.

FIG. 11 is a schematic view showing a state in which a granular filling is closed in a nozzle by a conventional blind nozzle to prepare for the start of casting.

FIG. 12 is a schematic view of a state in which a blind nozzle is pushed out from the state of FIG. 11 and replaced with a lower nozzle.

FIG. 13 is a schematic diagram of a state in which casting is started from the state of FIG.

FIG. 14 is a schematic view showing a state where a blind nozzle is sandwiched between a lower nozzle and a hydraulic cylinder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tundish nozzle replacement device 2 Tundish 3 Base plate 5 Nozzle replacement device frame 6 Upper nozzle 7 Hydraulic cylinder 8 Lower nozzle 10 Movable rail 14 Metal fitting 15 Pin 16 Stopper 17 Spacer 18 Square recess 19 Granular refractory filling 20 Heat resistant rope 21 Blind nozzle 22 Mold 23 Ladle 24 Slide gate 25 Molten steel

Claims (7)

[Claims] 1. A lower nozzle is extruded laterally in contact with a lower surface of an upper nozzle of a lower portion of a tundish, and before the start of casting, the upper nozzle is pushed forward from an opening of the lower nozzle by a front upper surface portion in the extrusion direction. The opening is closed to hold the particulate refractory filler in the opening of the upper nozzle at the front upper surface, and then the lower nozzle is extruded to the center of the upper nozzle to remove the filler to the opening of the lower nozzle. , And a casting operation is started in the continuous casting machine. 2. A lower nozzle is extruded laterally in contact with a lower surface of an upper nozzle of a lower portion of a tundish, and when casting is stopped, an opening of the upper nozzle is formed on a rear upper surface rearward in an extrusion direction from an opening of the lower nozzle. A method for operating a tundish nozzle in a continuous casting machine, characterized by closing and stopping casting. 3. An upper nozzle disposed at a lower part of the tundish, and a lower part provided so as to be slidable laterally in contact with a lower surface of the upper nozzle and to be able to be taken out from the lower part of the tundish in a sliding direction. A nozzle provided at a lower position of the tundish behind the lower nozzle in the sliding direction and a lower nozzle pushing means for pushing the lower nozzle forward in the sliding direction, the nozzle on the upper surface of the lower nozzle A tundish nozzle device for a continuous casting machine, wherein a length in a sliding direction from a center to a leading edge and a trailing edge is approximately 1.8 times or more the diameter of the upper nozzle. 4. The continuous casting machine according to claim 3, wherein said lower nozzle pushing means has a structure in which a mounting position is stepwise variable with respect to a lower portion of said tundish. Dish nozzle device. 5. A tundish for a continuous casting machine according to claim 4, wherein said stepwise variable structure of the mounting position of said lower nozzle pushing means is a structure for changing a mounting position of a spacer. Nozzle device. 6. A stepwise variable structure of a mounting position of said lower nozzle pushing means is a mounting groove provided in an apparatus frame by arranging a plurality of said nozzles in a sliding direction of said lower nozzle. Item 5. A tundish nozzle device for a continuous casting machine according to item 4. 7. The continuity according to claim 4, wherein said stepwise variable structure of the mounting position of said lower nozzle pushing means is an attachment which is exchangeably provided at a tip of a pushing rod. Tundish nozzle device of casting machine.