JPH0511011Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a continuous casting machine, and is intended to be able to cast multiple types of slabs by sharing a dummy bar.

B. Summary of the idea When pulling out a dummy bar with different diameters between the tip and the main body, a sensor detects the passing of the dummy bar, and based on the detection signal of this sensor, the circumferential speed of the pinch roll and the pulling speed of the dummy bar are determined. A continuous casting machine that controls the speed of the pinch roll drive motor so that the

C. Prior Art FIG. 6 shows a generally used continuous casting machine. As shown in the figure, molten steel whose composition has been adjusted in a converter is transferred to a ladle 1. ladle 1
is carried onto the ladle turret 2 by a ladle crane (not shown). The ladle turret 2 rotates to set the ladle 1 containing molten steel at the casting position.

The molten steel in the ladle 1 is poured into the tundish 3 from the lower part of the ladle 1, and when the amount of molten steel in the tundish 3 exceeds a certain level, it is poured into the mold 4 from the sliding nozzle (not shown) of the tundish 3. Molten steel is injected into the Prior to the start of this casting, the dummy bar 5 is fed by the pinch rolls 6, and the tip of the dummy bar 5 is tightly fitted into the opening at the bottom of the mold 4, so that the bottom of the mold 4 is closed.
Note that the pinch roll 6 is driven and rotated by a motor.

The molten steel injected into the mold 4 loses heat through contact with the mold 4 and solidifies from the outer circumferential side.
Therefore, the pinch rolls 6 are gradually accelerated in accordance with this solidification speed, and the dummy bar 5 is pulled out in the unloading direction. Then, slabs formed by cooling and solidifying the molten steel are drawn by the dummy bar 5 and are continuously formed.

When the dummy bar 5 reaches the separation position A, the slab 7 and the dummy bar 5 are separated. The separated dummy bar 5 is wound up by a dummy bar winch 8 and stored on a dummy bar table 9. on the other hand,
The separated slab 7 is transferred to the table 1 after being pinch rolled.
0, it advances on the torch front table 11, is cut into a predetermined length by the torch cutter 12, and is carried out by the torch lower table 13 and the torch rear table 14.

The cross-sectional shape of the slab 7 is determined by the opening shape of the mold 4. That is, if the opening shape of the mold 4 is circular, the slab 7 will be a round piece, and if the opening shape is square, the slab 7 will be a square piece. Furthermore, since the dummy bar 5 has the function of blocking the bottom opening of the mold 4 to prevent molten metal from leaking out prior to the start of casting, the cross-sectional shape of at least the tip of the dummy bar 5 has the same shape as the opening shape of the mold 4. There is. After all, to cast a round material, the opening shape of the mold 4 and the cross-sectional shape of the tip of the dummy bar 5 must be circular, and to cast a square material, the opening shape of the mold 4 and the cross-sectional shape of the tip of the dummy bar 5 must be square. .

In order to produce a round material and a square material using the same continuous casting machine as described above, as shown in FIG. 7, the shape of the pinch roll 6 is made into a columnar shape with a semicircular depression in the center. When transporting a cylindrical dummy bar 5a as shown in FIG. 8 to produce a round material,
As shown in FIG. 7, the pinch rolls 6 transport the dummy bar 5a and the slab while pinching them on the small-diameter circumferential surface of the central recess. In addition, when transporting a prismatic dummy bar 5b as shown in FIG. 9 to produce a square material, the pinch rolls 6 are used to transport the dummy bar 5b and slab with the large-diameter peripheral surfaces on both sides, as shown in FIG. Hold and transport.

D Problems to be solved by the invention By the way, when using the same continuous casting machine to produce slabs with different cross-sectional shapes, such as round and square pieces, it is necessary to prepare dummy bars with a circular cross-section and dummy bars with a square cross-section. I have to keep it. However, when a plurality of long dummy bars are installed in this way, there is a problem that the equipment structure becomes large.

Therefore, it is possible to replace only the tip of the dummy bar to match the mold opening shape and share the main body, but this is difficult to realize because the contact diameter of the pinch rolls during the process of pulling out the dummy bar is different. There was a problem.

SUMMARY OF THE INVENTION In view of the above-mentioned prior art, an object of the present invention is to provide a continuous casting machine that can cast both round and square materials without increasing the size of the equipment structure.

E. Means for Solving the Problems The configuration of the present invention that achieves the above object is as follows: The tip of the dummy bar is tightly fitted into the bottom opening of the mold into which molten steel is injected, and the dummy bar is biased toward the dummy bar. In the continuous casting machine, when the dummy bar is pulled downward by rotating a large number of pinch rolls that clamp the dummy bar, a slab formed by cooling and solidifying molten steel is drawn out following the dummy bar. The dummy bar is thin at the tip and thick at the remaining main body, and the cross-sectional shape is different between the tip and the main body. and a large-diameter circumferential surface with which the main body of the dummy bar comes into rolling contact, and furthermore, as the dummy bar is pulled out, the main body of the dummy bar is first clamped, and then the tip of the dummy bar and the slab are clamped. It corresponds one-to-one to the pinch rolls and is located upstream of each pinch roll with respect to the dummy bar pullout route,
It is equipped with a plurality of sensors that detect the passing of the tip of the dummy bar, and when each sensor detects the passing of the tip of the dummy bar, the pinch roll corresponding to the detected sensor detects the small diameter tip of the dummy bar after a predetermined time. Equipped with a controller that individually controls the speed of the motor that rotationally drives the pinch rolls so that the circumferential speed of the small diameter circumferential surface of the pinch roll is the same as the pulling speed of the dummy bar when pinching at the small diameter circumferential surface. It is characterized by

F. Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 shows an embodiment of the invention. As shown in the figure, the tip 22a of the dummy bar 22 is tightly fitted into the mold 20 having a circular bottom opening. In this way, the dummy bar 22
Molten steel 24 is injected from above into the mold 20 whose lower part is closed until it reaches a certain level. The injected molten steel 24 is deprived of heat by the mold 20 and solidifies from the outer peripheral side to become a slab 26.

The dummy bar 22 has pinch rolls 28a, 28
It is held by a large number of pinch rolls such as b, 28c, and 28d. In addition, each pinch roll 28a, 28b,
28c and 28d are DC motors 30a and 28d, respectively.
They are individually driven and rotated by 30b, 30c, and 30d.

As shown in FIG. 2, the dummy bar 22 of this embodiment has a tip 22a that is thin and cylindrical.
The remaining main body portion 22b is thick and has a prismatic shape.
In addition, the pinch rolls 28 (28a, 28
(representatively indicated by 28) has a small diameter (D ₁ ) at the center and a large diameter (D ₂ ) at both sides, as shown in FIGS. 3 and 4. The pinch rolls 28 are biased toward the dummy bar 22 and clamp the dummy bar 22. Therefore, the tip 22
a enters the small diameter peripheral surface of the central part of the pinch roll 28 and is held therein, and the main body part 22b is held by the pinch roll 28.
It is held between the large-diameter peripheral surfaces of both side parts of 8.

Also, along the pulling path of the dummy bar 22, a sensor 32a is provided on the upstream side of the pinch roll 28b.
However, there is a sensor 32b on the upstream side of the pinch roll 28c.
However, there is a sensor 32c on the upstream side of the pinch roll 28d.
are provided for each. Each sensor 32a, 3
2b and 32c output a detection signal when the tip of the dummy bar 22 passes, and this detection signal is sent to the controller 34.
is input. This controller 34 controls the DC motor 30
The field currents of a, 30b, 30c, and 30d are controlled to control the speed of the motor.

Next, the operation of this embodiment will be explained. The DC motors 30a, 30b, 30c, and 30d are operated so as to pull out the dummy bar 22 in the direction of arrow B in accordance with the solidification speed of the molten steel 24 solidifying into the slab 26.
Pinch rolls 28a, 28b, 28c, 2
Rotate 8d.

Immediately after starting to pull out, the tip 2 of the dummy bar 22
2a is in rolling contact with the small diameter circumferential surface of the center portion of the pinch roll 28a, and the main body portion 22b is in contact with the small diameter circumferential surface of the pinch roll 28a, and the main body portion 22b is connected to the pinch roll 28b, 2
It rolls into contact with the large-diameter peripheral surface portions of both side portions of 8c and 28d. At this time, the dummy bar 22 and the pinch roll 28
In order to prevent excessive frictional force or slip from occurring between the small-diameter circumferential surface of a and between the dummy bar 22 and the large-diameter circumferential surfaces of the pinch rolls 28b, 28c, and 28d,
In other words, the pulling speed of the dummy bar 22, the peripheral speed of the small diameter peripheral surface of the pinch roll 28a, and the pinch roll 28
The number of rotations of the pinch roll 28a is set higher than the number of rotations of the pinch rolls 28b, 28c, and 28d so that the circumferential speeds of the large diameter circumferential surfaces of the rollers b, 28c, and 28d are equal. Specifically, the controller 34 changes the field current of the DC motor 30a to the DC motors 30b,
The field current should be made weaker than the field currents of 30c and 30d.

As the drawing progresses and the tip 22a of the dummy bar 22 passes the installation position of the sensor 32a, the sensor 32
A detection signal is sent to the controller 34 from a. After a predetermined period of time from this point, the pinch roll 28b will pinch the tip 22a of the dummy bar 22 with its small diameter circumferential surface. Therefore, the controller 34 weakens the field current of the DC motor 30b and increases the rotation speed of the pinch roll 28b so that the peripheral speed of the small diameter peripheral surface of the pinch roll 28b becomes equal to the pulling speed of the dummy bar 22 after the predetermined time. let Therefore, when the tip 22a of the dummy bar 22 is pinched by the small diameter circumferential surface of the pinch roll 28b after a predetermined time,
Excessive frictional force or slip will not occur between the small-diameter circumferential surface of the pinch roll 28b and the tip portion 22b. Note that if the field of the DC motor 30b is weakened, the torque will be reduced, but this is advantageous in terms of control characteristics. This is because when the position where the pinch roll 28b contacts the dummy bar 22 changes from the large-diameter circumferential surface to the small-diameter circumferential surface, the required torque (=contact pressure x diameter of roll contact portion) also becomes smaller.

Furthermore, the drawing progresses and the tip 2 of the dummy bar 22
When the sensor 2a passes the installation position of the sensor 32b, a detection signal is sent from the sensor 32b to the controller 34.
After a predetermined time from this point, the pinch roll 28
c is the small diameter circumferential surface of the tip 22 of the dummy bar 22.
It will hold a. Therefore, the controller 34
In the same manner as described above, the field current of the DC motor 30c is weakened and the rotation speed of the pinch roll 28c is increased. Therefore, after a predetermined time, the pinch roll 2
The tip 22a of the dummy bar 22 on the small diameter circumferential surface of 8c
When the pinch roll 28c is pinched, no excessive frictional force or slip occurs between the small diameter circumferential surface of the pinch roll 28c and the tip 22b.

In addition, the tip 2 of the dummy bar 22 is detected by the sensor 32c.
When the passage of 2a is detected, as described above,
The controller 34 weakens the field current of the DC motor 30d. In this way, excessive frictional force or slip does not occur between the small-diameter circumferential surface of the pinch roll 28d and the tip portion 22b. Thereafter, similar control is performed one after another.

Note that in order to detect the passage of the tip 22a of the dummy bar 22, the boundary between the main body 22b and the tip 22a may be detected, or the tip of the tip 22a (the boundary with the slab) may be detected. It is also possible to do this.

Furthermore, the tip of the dummy bar may have the same cross-sectional shape as the opening in the bottom of the mold, and the portion inserted into the opening may be only the leading portion of the tip of the dummy bar.

It should be noted here that if excessive frictional force or slip occurs between the pinch roll and the tip of the dummy bar without the above-mentioned control, the dummy bar or pinch roll will be damaged and the casting machine will not function properly. Functionality will no longer be fully demonstrated.

In the example shown in FIG. 1, a round material is formed, but in order to form a square material, as shown in FIG. A mold 20' having a rectangular bottom opening is replaced with the tip part 22a'.
The prismatic tip 22a' of the dummy bar 22 may be inserted into the dummy bar 22 and pulled out. In other words, by simply replacing the mold and the tip of the dummy bar, both round and square materials can be cast using the same dummy bar main body 22b.

In the case of FIG. 5, the main body 22b, the tip 22a', and the slab 26 of the dummy bar 22 are all held by the large-diameter circumferential surfaces of the pinch rolls 28a to 28d, so that the pulling operation of the dummy bar 22 is difficult. Accordingly, there is no need to change the rotational speed of the pinch rolls as in the embodiment shown in FIG. 1 described above.

G. Effects of the Invention According to the present invention, as specifically explained in conjunction with the embodiments above, slabs of different shapes can be cast using a single dummy bar. Therefore, it is possible to prevent the equipment structure from increasing in size.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of the present invention, Fig. 2 is a perspective view showing the dummy bar, Fig. 3 is an explanatory drawing showing the state in which the cylindrical tip of the dummy bar is held between pinch rolls, and Fig. 4 The figure is an explanatory diagram showing the state in which the main body of the dummy bar is held between pinch rolls, Fig. 5 is an explanatory diagram showing the fitted state of the dummy bar and the mold when casting a square material, and Fig. 6 is an explanatory diagram showing the configuration of the prior art. 7 is an explanatory view showing a state in which a cylindrical dummy bar is held between pinch rolls, FIG. 8 is a perspective view showing a conventional cylindrical dummy bar, FIG. 9 is a perspective view showing a conventional prismatic dummy bar, and FIG. FIG. 10 is an explanatory diagram showing a state in which a prismatic dummy bar is held between pinch rolls. In the drawing, 20 is a mold, 22 is a dummy bar,
22a is a tip, 22b is a main body, 24 is molten steel,
26 is a slab, 28a, 28b, 28c, 28d are pinch rolls, 30a, 30b, 30c, 30d
is a DC motor, 32a, 32b, 32c are sensors, and 34 is a controller.

Claims (1)

[Claim for Utility Model Registration] The tip of a dummy bar is tightly fitted into the bottom opening of a mold into which molten steel is injected, and a number of pinch rolls each pinch the dummy bar by being biased toward the dummy bar. In a continuous casting machine, when a dummy bar is rotated by a motor and pulled out downward, a slab formed by cooling and solidifying molten steel is pulled out following the dummy bar. The pinch roll is thick and has a different cross-sectional shape between the tip and the main body. and, further, one-on-one correspondence with the pinch rolls that initially clamp the main body of the dummy bar and then clamp the tip end of the dummy bar and the cast slab as the dummy bar is pulled out; Located upstream of each pinch roll with respect to the route,
It is equipped with a plurality of sensors that detect the passing of the tip of the dummy bar, and when each sensor detects the passing of the tip of the dummy bar, the pinch roll corresponding to the detected sensor detects the small diameter tip of the dummy bar after a predetermined time. Equipped with a controller that individually controls the speed of the motor that rotationally drives the pinch rolls so that the circumferential speed of the small diameter circumferential surface of the pinch roll is the same as the pulling speed of the dummy bar when pinching at the small diameter circumferential surface. A continuous casting machine characterized by: