JPH0615414A - Twin roll continuous casting method and apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The present invention relates to improvement of the side dam action position control in twin roll continuous casting, and the side dam action position (height) is adjusted according to the variation of the protrusion start position (height) during casting. The continuous twin-roll casting method that ensures the sealing effect of the side dams, prevents the occurrence of peeling and burrs, and enables stable production of good plate-shaped slabs. And to provide a device. [Configuration] At least one of the shape and size of the part where the side edge of the slab protrudes outward from the end surface of the cooling roll below the side dam is continuously detected during casting, and the detection data obtained Based on the above, the height of the lower end of the side dam is adjusted according to the start position of the protrusion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a twin roll continuous casting method and apparatus, and more particularly, to improvement of side dam working position control. Twin roll continuous casting method, in the continuous casting mold composed of a pair of cooling rolls arranged at a predetermined interval with the rotation axis horizontal and parallel to each other, and a pair of side dams pressed against both end faces of these cooling rolls, metal, While continuously pouring the molten metal to form a pool, a pair of solidified shells grow on the surfaces of the rotating chill rolls, and the solidified shells are united at the positions closest to both chill rolls to form a strip casting. This is a continuous casting method in which a slab is cut into pieces and sent downward from the closest position by rotation of a cooling roll.

[0002]

2. Description of the Related Art In a twin roll continuous casting method, a side dam is brought into close contact with an end surface of a cooling roll to prevent molten metal from leaking from a pool and at the same time, to secure a sealing effect by a side dam so that a side edge of a slab has a desired shape. is necessary. The solidified shells are carried by the rotation of the cooling rolls while growing on the surfaces of both cooling rolls, and the two solidified shells are united at a position closest to the cooling rolls to form one strip-shaped slab.
In order to completely generate a slab by coalescing, when the solidified shells are united, a reduction is applied by both cooling rolls to press the solidified shells together.

The pressing of the chill roll causes the material to ooze out from both side edges of the slab. At that time, it is important to freely generate the protrusion without restraint. In other words, when the side dam restrains the leakage from the crimping portion, the generated leakage pressure pushes the side dam to the outside, and the adhesive force between the side dam / cooling roll end face is reduced by that amount, which is sufficient. The sealing effect cannot be obtained, and a relatively small amount of molten metal leaks from the side surface of the side dam / cooling roll, which is cooled by the outside air and solidifies, causing peeling and burrs, which causes defective plate shape of the slab.

Therefore, at the position where the side dam acts on the end surface of the cooling roll, the lower end of the side dam needs to be above the position where the protrusion occurs so that the protrusion is not restricted. However, on the other hand, if the lower end of the side dam is excessively higher than the position where the squeeze out occurs, the sealing effect of the side dam will not work against the unsolidified molten metal immediately above the position where the spill out occurs, and the molten metal will leak out. .

Thus, by setting the working position of the side dam, particularly the lower end position (height) of the side dam, in accordance with the protruding position (height), a good plate-shaped slab can be stably obtained. It becomes very important in manufacturing. Conventionally, as a method of preventing a seal failure due to leaching, in JP-A-61-144,245, a side dam is divided into a side dam for a molten metal pool portion (hot water pool) and a side dam for a solidified shell crimping portion, the latter. It has been proposed that the can be retracted to the outside. Even if the side dam of the solidified shell crimping portion is pushed out by the pressure of leaching, the side dam of the molten metal pool portion is not affected by this and always ensures the sealing action.

In this structure, the side pool dam for the molten metal pool is fixed to the stand frame via the bracket, and the cooling roll is also fixed to the same stand frame via the bearing. Therefore, the lower end position of the molten pool pool side dam is fixed to the closest position of the cooling roll. However, in actual casting, the starting position of leaching with respect to the position closest to the cooling roll differs depending on the temperature and solidification characteristics of the molten metal and the cooling roll rolling force, and strictly speaking, it always fluctuates during casting. It is something to think about.

In the above-mentioned conventional method, the side dam is moved up and down 2
Despite the need for a complicated structure divided into parts, the lower end position of the side pool dam for the molten metal pool is fixed with respect to the position closest to the cooling roll, and it constantly fluctuates during casting. There is a drawback that the sealing effect corresponding to the starting position cannot be obtained, and the occurrence of peeling and burrs cannot be sufficiently prevented.

[0008]

SUMMARY OF THE INVENTION Therefore, according to the present invention, by constantly controlling the operating position (height) of the side dam in accordance with the variation of the starting position (height) during the casting, the sealing effect of the side dam is obtained. It is an object of the present invention to provide a twin-roll continuous casting method and apparatus capable of sufficiently preventing the occurrence of peeling and burrs and stably producing a good plate-shaped slab.

[0009]

In order to achieve the above-mentioned object, a twin roll continuous casting method of the present invention comprises a pair of cooling rolls having rotating shafts arranged horizontally and parallel to each other and a pair of cooling rolls. In a continuous casting mold composed of a pair of side dams pressed against both end faces of the rolls, a molten metal is continuously injected to form a pool of molten metal, while a pair of solidified shells are formed on the surfaces of both rotating cooling rolls. In the twin-roll continuous casting method in which both solidified shells are allowed to grow and coalesce both solidified shells at the position closest to both cooling rolls to form a strip-shaped slab, and the slab is sent downward from the position closest to the cooling roll by a twin-roll continuous casting method. At least one of the shape and size of the part where the side edge of the slab bulges outward from the end surface of the cooling roll is continuously detected during casting, and the leaching start position is based on the obtained data. Depending and adjusting the height of the side dams lower ends.

It is desirable to control the elevation of the side dam so that the lower end of the side dam is always located right above the start position of the protrusion during casting. It is also possible to continuously detect the force of pressing the side dam against the end surface of the cooling roll during casting, and adjust the height of the lower end of the side dam based on the obtained pressing force data and the shape / dimension data.

The twin roll continuous casting apparatus for carrying out the above-mentioned method of the present invention comprises a pair of cooling rolls whose rotation axes are horizontal and parallel to each other and arranged at predetermined intervals, and a pair of cooling rolls pressed against both end faces of these cooling rolls. While continuously pouring molten metal into a continuous casting mold composed of side dams to form a pool of molten metal, a pair of solidified shells grow on the surfaces of both rotating chill rolls, and the closest contact between both chill rolls. In a twin-roll continuous casting machine, in which solidified shells are joined together at a position to form a single strip-shaped slab, and the slab is sent downward from the closest position by rotation of the cooling roll, a device that raises and lowers the side dam and a part below the side dam. A device that continuously detects at least one of the shape and size of the part where the side edge of the slab protrudes outward from the end surface of the cooling roll, and based on the above detection data Characterized in that it has a device for controlling the lifting device of the side dams to adjust the height of the side dams lower depending on the look out starting position.

[0012]

According to the present invention, at least one of the shape and the size of the protruding portion on the side edge of the slab is continuously detected during casting, and the starting position of the protrusion is determined based on the obtained data. By adjusting the height of the lower end of the side dam, it is possible to respond to fluctuations in the start point of leaching during casting, and even if there is a seal failure due to leaching pressure at the crimping portion of the solidified shell, unsolidified above the crimping portion of the solidified shell The lower end of the side dam can always be controlled to an appropriate position where no material leaks.

Hereinafter, the present invention will be described in more detail with reference to examples.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A configuration example of a twin roll continuous casting apparatus according to the present invention and its operation will be described with reference to FIGS. Figure 1
Is a side view seen from the end face direction of the cooling roll 1, FIG. 2 is a front view seen from the plate surface direction of the slab 8, FIG. 3 is a perspective view seen obliquely from above the cooling roll 1, and FIG. 4 is a cooling roll. 2 is a cross-sectional view taken along a plane perpendicular to the rotation axis 2 near the center of the body length of FIG.

A pair of cooling rolls 1 (diameter D) are attached to the rotary shaft 2.
Are arranged horizontally and parallel to each other at predetermined intervals. Both cooling rolls 1 rotate in the directions of arrows Ya and Yb, respectively. The cooling roll interval T at the closest position is approximately equal to the plate thickness t of the cast piece to be cast. The pair of side dams 3 are pressed against both end surfaces 5 of the cooling roll 1 by the side dam pressing device 4 to form a continuous casting mold that penetrates vertically. Molten metal is continuously poured into this mold from a tundish (not shown) to form a pool 6. In the pool 6, the molten metal solidifies on the surface S of both cooling rolls 1, and a pair of solidified shells 7 grow. The solidified shells 7 coalesce at the positions closest to each of the cooling rolls 1 (positions at the cooling roll interval T) to form a single strip-shaped slab 8, which is fed downward from the position closest to the cooling rolls 1 by rotation.

When two solidified shells 7 are united at the position closest to the cooling roll 1 to form a slab 8, the cooling roll 1 presses down the slab 8 from both sides by a pressurizing means (not shown). Completely crimp 7 pieces. Due to this reduction, the material in the central portion of the wall thickness of the cast slab 8 oozes out to both side edges of the slab 8, and a squeezed-out portion 9 is formed. According to the present invention, by continuously controlling the position (height) of the side dam during casting so that the protruding portion 9 is generated with a stable shape and dimension (d),
Prevents peeling and burrs and ensures stable production of good plate-shaped slabs.

The upper ends of the two side dams 3 are connected to the side dam elevating device 11 such as a hydraulic cylinder via a connecting rod 10 in order to raise and lower the side dam 3 during casting and always hold it at an appropriate position. Below the side dam 3, a protrusion detection device 12 (video device or the like) for detecting the shape and size of the protrusion portion 9 on the side edge of the slab.
Is provided.

The lifting control device 13 is a protrusion detection device 12
Detection data (arrow i in the figure) is taken in, and the operation of the lifting device 11 is controlled based on the detection data, whereby the side dam 3 moves up and down so that its lower end 14 is at an appropriate position. The arrow k in the figure indicates the control data from the lift control device 13. In the conventional method, for example, the lower end 1 of the side dam 3 is
When 4 is located below the bulging start position 15 and the side dam 3 covers the bulging portion 9, the bulging portion 9 is pulled by the side dam 3 and peels off.
The protruding dimension d fluctuates remarkably, the pushing reaction force of the side dam also fluctuates suddenly, and the pushing reaction force becomes a high level with large undulations. On the other hand, when the lower end 14 of the side dam 3 is located too far away from the protruding start position 15 and is located above, the unsolidified portion leaks out and remelts the side edge portion of the slab 8, so that the slab side edge position is changed. Not uniform but significant width change occurs. In this case, the protruding portion shape / dimension detection device outputs plate width data narrower than a predetermined cast plate width.

In the present invention, the lower end 1 of the side dam 3
During the casting, the side dam 3 is controlled by raising and lowering so that it is always at a proper position with respect to the protruding start position 15.
The lower end 14 is positioned directly above the leaching start position 15 in a range where the unsolidified molten metal does not leak out, and the bulging portion 9 is stably maintained in a preferable shape. As a result, the protruding portion 9 is continuously generated with a stable small dimension d. In this proper state, since there is no repulsion due to fluctuations in the pressure of protrusion, the side dam pressing reaction force also continues stably.

The pressing force detection device 16 continuously detects the force (or the reaction force from the end face 5) by which the side dam pressing device 4 presses the side dam 3 against the end face 5 of the cooling roll 1 during casting. The detection data (j) of the pressing force detection device 16 and the detection data (i) of the sticking out detection device 12 are taken into the lifting control device 13, and the lifting device 11 is controlled based on both data. You can also

[0021]

As described above, according to the present invention,
Depending on the variation of the protrusion start position (height) of the slab side edge,
By constantly controlling the operating position (height) of the side dam, especially its lower end position, during casting, the side dam ensures a sealing effect, prevents peeling and burrs, and stabilizes a good plate-shaped slab. Can be manufactured.

[Brief description of drawings]

FIG. 1 is a side view showing a configuration example of a twin roll continuous casting apparatus of the present invention.

FIG. 2 is a front view showing a configuration example of a twin roll continuous casting apparatus of the present invention.

FIG. 3 is a perspective view showing a continuous casting mold composed of a pair of cooling rolls and a pair of side dams in the twin roll continuous casting device, a pool of molten metal in the mold, and a strip-shaped cast piece fed downward.

FIG. 4 is a pair of cooling rolls in a twin-roll continuous casting apparatus, a pool of molten metal formed between the cooling rolls, a pair of solidified shells growing on the surface of the cooling rolls, and a cast piece formed by the unification of these solidified shells and delivered downward. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... A pair of cooling rolls (diameter D) 2 ... The rotating shaft of the cooling roll 1 3 ... A pair of side dams 4 ... Side dam pressing device 5 ... Both end surfaces of the cooling roll 1 6 ... Melt pool 7 ... Leakage section 10 ... Connecting rod 11 ... Side dam lifting device 12 ... Leakage detection device (video device etc.) 13 ... Lifting control device 14 ... Side dam 3 lower end 15 ... Leakage start position 16 ... Pressing force detection device

Claims (5)

[Claims] 1. A molten metal is placed in a continuous casting mold composed of a pair of cooling rolls whose rotation axes are horizontal and parallel to each other and arranged at a predetermined interval, and a pair of side dams pressed against both end faces of these cooling rolls. Are continuously poured into the pool to form a pool, and a pair of solidified shells are grown on the surfaces of both rotating chill rolls. In the twin roll continuous casting method in which the slab is fed downward from the closest position by the rotation of the cooling roll, the side edge of the slab below the side dam erodes outward from the end surface of the cooling roll. At least one of the shape and size of the protruding portion is continuously detected during casting, and the height of the lower end of the side dam is adjusted according to the start position of the protrusion based on the obtained detection data. To Roll continuous casting method. 2. The twin roll continuous casting method according to claim 1, wherein the lower end of the side dam is always positioned immediately above the protruding start position during casting. 3. A force for pressing the side dam against the end surface of the cooling roll is continuously detected during casting, and the lower end height of the side dam is adjusted based on the obtained pressing force data and the shape / dimension data. Claim 1 characterized by the above-mentioned.
Or the twin roll continuous casting method described in 2. 4. A molten metal is placed in a continuous casting mold comprising a pair of cooling rolls whose rotation axes are horizontal and parallel to each other and arranged at a predetermined interval, and a pair of side dams which are pressed against both end faces of these cooling rolls. Are continuously poured to form a pool of water, and a pair of solidified shells are grown on the surfaces of both rotating chill rolls, and the solidified shells are bonded to each other at the closest positions of both chill rolls to form a single solid shell. In a twin roll continuous casting apparatus that forms a strip-shaped cast piece and sends the cast piece downward from the closest position by rotation of the cooling roll, a device for raising and lowering the side dam, and a side edge of the cast piece under the side dam are A device for continuously detecting at least one of the shape and the size of the portion protruding outward from the end surface of the cooling roll during casting, and the side according to the protrusion start position based on the detection data. A twin roll continuous casting device, comprising: a device for controlling the lifting device for the side dam so as to adjust the height of the lower end of the dam. 5. A device for continuously detecting a force for pressing the side dam against the end surface of the cooling roll during casting, wherein the control device controls the control based on the pressing force data and the shape / dimension data. The twin roll continuous casting apparatus according to claim 4, which is performed.