JP2679909B2 - Twin drum continuous casting method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to twin-drum continuous casting, and more particularly to improvement of a method for pressing a side weir against an end surface of a cooling drum.

[0002]

2. Description of the Related Art In twin-drum continuous casting, as shown in FIG. 3, a pair of cooling drums 1 having rotating shafts 2 horizontally and parallel to each other and arranged at predetermined intervals are provided on both end surfaces 5 of these cooling drums 1. Growing on the surface of both cooling drums 1 rotating in the direction of arrow D, while continuously pouring molten metal into a continuous casting mold formed of a pair of pressed side dams 3 to form a pool 6 The pair of solidified shells thus formed are united to form a strip-shaped slab 8, and the slab 8 is sent downward by the rotation D of the cooling drum 1.

As shown in FIG. 4, a pressing mechanism 4a, 4 by a hydraulic cylinder or the like is provided on the rear surface of each side dam 3 at a total of three places including an upper two places (4a, 4b) and a lower one place (4c).
b, 4c are attached, and the upper push rod 11
The front surface of the side weir 3 is pressed against the end surface of the cooling drum 1 by the pressing force applied to the rear surface via the a and 11b and the lower push rod 11c, and the cooling drum 1 and the front surface of the side weir 3 are rotated along with the rotation D. Move.

From the viewpoint of maintenance cost, the wear caused by the frictional force on the sliding surface is preferentially generated on the side dam side rather than on the cooling drum side. Then, the side dam is continuously moved forward toward the end surface of the cooling drum during operation so as to offset the decrease of the side dam sliding surface due to wear and ensure the sealing action.

Here, it is important that the wear of the side dam progresses uniformly over the entire sliding surface. If the side weirs are unevenly worn, the seal cannot be uniformly maintained over the entire sliding surface, a defective seal is locally generated, and molten metal leaks, making it impossible to stably continue casting. In addition, uneven wear substantially shortens the life of the side dam. In particular, if there is a wear deviation between the upper and lower sides of the weir, it is likely to cause hot water leakage.
Its prevention is extremely important.

The amount of wear of each part of the side dam sliding surface is substantially determined by the frictional force acting on the sliding surface, and the frictional force is determined by the reaction force from the end surface of the cooling drum to the sliding surface. Japanese Patent Laid-Open No. 3-
Paying attention to this point, Japanese Patent No. 230848 (Japanese Patent Application No. 2-20481) measures the reaction force acting from the end surface of the cooling drum to the pressing mechanism at three places on the back surface of the side dam, and based on this measurement value, We propose a method to control the amount of forward displacement and obtain an appropriate pressing force.

However, the reaction force cannot correctly detect the surface pressure on the sealing surface. That is, (1) it is practically impossible to obtain a completely flat surface due to thermal deformation on the surface of the side weir, and (2) there is variation in the crimping state at the start of pressing and reaction force is received. This is because a state where they are not in close contact with each other occurs. Also, due to the frictional force with the drum end surface at the start of pressing, the position of the side dam is displaced to create a gap, and the reaction force increases at this gap generation part, so the pushing force loading cylinder retracts and the gap further expands, Hot water leaks.

Even during casting, the friction coefficient between the drum end surface / side weir changes due to various factors, so that the surface pressure received by each part of the side weir sliding surface also changes individually, causing uneven wear. . Factors that cause a change in the friction coefficient include minute metal adhesion to the end surface, a change in the end surface irregularity state, and peeling of the end surface coating that do not result in a defective seal.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a twin-drum continuous casting method and apparatus which solves the above-mentioned conventional problems and effectively prevents uneven wear of side dams and defective sealing. .

[0010]

In order to achieve the above object, a twin-drum continuous casting method according to the present invention comprises a pair of cooling drums whose rotation axes are horizontal and parallel to each other and which are arranged at predetermined intervals, and a rear surface. In a twin-drum continuous casting method in which a continuous casting mold is configured by a pair of side dams whose front surface is pressed against the end surface of the cooling drum by a pressing force applied to the cooling drum, one lower part and two upper parts of the back surface of the side dam are It is characterized in that three pressing mechanisms for respectively applying the pressing force to a total of three locations are simultaneously displaced forward in the direction of the pressing force at the same speed.

Further, the twin-drum continuous casting apparatus for carrying out the method of the present invention comprises a pair of cooling drums whose rotating shafts are horizontal and parallel to each other and arranged at predetermined intervals, and a pressing force applied to the back surface. In a twin-drum continuous casting device in which a continuous casting mold is composed of a pair of side weirs whose front surface is pressed against the end surface of the cooling drum, the above-mentioned pressing is performed at a total of three places, one lower part and two upper parts on the back side of the side dam. It is characterized in that the three pressing mechanisms for applying force are simultaneously displaced forward in the direction of the pressing force at the same speed.

[0012]

In the present invention, regardless of the reaction force, the side weirs are forwardly displaced at a total of three points in the vertical direction at the same speed at the same time, so that there is no unavoidable defect in the conventional control by the reaction force, and when the pressing is started. It is possible to completely prevent the generation of a gap, always secure a stable seal without being affected by the change in the friction coefficient during casting, and prevent uneven wear of the side dam.

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

[0014]

【Example】

Example According to the present invention, a strip of SUS304 stainless steel was cast under the following conditions. Casting conditions Cooling drum diameter: 1200 mm Cooling drum width: 800 mm Cast piece plate thickness: 2.3 mm Pressing device: Stepping cylinder Rigidity ratio of pressing mechanism: Lower side / Upper side = 3 Casting speed: 80 m / min Initial setting reaction force: Upper side 130 kg The lower 400 kg pressing mechanism was controlled such that the forward displacement speed of the pressing mechanism was the same and constant predetermined values for the upper and lower three points. Ie up and down 3
Both points are 6 μm / sec from the start of casting to 1 minute,
It was 4 μm / sec from 1 minute to 3 minutes and 3 μm / sec from 3 minutes to the end of casting.

FIG. 1 shows the transitions of (1) displacement of the pressing cylinder and (2) reaction force during the casting process. The side weir did not lose its posture, the reaction force did not change suddenly, and a stable seal made it possible to satisfactorily cast 10 tons without causing molten metal leakage. [Conventional Example] Casting was performed under the same conditions as in the examples. However, the position of the pressing cylinder was controlled so that the reaction force at the three pressing points was a predetermined value.

FIG. 2 shows transitions of (1) displacement of the pressing cylinder and (2) reaction force during the casting process. As the casting progressed, the posture of the side weir collapsed and the lower side tended to open, and the molten metal leaked below the side weir and the casting was interrupted.

[0017]

As described above, according to the present invention,
In twin-drum continuous casting, it is possible to stably secure the sealing action of the side weir, effectively prevent uneven wear of the side weir, and perform stable casting.

[Brief description of the drawings]

FIG. 1 is a graph showing changes in (1) displacement of a pressing cylinder and (2) reaction force in a casting process according to the present invention.

FIG. 2 is a graph showing a transition of (1) displacement of a pressing cylinder and (2) reaction force in a casting process by a conventional method.

FIG. 3 is a perspective view showing a main part of a twin-drum continuous casting device.

FIG. 4 is a front view showing details of a sliding portion between an end surface of a cooling drum and a side weir of 13.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cooling drum 2 ... Rotating shaft 3 ... Side weirs 4a, 4b ... Upper pressing mechanism 4c ... Lower pressing mechanism 5 ... End surface of cooling drum 1 ... Hot water pool 8 ... Strip cast 10a, 10b ... Upper pressing force generating cylinder 10c ... Lower pushing force generating cylinders 11a, 11b ... Upper pushing rod 11c ... Lower pushing rod

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kensuke Shimomura 3434 Shimada, Hitsu-shi, Yamaguchi Yamada Pref., Nippon Steel Co., Ltd., Hikari Works, Ltd. (72) Inventor Yoichi Wakiyama 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Prefecture Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Inventor Hidenori Hattori 4 Kanon-shin-machi, Nishi-ku, Hiroshima City, Hiroshima Prefecture 6-22 No. 22 Hiroshima Works, Mitsubishi Heavy Industries, Ltd. (56) Reference Japanese Unexamined Patent Publication No. 2-46951 (JP, A) Shoukai 62-10936 (JP, U)

Claims (2)

(57) [Claims] 1. A pair of cooling drums whose rotation axes are horizontal and parallel to each other and are arranged at predetermined intervals, and a pair of side dams whose front surface is pressed against the end surface of the cooling drum by a pressing force applied to the back surface. In the twin-drum continuous casting method of constructing a continuous casting mold with three, three pressing mechanisms for respectively applying the pressing force to a total of three positions, that is, one lower part and two upper parts on the back surface of the side dam, A twin-drum continuous casting method, characterized in that forward displacement is simultaneously performed at the same speed. 2. A pair of cooling drums whose rotation axes are horizontal and parallel to each other and are arranged at a predetermined interval, and a pair of side dams whose front surface is pressed against the end surface of the cooling drum by a pressing force applied to the back surface. In the twin-drum continuous casting apparatus that constitutes a continuous casting mold with the above, the three pressing mechanisms that apply the pressing force to a total of three positions, that is, one lower part and two upper parts on the back surface of the side weir, are arranged in the direction of the pressing force. A twin-drum continuous casting device, characterized in that the forward displacement is performed simultaneously at the same speed.