JPH04224052A - Method and device for controlling pushing force to side weir in continuous caster for cast strip - Google Patents

Abstract

PURPOSE:To always maintain the necessary min. limit of closely contacting pressure to seal with molten metal in twin drum type continuous caster for cast strip. CONSTITUTION:Friction force generated between both end faces in the axial direction of the cooling drums 1, 1 and side weir 2, is detected, and by obtaining the change of pressure caused by this friction force to control the pushing force to the side weir and after that, the side weir 2 is pushed toward both end faces in the axial direction of cooling drums 1, 1 with this pushing force to the side weir. By this method, without influence with disturbance of the friction force, sealing is executed with the desired facing pressure, and unsymmetrical wearing phenomenon of the side weir and leakage of the molten metal caused by shortage of facing pressure to sealing are avoided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a twin-drum casting technique for continuously casting thin slabs from molten metal, and more particularly to a technique for controlling side weir pressing force.

0002

2. Description of the Related Art In general, a twin-drum continuous casting machine (hereinafter referred to as a continuous casting machine) has cooling drums 1, 1 arranged so as to rotate in parallel and in opposite directions, as shown in FIG.
, 1 are provided with side weirs 2, (2) (the side weirs (2) are not shown) to form a pool, and the molten metal M in the pool is cooled by the rotation of the cooling drums 1, 1. A thin slab S is cast while cooling. Also, side weir 2
, (2) are pressed against both end surfaces of the cooling drums 1, 1 by a presser 4, and are maintained in a sealed state by wear due to rotation of the cooling drums to prevent hot water from leaking.

Various proposals have been made regarding such side weir pressing techniques. For example, Japanese Patent Application Laid-Open No. 63-17794 disclosed a technology for controlling the expanding force that acts on the side weir during casting.
This is disclosed in Publication No. 4 or Japanese Patent Application Laid-Open No. 64-83337.

0004

[Problems to be Solved by the Invention] However, since the conventional technology does not take into account the frictional force generated on the side weir, even if the pressure is adjusted by the side weir pressing means to obtain the desired sealing surface pressure, it is difficult to actually The seal surface pressure that acts on both end faces of the cooling drum is accompanied by an error corresponding to the increase or decrease in pressing pressure due to frictional force, and the pressure error gradually expands due to the increase or decrease in frictional force, resulting in the phenomenon of one-sided wear of the side weir. In the worst case, it becomes difficult to maintain the contact pressure necessary for the seal, leading to leakage of the metal and making it impossible to continue casting.

The present invention is intended to solve the above-mentioned problems regarding the pressing force of the side weir in a continuous casting machine.

[0006]

[Means for Solving the Problems] The present invention was made by elucidating the pressure situation in the close contact area between both end faces of a rotating cooling drum and the side weir flat part, and its characteristics are as follows: The frictional force generated between the weir and the weir is detected, and the pressure increase/decrease in the side weir pressing force caused by this frictional force is determined and the pressing force is adjusted.Then, the side weir is moved to both ends of the cooling drum using the adjusted pressing force. It is in the place where it is pressed against the surface.

The present invention will be explained in detail below.

[0008]

[Operation] A friction force determined by the friction coefficient and the pressing force acts between both end surfaces of the rotating cooling drum and the side weir. This frictional force has the effect of pushing down the side weir and the effect of pushing it toward the opposing cooling drum side. This acting force generates a moment centered on the horizontal axis parallel to both end surfaces of the cooling drum and a moment centered on the vertical axis through the support point of the pressing means, and the pressing direction force corresponding to the moment is applied to the cooling drum by the pressing means. Increase or decrease the contact pressure (seal surface pressure) between both end faces of the drum and the side weir.

[0009] Therefore, by detecting this frictional force and calculating the increase/decrease pressure at the seal portion, and pressing the side weir against both end faces of the cooling drum with the pressing force adjusted using this value, the desired seal surface pressure can be achieved with high precision. Can be secured continuously.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained based on the drawings. In the figure, a side weir support shaft 3 is fixedly installed on the side surface of the side weir 2 opposite to the surface in contact with the end surfaces of the cooling drums 1, 1, and the support shaft 3 is connected to a side weir support cylinder 6 having a rectangular cross section.
to be inserted into. Moreover, the rods 4-1 to 4-3 of the presser 4 are fixed on the opposite side, and each rod is attached to the hydraulic cylinder 5.
-1 to 5-3. Note that the ends of the side weir support shaft cylinder 6 and the hydraulic cylinders 5-1 to 5-3 are each fixed to the base 8. Load detectors 7-1 to 7-4 are disposed in the cylinder 6 so that their detection ends are in contact with the peripheral surface of the side weir support shaft 3 in the right angle direction. The load detectors 7-1 to 7-4 are connected with a friction force calculation device 9 that sends signals detected by the detectors, and a pressing force adjustment calculation device 10 that sends friction force signals is connected to the calculation device 9. Furthermore, pressing force drive control devices 11-1 to 11-3 that send pressing force adjustment signals are connected to the arithmetic unit 10, and the control devices are connected to the hydraulic cylinders 5-1 to 5-3 of the presser 4. Connect to.

The apparatus of the present invention has the above-mentioned structure, and is operated as follows. First, the side weir 2 is installed on the end face of the cooling drum 1, 1 by the hydraulic cylinders 5-1 to 5-5.
-3 to press with a desired pressure and rotate the cooling drums 1,1. The molten metal in the pool is cooled from the part in contact with the cooling drum to form a shell, which is pressed against the cooling drum to produce thin slabs, but as casting progresses, the pressing force increases as the side weirs wear out. As a result, the frictional force at the close contact portion between the end face of the cooling drum and the side weir increases. The above frictional force generates a moment centered on the horizontal axis parallel to both end surfaces of the cooling drum and a moment centered on the vertical axis, deforming the side weirs inwardly into a concave or convex shape, thereby causing the side weirs and the cooling drum to deform, respectively. Although the surface pressure of the close sealing portion with the end face portion is increased or decreased, as the frictional force increases as described above, the above phenomenon increases. Therefore, during casting, the frictional force on the end surface of the cooling drum in each direction is constantly detected.

The multidirectional frictional forces are detected by four load detectors 7-1 to 7-4 provided around the side weir support shaft 3, and signals from the detectors are sent to the frictional force calculation device 9. This is where the frictional force is calculated. Thereafter, the frictional force signal from the calculation device 9 is sent to the pressing force adjustment calculation device 10, where an increase or decrease in the pressing force due to the frictional force is determined from the frictional force data through calculation processing. Since the desired seal surface pressure is determined by desired seal surface pressure=friction increase/decrease pressure+adjusted pressing force, the adjusted pressing force can be determined from the above formula. The adjusted pressing force signal is then sent to the pressing force drive control devices 11-1 to 11-3, which control the pressing operations of the hydraulic cylinders 5-1 to 5-3 of the presser.

That is, the side weir is pressed by the pressing means so as to maintain the desired sealing surface pressure while correcting the change due to frictional force (frictional increase/decrease pressure) with the adjusted pressing force. Note that the frictional force may be detected by a bending detector of the side weir support shaft instead of the load detector described above.

[0014]

As described above, according to the present invention, it is possible to constantly maintain the minimum contact pressure necessary for sealing the molten metal, which is the desired sealing surface pressure, without being affected by disturbances of frictional force. This makes it possible to avoid the uneven wear of the side weir and leakage due to lack of seal surface pressure, which has the excellent effect of allowing stable casting to continue for a long time.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional plan view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line X-X in FIG.

FIG. 3 is a schematic side view showing a conventional continuous casting machine.

[Explanation of symbols]

1...Cooling drum 2...Side weir 3...Side weir support shaft 4...Press device 4-1 to 4-3...rod 5-1 to 5-3...Hydraulic cylinder 6...Side weir support shaft cylinder 7-1 to 7-4...Load detector 8...Foundation 9...Frictional force calculation device 10...Press force adjustment calculation device

Claims (4)

[Claims] 1. Molten metal is poured into a pool formed by pressing side weirs on both axial end surfaces of a pair of cooling drums, and the molten metal is cooled by rotation of the cooling drums to continuously form a thin layer. When casting a piece, the frictional force generated between both axial end surfaces of the cooling drum and the side weir is detected, and the increase/decrease pressure in the side weir pressing force caused by the frictional force is determined to calculate the side weir pressing force. 1. A method for controlling a side weir pressing force in a continuous casting machine for thin slabs, comprising: controlling the side weir pressing force, and then pressing the side weir against both axial end surfaces of the cooling drum by the side weir pressing force. 2. A pool is formed by a pair of cooling drums and side weirs pressed against both axial end surfaces of the cooling drum, and the molten metal in the pool is cooled by rotation of the cooling drum. In a twin-drum continuous casting machine that continuously casts thin slabs, a friction force detector is provided at a supporting portion of the side weir to detect the frictional force generated between the side weir and both end surfaces of the cooling drum. furthermore, a friction force calculation device that calculates the friction force from the detected value by the detector, a pressing force adjustment calculation device that calculates the increase or decrease of the side weir pressing force due to the friction force, and a press force adjustment device that operates in response to the increase or decrease pressure signal. A side weir pressing force in a continuous casting machine for thin slabs, characterized in that a pressing force drive control device is provided, and a presser driven by an adjustment pressure signal from the pressing force drive control device is provided in the side weir. Control device. 3. The control device according to claim 2, wherein the frictional force detector is a load detector provided on a side weir support shaft. 4. The control device according to claim 2, wherein the frictional force detector is a bending detector of a side weir support shaft.