JP2008504969A - Method and apparatus for reducing vibration of a stickel mill - Google Patents

Abstract

The invention relates to a method and a corresponding device for reducing vibrations that are caused by a flat spot of a Steckel roll (1) in a Steckel mill. An adjustable roll (3) is mounted between the Steckel roll (1) of the Steckel furnace and the driver (2) of the roll stand (5) and can be contacted with the rolling stock (6). The invention is characterized in that the force which is exerted onto the rolling stock (6) by the roll (3) is adjusted to a defined value.

Description

  The present invention relates to a method and corresponding apparatus for mitigating vibration caused by a flat spot of a stickel roll in a stickel mill. It is arrange | positioned between the drive apparatuses of a rolling mill stand.

  In the known method, a vibration is generated in the stickel mill, and such a stickel mill has a slot provided to receive a front end portion (strip head) of the rolling material, although it is cylindrical. This slot is connected to the cylindrical casing of the Steckel roll by means of a corresponding transition radius, and the peripheral shape of the rolled material wound on the Steckel roll is not circular but has a flat spot corresponding to the string. is doing.

  Accordingly, at each flat spot during winding and unwinding of the rolled material, a decrease in the tension of the strip occurs or an increase in the tension of the strip occurs during each winding and unwinding of the rolled material. The decrease corresponds to the elongation of the rolling material positioned between the stickel roll and the rolling mill stand, and the increase in the tension corresponds to the shortening of the rolling material positioned between the stickel roll and the rolling mill stand. In the case of strip tension reduction, the strip tension may be very low in this region and may even disappear altogether.

A solution to this problem has been proposed in US Pat. No. 6,057,086, in which a movable drive roll changes the length of movement of the rolling stock, in particular as a function of the rotation angle of the stickel roll. However, in this case, the angle position of the flat spot of the stickel roll or the flat spot of the stickel roll needs to be determined, and the required position of the drive roll depending on the position of the deflection roll is It must be determined from the angular position of the flat spot of the roll.
European Patent Application No. 1180402

  The object of the invention is therefore to simplify the known methods for vibration reduction in terms of adjustment.

  This object is achieved by a method according to claim 1 and by an apparatus according to claim 8.

  The force applied by the roll to the rolled material is adjusted to a predetermined value. That is, the roll is pressed against the rolled material with a predetermined force, so that when a flat spot arrives during winding, the drop in strip tension will cause movement of the roll relative to the strip. Therefore, the movement of the roll relative to the strip is effected by a predetermined force on the roll.

  In this case, there is no influence on the drive control of the stickel roll or the adjustment of the tension of the strip, and the drive control of the stickel roll or the adjustment of the tension of the strip is operated independently of the adjustment of the force applied to the roll. . In general, the tension of the strip is adjusted via the two work roll drive units of the rolling mill stand and the two stickel roll drive units. For example, the rotation speed of the steckel roll is obtained from the rolling speed and the diameter of the coil at that time, and the torque of the steckel roll is obtained from the predetermined tension of the strip and the diameter of the coil.

  The deflection of the roll at the flat spot causes a geometric change in the action of the force. The force applied to the roll remains the same and only the point of action of the force applied to the rolled material changes. Depending on the direction of deflection, this means that the tension of the strip changes slightly due to a predetermined force on the roll.

  After the flat spot has passed, adjustment of the drive unit of the stickel roll can compensate for errors in the length of the rolled material due to changes in rotational speed, and the roll can be moved to the original position upstream of the flat spot. Can be pulled back to. This is done automatically by means of the existing adjustment of the stickel roll.

  In one possible embodiment of the invention, the force is kept constant during one or more rotations of the stickel roll.

  Thus, if too little of the strip is taken up in a short time during the rolling of the rolled material, the tension of the strip decreases as the rear passes through the flat spot. Since the forward force applied to the roll is constant, the roll is moved at that position until the force is in equilibrium with the rolling material at the new position. Since the position has changed slightly, the angle between the two parts of the rolling stock located upstream and downstream of the roll decreases. In the case of a constant force, the advance moment is reduced by the advance drive when the strip tension decreases, and the advance moment increases when the strip tension increases. However, the strip tension is not zero. In general, the tension of the strip is selected as a function of the thickness of the rolled material (strip thickness), temperature, thickness, width and material properties of the rolled material, but this is detailed here because it is general expertise. Not to mention.

  In another possibility for the solution, an additional force is applied to the force that is constant during one or more rotations of the Steckel roll during a specific time of each rotation. This can be achieved by increasing this constant force for a certain time prior to the appearance of a drop in strip tension and then decreasing it again to the original constant value after this time. At any time, the drop in strip tension is compensated more quickly than with a constant force during rotation. In this case, the inertia of the roll can be compensated more quickly by applying the additional force in a preceding form.

  The time for applying the additional force corresponds to approximately 1/3 of the time for unwinding or winding the rolled material across the flat spot. To determine the application of additional force, the angular position of the stickel roll or of the flat spot can be determined.

  It is also possible to vary the force as a function of the coil diameter of the rolled material on the stickel drum. That is, for example, the force remains essentially constant during the rotation of the stickel roll and continuously increases or decreases with the diameter of the coil. In embodiments that include the periodic application of additional forces, a constant force, as well as an additional force, is likewise continuously increasing.

  At a given position on the roll, the force on the roll and the force applied on the roll by strip tension and looping of the rolling stock are in equilibrium. Therefore, when the diameter of the coil increases or decreases, the spatial position of the rolling material between the roll and the stickel roll changes, thereby changing the force balance state and restoring the initial force balance. The force on the roll or the spatial position of the roll changes. The required change in force can be determined or calculated from the parallelogram of the force formed from the force on the roll (stripping tension and forward force on the roll).

  There are therefore two possible solutions, in which case the force on the roll depends only on the combined tension of the strip at a particular time point and is therefore essentially constant throughout the winding period. (Excluding the periodic additional force applied as needed), and thus, for example, during winding, the composite tension of the strip in the roll becomes higher due to the increase of the coil diameter, and the roll is increasingly It is pushed further away from the path of the rolling material. In this way, the roll position is variable except for the deflection due to the flat spot of the stickel roll, and the roll is continuously from the initial position at the start of the winding operation to the final position at the end of the winding operation. Move to.

  Alternatively, the force on the roll can be predetermined as both a function of the strip tension and a function of the coil diameter, and the force can be selected to maintain equilibrium with the instantaneous composite tension of the strip. Yes, the roll changes its position only during the increase or decrease of the strip tension and then returns again to its original position before the increase or decrease of the strip tension.

  Thus, the spatial position of the roll is maintained fixed during the entire winding or unwinding operation, except for deflection due to the flat spot of the stickel roll.

  In general, the force is selected at a predetermined location on the roll to offset the force acting on the roll by a predetermined strip tension. In the first case of the variable position of the roll, the required force is geometrical, such as at the start of a winding operation based on a predetermined strip tension resulting from the parallelogram of the force, for example. Is determined based on various conditions (position of the rolled material relative to the roll).

  In the second case of the fixed position of the roll, the force on the roll is a geometry that varies with the increase or decrease of the coil diameter of the combined tension of the strip due to the parallelogram of the forces acting on the roll during the winding operation. It changes continuously in conjunction with scientific conditions.

  The fact that the roll and / or the bearings of the roll, for example a pivoting arm, is advanced hydraulically, this movement can be performed quickly and accurately compared to pneumatic actuation or motor actuation. It has the advantage of.

  Since the roll moves essentially perpendicular to the plane of the rolling stock located between the stick roll and the drive, the maximum possible effect is achieved with a low deflection of the roll. However, the movement of the roll can also be achieved by a forward cylinder inclined with respect to this plane.

  The apparatus for carrying out the method may comprise at least one, preferably hydraulic advance cylinder, which engages a roll mounting member such as a pivot arm.

  The advance cylinder preferably has a position measuring device for determining the starting position and for monitoring the position of the roll during the winding operation.

  Further, the advance cylinder has pressure measuring devices on both the rod side and the piston side, and its advantage is that the actual pressure can be monitored.

  Since the increase or decrease in the tension of the strip is quickly compensated by means of the roll according to the invention, a roll with a low mass inertia should be provided. For this purpose, the roll can be designed cylindrically. It is considered that the ratio of the wall thickness of the cylinder of about 1:10 and the outer diameter of the cylinder is sufficiently stable.

  When the roll is attached to a pivot arm with which the advance cylinder is engaged, the lever arm of the advance cylinder relative to the axis of the pivot arm is less than the distance between the axis of the roll and the axis of the pivot arm Has proven to be advantageous from a liquid mechanics point of view. As a result, advance cylinders with small valves and short switching times can be used because the advance cylinder must only move at a slower speed than the roll speed.

  The invention has been described with reference to the examples according to the attached FIGS.

  According to FIG. 1, an additional advanceable roll 3, which is known as a stickel furnace (coiler furnace), is arranged between a stickel roll 1 and a drive device 2, the drive device 2 being a rolling mill stand. 5 and the fixed position downstream of the upper drive roll. The roll is attached to the pivot arm and engages the rolling blank 6. At this point, the driving device 2 is open at the fixed position of the upper driving roll. The mounting slot 7 of the stickel roll 1 causes a flat spot on the rolled material 6 to be wound.

  FIG. 2 shows the position a) of the device according to the invention before the strip tension reduction caused by the flat spot in the upper left, b) at the lower left, and the position b) of the device according to the invention during the strip tension reduction in the lower left. Show. The stickel roll 1 rotates counterclockwise according to the arrow shown around the rotation axis and winds the rolled material 6. Both ends of the roll 3 are attached to a pivot arm 4 to which a hydraulic advance cylinder 8 is engaged in each case of winding and rewinding. The two pivot arms 4 are pivotable about a pivot axis 9 and are connected to each other in the rear region. The acting strip tension is illustrated by vector 10. The composite tension of the strip acting on the roll 3 can be obtained from the parallelogram of force shown in the lower part of this figure. In the parallelogram of force, the direction is opposite to the composition of the strip tension, but the magnitude is Equally, the force 11 that the advance cylinder 8 must apply to the roll at this point can be taken.

  In position b), the strip tension has already decreased. The roll 3 has already been lowered by the advance cylinder 8 and absorbs the drop in strip tension. Depending on the dimensions of the advance device, the advance moment is reduced for a constant cylinder force.

  In the lower right of FIG. 2, only the shape of the roll with the rolling material and the pivot arm is shown in a simplified manner, with the two positions a) and b) being superimposed. An arrow 12 indicates the direction of movement of the roll 3 during winding across the flat spot of the stickel roll 1.

  The adjustment of the drive of the stickel roll 1 reacts to the decrease in strip tension by increasing the rotational speed, and the roll 3 is pulled back to the initial position before the decrease in strip tension. This compensates for the roll 3 always returning to the initial position of the roll before passing the flat spot during winding, so that the force on the roll 3 is instantaneous (as a function of the coil diameter) and the combined tension of the strip. Is expected to be added to In another state (of the variable position of the roll), the roll is continuously raised from a low position to a high position by a constant force of the advance cylinder 8.

  During winding, the flat spot of the stick roll 1 causes the rolling material 6 to elongate and thus the strip tension to decrease. The roll 3 is lowered by the rolling material 6.

  The size of the occlusion of the hydraulic advance cylinder 8 is selected such that the force on the level arm of the cylinder relative to the center of gravity of the pivot arm 4 is reduced, so that despite the deflection of the pivot arm 4 the strip tension is Slightly decreases. The torque adjustment of the stickel roll 1 responds to this decrease due to the increase in rotational speed until the desired strip tension is restored. The roll 3 is thereby returned to the position before the strip tension is reduced.

  FIG. 3 shows, as in FIG. 2, the position a) of the device according to the invention before the increase in strip tension caused by the flat spot, on the upper left, the position b) of the device according to the invention during the increase in strip tension. Is shown in the lower left.

  During unwinding, the flat spot of the stick roll 1 shortens the rolled material 6 and thus increases the tension of the strip. The roll 3 is raised by the rolled material 6.

  The occlusal dimensions of the hydraulic advance cylinder are selected so that the force on the cylinder level arm relative to the center of gravity of the pivot arm 4 is increased, resulting in a slight strip tension despite the deflection of the pivot arm 4 To increase. The torque adjustment of the stickel roll 1 responds to this increase due to the decrease in rotational speed until the desired strip tension is restored. The roll 3 is thereby returned to the position before the increase in strip tension.

  This compensates for the roll 3 returning to the roll's initial position prior to the passage of the flat spot during unwinding, and it is expected that the force on the roll 3 will be added to the instantaneous composite tension of the strip. In another state (of the variable position of the roll), the roll moves continuously from a high position to a low position by a constant force of the advance cylinder 8.

  The adjustment of the other stickel rolls on the other side of the mill stand is done in the same way, in each case only one stickel roll is used in each case except for the first and last pass. The stickel roll is wound up and the other is rewound.

It is a figure of a stickel mill. FIG. 5 shows the position of the roll during winding before and during the drop of the strip tension. FIG. 5 shows the position of the roll during unwinding before and while the strip tension rises.

Explanation of symbols

1 ... Sticker roll
2 ... Drive device
3 ... roll
4 ... Pivot arm
5 ... Roller stand
6 ... rolling material
7 ... Installation slot
8 ... Forward cylinder
9 ... Pivot axis
10 ... Strip tension
11 ... Power on roll
12: Direction of roll movement

Claims (15)

A method of reducing vibration caused by a flat spot on a stickel roll (1) of a stickel mill,
A forward roll (3) that engages the rolling material (6) is disposed between the stickel roll (1) of the stickel furnace and the drive device (2) of the rolling mill stand (5),
A method comprising the step of adjusting the force applied by the roll (3) to the rolled material (6) to a predetermined value.   Method according to claim 1, characterized in that it comprises the step of keeping the force constant during one or more rotations of the stickel roll (1).   2. The method according to claim 1, further comprising the step of applying an additional force for a specific time of each rotation to the force that is kept constant during one or more rotations of the stickel roll (1). The method described.   4. A method according to any one of the preceding claims, comprising the step of changing the force as a function of the coil diameter of the rolled material (6) on the stick roll (1).   Selecting the force to cancel the force applied to the roll by a predetermined strip tension at a predetermined position of the roll. Item 5. The method according to any one of Items 1 to 4.   6. The method according to any one of the preceding claims, comprising hydraulically feeding the roll (3) and / or a mounting member of the roll, such as a pivot arm (4), for example. the method of.   Moving the roll (3) essentially perpendicular to the plane of the rolling stock (6) located between the stickel roll (1) and the drive (2). The method according to any one of claims 1 to 6. An apparatus for performing the method according to claim 1,
Comprising at least one advance roll (3) disposed between the stickel roll (1) and the driving device (2) of the rolling mill stand (5);
The roll can be engaged with a rolled material (6),
An apparatus (4, 8) is provided, by which the force applied by the roll (3) to the rolling material (6) can be adjusted to a predetermined value.   9. The device according to claim 8, characterized in that it comprises at least one preferably hydraulic advance cylinder (8) which engages a mounting member such as a pivot arm of the roll (3). Equipment.   10. Device according to claim 9, characterized in that the advance cylinder (8) has a position measuring device.   11. Device according to claim 9 or 10, characterized in that the advance cylinder (8) has pressure measuring devices on both the rod side and the piston side.   The roll (3) can be moved essentially perpendicularly to the plane of the rolling blank (6) located between the stickel roll (1) and the drive (2). The apparatus according to any one of claims 8 to 11.   The apparatus according to claim 8, wherein the roll is designed as a cylinder.   The roll (3) is attached to the pivot arm (4), the forward cylinder (8) is engaged with the pivot arm (4), and the cylinder relative to the axis (9) of the pivot arm 14. A device according to any one of claims 9 to 13, wherein the lever arm of (8) is shorter than the distance between the axis of the roll and the axis of the pivot arm.   15. The device according to claim 8, wherein the device (4, 8) is arranged such that the forward moment decreases when the tension of the strip decreases and increases when the tension of the strip increases. The device according to any one of the above.

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