DE102016202367A1 - Apparatus for suppressing chatter vibrations with coated rolls in a rolling train - Google Patents

Abstract

The invention relates to a device (9) for suppressing chatter vibrations in a roll stand (5) of a rolling train (1), with respect to a conveying direction (3) of a metal strip (2) to be rolled through the rolling train (1) at least one further roll stand (4 ), comprising at least one between the rolling stand (5) and this upstream rolling mill (4) arranged, in physical contact with the metal strip (2) engageable roller (10), wherein an axis of rotation (11) of the roller (10) in parallel to rotation axes (12) of rollers (6, 7) of the roll stand (5). In order to enable a suppression of chatter vibrations in a roll stand (5) with little design effort and to eliminate the disadvantages associated with the occurrence of chatter vibrations, the invention proposes that a lateral surface of the roller (10) at least partially with an elastic and the Chatter vibration damping coating (13) is provided.

Description

The invention relates to a device for suppressing chatter vibrations in a rolling stand of a rolling line, which is preceded by a rolling mill at least one further rolling stand with respect to a conveying direction of a metal strip to be rolled, having at least one between the rolling stand and the upstream of this roll stand arranged, in physical contact with roll that can be brought into the metal strip, wherein the axis of rotation of the roll runs parallel to the axes of rotation of rolls of the roll stand.

The invention further relates to a rolling train for cold rolling a metal strip, comprising at least two rolling stands connected downstream of the rolling line with respect to a conveying direction of the metal strip to be rolled, and at least one device for suppressing chatter vibrations in a rolling stand of the rolling line, which is preceded by at least one further rolling stand.

When cold rolling of steel, aluminum or other metal strip occurs in two or more scaffold tandem roads often to chatter vibrations in a rolling mill, which is preceded by at least one further rolling mill with respect to a conveying direction of the metal strip through the tandem mill.

In particular, different chatter vibrations occur in quarto cold rolling stands and sexto cold rolling stands, which adversely affect the rolling process to be carried out and the quality of the cold-rolled metal product in terms of thickness, flatness and surface quality.

Different chatter vibration modes occur in different frequency ranges. Particularly characteristic or frequent here are the so-called "3. Octave chatter vibrations ", which are typically in a frequency range of 80 Hz to 200 Hz. In a 3rd octave chatter vibration, a strip tension vibration occurs on the inlet side of the rattling rolling stand and a vertical vibration of the rollers in the rolling stand. The upper and lower sets of rolls of the rolling stand oscillate in opposite directions, so that a band thickness variation is generated in the outlet of the roll stand, as in the appended 1 is shown. If no countermeasures, such as a reduction of the rolling speed, are introduced to the 3rd octave chatter vibrations, the 3rd octave chattering increases and the metal strip can crack. Often, therefore, the maximum possible rolling speed for certain materials and thus the production capacity of a rolling mill is limited.

A third octave chatter vibration is, in particular, a self-excited mode of vibration which can lead to thickness errors oriented perpendicularly to the belt conveying direction and consequently to high-amplitude band breaks. The 3rd octave chatter vibration is created in particular by destabilizing a specific natural vibration mode of the complete roll stand with set of rolls by means of a system-inherent feedback in the rolling process. The rattle-relevant intrinsic vibration form of the roll stand is usually the one in which an upper and a lower roll set in the rolling stand essentially oscillate against each other. The frequency of this natural mode is usually between 80 Hz and 200 Hz. The destabilizing feedback caused by the rolling process itself caused by changes in the outlet thickness changes in the inlet velocity due to the mass flow law fluctuations of the intake train, in turn, the rolling force back (so-called Zugrückwirkung) and so in turn affect the outlet thickness.

There are already various approaches to reduce chatter vibrations with passive and active damping measures in the rolling stand. For example, with US Pat. No. 7,225,657 B2 proposed to set the backup rollers or work rolls leading chocks to reduce chatter vibrations by means of clamping means on a roll stand. A similar approach is used JP 2008 212 974 A1 tracked. On the other hand is with EP 2 052 796 A1 proposed an application of a hydraulic Anstellzylinders a rolling stand with a hydraulic medium, wherein to suppress the rattle actively pressure changes are generated in the hydraulic medium. With WO 1997/027953 A1 and WO 2012/046211 A1 In each case an active damping of rattling with fast hydraulic systems in the Anstellzylindern or bending cylinders is proposed. Furthermore, it is known to influence a nip lubrication or a work roll roughness to adjust the friction in the nip.

Another approach to chatter vibration suppression in a rolling mill is to actively damp or avoid vibrations in the strip train. For example, beats EP 1 343 598 B2 influencing the dynamics of the rotation of a pulley in order to influence the strip tension. With WO 1996/027454 A1 a plastic bending of the belt is suggested by pulleys to reduce the chattering. Out JP 8238511 A a device for damping band vibrations is known, which comprises a set against the metal strip, arranged between two stands, whose inertia is actively influenced.

An object of the invention is to enable a suppression of chatter vibrations in a rolling stand with little design effort and to eliminate the disadvantages associated with the occurrence of chatter vibrations.

This object is solved by the independent claims. Advantageous embodiments are specified in particular in the dependent claims, each of which taken alone or in different combinations with each other can represent an aspect of the invention.

An apparatus according to the invention for suppressing chatter vibrations in a rolling stand of a rolling line, which is preceded by at least one further rolling stand through the rolling train with respect to a conveying direction of a metal strip to be rolled, comprises at least one roll stand which can be arranged between the rolling stand and the rolling stand arranged in front of it, in physical contact with the metal strip engageable role. The axis of rotation of the roller is parallel to the axes of rotation of rolls of the rolling stand. According to the invention, a lateral surface of the roller is at least partially provided with an elastic coating which damps the chatter vibrations.

With the roller arranged in the strip run between the roll stands, a strip tension oscillation, which results from the rattle of the downstream roll stand, can be passively damped. The roller dives into the metal strip, so that a change in the forces on the roller acts on the strip tension fluctuations. As a result, the elastic coating is partially compressed or partially yields the elastic coating, which counteracts the strip tension fluctuations. This influences the dynamic behavior of the metal strip. Thereby and by the chatter vibration damping property of the elastic coating, the chatter vibration of the downstream rolling mill is damped or completely suppressed. The damping property of the elastic coating is adapted to the particular application, in particular to the suppression of 3rd octave chatter vibrations. The elastic coating may be made of a rubber-like material or an elastic plastic, in particular an elastomer.

The roller may be located above or supporting below the metal strip. The device may also comprise two or more rollers which can be arranged between the rolling stand and the roll stand arranged in front of it and which can be brought into physical contact with the metal strip in order to damp the chatter vibrations in the downstream rolling stand. With two or more rollers, these may be arranged on the same side of the metal band or on opposite sides of the metal band.

The rolling stands can each be designed as a four-high rolling stand or as a six-high rolling stand.

According to an advantageous embodiment, the thickness of the coating and the material properties of the coating are coordinated such that the spring stiffness of the device is smaller than the spring stiffness of the metal strip. As a result, the chatter frequency to be suppressed can be optimally damped or completely suppressed. The mass and spring stiffness of the coating can be adjusted by varying its layer thickness or material properties.

According to a further advantageous embodiment, the device comprises at least one controllable adjusting device, with which the roller is movable and against the metal band can be adjusted. This makes it possible to immerse the role only in case of need, for example, in the occurrence of chatter vibrations in the metal strip. In a normal operation without chatter vibrations, however, the roller can be moved away from the metal strip by means of the adjusting device and kept at a distance from the metal strip. The adjusting device may have a hydraulic cylinder or otherwise, for example, electromechanical, be formed.

According to a further advantageous embodiment, the device comprises at least one in the conveying direction of the metal strip or opposite thereto offset to the roll and on an opposite side of the metal strip can be arranged counter-roll. As a result, the tape guide is improved. The device can also have two counter-rollers which can be arranged on the opposite side of the metal strip, of which one can be arranged offset in the conveying direction of the metal strip and the other opposite to the conveying direction of the metal strip to the roller.

A rolling mill according to the invention for cold rolling a metal strip comprises at least two rolling stands connected downstream of the rolling line with respect to a conveying direction of the metal strip to be rolled, and at least one device for suppressing chatter vibrations in a rolling stand of the rolling line, which is preceded by at least one further roll stand. According to the invention, the device according to one of the aforementioned embodiments or any combination thereof is formed.

With the rolling mill, the advantages mentioned above with respect to the device are connected accordingly. The rolling train can be designed as a cold rolling train, in particular a two or more-stand tandem mill.

In the following, the invention will be explained by way of example with reference to the attached figures with reference to a preferred embodiment, wherein the features explained below may represent an aspect of the invention both individually and in different combinations with each other. Show it:

1 : a schematic representation of the 3rd octave rattling and the associated effects; and

2 : schematic representation of an embodiment of a rolling mill according to the invention.

In the figures, identical or functionally identical components are provided with the same reference numerals.

1 shows a schematic representation of the 3rd octave rattling and the associated effects. It is a rolling mill 1 for cold rolling a metal strip 2 shown, which is designed as a tandem street. The rolling mill 1 includes two with respect to a conveying direction 3 of the metal strip to be rolled 2 through the rolling mill 1 at a distance l ₀ cascaded rolling stands 4 and 5 , Every rolling stand 4 respectively. 5 includes two work rolls 6 and two back-up rolls 7 , With the rolling stand 5 is the rolling force F _W generated with the metal strip 2 is charged. Regarding the rolling stand 5 has the metal band 2 an incoming strip thickness h ₀ , an inlet side strip speed v ₀ , an intake train z ₀ and an outgoing strip thickness h ₁ , an outlet side strip speed v ₁ and a discharge line z ₁ . At a third octave rattle swing the work rolls 6 of the rolling stand 5 according to the double arrows 8th in opposite directions, which leads to the fluctuation of the outlet side band thickness h _{1 shown} .

2 shows a schematic representation of an embodiment of a rolling mill according to the invention 1 for cold rolling a metal strip 2 , which is designed as a tandem road. The rolling mill 1 includes two with respect to a conveying direction 3 of the metal strip to be rolled 2 through the rolling mill 1 cascaded rolling stands 4 and 5 , Every rolling stand 4 respectively. 5 includes two work rolls 6 and two back-up rolls 7 ,

Furthermore, the rolling mill includes 1 a device 9 for suppressing chatter vibrations in the rolling stand 5 the rolling mill 1 to which the mill stand 4 upstream. The device 9 includes one between the rolling stand 5 and the upstream rolling stand 4 as well as above the metal band 2 arranged, in physical contact with the metal band 2 standing or in the metal band 2 dipping role 10 , An axis of rotation 11 the role 10 runs parallel to axes of rotation 12 the rollers 6 and 7 of the rolling stand 5 , A lateral surface of the roll 10 is with a resilient and the chatter vibrations damping coating 13 Mistake.

Preferably, the thickness of the coating 13 and the material properties of the coating 13 coordinated so that the spring stiffness of the device 9 smaller than the spring stiffness of the metal band 2 ,

The device 9 includes a controllable Anstelleinrichtung 14 with which the role 10 movable and against the metal band 2 is adjustable and attached to a fixed camp 15 supported.

Furthermore, the device comprises 9 one in the conveying direction of the metal strip 2 offset to the role 10 and on an opposite side of the metal band 2 arranged counter role 16 and one opposite to the conveying direction of the metal strip 2 offset to the role 10 and on an opposite side of the metal band 2 arranged counter role 17 , Both counter roles 16 and 17 each based on a fixed camp 18 from.

LIST OF REFERENCE NUMBERS

1

 rolling train

2

 metal band

3

 Belt conveying direction

4

 rolling mill

5

 rolling mill

6

 Stripper

7

 supporting roll

8th

Double arrow (oscillation of 6 )

9

 contraption

10

 role

11

Rotation axis of 10

12

Rotation axis of 6 . 7

13

 coating

14

 adjusting unit

15

 fixed bearing

16

 counter-roller

17

 counter-roller

18

 fixed bearing

l ₀

 stand distance

_FW

 rolling force

h ₀

 incoming strip thickness

h ₁

 leaking strip thickness

v ₀

 inlet side belt speed

v ₁

 outlet belt speed

z ₀

 Einlaufzug

z ₁

 Auslaufzug

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7225657 B2 [0007]
• JP 2008212974 A1 [0007]
• EP 2052796 A1 [0007]
• WO 1997/027953 A1 [0007]
• WO 2012/046211 A1 [0007]
• EP 1343598 B2 [0008]
• WO 1996/027454 A1 [0008]
• JP 8238511 A [0008]

Claims (5)

Contraption ( 9 ) for suppressing chatter vibrations in a rolling stand ( 5 ) of a rolling mill ( 1 ), with respect to a conveying direction ( 3 ) of a metal strip to be rolled ( 2 ) through the rolling mill ( 1 ) at least one further roll stand ( 4 ) is arranged upstream, comprising at least one between the roll stand ( 5 ) and the preceding rolling stand ( 4 ), in physical contact with the metal strip ( 2 ) can be brought ( 10 ), wherein the axis of rotation ( 11 ) of the role ( 10 ) parallel to the axes of rotation ( 12 ) of rolls ( 6 . 7 ) of the roll stand ( 5 ), characterized in that a lateral surface of the roller ( 10 ) at least partially with an elastic and the chatter vibrations damping coating ( 13 ) is provided. Contraption ( 9 ) according to claim 1, characterized in that the thickness of the coating ( 13 ) and the material properties of the coating ( 13 ) are matched to one another such that the spring stiffness of the device ( 9 ) is smaller than the spring stiffness of the metal strip ( 2 ). Contraption ( 9 ) according to claim 1 or 2, characterized by at least one controllable adjusting device ( 14 ), with which the coated roll ( 10 ) and against the metal band ( 2 ) is adjustable. Contraption ( 9 ) according to one of claims 1 to 3, characterized by at least one in the conveying direction ( 3 ) of the metal strip ( 2 ) or inversely offset to the coated roll ( 10 ) and on an opposite side of the metal strip ( 2 ) Anordbare counter role ( 16 . 17 ). Rolling mill ( 1 ) for cold rolling a metal strip ( 2 ), comprising at least two with respect to a conveying direction ( 3 ) of the metal strip to be rolled ( 2 ) through the rolling mill ( 1 ) rolling mills ( 4 . 5 ) and at least one device ( 9 ) for suppressing chatter vibrations in a rolling stand ( 5 ) of the rolling mill ( 1 ), to which at least one further roll stand ( 4 ), characterized in that the device ( 9 ) is designed according to one of claims 1 to 4.

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