EP1206981A2 - Multi-roll stand - Google Patents

Abstract

A multi-roll stand (1) with a number of driven support rolls (6, 8) and with a number of work rolls (2, 4) entrained by them via friction drive, in which the work rolls (2, 4) form a roll gap (12) which The thickness of a rolling stock (10) guided between the work rolls (2, 4) in a rolling direction (x) should, on the one hand, be able to be used in a comparatively high rolling force range, on the other hand, the rolling gap (12) and thus the thickness should also be used with comparatively small rolling forces of the rolling stock (10) can be adjusted particularly precisely. For this purpose, the work rolls (2, 4) for adjusting the gap width of the roll gap (12) can be moved in a direction essentially parallel to the rolling direction (x). <IMAGE>

Description

The invention relates to a multi-roll stand with a number of driven Back-up rolls and with a number of these via friction drive entrained work rolls, the work rolls forming a nip, which is the thickness of one passed between the work rolls in one rolling direction Rolling stock pretends.

A roll stand can be used to roll a rolling stock, for example in a rolling mill are used. The roll stand is often a so-called Multi-roll stand and includes a number of working and a number of backup rolls. The back-up rolls are usually of one assigned drive driven, each backup roller with an associated Work roller is in frictional contact. Through the friction drive thus produced each work roll is supported by its associated support roll with powered. The work rolls act on both sides of a rolling stock, the thickness of the between the work rolls through the multi-roll stand guided rolling stock determined by the roll gap formed by the work rolls becomes. The thickness of the rolling stock passed through the multi-roll stand can thereby by means of a corresponding variation of what is also referred to as the rolling force The contact pressure of each work roll can be set.

When processing a comparatively high-quality rolling stock such as Steel or stainless steel can, especially for the so-called skin pass of such rolling stock, be significant that the respective multi-roll stand is designed to cover a comparatively high rolling force range. A provision provided for this, via which, among other things, the setting of the Thickness of the rolling stock takes place, thus also covers the value range comparatively large rolling force range. However, with such System the essential components usually designed such that Measuring errors such as errors in the rolling force measurement depending on Maximum value of the respective measured value are. Especially when measuring the rolling force, whose range of values covers a comparatively large rolling force range, the absolute measurement error is therefore comparatively large.

On the other hand, the so-called skin-passaging of IF steel also applies to such Multi-roll stands the setting of comparatively small rolling forces required. Accordingly, in the case of a multi-roll stand, which can be used on the one hand Dressing IF steel should be used and on the other hand to cover a overall comparatively large rolling force range is provided, the Measurement errors in the determination of the rolling force greater than that for skin passaging the IF steel intended rolling force itself. The thickness and / or skin pass level control in such a multi-roll stand is therefore comparatively imprecise.

The invention is therefore based on the object, a multi-roll stand of the above Specify the type mentioned, on the one hand in a comparatively high rolling force range can be used, and on the other hand also with comparatively small ones Rolling forces in terms of its roll gap and thus in terms of the thickness of the Rolling stock is particularly precisely adjustable. Furthermore, a method of operation is said to of such a multi-roll stand can be specified that also at comparatively small rolling forces a particularly precise thickness control of the Rolling stock enables.

With regard to the multi-roll stand, this object is achieved according to the invention, by the work rolls to adjust the gap width of the roll gap in one Direction are essentially parallel to the rolling direction.

The invention is based on the consideration that the thickness setting of Rolled stock can be made with a particularly high accuracy by using a control parameter with a comparatively large travel range. The real one Control variable for the thickness setting, namely the position of the respective Work roll perpendicular to the rolling direction to form the nip, but points only a comparatively short travel range. It is therefore used in a manipulated variable with a comparatively longer travel range, namely the position of the work roll in a direction parallel to the rolling direction. When adjusting rolls the work roll on the surface of the spatially stationary support roll, so that a unique relationship between the position of the work roll perpendicular to the rolling direction and their position in the rolling direction. Especially in one area the geometric conditions are located directly below the backup roller such that a comparatively large displacement of the work roll in Rolling direction in only a slight change in their position in the direction results perpendicular to the rolling direction.

A rolling mill for carrying out the rolling stock is usually essentially horizontal rolling direction. The are therefore advantageously Work rolls adapted to adjust the gap width of the roll gap in the can be moved horizontally.

For a particularly reliable, automated thickness adjustment of the rolling stock a control device is advantageously assigned to the multi-roll stand. This is expediently on the output side with a number of adjusting devices connected, each of which has a work roll for adjusting its Position in the rolling direction is assigned. The control device gives for each control device has a control value for the positioning of the respective Work roll in the rolling direction, the respective manipulated variable depending on a measured actual value for the thickness of the rolling stock is selected.

Various types can be used for the actuating devices acting on the work rolls Embodiments, for example in the form of rotating spindles, may be provided. However, the actuating devices are advantageously in the form of hydraulic actuating devices trained, achieving a particularly high setting accuracy leaves.

For a timely and particularly responsive control is advantageous a direct application of the control device with a for the thickness of the Rolled characteristic characteristic value provided. This is the control device advantageously on the input side with a for detecting the thickness of the rolling stock designed transmitter connected.

To be in the manner of a selectable rolling program for a variety of different The purpose is to have suitably predefined operating parameters available Control device in a further expedient embodiment, a memory module assigned in which a number of target values for the thickness of the rolling stock can be stored is. Depending on the current application, it can be particularly simple Can be switched between different rolling programs by a new updated target value for the thickness of the rolling stock from each setpoints stored in the memory block is selected.

With regard to the method for operating a multi-roll stand, the said Task solved by changing the thickness of the rolling stock by a shift of the work rolls in a direction substantially parallel to the rolling direction is set.

The setting of the position of the work rolls in the rolling direction is advantageous based on a comparison of a currently determined thickness of the rolling stock with a target value for the thickness of the rolling stock.

The advantages achieved with the invention are in particular that the displacement of the work rolls in the rolling direction for the purpose of adjustment the gap width of the roll gap indirectly influences the thickness of the rolling stock and via a control parameter with a comparatively large travel range. Precisely due to the geometrical relationships between the support rollers and the Work rolls are thus the displacement strokes of the work rolls, that is to say the achievement a specifiable change in the gap width of the roll gap required Changes in position, especially large, so that the sensitivity and Accuracy in setting the gap width of the roll gap is particularly high. In addition, the position of the work rolls is adjusted to the rolling force in the substantially vertical direction, so that coupling to the rolling force only via the deflection in the work roll itself. Incidentally, at such an adjustment of the gap width of the roll gap especially the framework friction kept low.

An embodiment of the invention is explained in more detail with reference to a drawing. The figure shows a multi-roll stand.

The multi-roll stand 1 is designed as a four-roll stand and comprises one upper and lower work rolls 2 and 4, which are substantially vertical of each a support roller 6 and 8 are supported. The work rolls 2, 4 are not assigned roller bending devices, which are used to set a Apply the vertical roll bending forces to the work rolls 2, 4.

The support rollers 6, 8 can each be driven by a drive, not shown in detail, keeping them rotating around their central axis. Every work roll 2, 4 is with the respective support roller 6 or 8 in frictional contact, so that it is driven by the one assigned to it Back-up roller 6 or 8 is taken along in the friction drive.

Between the work rolls 2, 4 is in one indicated by the arrow a rolling stock 10 is guided essentially in the horizontal rolling direction x. The work rolls 2, 4 form in substantially perpendicular to the rolling direction x Direction of a roll gap 12, the thickness of the leaving the multi-roll stand 1 Rolling stock 10 specifies.

The multi-roll stand 1 is on the one hand for loading the rolling stock 10 with a rolling force oriented substantially perpendicular to the rolling direction x formed a comparatively large rolling force range. It is by means of a Not shown actuator, the rolling force on the support rollers 6, 8th adjustable, which is transferred via the work rolls 2 and 4 to the rolling stock 10. The multi-roll stand 1 is both for comparatively low rolling forces, as they are required, for example, for the dressing of IF steel, as well as for comparatively high rolling forces designed and therefore in terms of its purpose particularly flexible.

On the other hand, the multi-roll stand 1 is also - especially in comparison small rolling forces - for a particularly precise adjustment of the thickness of the rolling stock 10 trained. For this purpose, the multi-roll stand 1 is a control device 20 assigned over which the work rolls 2, 4 for setting the gap width of the Rolling gap 12 can be displaced in a direction essentially parallel to the rolling direction x are. For this purpose, each work roll 2, 4 is parallel in one direction at the end slidably supported to the rolling direction x. In addition, each work roll 2, 4 is each an adjusting system 22 or 24 assigned. The assigned to the work roll 2 Control system 22 comprises a hydraulically actuated control piston 26, the Actuating pressure can be applied via an adjusting device 28 designed as a pressure transmitter is. Analogously, the control system assigned to the second work roll 4 comprises 24 an actuating piston 30, which is configured as a pressure transmitter 32 can be acted upon with signal pressure.

The control device is used to adjust the position of each work roll 2, 4 in the rolling direction x via data lines 34, 36 on the output side with the actuating devices 28, 32 connected. The control device outputs the data lines 34, 36 the actuating devices 28 and 32 each have a manipulated value S based on them the setting of a signal pressure via the respective adjusting device 28 or 32 takes place, which in turn the respective position of the work roll 2 or 4 in Roll direction x specifies.

The control device 20 is for tracking the position setting of the work rolls 2, 4 in the rolling direction x as a function of the thickness of the rolling stock 10 educated. For this purpose, the control device 20 is on the input side via a data line 40 with a transducer designed to detect the thickness of the rolling stock 10 42 connected. The control device uses the control values S the positions of the work rolls 2, 4 in the rolling direction x until the Sensor 42 detected thickness of the rolling stock 10 a predetermined target value Sw equivalent. The setpoint Sw is dependent on a predefinable purpose, from a plurality of in one connected to the control device 20 Data store 44 stored setpoints Sw can be read out.

Due to the continued contact between the rolling force each work roll 2, 4 and the respective support roll 6 or 8 rolls the respective work roll 2, 4 on the surface of the assigned Support roller 6, 8 from. The shift results due to these boundary conditions the respective work roll 2, 4 in a direction parallel to the rolling direction x also in a change in the position of the respective work roll 2, 4 in one direction perpendicular to the rolling direction x and thus in a change in the gap width of the roll gap 12. Because of the geometric conditions in the arrangement of the work rolls 2, 4 results approximately in the middle between the support rolls 6, 8 a comparatively large-scale movement of the work rolls 2, 4 in one Direction parallel to the rolling direction x with only a slight change in it Position in a direction perpendicular to the rolling direction x. So it's about a comparative large travel in the direction parallel to the rolling direction x a comparatively small and therefore high-resolution change in the gap width of the Roll gap 12 accessible. Accordingly, the regulation for setting the Roll gap 12 of high accuracy even with comparatively low rolling forces.

LIST OF REFERENCE NUMBERS

1

More rolling mill

2, 4

strippers

6, 8

backup rolls

10

rolling

12

nip

20

control device

22, 24

tellsystem

26

actuating piston

28

setting device

30

actuating piston

32

setting device

34, 36

data lines

40

data line

42

transmitter

44

data storage

S

control value

sw

setpoint

x

rolling direction

Claims (8)

Multi-roll stand (1) with a number of driven support rolls (6, 8) and with a number of work rolls (2, 4) entrained by them via friction drive, the work rolls (2, 4) forming a roll gap (12) which defines the thickness specifies a rolling stock (10) guided between the work rolls (2, 4) in a rolling direction (x),
characterized in that the work rolls (2, 4) for adjusting the gap width of the roll gap (12) can be displaced in a direction essentially parallel to the rolling direction (x). Multi-roll stand according to claim 1,
characterized in that the work rolls (2, 4) for adjusting the gap width of the roll gap (12) are essentially horizontally displaceable. Multi-roll stand according to claim 1 or 2,
characterized in that each work roll (2, 4) is assigned a setting device (28, 32) for setting its position in the rolling direction (x), the setting devices (28, 32) of the work rolls (2, 4) having a common control device (20) are connected, which for each actuating device (28, 32) each have a manipulated value (S) as a function of a measured actual value for the thickness of the rolling stock (10) and a predefinable target value (Sw) for the thickness of the rolling stock (10 ) issues. Multi-roll stand according to claim 3,
characterized in that the actuating devices (28, 32) acting on the work rolls (2, 4) are designed as hydraulic actuating devices. Multi-roll stand according to claim 3 or 4,
characterized in that the control device (20) is connected on the input side to a transducer (42) designed to detect the thickness of the rolling stock (10). Multi-roll stand according to one of claims 3 to 5,
characterized in that the common control device (20) is assigned a memory module in which a number of target values (Sw) for the thickness of the rolling stock (10) can be stored. Method for operating a multi-roll stand (1) according to one of claims 1 to 6,
characterized in that the thickness of the rolling stock (10) is adjusted by shifting the work rolls (2, 4) in a direction essentially parallel to the rolling direction (x). Method according to claim 7,
characterized in that the setting of the position of the work rolls (2, 4) in the rolling direction (x) is carried out on the basis of a comparison of a currently determined thickness of the rolling stock (10) with a target value (Sw) for the thickness of the rolling stock (10).

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