EP2473295B1 - Method for adjusting the rolls of a roll stand and roll stand - Google Patents

Description

The invention relates to a method for adjusting the rolls of a roll stand, wherein the roll stand has at least two cooperating work rolls, wherein one of the work rolls in the rolling stand for adjusting a roll gap is slidably disposed and wherein the other work roll in the rolling stand in a working position rotatable, but to define a Pass line in the direction normal to the surface of the rolling stock is determined immovable. Furthermore, the invention relates to a rolling mill with at least two cooperating work rolls. The rolling stand according to the invention may in particular be a 6-high, a 20-roll or a Z-high rolling stand.

It is generally known to arrange the work rolls located in a framework for the rolling of a rolling stock, as well as the support rolls, which continue to be used in most cases, in such a way that the "lower" rolls in the rolling stand are fixed in a defined position in their chocks in the rolling stand a pass line is defined for the rolling stock. Meanwhile, the "upper" rolls are kept adjustable in the vertical direction, so that the size of the nip between the two work rolls can be adjusted. Accordingly, while the "upper" rollers corresponding adjustment means are known to be able to position them in the desired or required vertical position in the rolling stand, this is not true for the "lower" rollers, since they do not have to be adjustable in the vertical direction and should.

The US 5,479,809 or the EP 0 513 946 A2 describe an apparatus for leveling the upper edge of the lower work roll in rolling stands by means of a staircase stepped pair of wedges beneath each lower roll chock.

The JP 08-229605 describes a rolling mill with an upper and a lower work roll, which are each formed at their ends with eccentric bushings which are mounted in worm wheels, which are rotated to adjust the roll gap by means of adjusting motors.

For the position of the rolls in the rolling mill always high effort is operated to keep them as parallel as possible to each other, which is not only necessary for the production of a rolling stock with sufficient quality, but also for optimum operation of the rolling stand subsequent Downstream equipment (eg pulleys or reels). Roller misalignments in the rolling process create a distorted strip tension distribution and disruptive axial forces in the roller bearings, resulting in quality reductions and higher wear.

In constructing the rolling stand, appropriate efforts are made to ensure the parallelism of the rolls. The problem is that the size of the required components (up to 20 m height, up to 300 t weight), the limits for the achievable accuracies and tolerances are reached quickly from an economic point of view. When mounting sliding plates, thrust pieces and other necessary components, the tolerances add up to a maximum and minimum value.

Usually, therefore, the upper support roller including work roll for thickness control (adjustment of the roll gap) is moved vertically. However, the lower support roller remains together with work roll in the once set before rolling start position. The lower work roll is thus firmly on and is underlined for the purpose of accurate positioning with shims or with a movable auxiliary position (wedge or spindle adjustment). In this case, however, can occur by tolerance addition imbalances of the rolls of up to 0.5 mm / m. Such imbalances influence the rolling process with respect to other control circuits, such as the flatness control, since these depend on measured values of the tension distribution over the strip cross section.

The present invention is therefore based on the object to provide a method by which it is possible to ensure in a precise manner, the parallelism of the rolls, the manufacturing tolerances and imbalances by different wear, which determines the horizontal position of the rolls can be compensated , which makes the rolling process easier to control.

1. a) Ermittlung der Lage der fest im Walzgerüst angeordneten Arbeitswalze;
2. b) Vergleichen des ermittelten Wertes der Lage mit einem Sollwert;
3. c) Verstellen der fest im Walzgerüst angeordneten Arbeitswalze in Abhängigkeit des gemäß Schritt b) ermittelten Vergleichswerts mit mindestens einem Stellelement, so dass die Lage der fest im Walzgerüst angeordneten Arbeitswalze den Sollwert zumindest weitgehend erreicht.

The solution of this object by the invention is characterized in that the method comprises the steps of:

1. a) determination of the position of the work roll fixedly arranged in the roll stand;
2. b) comparing the determined value of the position with a desired value;
3. c) Adjustment of the work roll fixedly arranged in the roll stand as a function of the comparison value determined according to step b) with at least one control element, so that the position of the work roll fixedly arranged in the roll stand at least largely reaches the desired value.

The process is preferably carried out before rolling the rolling stock. It is also recommended after a roll change.

According to the invention, the position determination according to step a) above takes place at a reference point of the roll chock of the lower work roll fixedly arranged in the roll stand.

The determination of the location after step a) above is preferably carried out in both axial end regions of the work roll fixedly arranged in the roll stand.

The work rolls are preferably each supported by at least one back-up roll, wherein the adjustment after the above step c) takes place on the back-up roll of the work roll fixedly arranged in the roll stand. The adjustment is preferably carried out on the roll chock of the support roller.

The adjustment after the above step c) is further preferably carried out by using a tension or pressure spindle with combined right-left thread. It is also possible, however, the use of shims or Unterlegescheiben.

The rolling stand with at least two cooperating work rolls, wherein one of the work rolls in the rolling stand for adjusting a roll gap is slidably disposed and wherein the other work roll in the rolling stand in a working position rotatable, but is set immovable to define a pass line in the direction normal to the surface of the rolling characterized in that measuring means are provided for determining the position of the lower work roll fixedly arranged in the roll stand, that comparison means are provided for comparing the determined value of the layer with a desired value and that at least one adjusting element is provided for adjusting the lower work roll fixedly arranged in the roll stand as a function of the difference value between the determined value and the desired value determined by the comparison means.

The roll chock has according to the invention a reference point for the measurement by the measuring means.

The measuring means can be arranged permanently in the rolling stand or can be arranged exchangeably in the rolling stand for temporary measurement.

The adjusting element is preferably a tension or pressure spindle with combined right-left thread.

The invention is based on the idea to determine the position of the roll fixedly positioned in the roll stand, to compare this value with a target value and to compensate for the deviation between the actual and target value by an actuator before the rolling stock is rolled. Preferably, the method is carried out after a roll change.

The position of the roll can ideally be tapped on the roll bale, alternatively also at measuring points on the roll chocks. For picking In the roll position, movable or stationary sensors can be used.

The actuators can in the simplest form consist of inserts but also from individually adjustable auxiliary positions or from pairwise rotatable right-left threads, which are incorporated in printing or drawing spindles. Such spindles are for rolling mills from the EP 1 601 475 B1 known. The drive or operating side of the rolling stand is moved or underlaid in such a way that the "fixed" roller exactly reaches the setpoint.

Fig. 1

die Seitenansicht eines Walzgerüsts mit zwei Arbeits- und zwei Stützwalzen in schematischer Darstellung und

Fig. 2

einen Teil des Walzgerüsts in Walzrichtung gesehen.

In the drawing, an embodiment of the invention is shown. Show it:

Fig. 1

the side view of a rolling stand with two working and two support rollers in a schematic representation and

Fig. 2

a part of the rolling stand seen in the rolling direction.

In the figures, a rolling stand 5 is outlined, in which a total of four rollers are installed, namely two cooperating work rolls 1 and 2 and two support rollers 3, 4. Each roller 1, 2, 3, 4 is mounted in a chock and fixed in the rolling stand 5 , namely the lower work roll 2 in the chock 7, the lower support roll 4 in the chock 12, the upper work roll 1 in the chock 10 and the upper support roll 3 in the chock 11th

The two lower rollers 2 and 4 are arranged "fixed", ie they are set in such a height in the rolling stand 5, that the uppermost point of the work roll 2 forms a pass line P for the (not shown) rolling stock. In order to set a nip between the work rolls 1, 2, consequently, the lower work roll 2 remains in its height position; meanwhile, the upper work roll 1 together with the support roll 3 is moved vertically in the roll stand 5.

In order to optimally adjust the rolls in the roll stand 5 before rolling a rolling stock, the procedure is as follows:

First, the determination of the position S _{Ist is} the work roll 2 fixedly arranged in the roll stand 5. For this purpose, a measuring means 8 is arranged in the roll stand 5. More precisely, there are two measuring means 8, which in the region of the two axial ends (s. Fig. 2 ) are provided. According to the invention, a reference point 13 (reference point) which is measured on the chock 7 (see FIG. Fig. 1 ) is arranged.

The measured actual values S _actual (or S _actual and S _{actual 2} ) of the position are then compared with a stored nominal value S _Soll . For this purpose, a comparison means 9 is used.

Depending on the detected difference between the actual value and the desired value, an adjustment of the work roll 2 in the roll stand 5 then takes place in the vertical direction. For this purpose, at least one, preferably two adjusting elements 6 are used, which are used for height adjustment of the chock 7 of the work roll.

Schematically indicated in Fig. 2 Tensioning or pressure spindles 6, which are provided with a combined right and left hand thread, so that upon rotation of the spindle, the two axial end portions of the spindle are moved together or apart. The adjustment is chosen so that the position S of the fixed in the roll stand 5 arranged work roll 2 assumes the target value S _Soll .

It goes without saying that the difference value between the actual position and the target position determined in the comparison means 9 is converted into an adjustment movement by suitable control or regulating means, which are not shown in the figures.

LIST OF REFERENCE NUMBERS

1

Roller (work roll)

2

Roller (work roll)

3

Roller (support roller)

4

Roller (support roller)

5

rolling mill

6

actuator

7

Roller chock of the work roll 2

8th

measuring Equipment

9

comparison means

10

Roller chock of the work roll 1

11

Roller chock of the back-up roller 3

12

Roller chock of the support roller 4

13

reference point

S

Position of the stripper

S _is

Actual position of the work roll

S _Soll

Target position of the work roll

W

rolling direction

P

pass line

Claims (15)

1. Method of setting the rolls (1, 2, 3, 4) of a roll stand (5), wherein the roll stand (5) comprises at least two co-operating work rolls (1, 2), wherein one of the work rolls (1) is arranged in the roll stand (5) to be displaceable for setting a rolling gap and wherein the other work roll (2) is located in the roll stand (5) to be rotatable in a working position, but, for definition of a pass line (P), to be non-displaceable in a direction normal to the surface of the rolling stock,
   characterised in that
   the method for setting the height positions of the lower work rolls (2) prior to rolling comprises the steps:

   a) determining the position (S_Ist) of the lower work roll (2), which is fixedly arranged in the roll stand (5), by a measuring means (8) at a reference point (13) of the roll chock;

   b) comparing the determined value (S_Ist) of the position with a threshold value (S_Soll); and

   c) adjusting the lower work roll (2), which is arranged in the roll stand (5) and mounted in a chock (7), in height in vertical direction in dependence on the comparison value, which is determined in accordance with step b) by at least one setting element (6) above the lower backing roll (4) so that the position (S) of the lower work roll (2), which is arranged in the roll stand (5), for forming a pass line (P) for the rolling stock achieves the target value (S_Soll).
2. Method according to claim 1, characterised in that it is carried out - with or without rolling stock in the stand - prior to rolling of the rolling stock.
3. Method according to claim 1 or 2, characterised in that it is carried out - with or without rolling stock in the stand - after a roll change.
4. Method according to any one of claims 1 to 3, characterised in that the positional determination in accordance with step a) according to claim 1 is carried out in both axial end regions of the work roll (2) fixedly arranged in the roll stand (5).
5. Method according to any one of claims 1 to 4, characterised in that the work rolls (1, 2) are each supported by at least one backing roll (3, 4), wherein the adjustment in accordance with step c) according to claim 1 is carried at the backing roll (4) of the work roll (2) fixedly arranged in the roll stand (5).
6. Method according to claim 5, characterised in that the adjustment is carried at the roll chock (7) of the backing roll (4).
7. Method according to any one of claims 1 to 6, characterised in that the adjustment in accordance with step c) according to claim 1 is carried out by use of a tension or compression spindle with a combined righthand/lefthand thread.
8. Method according to any one of claims 1 to 6, characterised in that the adjustment in accordance with step c) according to claim 1 is carried out by use of shims or washers.
9. Roll stand (5) comprising at least two co-operating work rolls (1, 2), wherein one of the work rolls (1) is arranged in the roll stand (5) to be displaceable for setting a rolling gap and wherein the other work roll (2) is located in the roll stand (5) to be rotatable in a working position, but, for definition of a pass line (P), to be non-displaceable in a direction normal to the surface of the rolling stock during rolling, particularly for carrying out the method according to any one of claims 1 to 8,
   characterised in that
   measuring means (8) are present for determining the position (S_Ist) at a reference point (13) of the lower work roll (2), which is fixedly arranged in the roll stand (5),
   comparison means (9) are present for comparing the determined value (S_Ist) of the position with a target value (S_Soll) and
   at least one setting element (6) is present for adjusting the chock (7) of the lower work roll (2), which is arranged in the roll stand (5), in dependence on the difference value, which is determined by the comparison means (9), between the determined value (S_Ist) and the target value (S_Soll), wherein a pass line (P) for rolling stock can be formed by the uppermost point of the lower work roll (2).
10. Roll stand according to claim 9, characterised in that the measuring means (8) are positioned for measuring the position (S_Ist) of the roll circumference of the work roll (2).
11. Roll stand according to claim 10, characterised in that the roll chock (7) has a reference point (13) for the measurement by the measuring means (8).
12. Roll stand according to any one of claims 9 to 11, characterised in that the measuring means (8) are permanently arranged in the roll stand (1).
13. Roll stand according to any of claims 9 to 11, characterised in that the measuring means (8) are exchangeably arranged in the roll stand (1) for temporary measurement.
14. Roll stand according to any one of claims 9 to 13, characterised in that the adjusting element is a tension or compression spindle with combined righthand/lefthand thread.
15. Roll stand according to any one of claims 9 to 14, characterised in that the roll stand is a 6-high, a 20-roll or a Z-high roll stand.

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