U.S. patent application number 10/483706 was filed with the patent office on 2004-09-16 for cold rolling mill and method for cold roll forming a metallic strip.
Invention is credited to Brockes, Udo, Jepsen, Olaf Norman, Stachuletz-Kuhbacher, Angela, Stachuletz, Manfred, Zielenbach, Michael.
Application Number | 20040177666 10/483706 |
Document ID | / |
Family ID | 7691436 |
Filed Date | 2004-09-16 |
United States Patent
Application |
20040177666 |
Kind Code |
A1 |
Brockes, Udo ; et
al. |
September 16, 2004 |
Cold rolling mill and method for cold roll forming a metallic
strip
Abstract
The invention relates to a method for cold roll forming a
metallic strip (8), a steel strip in particular, comprising a
single fame (1), having means for adjusting a roll gap, a winding
device (9) which is arranged upstream of the cold roll single frame
for unwinding the strip (8), and a winding device (10) which is
arranged downstream of the cold roll single frame (1) for winding
the strip (8). The aim of the invention is to eliminate all
problems connected to strip tension when the thickness of the strip
varies and to increase the speed of the strip. To achieve this, a
strip accumulator (2) is arranged between the upstream winding
device (9) and the single frame (1) for controlling the mass flow
and/or tension of the rolling process, particularly when flexible
rollers are used.
Inventors: |
Brockes, Udo;
(Niederkruchten, DE) ; Jepsen, Olaf Norman;
(Siegen, DE) ; Zielenbach, Michael; (Siegen,
DE) ; Stachuletz, Manfred; (Dusseldorf, DE) ;
Stachuletz-Kuhbacher, Angela; (Dusseldorf, DE) |
Correspondence
Address: |
THE FIRM OF KARL F ROSS
5676 RIVERDALE AVENUE
PO BOX 900
RIVERDALE (BRONX)
NY
10471-0900
US
|
Family ID: |
7691436 |
Appl. No.: |
10/483706 |
Filed: |
February 17, 2004 |
PCT Filed: |
July 10, 2002 |
PCT NO: |
PCT/EP02/07689 |
Current U.S.
Class: |
72/205 |
Current CPC
Class: |
B21B 39/08 20130101;
B21B 1/36 20130101; B21B 37/54 20130101; B21B 37/48 20130101; B21B
41/00 20130101; B21B 37/24 20130101; B21B 2037/002 20130101 |
Class at
Publication: |
072/205 |
International
Class: |
B21B 039/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 11, 2001 |
DE |
101 33 756.6 |
Claims
1. A cold rolling mill for the cold rolling metallic strip (8),
especially steel, with a single-frame mill (1) with means for
adjusting a rolling gap as well as a coiler device (9) upstream of
the single-frame cold rolling mill for unwinding the strip (8) of
the single-frame cold rolling mill for unwinding the strip (8) and
a coiling device (10) downstream of the single-frame cold rolling
mill (1) for winding up the strip (8), characterized in that
between the upstream coiling device (9) and the single frame
rolling mill (1) a strip storage (2) is arranged for a mass flow
control and/or strip tension control of the rolling process,
especially in the case of flexible rolling.
2. A cold rolling mill according to claim 1, characterized in that
in addition to the first strip storage (2) arranged between the
upstream coiler device (9) and the single frame mill (1), a second
strip storage (3) is arranged between the single frame mill (1) and
the downstream coiler device (10).
3. A method of cold rolling a metal strip (8) especially of steel,
in a cold rolling mill with a single frame (1) with means for
adjusting a rolling gap for the cold rolling of the strip as well
as a coiler device (9) arranged upstream of the single frame (1)
for unwinding the strip (8) and a coiler device (10) downstream of
the single frame (1) for winding up the strip (2), characterized in
that by means of the single frame (1) a rolling, especially a
flexible rolling is carried out in which the strip thickness during
the rolling is continuously changed in accordance with a
predetermined pattern and that by means of a strip storage (2)
which is arranged between the upstream coiler device (9) and the
single frame mill (1) a mass flow control and/or a strip tension
control of the rolling process is effected.
4. The method according to claim 3, characterized in that the
coiler devices (9, 10) are speed-controlled coiler devices.
5. The method according to claims 3 or 4, characterized in that in
a control circuit for the control of the position of the strip
storage (2, 3), especially of a dancer roller (6, 7), a force
correction value is calculated by means of a force controller from
an actual force value and a setpoint force value obtained from the
positioning unit (18) whereby the setpoint force value is
calculated from an actual angle value derived from the dancer
roller and a predetermined setpoint tension value.
6. The method according to one of claims 3 to 5, characterized in
that the strip storage (2, 3) is controlled as a function of a
known variation in the strip thickness pattern.
Description
[0001] The invention relates to a cold rolling mill and to a method
of cold rolling metal strip, especially steel strip, with a
single-frame rolling mill with means for adjusting a rolling gap
and a coiler device upstream of the cold rolling mill frame for
uncoiling the strip fed to the mill.
[0002] In previously known cold rolling with single frame mills,
only incoming strip with a narrow thickness tolerance can be used
and the strip thickness reduction is maintained constant over the
strip length. To the extent that these requirements cannot be met,
the strip speed is greatly limited and problems have to be expected
with respect to the rolling operation.
[0003] In WO 99/55474 a Steckel rolling mill is described for hot
rolling, having at least one reversible rolling mill frame as well
as coilers disposed upstream and downstream thereof. Between the
coilers and the reversing mill frame, respective loop lifters are
provided which supply actual values for a tension control and a
mass flow control. Such a Steckel rolling mill, however, relates to
hot rolling mills and, therefore, not to any cold rolling
process.
[0004] Starting from the background of cold rolling technology, the
invention has as its object to provide a method of cold rolling as
well as a cold rolling mill with a single-frame mill and which in
spite of changes in the strip thickness and large strip speeds does
not have any problems with respect to the mass flow and/or the
strip tension.
[0005] These objects are achieved with a cold rolling mill with the
features of claim 1 as well as by a method with the features of
claim 3. Advantageous further developments are described in the
dependent claims.
[0006] According to the invention it is proposed that between the
upstream coiler and the single mill frame for the cold rolling, a
strip storage is disposed for a mass flow regulation and/or a
stripper tension regulation of the rolling process, especially in
the case of flexible rolling.
[0007] Because of the strip storage in the strip travel direction
upstream of the single mill frame, mass flow changes or strip speed
changes which have their origins in a variation in the strip
thickness or a variation in the strip thickness pattern in flexible
rolling are compensated. This has the advantage that a rolling
remains possible at higher speeds even in the case of changing
strip thicknesses or strip thicknesses which sequentially follow
one another.
[0008] The speed changes because of changes in the strip
thicknesses in the rolling gap are greatest at the inlet side of
the single mill frame so that the strip storage according to the
invention is provided at least at the inlet side or in the inlet
region. Since the detriment caused by changes in the strip
thickness pattern in the case of flexible rolling occur as well,
although they are not as great, at the outlet side and are
reflected in changes in the strip speed at the outlet side in a
preferred embodiment of the invention, it is also proposed to
dispose a strip storage at the outlet side of the single mill
frame.
[0009] Preferably each of the strip storages has a dancer roller. A
dancer roller or a dancer roller arrangement includes a roller
which is pressed with a certain force against the strip and which
is adjustable within a certain angle so that a loop is formed in
the strip around the dancer roller and such that the loop length
varies with the position of the roller. In this manner more or less
of the strip can be stored. According to a preferred embodiment of
the invention, a respective dancer roller is provided both at the
inlet and at the outlet regions of the single mill frame and both
are advantageously of identical construction.
[0010] The proposed method is described in detail with the aid of
the following Figures in which the individual Figures show:
[0011] FIG. 1 a layout of an apparatus of an embodiment of a cold
rolling frame according to the invention with flexible cold rolling
with respective dancer rollers at the inlet and outlet regions;
[0012] FIG. 2 a detailed elevation of the dancer roller as well as
a preferred embodiment of its positioning and control;
[0013] FIG. 3 an overview of the strip tension and mass flow
control circuits with flexible cold rolling using a single frame
mill;
[0014] FIG. 4 an overview of the strip thickness control circuit in
combination with the strip tension control as well as a
compensation of the mass flow faults with flexible cold rolling
with a single frame mill.
[0015] FIG. 1 provides an overall view of an apparatus having a
single frame cold rolling mill 1 with strip storage 2, 3 at both
the inlet region (4) and the outlet region (5) of the single frame
mill 1 and each of which encompasses a dancer roller 6, 7. The
coiled up strip 8 is uncoiled with the aid of a coiling device 9
and is fed into the rolling frame 1 in the direction of the arrow.
After traversing the single frame mill 1, the strip is coiled up by
means of a second coiler 10. In each of the inlet regions (4) and
the outlet regions (5), a respective dancer roller 6, 7 is
provided, the dancer coilers being of identical construction and
have been illustrated in detail in FIG. 2 with other adjustability.
The single frame mill 1 itself is comprised, in the illustrated
embodiment, of two backup rolls 11, two intermediate rolls 12 and
the working rolls 13, 14. Any other arrangement of rolls in a
single frame can also be used. Between the roll frame 1 and the
dancer rolls 6, 7, for example at the outlet side 5, a marking
device 15 can be arranged in the strip line.
[0016] FIG. 2 shows the mechanism and control of a dancer roller 6
with a flexible cold rolling. With the aid of the adjustment of the
dancer roll on the strip 8 with respect to two neighboring rollers
16, 17, a loop is formed inteh striper 8 with a loop length which
changes with the position of the dancer roller 6 or its angular
setting with respect to the roller 16. The deeper the dancer roller
6 penetrates into the strip 8, the more of the strip which is
stored. The illustrated embodiment shows a hydraulic adjustment 18
for the dancer roller 6.
[0017] The dancer roller 6 is associated with a force controller
19. For this control, an actual force value as well as an actual
angle value of the positioning of the dancer roller 6 are obtained.
This actual force value is supplied to the force controller 19
together with a force setpoint value. In this case, the force
setpoint value is not predetermined but rather is calculated from
the measured actual angle value and a predetermined setpoint
tension. The force control circuit provides, as a result of the
comparison of the setpoint and actual force values, a force
correction value which is applied to the positioning unit 18, here
a hydraulic piston and cylinder unit for the dancer roller 6. By
means of the force correction, a correction of the tension
developed by the strip in traction is achieved.
[0018] The actual angle value measured at the dancer roller is also
used for the control of the rotary speed setting of the coiler
devices (9, 10) and thus torque control of the coilers for mass
flow control. For this purpose the actual angle value as well as a
predetermined setpoint angle are fed to an angle controller. As a
function of the result of the setpoint-actual value comparison, an
angle correction value is calculated. This angle correction value
serves for control of the speed in the coiler devices for mass flow
control.
[0019] An overview of this strip tension control and mass flow
control by means of the dancer rollers 6, 7 at the inlet and outlet
regions (4, 5) of a cold rolling frame 1 has been shown in FIG. 3.
The strip tension control is effected by calculating a setpoint
force for controlling the hydraulic setting of the dancer roller,
starting from the actual force value while the mass flow control
results from control of the speed of the coilers.
[0020] In the control circuit for coiler speed, that is the
uncoiler speed or the recoiler speed, the setpoint value is the
strip speed. This also serves as a setpoint for the roll speed
control.
[0021] With the aid of FIG. 4, the strip thickness control has been
shown in the case of flexible rolling. A flexible rolling process
means that there will be a change in the rolling gap in the course
of rolling and thus an valuation in strip thickness patterns over
the strip length. A setpoint strip thickness pattern is
predetermined. This setpoint value of the course of the strip
thickness is used for initial control of the inlet side dancer
roller. From the setpoint course of the strip thickness, the change
in the inlet speed of the strip in the rolling mill frame is
calculated together with the strip tension required for it to
maintain a constant strip tension. For mass flow compensation, the
inlet tension can be further smoothed out. Additionally the values
of the setpoint strip thickness course can be supplied to a
thickness controller which with the aid of actual strip thickness
values obtained at the inlet and outlet side, corrections and
values for the strip thickness can be calculated, these correction
values further supplied to a position controller which controls the
rolling gap setting in the cold rolling frame.
* * * * *