U.S. patent application number 11/660174 was filed with the patent office on 2007-11-15 for rolling mill for rolling a metallic strip.
Invention is credited to Olaf Norman Jepsen, Hans-Peter Richter, Michael Zielenbach.
Application Number | 20070261456 11/660174 |
Document ID | / |
Family ID | 35033388 |
Filed Date | 2007-11-15 |
United States Patent
Application |
20070261456 |
Kind Code |
A1 |
Jepsen; Olaf Norman ; et
al. |
November 15, 2007 |
Rolling Mill for Rolling a Metallic Strip
Abstract
In a rolling mill for rolling metal strip (1), especially steel
strip, which has at least one rolling stand (2), an upstream coiler
(3), and a downstream coiler (4), wherein an "S" roll unit (5, 6),
which has two rolls (7, 8; 9, 10) that guide the strip (1) in the
form of an "S", is arranged between the upstream coiler (3) and the
rolling stand (2) and/or between the rolling stand (2) and the
downstream coiler (4), the invention provides that a first roll (7,
9) of the "S" roll unit (5, 6) is arranged in a fixed manner, and a
second roll (8, 10) of the "S" roll unit (5, 6) is arranged in such
a way that it can move relative to the first roll (7, 9).
Inventors: |
Jepsen; Olaf Norman;
(Siegen, DE) ; Richter; Hans-Peter; (Friedewald,
DE) ; Zielenbach; Michael; (Siegen, DE) |
Correspondence
Address: |
FRIEDRICH KUEFFNER
317 MADISON AVENUE, SUITE 910
NEW YORK
NY
10017
US
|
Family ID: |
35033388 |
Appl. No.: |
11/660174 |
Filed: |
August 10, 2005 |
PCT Filed: |
August 10, 2005 |
PCT NO: |
PCT/EP05/08686 |
371 Date: |
February 14, 2007 |
Current U.S.
Class: |
72/227 |
Current CPC
Class: |
B21B 39/082 20130101;
B21B 37/54 20130101; B21B 1/36 20130101; B21B 37/24 20130101; B21B
37/48 20130101 |
Class at
Publication: |
072/227 |
International
Class: |
B21B 41/00 20060101
B21B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 26, 2004 |
DE |
10 2004 041 321.5 |
Claims
1. Rolling mill for rolling metal strip (1), especially steel
strip, which has at least one rolling stand (2), an upstream coiler
(3), and a downstream coiler (4), wherein an "S" roll unit (5, 6),
which has two rolls (7, 8; 9, 10) that guide the strip (1) in the
form of an "S", is arranged between the upstream coiler (3) and the
rolling stand (2) and/or between the rolling stand (2) and the
downstream coiler (4), characterized by the fact that a first roll
(7, 9) of the "S" roll unit (5, 6) is arranged in a fixed manner,
and a second roll (8, 10) of the "S" roll unit (5, 6) is arranged
in such a way that it can move relative to the first roll (7,
9).
2. Rolling mill in accordance with claim 1, characterized by the
fact that the second roll (8, 10), which can move relative to the
first roll (7, 9), is rotatably mounted on a swivel arm (11), which
is supported at one end in a stationary axis (12).
3. Rolling mill in accordance with claim 2, characterized by the
fact that the stationary axis (12) coincides with the axis of
rotation of the first roll (7, 9).
4. Rolling mill in accordance with claim 2 or claim 3,
characterized by the fact that a linear actuator (14) articulates
with the swivel arm (11) in a pivot (13) some distance from the
stationary axis (12).
5. Rolling mill in accordance with claim 4, characterized by the
fact that the linear actuator (14) is a hydraulic piston-cylinder
system.
6. Rolling mill in accordance with any of claims 1 to 5,
characterized by means for driving at least one of the rolls (7, 8,
9, 10) of the "S" roll unit (5, 6).
7. Rolling mill in accordance with any of claims 1 to 6,
characterized by the fact that it is designed as a cold rolling
mill.
8. Rolling mill in accordance with any of claims 1 to 7,
characterized by the fact that the rolling stand (2) is a single
stand.
9. Rolling mill in accordance with any of claims 1 to 8,
characterized by the fact that the rolling stand (2) is equipped
with means for flexible adjustment of the roll gap.
10. Rolling mill in accordance with any of claims 1 to 9,
characterized by the fact that at least one of the coilers (3, 4)
is equipped with means for rotational speed control.
Description
[0001] The invention concerns a rolling mill for rolling metal
strip, especially steel strip, which has at least one rolling
stand, an upstream coiler, and a downstream coiler, wherein an "S"
roll unit, which has two rolls that guide the strip in the form of
an "S", is arranged between the upstream coiler and the rolling
stand and/or between the rolling stand and the downstream
coiler.
[0002] The increasing necessity for weight savings, especially in
the automobile industry, has led to the development and use of
load-adapted parts, so-called tailored blanks. The essential
feature of these parts that is of special importance in this
connection is that they have a variable thickness. Tailored
blanks-were originally produced mainly by welding. However, it was
found that they can also be produced in an especially favorable way
by flexible cold rolling, which can be used to produce tailored
blanks.
[0003] In flexible cold rolling, the thickness of the rolling stock
is varied during rolling. In this regard, the roll gap can be
periodically varied. The thickness variation results in mass flow
disturbances and tension fluctuations, especially on the entry side
of the rolling stand but also on the delivery side of the rolling
stand. At the rolling speeds necessary for profitable production,
these mass flow disturbances and tension fluctuations can no longer
be compensated by the dynamics of the coiler motors, so that
so-called dancer rolls are used between the rolling stand and the
coilers in installations of this type.
[0004] WO 03/008,122 A1 describes a solution of this type. It
discloses a cold rolling mill for cold rolling metal strip, which
has a single stand with means for adjusting the roll gap, a coiler
for uncoiling the strip upstream of the single cold rolling stand,
and a coiler for coiling the strip downstream of the rolling stand.
To achieve flexible rolling, a strip accumulator is arranged
between the upstream coiler and the rolling stand for controlling
the mass flow and the strip tension. This strip accumulator
consists of at least three rolls. The middle roll is designed as a
dancer roll and can be moved perpendicularly to the direction of
conveyance of the strip.
[0005] EP 1 121 990 A2 discloses a similar solution--but with the
use of a larger number of rolls. The same is true of a design
disclosed by JP 10-034,204 A1.
[0006] The dancer rolls described in the cited documents are
connected with a linear actuator, with which they can be moved
perpendicularly to the direction of conveyance of the strip under
open-loop or closed-loop control. The strip accumulator function
that is essential for flexible cold rolling can be fulfilled in
this way.
[0007] DE 198 18 207 C2 and JP 60-231,516 disclose so-called
loopers, i.e., rolls which are applied to the strip fed to the
rolling stand or carried away from the rolling stand, in order, for
example, to be able to undertake a determination of the tensile
force in the strip.
[0008] During rolling, the rolling force can be reduced by tensile
forces on each side of the roll gap. However, it is only in the
last pass that it must not be too high, since otherwise, as is
known from experience, problems can arise in the subsequent process
steps, especially during annealing. "S" roll units ("S" rolls) can
be used to develop a tension difference between the rolling stand
and coiler.
[0009] When both a strip accumulator function is to be realized,
generally with dancer rolls, and a desired tension difference
between the rolling stand and the coiler is to be produced,
generally by "S" roll units, considerable equipment expense is
required in the prior-art solutions.
[0010] Therefore, the objective of the invention is to modify a
metal strip rolling mill of the aforementioned type in such a way
that simple and thus economical means can be employed both to
realize a strip accumulator function, especially in the case of
flexible rolling, and to maintain a tension difference between the
rolling stand and coilers that can be controlled in a well-defined
way.
[0011] In accordance with the invention, this objective is achieved
by arranging a first roll of the "S" roll unit in a fixed manner
and arranging a second roll of the "S" roll unit in such a way that
it can move relative to the first roll.
[0012] Apart from guide rolls for the strip that may additionally
be present, only the "S" roll unit is intended, in accordance with
the invention, to be provided between the coiler and rolling stand,
but both the strip accumulator function can be provided and the
required tension on the strip can be exerted with the proposed
design of the "S" roll unit.
[0013] In a preferred embodiment, the second roll, which can move
relative to the first roll, is rotatably mounted on a swivel arm,
which is supported at one end in a stationary axis. The two axes of
the rolls of the "S" roll unit are arranged parallel to each other.
It is advantageous for the stationary axis to coincide with the
axis of rotation of the first roll.
[0014] To swivel the second roll relative to the first roll, a
linear actuator articulates with the swivel arm, preferably in a
pivot some distance from the stationary axis. It is advantageous to
use a hydraulic piston-cylinder system as the linear actuator.
[0015] To be able to influence the development of tension in the
strip in an optimum way, means can be provided for driving at least
one of the rolls of the "S" roll unit.
[0016] The proposal of the invention can be used to advantage in a
cold rolling mill. In addition, the rolling stand is preferably a
single stand. The proposed system is suitable especially for
flexible rolling, which is why the rolling stand can have means for
flexible adjustment of the roll gap.
[0017] Finally, strip conveyance or handling is improved by
equipping at least one of the coilers with means that allow
rotational speed control.
[0018] The proposed system makes it possible in a very simple and
thus inexpensive way to provide a rolling plant for flexible
rolling that makes available a strip accumulator, which is
essential in this type of operation. In addition, the strip is also
maintained at the required tension, so that the rolling itself can
be carried out in an advantageous way from the standpoint of
process engineering.
[0019] A specific embodiment of the invention is illustrated in the
drawings.
[0020] FIG. 1 shows a schematic side view of a rolling mill for the
flexible rolling of metal strip.
[0021] FIG. 2 shows an enlarged view of an "S" roll unit on the
discharge side of the rolling mill.
[0022] FIG. 1 shows a schematic view of a rolling mill, in which a
coiled steel strip 1 is uncoiled from an upstream coiler 3 and fed
to a single cold rolling stand 2. Another coiler 4, which re-coils
the rolled metal strip 1, is installed downstream of the rolling
stand 2 in the direction of conveyance R of the metal strip 1. The
coilers 3, 4 are provided with drives (not shown), so that the
strip 1 can be uncoiled and coiled under open-loop or closed-loop
control.
[0023] Flexible cold rolling of the strip is carried out in the
rolling stand 2. The strip 1 has a nonconstant thickness--as viewed
in its longitudinal direction. This means that, during the rolling
process, the roll gap is varied in accordance with a preset profile
to produce a strip whose thickness varies periodically.
[0024] To allow this process to be carried out under conditions
that are favorable from the standpoint of process engineering, it
is necessary to compensate the change in mass flow in the strip
that results from the variable strip thickness. Furthermore, a
well-defined tension must be developed and maintained in the strip
1 to keep the rolling force low.
[0025] To accomplish this, an "S" roll unit 5, 6 is installed
between the upstream coiler 3 and the rolling stand 2 and between
the rolling stand 2 and the downstream coiler 4, respectively. Each
"S" roll unit has two rolls 7, 8 and 9, 10, respectively, which are
arranged relative to each other in a well-known way, so that the
strip 1 is guided in an S-shaped path. The resulting wrapping of
the rolls 7, 8, 9, 10 makes it possible, with suitable driving of
the rolls, to transmit a force to the strip 1 and thus to maintain
the desired tension in the strip 1 between the "S" roll unit 5, 6
and the rolling stand 2.
[0026] To be able to achieve both the application of tension in the
strip and the strip accumulator function, the "S" roll units 5 and
6 are constructed as shown in FIG. 2. Each unit has one roll 9 (or
7) that feeds the strip 1 to or guides it away from the rolling
stand 2. This roll 9 (or 7) is supported in a fixed position. By
contrast, the other roll 10 (or 8), is movably supported and can
swivel relative to the first roll 9, 7. To this end, it is mounted
at the end of a swivel arm 11. The other end of the swivel arm 11
is supported in a stationary axis 12, which coincides with the axis
of rotation of the first roll 9, 7.
[0027] One end of a linear actuator 14, which is realized as a
hydraulic piston-cylinder system, articulates with the swivel arm,
namely, in a pivot 13 some distance from the axis of rotation of
the second roll 8, 10. The actuator 14 is supplied with hydraulic
oil as indicated in FIG. 2.
[0028] When the piston-cylinder system 14 is acted upon by
hydraulic oil under open-loop or closed-loop control, the pivot 13
can be raised or lowered, so that the second roll 8, 10 can be
swiveled about its axis of rotation 12. This results in a longer or
shorter distance for the strip 1 between the rolling stand 2 and
coilers 3 or 4, thereby enabling the "S" roll units 5, 6 to carry
out a strip accumulator function.
[0029] The above-described construction of the rolling mill and
especially of the two "S" roll units 5, 6 makes it possible, with a
very simple design, to compensate the mass flow variation that
occurs during flexible cold rolling and at the same time to develop
the tension difference between the rolling stand 2 and coilers 3, 4
that allows an optimum rolling operation. With suitably fast
automatic control of the linear actuator 14, it is possible to
compensate the mass flow disturbances without any appreciable
tension fluctuations.
[0030] To achieve this goal in the past, it was necessary to use a
large number of rolls, which made these installations
expensive.
[0031] As a result of the compensation of the mass flow
disturbances and the associated reduction of the tension
fluctuations, the automatic control of strip thickness can be
improved. It becomes possible to make adjustments of the tensile
stresses favorable for the rolling process without regard to the
tensile stresses present at the coilers.
[0032] The compensation of the mass flow disturbances and the strip
accumulator function are now realized in one piece of equipment,
namely, the "S" roll unit described above, for which separate
pieces of equipment were previously needed.
List of Reference Symbols
[0033] 1 metal strip (steel strip) [0034] 2 rolling stand [0035] 3
upstream coiler [0036] 4 downstream coiler [0037] 5 "S" roll unit
[0038] 6 "S" roll unit [0039] 7 roll [0040] 8 roll [0041] 9 roll
[0042] 10 roll [0043] 11 swivel arm [0044] 12 stationary axis
[0045] 13 pivot [0046] 14 linear actuator [0047] R direction of
conveyance of the strip
* * * * *