A ROLLING MILL FOR ROLLING PLATES OR STRIPS

LAMINOIR POUR FEUILLARDS OU PRODUITS PLATS

English Abstract

A mill for rolling strips or plates, comprising:
frames of the rolling stand, upper and lower crossbeams,
screw-down means, upper and lower roll groups and roll
chocks. The upper/lower crossbeam is respectively
mounted on the upper/lower side of the frames, to which
the screw-down means are fixed, and the screw-down
means are located at the end portions of the upper
crossbeam to enable the latter to move for adjusting roll
gap. The roll chocks and the upper and lower roll groups
are arranged between the upper and lower crossbeams.
Supporting blocks are placed between the roll chocks
and the crossbeams, and the bearings are provided
between the upper/lower roll groups and the roll chocks.
Both the bearings and the supporting blocks are
positioned at the middle part of the rolls and in the area
of the roll bodies.

French Abstract

L'invention concerne un laminoir pour feuillards ou produits plats, comportant les montants de la cage du laminoir, des traverses supérieure et inférieure, des moyens de serrage, des groupes de cylindres supérieurs et inférieurs, ainsi que des empoises. La traverse supérieure/inférieure est montée respectivement sur la face supérieure/inférieure des montants, sur lesquels sont fixés les moyens de serrage, et ces derniers sont situés sur les parties terminales de la traverse supérieure afin de permettre le déplacement de celle-ci en vue du réglage de l'écartement entre cylindres. Les empoises ainsi que les groupes de cylindres supérieurs et inférieurs sont disposés entre les traverses supérieure et inférieure. Des blocs de support sont placés entre les empoises et les traverses, et les coussinets sont disposés entre les groupes de cylindres supérieurs/inférieurs et les empoises. Les coussinets ainsi que les blocs de support sont positionnés au niveau de la partie centrale des cylindres et dans la région des corps des cylindres.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A rolling mill for rolling plate or strip comprising a mill stand (4), an
upper crossbeam
and a lower crossbeam (8, 8'), a pressing device (6), roll seats (16, 16'; 26,
26 ; 36, 36'), upper
roll system (12; 22; 23; 32, 33), and lower roll system (12 ; 22', 23' 32',
33'), wherein said
upper and lower crossbeam are mounted on the upper and lower end of the mill
stand (4)
respectively, said pressing device (6) being mounted on the mill stand (4)
corresponding to
the two ends of the crossbeam and being capable of moving one of the upper and
lower
crossbeams for adjusting the magnitude of the clearance between the two rolls,
the upper and
the lower roll system and one of the roll seats being disposed between the
upper and lower
crossbeams, supporting pads (18, 18 ; 28, 28 ; 38, 38') being disposed between
the roll seats
and the upper and the lower crossbeams, bearings (14, 14 ; 24, 24 ; 34, 34')
being disposed
between the roll systems and the roll seats, and said supporting pads and said
bearings being
positioned to align to the central portion of the roll systems within the
range of the rolls'
length.

2. A rolling mill as set forth in claim 1, wherein upper and lower roll
systems and upper and
lower roll seats are disposed between upper and lower crossbeam.

3. A rolling mill as set forth in claim 1 or claim 2, wherein said bearings
are arc-shaped
sliding bearings.

4. A rolling mill as set forth in any one of claims 1 to 3, wherein said upper
roll system is
composed of one working roll (12), said sliding bearing (14) is disposed
between the working
roll (12) and roll seat (16).

5. A rolling mill as set forth in claims 1, 2, 3 or 4, wherein said lower roll
system is
composed of one working roll (12'), said sliding bearing (14') is disposed
between lower
working roll (12') and roll seat (16).

6. A rolling mill as set forth in claims 1, 2, 3 or 4, wherein said upper roll
system is
composed of one working roll (22) and one supporting roll (23), and said
sliding bearing (24)
is disposed between the supporting roll (23) and roll seat (26).


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7. A rolling mill as set forth in claim 1, 2, 3, 4, 5 or 6, wherein said lower
roll system is
composed of one working roll (22') and one supporting roll (23'), and said
sliding bearing
(24') is disposed between the supporting roll (23') and roll seat (26').

8. A rolling mill as set forth in claim 1, 2, 3, 4, 5, 6 or 7, wherein said
upper roll system is
composed of one working roll (32) and at least two supporting rolls (33), said
sliding bearing
(34) is disposed between the supporting roll (33) and the roll seat (36).

9. A rolling mill as set forth in claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein said
lower roll system is
composed of one working roll (32') and at least two supporting rolls (33'),
said sliding
bearing (34') is disposed between the supporting roll (33') and the roll seat
(36').

10. A rolling mill as set forth in claim 1, wherein said upper roll system is
composed of one
working roll (22, 32) and at least one supporting roll (23, 33), said
supporting roll comprises
a rolling bearing which is composed of an inner race and an outer ring.

11. A rolling mill as set forth in any one of claims 1 to 10, wherein said
lower roll system is
composed of one working roll (22', 32') and at least one supporting roll (23',
33'), said
supporting roll is a rolling bearing which is composed of an inner race and an
outer ring.

12. A rolling mill as set forth in any one of claims 1 to 11, wherein one of
the upper and
lower crossbeams is secured on the mill stand (4), and another one can move up
and down
under the actions of a pressing device at its two ends.

13. A rolling mill as set forth in any one of claims 1 to 11, wherein the
upper and the lower
crossbeams are capable of moving up and down under the actions of the pressing
device at
their two ends.

14. A rolling mill as set forth in any one of claims 1 to 11, wherein bearings
are provided
between the upper roll system and the upper roll seat and between the lower
roll system and
the lower roll seat.

15. A rolling mill for rolling plate or strip comprising a mill stand (4), an
upper crossbeam (8)
and a lower crossbeam (8'), a pressing device (6), roll seats (46, 46'), an
upper roll system
(42) and a lower roll system (42'), wherein said upper and lower crossbeam are
secured on an
upper end and a lower end of the mill stand (4) respectively, at least one
roll seat and upper
and lower roll system are provided between the upper and the lower crossbeam,
and said

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pressing device (6) is provided on the central portion of the at least one of
said upper and
lower crossbeams, the pressing device is capable of moving the roll seats (46,
46), which is in
contact with the pressing device, up and down for adjusting the clearance
between two rolls,
bearings (44, 44') are provided between roll seats and the upper and the lower
roll systems,
and said bearings are located to align to the central portion of the roll
systems within the
range of rolls' length.

16. A rolling mill as set forth in claim 15, wherein the upper and lower roll
systems and upper
and lower roll seats are provided between the upper and lower crossbeams.

17. A rolling mill as set forth in claim 15 or 16, wherein said bearings are
arc-sliding bearings
(44, 44').

18. A rolling mill as set forth in claiml7, wherein said upper roll system is
composed of one
working roll (42), said sliding bearing (44) is disposed between the working
roll (42) and roll
seat (46).

19. A rolling mill as set forth in claim 17 or 18, wherein said lower roll
system is composed
of one working roll (42'), said sliding bearing (44') is disposed between
lower working roll
(42') and roll seat (46').

20. A rolling mill as set forth in claim 17, wherein said upper roll system is
composed of one
working roll and at least one supporting roll, said sliding bearing is
disposed between the
supporting roll and the roll seat.

21. A rolling mill as set forth in claim 17 or 20, wherein said lower roll
system is composed
of one working roll and at least one supporting roll, said sliding bearing is
disposed between
the supporting roll and the roll seat.

22. A rolling mill as set forth in claim 16, wherein said upper roll system is
composed of one
working roll and at least one supporting roll, said supporting roll is a
rolling bearing which is
composed of an inner race and an outer ring.

23. A rolling mill as set forth in claim 16 or 22, wherein said lower roll
system is composed
of one working roll and at least one supporting roll, said supporting roll is
a rolling bearing
which is composed of an inner race and an outer ring.




24. A rolling mill as set forth in any one of claims 15 to 23, wherein said
pressing device is
provided at the central portions of said upper and lower crossbeam.

25. A rolling mill as set forth in any one of claims 15 to 23, wherein said
pressing device (6)
is only provided at the central portion of said upper crossbeam, a supporting
pad (48') is
provided between said lower crossbeam and roll seat, and the supporting pad is
located to
align to the central portion of said roll system within the range of rolls'
length.

11

Description

CA 02302424 2000-03-02
The invention relates to a rolling mill for producing plate or strip, and more
particularly relates to a rolling mill in which a roll is supported by a
central support for
controlling the flexure of the roll, thereby the rolled plate or strip has a
high thickness
precision in their cross sections.
There are a variety of rolling mills for rolling plate or strip. The most
commonly used
rolling mills are two-high rolling mills, four-high rolling mills and HC
mills. These
conventional rolling mills have some drawbacks. When a rolled piece passes the
mill stand, a
larger flexural deformation on the rolls is resulted since the necks of the
rolls are subjected to
tremendous rolling force. The deformations of the rolls will result in the
thickness error in
the cross section of the rolled piece (rolled plate or strip), thus seriously
affecting the quality
of the rolled piece. To solve the above problem, it has been suggested to
increase the
diameter of the rolls. As for the four-high rolling mills and HC mills, it has
been suggested
to increase the diameter of the supporting rolls. However, as the diameters of
the rolls
increase, it will result in an abrupt increase in the rolling force. The
change of the rolling
force in turn causes an increase of the flexural deformation of the rolls,
which still result in a
larger thickness error in the cross section of the rolled piece.
Object of the Invention
Therefore, the invention is aimed to solve the above problem of the flexural
deformation of the roll barrels. The object of the invention is to provide a
high precision
rolling mill for rolling plate or strip, wherein the flexural deformation of
the rolls is reduced
significantly, thereby the dimension accuracy of the rolled piece is highly
increased.
The object of the present invention is achieved by providing a rolling mill
for rolling
plate or strip comprising a mill stand, an upper crossbeam and a lower
crossbeam, a pressing
device, roll seats, upper roll system, and lower roll system, wherein said
upper and lower
crossbeam are mounted on the upper and lower end of the mill stand
respectively, said


CA 02302424 2000-03-02
pressing device being mounted on the mill stand corresponding to the two ends
of the
crossbeam and being capable of moving at least one of the upper and lower
crossbeams for
adjusting the magnitude of the clearance between the two rolls, the upper and
the lower roll
system and at least one of the roll seats being disposed between the upper and
lower
crossbeams, supporting pads being disposed between the roll seats and the
upper and the
lower crossbeams, bearings being disposed between the roll systems and the
roll seats, and
said supporting pads and said bearings being positioned to align to the
central portion of the
roll systems within the range of the rolls' length.
Preferably the bearings are arc-shaped sliding bearings.
According to another aspect of the present invention, there is provided a
rolling mill for
rolling plate or strip comprising a mill stand, an upper crossbeam and a lower
crossbeam, a
pressing device, roll seats, an upper roll system and a lower roll system,
wherein said upper
and lower crossbeam are secured on an upper end and a lower end of the mill
stand
respectively, at least one roll seat and upper and lower roll system are
provided between the
upper and the lower crossbeam, and said pressing device is provided on the
central portion of
the at least one of said upper and lower crossbeams, the pressing device is
capable of moving
the roll seats, which is in contact with the pressing device, up and down for
adjusting the
clearance between two rolls, bearings are provided between the roll seats and
the upper and
the lower roll systems, and said bearings are located to align to the central
portion of the roll
systems within the range of rolls' length.
In the present invention, since the supports is provided to align to the
central portion of
the rolls rather than on the roll's two end necks of the prior art to the
center portion. Namely,
by means of arranging the supporting devices such as bearings, supporting pads
or pressing
devices etc. in the region corresponding to the central portion of the roll
body axis of the
working roll, the flexural deformation of the rolls would reduce significantly
during the
rolling operation. As a result, the thickness error in the cross section of
the rolled piece will
reduce and the dimension accuracy will increase.
The embodiments of the present invention will be described in detail in
combination
with the accompanying drawings. In the drawings:
Fig. 1 is a front schematic view of the first embodiment of the invention;
Fig. 2 is a side schematic view of the first embodiment of the invention;
Fig. 3 is a front schematic view of the second embodiment of the invention;
2


CA 02302424 2000-03-02
Fig. 4 is a side schematic view of the second embodiment of the invention;
Fig. 5 is a front schematic view of the third embodiment of the invention;
Fig. 6 is a side schematic view of the third embodiment of the invention;
Fig. 7 is a front schematic view of the fourth embodiment of the invention;
Fig. 8 is a side schematic view of the fourth embodiment of the invention;
Fig. 9 is a front schematic view of four-high rolling mill of the prior art;
and
Fig. 10 is a side schematic view of four-high rolling mill of the prior art.
The following is a detailed description of the present invention. In the above
schematic
drawings, the positioning modes of the working rolls of all rolling mill are
not indicated. The
equivalent or similar components in each drawing will be designated by the
same reference
number.
Figs. 9 and 10 are schematic views showing the conventional four-high rolling
mills.
The two ends of the rolls (working rolls or supporting rolls) are supported on
the frame of
the mill so that the necks of the roll is subjected to enormous rolling force.
During a rolling,
the flexural deformation of the roll will occur inevitably due to rolling
force such that the
rolled plate or strip will be of uneven thickness in its width direction. The
thickness of the
rolled piece will fail to meet the accuracy requirement and will significantly
affect the
quality of the rolled piece.
Figs. l and 2 show the first embodiment of rolling mill with central support
of the
present invention. The rolling mill includes a mill stand 4 composed of a
right piece and a
left piece. An upper crossbeam 8 and a lower crossbeam 8' are mounted adjacent
to the upper
and lower end portions of the mill stand 4. In a window of the mill stand
between the upper
and lower crossbeams, there are provided with working rolls 12 and 12',
bearings 14 and 14',
roll seats 16 and 16', and central supporting pads 18 and 18'. The rolled work
piece is
gripped between the two working rolls 12 and 12'. As can be seen from Figs. 1
and 2, the roll
body of the upper working roll 12 is supported on the upper roll seat 16 by
means of the
upper bearing 14. The bearing 14 is an arc or semi-circular sliding bearing.
The supporting
pad 18 is provided between the upper roll seat 16 and the upper crossbeam 8.
The supporting
pad 18 and the sliding bearing 14 are located at the central region of the
axis of the working
roll body. They should not be located at the neck portion on two ends of the
working roll and
they should be within the range of working roll's length. The supporting pad
may comprise
one piece or several pieces. In the embodiment of Figs. 1 and 2, the
supporting pad
3


CA 02302424 2000-03-02
comprises two pieces and the two pieces are symmetrically arranged. A pressing
device 6 is
disposed at the two ends of the upper crossbeam 8 on the mill stand 4. The
pressing device 6
is in contact with the two ends of the upper crossbeam 8 so as to receive the
rolling force. In
addition, the up and down movement of the pressing device 6 makes the upper
crossbeam 8
move up and down inside the window of the mill stand 4 to adjust the clearance
between the
two rolls. In the embodiment of Figs. 1 and 2, the pressing device is a
screwdown device,
however, it is obvious to those skilled in the art that the pressing device
could be a hydraulic
cylinder.
The roll body of the lower working roll 12' is supported on the lower roll
seat 16'
through a lower bearing 14'. The bearing 14' is also an arc or semi-circular
sliding bearing.
The supporting pads 18' are disposed between the lower roll seat 16' and lower
crossbeam 8'.
The supporting pad 18' and the sliding bearing 14' are located at the central
region of the axis
of the working roll body and within the range of the roll body's length. The
two ends of the
lower crossbeam 8' are supported on the mill stand 4. It is obvious that the
clearance of the
two rolls (rolling line) can be adjusted by selecting different thickness of
the central
supporting pad 18'. The adjustment of the clearance of the two rolls (rolling
line) can also be
realized by means of a hydraulic device or a screwdown device instead of the
central
supporting pad. In addition, the adjustment of the clearance of the two rolls
(rolling line) can
also be realized by disposing pads between the lower crossbeam 8' and mill
stand 4 or by
means of a hydraulic device or a screwdown device.
Due to the above-mentioned structure of the rolling mill of the present
invention, the
flexures of the rolls are effectively reduced. This is because that the
rolling mill of the
present invention includes the supporting pad members on a region
corresponding to the
central region of the axis of the working roll body and within the range of
the body's length.
Therefore, the rolling mill of the present invention can guarantee the proper
generating line's
profile, i.e. the linearity of the generating line. As a result, the flexural
deformation of the
working roll basically does not vary with the rolling force. Therefore, the
roll's flexural
deformation will be significantly reduced so as to reduce the error in
thickness of the rolled
plate or strip.
The rolling mill of the embodiment can be placed upside down, namely, the
pressing
device may change its acting force to upward while the device may have the
same effects.
Figs. 3 and 4 show the second embodiment of the rolling mill of the present
invention.
As can be seen from Fig.3 and 4, this embodiment is an example of four-high
rolling mill
according to the present invention. The rolling mill has a mill stand 4, a
pressing device 6, an
4


CA 02302424 2000-03-02
upper crossbeam 8 and a lower crossbeam 8'. In a window of the mill stand
located between
the upper and lower crossbeams, there are provided with working rolls 22 and
22',
supporting rolls 23 and 23', bearings 24 and 24', roll seats 26 and 26' and
central supporting
pads 28 and 28'. The differences between the second embodiment and the first
embodiment
is in that an additional supporting roll is disposed between the working roll
and roll seat
while the other structures and the operation mechanism are the same. It is
advantageous to
dispose an additional middle extracting roll between the working roll and
supporting roll, i.e.
applying the present invention in an HC mill.
Figs. 5 and 6 show the third embodiment of the present invention. As can be
seen from
the drawings, this embodiment is an example of the tower-like roll system
mill. The rolling
mill includes a mill stand 4, a pressing device 6, an upper crossbeam 8, and a
lower
crossbeam 8'. In a window of the mill stand located between the upper and the
lower
crossbeam, there are provided with working rolls 32 and 32', two upper
supporting rolls 33,
two lower supporting rolls 33', bearings 34 and 34', roll seats 36 and 36',
and central
supporting pads 38 and 38'. The invention is not limited to six rolls tower-
like roll system
mill as shown in the drawings, it is also applicable for use in the system
with other numbers
of rolls or other structures.
In the second and the third embodiment of the present invention, the bearings
may be
sliding bearings as used in the first embodiment. It is also possible to use
rolling bearings
instead of the sliding bearings. The rolling bearings can be made by the
supporting rolls
themselves, forming back-bushing bearing consisting of inner race and outer
ring.
Figs. 7 and 8 show the fourth embodiment of the rolling mill of the present
invention.
The rolling mill includes a mill stand 4, a pressing device 6, an upper
crossbeam 8, and a
lower crossbeam 8'. In the window of the mill stand located between the upper
and lower
crossbeam, there are provided with upper and lower working rolls 42 and 42',
bearings 44
and 44', upper and lower roll seats 46 and 46', and central supporting pads
48' which are
located between the lower roll seat 46' and the lower crossbeam 8'. Comparing
to the first
embodiment, the upper crossbeam 8 of the rolling mill in this embodiment is
secured to the
mill stand 4. The pressing device 6 is disposed on the upper crossbeam 8
corresponding to
the central region of the axis of the working roll body instead of on the mill
stand 4
corresponding to the two ends of the upper crossbeam. The upper supporting
pads 18 are
omitted in this embodiment. The pressing device 6 contact to the upper roll
seats directly. It
is thus obvious that, the present embodiment transfers the downward action of
the pressing
device from two ends of the crossbeam to its central portion, which makes the
devices have
s


CA 02302424 2000-03-02
the functions of both the pressing device and the upper supporting pads. In
addition, the
present embodiment can also apply the roll systems and the roll seats
described in the second
and the third embodiments which will not be repeatedly described herein.
Moreover, in this
embodiment, the upper and lower crossbeam 8 and 8' may splice, weld or cast
with mill
stand 4 and form an integral to achieve the same technical effects.
All the rolling mills described in the second, the third and the fourth
embodiments can
be placed upside down to achieve the same technical effects.
The screwdowns used in the second, the third, and the fourth embodiments can
also be
replaced by hydraulic cylinders.
In the second, the third and the fourth embodiments, the transmission of the
rolling
forces, and the principles and functions of the central portion supporting
system or central
downward action in the reduction of the flexural deformation of the working
rolls are also
substantially the same, this will not be repeatedly described herein.
Compared with the prior art, the rolling mill of the present invention has the
following
IS advantages:
Since the central supports or pressing devices of the rolling mill of the
present
invention are disposed on a region corresponding to the central region of the
axis of the
working roll body, which provide central supporting system onto the working
rolls within the
range of the working roll body's length. Therefore, the rolling mill of
present invention can
guarantee the proper generating line's profile, as a result, the flexural
deformation of the
working roll basically does not vary with the rolling force fluctuation so as
to result in the
reduction of the error in thickness of the rolled plate or strip.
The rolling mill of the present invention can simplify the design of the
original roll
shape (cambering) and the control of the roll shape during rolling. Since the
flexural
deformation of the working roll of the rolling mill of the present invention
basically does not
vary with the rolling force fluctuation, in the course of original roll shape
(cambering) design,
among the various factors such as the roll's flexural deformation, flattening
deformation,
heat expansion and wear etc., the most important one, i.e., flexural
deformation, can be left
out of consideration and the heat expansion and wear are slowly changing
factors, so that the
design of the roll shape and the control of the roll shape during rolling can
be greatly
simplified. In addition, the "roll pass" formed by the flexural deformation of
the two
working rolls in a conventional rolling mill is eliminated, thus facilitating
the reasonable
transverse flow of the metal and being advantageous to roll high-precision
plates and strips
with wedge-shaped blanks. The phenomenon of the "edge attenuation" of plates
and strips is
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CA 02302424 2000-03-02
significantly improved. The upper and lower roll assemblies including the roll
seats and the
roll systems in the first to the fourth embodiments can be combined to each
other. The roll
assemblies can also be combined to the roll assemblies in the prior art so as
to achieve the
object of the invention.
The rolling mill of the present invention is particularly applicable for use
in the
reforming of the existing two-high rolling mill, four-high rolling mill and HC
mill, which
can be done by replacing the roll systems in the former rolling mills.
The invention is not limited to cold rolling mill, but to hot rolling mills
for producing
hot rolled plates and strips.
Although the preferred embodiments of the invention have been described, those
skilled in the art could make various modifications to the invention without
going beyond
the scope and spirit of the attached claims of the invention.

Representative Drawing