U.S. patent application number 12/937399 was filed with the patent office on 2011-03-17 for plant for the reversible rolling of steel strip.
This patent application is currently assigned to SIEMENS VAI METALS TECHNOLOGIES SAS. Invention is credited to Bernard Rossigneux.
Application Number | 20110061435 12/937399 |
Document ID | / |
Family ID | 39870643 |
Filed Date | 2011-03-17 |
United States Patent
Application |
20110061435 |
Kind Code |
A1 |
Rossigneux; Bernard |
March 17, 2011 |
PLANT FOR THE REVERSIBLE ROLLING OF STEEL STRIP
Abstract
A rolling plant has a reversible rolling mill with two stands.
Each upright of the stands rests on a support structure via a
bearing surface and is fastened thereto by a bolt or shank integral
with the structure and cooperating with the upright via a removable
fastening device. The bearing surface of each upright is provided
on the lower face of the upright, without extending beyond the
lateral faces directed along the rolling direction of the uprights,
and is formed with a hole opening into a hollow housing provided in
the upright and having an orifice opening onto a lateral face of
the upright. The bolt or shank extends through the hole and
projects into the housing, and the removable fastening device is
placed inside the housing.
Inventors: |
Rossigneux; Bernard;
(Lezigneux, FR) |
Assignee: |
SIEMENS VAI METALS TECHNOLOGIES
SAS
Saint-Chamond
FR
|
Family ID: |
39870643 |
Appl. No.: |
12/937399 |
Filed: |
April 11, 2008 |
PCT Filed: |
April 11, 2008 |
PCT NO: |
PCT/FR08/00506 |
371 Date: |
November 19, 2010 |
Current U.S.
Class: |
72/199 |
Current CPC
Class: |
B21B 1/24 20130101; B21B
31/06 20130101 |
Class at
Publication: |
72/199 |
International
Class: |
B21B 1/22 20060101
B21B001/22 |
Claims
1-10. (canceled)
11. A rolling installation with a reversing mill, comprising: two
stands disposed adjacent one another in a rolling direction of the
rolling installation, each stand including two uprights for
supporting a plurality of rolls; a support structure carrying said
uprights, with each said upright resting on a support surface of
said support structure; wherein said support surface of each said
upright is provided on an internal face thereof, without projecting
beyond a lateral face of said upright in a rolling direction; said
upright having a hollow seat formed therein with an aperture
opening onto the lateral face of said upright, and at least one
through hole opening into said hollow seat; at least one shank
fixing each said upright to said support structure, said shank
being attached to said support structure, extending through said
bore, and projecting into said hollow seat, and a detachable fixing
device disposed in said hollow seat and cooperating with said
upright to affix said upright to said support structure.
12. The installation according to claim 11, wherein said hollow
seat is a cell, said cell being formed with an aperture opening
onto a lateral face of said upright, perpendicular to a direction
transverse to the rolling direction and oriented towards an outside
of the respective said stand.
13. The installation according to claim 11, wherein said hollow
seat is a slot, said slot being formed with an aperture opening
onto a lateral face of said upright, perpendicular to a direction
transverse to the rolling direction and oriented towards an outside
of the respective said stand.
14. The installation according to claim 11, wherein said detachable
fixing device is a nut, said shank is a threaded bolt, said support
structure is formed of solid concrete and said bolt is anchored in
said solid concrete, and said bolt projects through said through
hole in said upright of said stand and said nut is screwed onto
said bolt.
15. The installation according to claim 11, which further comprises
means for driving the rolls, including a reduction gear having an
input shaft to be connected to a motor, first and second output
shafts to be connected to the rolls to be driven, and at least one
intermediate shaft coupling said input shaft to first and second
output shafts, and wherein at least the axes of said output shafts
and intermediate shafts are vertically superposed to thereby reduce
a footprint in the rolling direction.
16. The installation according to claim 11, which further comprises
means to change rolls, including a carriage shared by said first
and second stands and movable, in a direction perpendicular to the
rolling direction, between a service position in a vicinity of said
first and second stands and a waiting position away from said first
and second stands, said carriage having at least two racks
configured to carry a train of rolls and arranged side by side in
the rolling direction, and a device for roll loading and roll
unloading configured to unload worn rolls from a stand onto an
empty rack and to load new rolls from a rack into a stand.
17. The installation according to claim 16, wherein said carriage
includes a mobile deck capable of movement in parallel to the
rolling direction, and wherein said at least two racks are placed
on said mobile deck.
18. The installation according to claim 17, wherein said at least
two racks of said carriage are four racks and said mobile deck is
movable between the first and second positions, such that, in the
first position of said mobile deck, the racks of a first pair of
racks are respectively placed in a vertical plane of the rolls of
said first stand and said second stand, and, in the second position
of said mobile deck, the racks of a second pair of racks are
respectively placed in the vertical plane of the rolls of said
first stand and said second stand, said carriage having first
loading/unloading means configured to serve the first stand and
second loading/unloading means configured to serve the second
stand, enabling the first and second stands to be loaded and/or
unloaded simultaneously or separately.
19. The installation according to claim 11, configured to roll
strips with an entry thickness of up to 10 mm and a width of up to
1,600 mm, and wherein a distance between said lateral face of an
upright of the first stand, perpendicular to the rolling direction
and oriented towards the second stand, and said lateral face of an
upright of the second stand, perpendicular to the rolling direction
and oriented towards the first stand, is less than 1,500 mm.
20. The installation according to claim 19, wherein the distance
between said lateral face of an upright of the first stand,
perpendicular to the rolling direction and oriented towards the
second stand, and said lateral face of an upright of the second
stand, perpendicular to the rolling direction and oriented towards
the first stand, is greater than a space strictly necessary to
enable an operator to pass for an exceptional intervention.
21. The installation according to claim 20, wherein the space
strictly necessary to enable an operator to pass is measured at
least 700 mm.
Description
[0001] The invention relates to a rolling installation of the type
comprising a two-stand reversing mill.
[0002] Steel strips may be rolled using different types of rolling
installation. "Reversing" rolling installations make it possible to
roll a strip, moving in a rolling direction, alternately in one
direction and then the other. The strip is rolled by passing it
through a mill comprising, between two coiling/uncoiling devices,
one stand or two stands arranged successively in the rolling
direction.
[0003] Two-stand reversing installations have a production capacity
of 300,000 to 1,000,000 metric tons per year compared to a
production capacity of 200,000 to 600,000 metric tons per year for
"single stand" reversing installations. Two-stand reversing
installations also have the advantage of reducing the number of
rolling passes in one direction and then the other. Patent EP 0 618
018 B1 describes such a two-stand reversing rolling installation
for cold rolling.
[0004] In the case of reversing rolling performed in more than
three passes, the head and tail ends of the strip remain clamped to
the mandrels of the coiling/uncoiling devices located on either
side of the two stands. A service length between, firstly, the head
or tail end of the strip and, secondly, the roll gaps in the stand
located near to the coiling/uncoiling device to which is attached
the head or tail end in question, is not rolled to the desired
thickness.
[0005] Furthermore, at the end of the pass, an inter-stand length
between the roll gaps of the two stands is not rolled to the
required thickness. In fact, this inter-stand length has only been
rolled by passing through one of the two stands, i.e. the stand
located close to the coiling/uncoiling device to which is attached
the head or tail end in question.
[0006] Thus, at each end of the strip, an end length corresponding
to the sum of a service length and an inter-stand length has a
thickness outside the tolerances. The two end lengths have to be
removed after rolling, creating offcuts. Offcuts affect the
performance of two-stand reversing installations.
[0007] For example, for a rolling mill using three passes to roll a
steel coil with a width of up to 1600 mm, an initial thickness of 3
mm and a length of 700 m, to obtain a steel strip with a target
thickness of 1 mm, a two-stand reversing rolling installation in
which each stand has a rolling capacity of around 2,400 metric tons
is required. To achieve this, each stand is for example fitted with
backup rolls with a diameter of 1,250 mm and work rolls with a
diameter of 450 mm. To withstand the corresponding stresses, each
stand typically has uprights 9,000 mm tall and 4,000 mm wide. The
center-to-center distance separating the planes of symmetry of the
two stands, vertical planes in which the roll axes rest, is 6,000
mm.
[0008] In such installations the quantity of strip lost on the
service lengths is 2% of the original coil. With a center-to-center
distance between the two stands of 6,000 mm, the offcut
corresponding to the two inter-stand lengths is 1% of the original
coil. Consequently, the resulting total loss is greater than 3% of
the original coil. This should be compared to the habitual loss of
a single-stand mill which is around 2% and that of a continuous
tandem mill which is negligible.
[0009] It should be noted that the center-to-center distance is
necessarily greater than a minimum resulting from the geometry of
the stands and their installation constraints on the building
structure. In particular, according to the prior art, the uprights
of the stands of the two-stand reversing mills include lugs in the
building structure. A lug on an upright forms a protuberance, in
the rolling direction, beyond the vertical plane of the face of the
upright bearing the lug. In particular, the side face of an upright
of the first stand, perpendicular to the rolling direction and
oriented towards the second stand, has a lug projecting towards the
second stand. Symmetrically, the side face of an upright of the
second stand, perpendicular to the rolling direction and oriented
towards the first stand, has a lug projecting towards the first
stand. The lugs result in a center-to-center distance of 6,000 mm,
or an inter-stand distance of 2,000 mm, the inter-stand distance
corresponding to the distance separating the two external lateral
faces located on each of the uprights of the first and second
stands and facing one another.
[0010] The lugs have throughbores to accommodate elements to attach
the uprights to the building structure. Moreover, the lower face of
these lugs constitutes the support surface for the upright on the
building structure. With regard to this, the lower face of the
upright drops below the level of the lower faces of the lugs, and
is situated above a pit created in the building structure, beneath
the stand, to collect used lubricating oils.
[0011] We have attempted to reduce offcuts in two-stand reversing
mills.
[0012] For example, the patent JP 03-138004 describes the use of
extensions welded onto each end of the strip to be rolled, and a
particular sequence for opening and closing the stands and the
clamp to roll the entire strip to the required thickness.
[0013] Apart from the fact that this method takes a long time to
implement, there is a risk of breaking around the junction between
the extensions and the strip, in particular during rolling under
traction.
[0014] The invention is therefore intended to reduce the length of
the strip cut off during operation of a two-stand reversing rolling
installation.
[0015] To achieve this the invention relates to a rolling
installation of the type comprising a reversing mill with two
stands, adjacent in a rolling direction, each stand having two roll
supporting uprights, each upright resting on a support structure by
means of a support surface and being fixed to the support structure
by means of at least one shank attached to the support structure
and cooperating with the upright by means of detachable fixing
means. The support surface of each upright is provided on the lower
face of the upright, without extending beyond the lateral faces of
the uprights oriented in the rolling direction and includes at
least one hole opening into a hollow seat provided for in the
upright and having an aperture opening onto a lateral face of the
upright. The shank attached to the support structure extends
through the hole and projects into the seat, and the detachable
fixing means is placed inside the seat.
[0016] According to the specific embodiments of the invention, the
rolling installation has one or more of the following
characteristics, separately or in any of the technically feasible
combinations: [0017] the hollow seat is a cell, the cell having an
aperture opening onto a lateral face of the upright, perpendicular
to a direction transversal to the rolling direction and oriented
towards the outside of the stand. [0018] the hollow seat is a slot,
the slot having an aperture opening onto a lateral face of the
upright, perpendicular to a direction transversal to the rolling
direction and oriented towards the outside of the stand. [0019] the
detachable fixing means is a nut, the shank is a pin and the
support structure is solid concrete, the pin being anchored in the
solid concrete and inserted into the hole passing through the
upright of the stand and the nut being screwed to the pin. [0020]
the installation also includes means for driving the rolls
comprising a reduction gear including an input shaft intended to be
connected to a motor, first and second output shafts intended to be
connected to the rolls to be driven and at least one intermediate
shaft coupling the input shaft to the first and second output
shafts, and at least the axes of the output and intermediate shafts
are vertically superposed such as to reduce the footprint in the
rolling direction. [0021] the installation also includes means to
change rolls, including a carriage shared by the first and second
stands that can be moved, in a direction perpendicular to the
rolling direction, between a service position near to the first and
second stands and a waiting position away from the first and second
stands, the carriage having at least two racks able to carry a
train of rolls and arranged side by side in the rolling direction,
and roll loading/unloading means enabling worn rolls to be unloaded
from a stand onto an empty rack and for new rolls to be loaded from
a rack into a stand. [0022] the carriage includes a mobile deck
that can be moved in parallel to the rolling direction, and said at
least two racks are placed on the mobile deck. [0023] the carriage
includes four racks and the mobile deck can be moved between the
first and second positions, such that, in the first position of the
mobile deck, the racks of a first pair of racks are respectively
placed in the vertical plane of the rolls of the first stand and
the second stand, and, in the second position of the mobile deck,
the racks of a second pair of racks are respectively placed in the
vertical plane of the rolls of the first stand and the second
stand, the carriage having first loading/unloading means to serve
the first rack and second loading/unloading means (324) to serve
the second stand, it being possible to load and/or unload the first
and second stands simultaneously or separately. [0024] the
installation is able to roll strips with an entry thickness of up
to 10 mm and up to 1,600 mm wide, and the distance between the
lateral face of an upright of the first stand, perpendicular to the
rolling direction and oriented towards the second stand, and the
lateral face of an upright of the second stand, perpendicular to
the rolling direction and oriented towards the first stand, is less
than 1,500 mm. [0025] the distance between the lateral face of an
upright of the first stand, perpendicular to the rolling direction
and oriented towards the second stand, and the lateral face of an
upright of the second stand, perpendicular to the rolling direction
and oriented towards the first stand, is greater than the space
strictly necessary to enable an operator to pass through for
exceptional interventions, a space of at least 700 mm.
[0026] The invention and its advantages can be better understood
from the description below, given purely by way of example, and
drafted with reference to the attached drawings, in which:
[0027] FIG. 1 is a schematic representation of a two-stand
reversing rolling installation;
[0028] FIG. 2 is a side view of a two-stand reversing rolling
installation according to one embodiment of the invention;
[0029] FIG. 3 is a top view of the installation in FIG. 2;
[0030] FIG. 4 is a partial perspective view of the fixing means on
the support structure of a stand of the installation in FIGS. 2 and
3;
[0031] FIG. 5 is a partial perspective view of an alternative
embodiment of the fixing means of a stand on the support
structure;
[0032] FIG. 6 is a front view of the reduction gears of the drive
means of the rolls of the installation in FIGS. 2 and 3; and,
[0033] FIG. 7 is a front view of an alternative embodiment of the
reduction gears of the drive means of the rolls.
[0034] FIG. 1 is a schematic representation of a two-stand
reversing rolling installation 1 for rolling a metal strip M moving
in a horizontal plane in a rolling direction A. The strip M is
driven to move alternately in a positive direction (from left to
right in FIG. 1) and in a negative direction (from right to left in
FIG. 1). The rolling installation 1 includes, placed successively
along the rolling direction A, a first stand 2 and a second stand
4. The first and second stands 2 and 4 are of the six-high type.
Each stand 2, 4 is fitted with a pair of work rolls 6 and 7, a pair
of intermediate rolls 8 and 9 and a pair of backup rolls 10 and 11.
The axes of the different rolls of a stand rest in a single
vertical plane P of symmetry of the stand.
[0035] The rolling installation 1 also includes, upstream of the
first and second stands 2 and 4, a strip uncoiler 12, a first
coiling/uncoiling device 14, a clamping device 16. The rolling
installation 1 includes, downstream of the first and second stands
2 and 4, a deflector roll 18 and a second coiling/uncoiling device
20. The first and second coiling/uncoiling devices 14 and 20 are
respectively provided with mandrels to apply traction to the strip
M during rolling such as to increase the thickness reduction rate
of the strip M.
[0036] The rolling installation 1 includes other elements, not
shown but known to the person skilled in the art, such as a
preparation device for the head end of the strip M, thickness
measurement means, etc.
[0037] FIGS. 2 and 3 show the rolling installation 1 according to
the invention in greater detail, in which the stand uprights are
adapted to minimize the center-to-center distance between the two
stands, the distance separating the planes of symmetry P of the
first and second stands 2 and 4.
[0038] The first stand 2 includes two lateral uprights 22 arranged
on either side of the rolling axis A in a transversal direction Y.
The two lateral uprights 22 of the stand 2 are linked to each other
in particular by upper crosspieces 24.
[0039] An upright 22 has an external shape contained within a
rectangular parallelepiped. It has a rear face 26, perpendicular to
the rolling direction A and oriented towards the second stand 4; a
front face 27, perpendicular to the rolling direction A and
oriented the opposite way to the rear face 26; a lower face 28,
perpendicular to the vertical direction Z and oriented downwards;
and an external lateral face 30, perpendicular to the transversal
direction Y and oriented towards the outside of the stand. The
upright 22 rests on a support structure 25, preferably made of
concrete, by means of its lower face 28 comprising a flat support
surface. The upright 22 is provided with an oblong window 32 in the
vertical direction Z. The upright 22 is consequently ring-shaped.
The window 32 is intended to receive the support means of the roll
chocks 6 to 11.
[0040] The second stand 4 includes a pair of uprights 42 arranged
on either side of the rolling direction A and connected to each
other by upper crosspieces 44.
[0041] An upright 42 has a front face 46, perpendicular to the
rolling direction A and oriented towards the first stand 2; a rear
face 47, perpendicular to the rolling direction A and oriented the
opposite way to the front face 46; a lower face 48, perpendicular
to the vertical direction Z and oriented downwards, forming a
support surface of the second upright 42 on the support structure
25; and it has an external lateral face 50 perpendicular to the
transversal direction Y and oriented towards the outside of the
second stand 4. One upright 42 is ring shaped, and defines
internally a window 52 for the support means of the roll chocks 6
to 11.
[0042] Thus, the rear face 26 of the first stand 2 and the front
face 46 of the second stand 4 are arranged opposite one another.
The distance separating the front and rear faces 26 and 46 is the
inter-stand distance D.
[0043] According to the invention, the inter-stand distance D is
minimized by bringing the first and second stands 2 and 4 closer to
one another in the rolling direction A. To enable this, the rear
and front faces 26 and 46 do not have any projections, in the
rolling direction A, forming a protuberance towards the other
stand. The rear and front faces 26 and 46 are flat. As shown in
detail in FIG. 2, an upright 22, 42 includes hollow seats intended
to receive means for fixing the upright to the support structure
25.
[0044] In a first embodiment shown in FIG. 4, the upright 22
includes, in its lower part, a hollow seat forming a cell 62. This
leads to the rear face 26 of the upright 22 and the external
lateral face 30 of the upright 22. The upright 22 also has a
throughbore 64, with a vertical axis opening, at one end, onto the
lower face 28 of the upright 22 and, at the other end, onto the
lower surface 66 of the cell 62.
[0045] The throughbore 64 enables the passage of a shank 80 of a
pin, of which one end is anchored to the support structure 25 and
the other end, threaded and free, protrudes out of the throughbore
64, inside the cell 62, above its lower surface 66. A nut 82 is
screwed to the shank 80 and tightened against the lower surface 66
of the cell 62 to attach the upright 22 to the support structure
25. Thus, the cell 62 forms a seat to receive the nut 82.
[0046] The upright 22 also has a second cell 63 along the edge
between its front face 27 and its external lateral face 30. A
throughbore 65 leads to a cell 63 and enables the passage of a pin
80. A nut 82, seated in the cell 63, is screwed to the threaded end
of the shank of the pin 80 and enables the fixing means of the
upright 22 to be tightened to the support structure 25 at a second
fixing point.
[0047] Similarly, an upright 42 of the second stand 4 has a first
cell 72 opening onto the front face 46 and onto the external
lateral face 50 of the upright 42, and a second cell 73 opening
onto the rear face 47 and onto the external lateral face 50 of the
upright 42. The throughbores 74 and 75 are arranged between the
lower face 48 and the first and second cells 72 and 75 to enable
the passage of pins 80. Nuts 82 are screwed to the threaded ends of
the shanks 80 to attach the upright 42 to the support structure
25.
[0048] Thus, according to the invention, the fixing means of an
upright to the support structure are within the footprint of the
upright in the rolling direction A.
[0049] FIG. 5 shows a second embodiment of the hollow seats. The
hollow seats of the lower part of an upright 122 is realized such
as to form a horizontal slot 162 on the external lateral face 130
of the upright 122. The slot 162 extends from the front face 127 to
the rear face 126 of the upright 122. A lower surface 166 of the
slot 162 has three throughbores 163, 164 and 165 that lead to the
lower surface 128 of the upright 122. They permit the passage of
shanks with one end anchored to the support structure 25 and the
other, threaded, end entering the slot 162. Nuts screwed to the
threaded ends of the shanks are inserted into the slot 162. They
enable, by tightening onto the lower face 166 of the slot 162, to
fix the upright 122 to the support structure 25 at different fixing
points.
[0050] To withstand the stresses applied to them, the person
skilled in the art will be able to determine the geometry of the
uprights as a function, among other things, of the shape of the
cells, the position of the anchor points on the support structure,
and the surface of the support face of the support structure
actually making contact.
[0051] Although it is beneficial to minimize the inter-stand
distance D to reduce the corresponding inter-stand length lost, a
minimum space must be left between the rear and front faces 26 and
46 of the stands 22 and 24. Indeed, this space must be sufficient
to enable the insertion and removal of tools such as the C-clamp of
an X-ray thickness gauge used to measure the thickness of the strip
in order to provide adjustment data to the control system of the
rolling installation. Furthermore, albeit exceptionally, the
possibility of a strip engagement problem in one of the stands or a
breakage of the strip in the gap between the two stands occurring
cannot be discounted. It is therefore necessary to retain an
inter-stand distance to enable an operator to pass through. To
assess the minimum dimension of the inter-stand distance, reference
may be made to machine safety standards, and in particular standard
EN 547 which proposes leaving a minimum space of 700 mm between two
machines to enable access on all fours while enabling the body to
move.
[0052] By way of example, and returning to the numerical data given
in the introduction, the first and second six-high stands 2 and 4
have a rolling capacity of around 2,400 metric tons each. The
backup rolls 10 and 11 have a diameter of 1,250 mm, the
intermediate rolls 8 and 9, a diameter of 550 mm, and the work
rolls 6 and 7, a diameter of 450 mm. Each stand 2, 4 typically has
uprights 22, 24 9,000 mm tall and 4,000 mm wide. According to the
invention the inter-stand distance D is reduced to 700 mm.
Consequently, the center-to-center distance is reduced by 1,300 mm
and the inter-stand length of the strip M is 4,700 mm. For a
production of 1,000,000 metric tons per year, the annual gain
realized by implementing this invention could reach 1,000 metric
tons of strip.
[0053] In the installation according to the invention, the drive
means of the work, intermediate or backup rolls, depending on the
installation type, have a reduced footprint in the rolling
direction A.
[0054] As shown in FIG. 3 and FIG. 6, in a first embodiment, the
drive means of the rolling installation have two reduction gears
200 arranged one after the other, parallel to the rolling direction
A, on the drive side of the first and second stands 2 and 4.
[0055] The reduction gear 200 includes: an input shaft 212, coupled
to a drive motor 214, and two output shafts 216 and 218, coupled
respectively to each of the rolls to be driven. Where appropriate,
a pair of extensions 220 couples the output shafts 116 and 118 and
the rolls to be driven. The reduction gear 200 also includes,
between the input shaft 212 and the output shafts 216 and 218, at
least one intermediate shaft 222 bearing a set of cogs meshed with
cogs either on the output shafts 216 and 218, or the input shaft
212.
[0056] In this first embodiment, the axes of the output shafts 216
and 218 and intermediate shaft 222 are arranged horizontally one
above the other in a vertical plane, while the axis of the input
shaft 212 is arranged laterally in relation to the axis of the
intermediate shaft 222. The reduction gear 200 has an "L"
layout.
[0057] A second embodiment of the reduction gear in the
installation according to the invention is shown schematically in
FIG. 7. According to this second embodiment, all of the axes of the
shafts of the reduction gear 210 are arranged horizontally one
above the other, in a vertical plane. The reduction gear 210 is
vertical and has a reduced footprint in the rolling direction
A.
[0058] In the installation according to the invention, the roll
change system has a single carriage 300 as shown in FIGS. 2 and 3.
The carriage 300 is fitted with wheels 302 and can be moved along
the rails 304, arranged in the transversal direction Y. The
carriage 300 is moved by actuating the movement means 306 between a
waiting position away from the first and second stands 2 and 4, and
a service position near to the first and second stands 2 and 4.
FIG. 3 shows the carriage 300 in its waiting position away from the
first and second stands 2 and 4.
[0059] The carriage 300 has a mobile deck 310 fitted with a row of
four racks 312a-d arranged side by side in the rolling direction A.
The racks 312a and 312b serve the first stand 2 and the racks 312c
serve the second stand 4. Each rack 312a-d is able to carry a train
of rolls comprising the work rolls 6 and 7 and the backup rolls 8
and 9. At the beginning of the roll change method, the two racks
312a and 312c carry a train of new rolls, fitted with their chocks,
while the other two racks 312b and 312d are empty, waiting to load
the used rolls removed from each of the first and second stands 2
and 4.
[0060] The mobile deck 310 is moveable by translation in the
rolling direction A, along the rails 316 provided on the carriage
300. The mobile deck 310 is moved in relation to the carriage 300
by actuating means such as a rack (not shown) on the carriage
300.
[0061] In the first position of the deck 310, the vertical plane of
symmetry of the racks 312b and 312d coincides with the plane of
symmetry respectively of the first and second stands 2 and 4. The
first and second push/pull devices 322 and 324, provided on the
carriage 300, can pull the used rolls from the first and second
stand 2 and 4 to place them on the racks 312b and 312d.
[0062] In the second position of the mobile deck 310, the vertical
planes of symmetry of the racks 312a and 312c coincide with the
planes of symmetry respectively of the first and second stands 2
and 4. The first and second push/pull devices 322 and 324 can then
be actuated to push the new rolls, waiting in racks 312a and 312c,
into each of the first and second stands 2 and 4.
[0063] Once the rolls have been replaced, the carriage 300 is moved
to its waiting position away from the mill.
[0064] In a synchronous roll-change method, the first and second
push/pull devices 322 and 324 are actuated simultaneously to pull
out the used rolls and push in the new rolls. This ensures a quick
roll change.
[0065] Alternatively, an asynchronous roll-change method is
possible in which the push/pull devices 322 and 324 are actuated
separately in order to enable the rolls of one of the stands of the
mill to be changed.
[0066] The person skilled in the art will be able to modify the
installation described above to implement other roll replacement
methods. Thus, in certain types of installation, the drive is
provided via the backup or intermediate rolls. The work rolls are
then driven by friction on the intermediate rolls. In this type of
installation the drive side of the mill is relatively unencumbered.
A roll loading/unloading carriage may therefore be provided on the
drive side of the mill. Furthermore, although a push/pull roll
change system has been described, alternatively, the roll change
system may be push-through only or pull-through only.
* * * * *