Patent Grant
10195652
The subject matter of the invention is a method for changing the configuration of a rolling mill, as well as a rolling mill for implementing the method.
The field of the invention is more particularly that of six-high rolling mills.
These six-high rolling mills find a particular application for example in annealing lines, or galvanisation lines or off-line rolling mills, reversible or non-reversible, for metallic strip.
The rolling mill according to the invention finds a particular application, in particular after annealing of the strip, for effecting a skin pass, very often for the purpose of eliminating the resilient level from the metallic strip, imparting roughness thereto and/or improving the brightness and/or flatness thereof.
A four-high rolling mill comprises a holding cage in which four cylinders are provided with parallel axes, namely respectively two working cylinders, top and bottom, defining the passage air gap for the strip to be rolled, and two supporting cylinders, top and bottom, bearing respectively on the working cylinders on the side opposite to that of the passage air gap.
A six-high rolling mill comprises two additional cylinders compared with a four-high, namely two intermediate cylinders interposed respectively between each working cylinder and the corresponding support cylinder.
In such rolling mills, each support cylinder, intermediate or working, is mounted so as to rotate at the ends thereof on chocks, by means of bearings, for example roller bearings or hydrostatic bearings. These chocks are supports that can be moved in a direction parallel to the gripping plane, between the two uprights of the cage.
Conventionally, first balancing actuators move the chocks of the working cylinders and second balancing actuators move the chocks of the intermediate cylinders. These balancing actuators make it possible to change the relative positions of the chocks and their cylinder, making it possible among other things to open the cage in order to facilitate the engagement of the product to be rolled, or to move these components in order to facilitate the removal of the cylinders. These balancing actuators may also make it possible to camber the cylinders, as developed hereinafter.
One advantage of a six-high rolling mill is the possibility of using, compared with a four-high cage, working cylinders with a smaller diameter, which makes it possible to obtain a greater reduction in thickness of the product to be rolled for the same rolling force.
A six-high rolling mill moreover offers the possibility of axially offsetting the two intermediate cylinders, or even also the two working cylinders, for the purpose of applying the rolling force only over the width of the strip to be rolled rather than over the entire length of the working cylinders. Such a possibility of axial adjustment of the cylinders, as in particular taught in the document U.S. Pat. No. 4,311,030, makes it possible to obtain better flatness of the product to be rolled, in particular at the edges of the rolled strip.
Since the rolling forces are applied only at the ends of the cylinders, each cylinder can flex under the action of the rolling forces, which very often results in unevenness of the strip.
Correcting these defects by applying cambering forces on the two ends of each of the working cylinders and/or on the two ends of each of the intermediate cylinders is then known.
For this purpose, it is possible to use the previously described balancing actuators to separate the chocks of the two working cylinders, thus achieving a positive camber. Some equipment also makes it possible to tighten the chocks of two working cylinders, thus achieving a negative camber. Alternatively or additionally, a positive and/or negative camber can also be provided on the intermediate cylinders.
A six-high rolling cage comprising, in a conventional manner, two working cylinders, two intermediate cylinders and two support cylinders is thus known from the prior art, in particular from the document EP 0 059 417.
In the rolling cage of the type in the document EP 0 059 417, the balancing actuators are double-acting hydraulic actuators and do not act directly on the chocks of the cylinders, but only by means of cambering units, each mounted so as to slide along a rail disposed over the height of one of the uprights of the cage. The movement of the working cylinders or intermediate cylinders, along the gripping plane, is obtained by sliding the corresponding cambering units with respect to the upright of the cage.
In such a rolling mill, the axial movement of the working cylinders, or the axial movement of the intermediate cylinders, can be obtained by sliding their respective chocks with respect to the corresponding cambering units. To this end, the chocks have guide parts oriented in a direction parallel to the axes of the cylinders, for example two horizontal tenons, projecting laterally on each side of the chock, able to slide respectively in corresponding parts of the corresponding two cambering units, for example in horizontal grooves in the two corresponding units.
Such a design is simple and can advantageously make it possible, using asymmetric chocks, to mount, in the same cage, two different cylinder diameter ranges, for the working cylinders and for the intermediate cylinders, simply by turning over the chocks. The change from one cylinder diameter configuration to the other configuration is therefore obtained by keeping the asymmetric chocks of the intermediate cylinders and the asymmetric chocks of the working cylinders.
These chocks are asymmetric in that the guide parts of the chocks are offset in a direction parallel to the gripping plane, with respect to the axis of the corresponding cylinder, which makes it possible, when the chocks of the working cylinders and the chocks of the intermediate cylinders are turned through 180°, to change the position of the rotation axis of the chocks.
The change in configuration is thus obtained by keeping the same rolling mill cage, the same camber force application means (ie the same cambering units) for the working cylinders and for the intermediate cylinders, and the same chocks for the working cylinders and for the intermediate cylinders.
Such a change in configuration of the cage makes it possible to extend the production range of a rolling installation and to make this equipment, which keeps a maximum amount of equipment from one configuration to another, profitable more quickly.
A rolling mill cage according to the document EP 0 059 417 does however have certain drawbacks.
First of all this cage uses, for the balancing actuators, units for cambering the double-acting hydraulic actuators that give rise to clearances, in particular when the direction of camber is reversed, namely from a positive camber to a negative camber, or vice versa. These double-acting hydraulic actuators create discontinuities of functioning, which may be particularly detrimental during certain productions.
In addition, and in accordance with the findings of the inventors, the balancing actuators do not act directly on the cylinder chocks, but only by means of said cambering units, themselves mounted so as to slide each by means of a rail or equivalent along the cage uprights.
According to the findings of the inventor, these cambering units are liable to create high friction, which will be greatly accentuated during the axial movements of the intermediate cylinders and/or working cylinders, traditionally made to apply the rolling force only over the width of the strip to be rolled.
This is because these axial movements are obtained by movement of the chocks with respect to the cambering units. During such movements, the vertical forces transmitted by each chock to the corresponding cambering unit are no longer centred along the axis of said corresponding cambering unit, but on the contrary greatly offset with respect to this. Such an offset causes a tilting force on the cambering unit, giving rise to an increase in friction between the unit and the upright. Naturally such friction disturbs the precision of the control of the cambering forces to be applied.
In order to limit this defect, for a design of rolling mill with cambering units according to the document EP 0 059 417, limiting the magnitude of the axial movements of the cylinders to ±160 mm is known, which generally makes it necessary to use, for the working cylinders and the intermediate cylinders, particular profiles, in the shape of bottles, for the cylinders, as taught by the document EP 0 543 014 B1, also known by the term “Continuous Variable Crown” (CVC). With traditional cylinder profiles typically comprising a cylindrical length section followed by a conical length section, the axial movement of travel necessary becomes too great and this design with cambering units is often considered to be unsuitable.
Four-high rolling mill cages able to use, in the same cage, two different working cylinder diameter ranges, while keeping the same chocks, are also known from the prior art. Such a change in configuration of the cage makes it possible to extend the production range of a rolling installation and to make this equipment profitable more quickly, which keeps a maximum amount of equipment from one configuration to another.
In this prior art, the chocks have parallel sliding faces on either side of the gripping plane, intended to cooperate with guide faces of the windows oriented in the gripping direction. Each chock has, on each side, laterally, a projecting tenon intended to serve as a support for single-acting balancing actuators, functioning solely under thrust. Some of the balancing actuators are provided below the tenon and act so as to thrust on the bottom face of the tenon of the chocks in order to camber the corresponding working cylinder in a first cambering direction. The other single-acting actuators are provided on the other side of the tenon, above the tenon, and act so as to thrust on the top face of the tenon of the chocks in order to camber the working cylinder in the other direction.
Such a design using only single-action balancing actuators to camber the cylinders, in one direction or the other, does not create any discontinuity during the reversal of the cambering direction.
The chocks are asymmetric, the tenons of the chocks of each working cylinder being offset with respect to the axis of the cylinder, in a direction parallel to the gripping plane. The change in configuration is effected by turning the chocks of the working cylinders through 180° in order to pass from one diameter range to another working cylinder range.
In such a design of a four-high rolling mill, and in accordance with the findings of the inventors, the single-acting balancing actuators cooperating with the same chock are disposed on either side of the chock tenons and thus occupy an excessively great vertical space for such a design to be able to be duplicated at a rolling mill cage of the six-high type.
Duplicating such an arrangement of balancing actuators for the chocks of the working cylinders and another additional arrangement of balancing actuators for the chocks of the intermediate cylinders is not possible because of the vertical bulk of the solution, greater than the space available in a cage of the six-high type.
The aim of the present invention is to overcome the aforementioned drawbacks by proposing a method for changing the configuration of a rolling mill of the six-high type from one working cylinder diameter range to another distinct range. The invention makes it possible to pass from one configuration to another while keeping in particular the same chocks, the same cambering means, and the same support cylinders, and optionally the same intermediate cylinders.
The invention also concerns a rolling mill suitable for implementing the method, with an improved performance compared with the prior art such as rolling mills with cylinders interchangeable by turning over chocks, in particular on the aspects of controlling the camber forces, or with regard to the possible magnitudes of axial movement of the intermediate cylinders.
Other aims and advantages will emerge from the description, which is given only by way of non-limitative example.
Thus the invention concerns first of all a method for changing the configuration of a rolling mill comprising:
According to the method in accordance with the invention:
According to an advantageous embodiment, the same intermediate cylinders are kept from the first configuration of the rolling mill to the second configuration.
Alternatively, it is also possible to change intermediate cylinder diameter from the first configuration of the rolling mill to the second configuration.
According to optional features of the method according the invention, taken alone or in combination:
The invention also concerns a rolling mill as such, suitable for implementing the method, comprising:
means for applying vertical camber forces on the intermediate cylinders, comprising two sets of hydraulic actuators.
According to the rolling mill in accordance with the invention:
According to an advantageous embodiment, it is possible to keep the same intermediate cylinders when the rolling mill passes from the first configuration to the second configuration.
According to optional features of the rolling mill taken alone or in combination:
The invention will be understood better from a reading of the description accompanied by the attached figures, among which:
Thus the invention relates to a rolling mill 1 comprising a holding cage 2 having pairs of uprights 20, 21, separated from each other and disposed at the two ends of the cage. The uprights 20, 21 of each pair define between them an access window for maintenance of the cages.
The rolling mill is of the six-high type and comprises a set of cylinders above one another with substantially parallel axes, comprising two working cylinders 3, 4; 3′, 4′, bottom and top, two intermediate cylinders 5, 6, bottom and top, and two support cylinders 7, 8, respectively bottom and top.
The two working cylinders 3 and 4 are situated on either side of the strip to be rolled, the separation thereof defining the passage air gap in operation. Each intermediate cylinder 5 or 6 is interposed between the working cylinder 3 or 4 and the corresponding support cylinder 7 or 8.
Each working cylinder 3 or 4 has two ends mounted so as to rotate, each on a bearing P1 carried by a chock E1. Likewise, each intermediate cylinder 5 or 6 has two ends mounted so as rotate, each on a bearing P2 carried by chock E2. The support cylinders 7 or 8 also have two ends mounted so as to rotate, each mounted on a bearing carried by a chock.
The chocks E1 of the working cylinders, the chocks E2 of the intermediate cylinders and the chocks of the support cylinders 7, 8 are mounted so as to slide in a direction parallel to the gripping plane, so as to enable the cage to be opened or closed, or to facilitate the maintenance and dismantling operations.
The rolling mill has means of applying a clamping force between the chocks of the support cylinders. These means, conventionally hydraulic, are not illustrated since they are well known to persons skilled in the art.
The rolling mill 1 also comprises means 9 for applying vertical camber forces to the working cylinders 3, 4; 3′, 4′, comprising two sets of hydraulic actuators V1, V2, V3 and means 10 for applying vertical camber forces to the intermediate cylinders, comprising two sets of vertical actuators V 1′, V2′, V3′.
In accordance with the rolling mill according to the invention, the chocks E1 of the working cylinders 3, 4; 3′, 4′ and the chocks E2 of the intermediate cylinders 5, 6 are supports comprising four support members O1, O2, O3, O4; O1′, O2′, O3′, O4′, as illustrated in detail by way of non-limitative example in
It should be noted that, for reasons of simplification,
The four support members O1, O2, O3, O4; O1′, O2′, O3′, O4′ are disposed laterally to the chocks E1 or E2. Thus the chocks E1 of the working cylinders each have, firstly two support members O1, O2 projecting on one side of the chock E1, namely a top support member O1 and bottom support member O2 defining a first interspace, and secondly two support members O3, O4 projecting on the other side of the chock, namely a top support member O3 and a bottom support member O4 defining a second interspace.
Likewise the chocks E2 of the intermediate cylinders each have, firstly two support members O1′, O2′ projecting on one side of the chock E2, namely a top support member O1′ and bottom support member O2′ defining a first interspace, and secondly two support members O3′, O4′ projecting on the other side of the chock, namely a top support member O3′ and a bottom support member O4′ defining a second interspace.
The hydraulic actuators V1, V2, V3 of the means 9 for applying vertical camber forces to the working cylinders are actuators disposed in the first and second interspaces of the chocks of the working cylinders 3, 4; 3′, 4′.
The actuators V1, V2, V3 disposed in the same interspace are parallel to each other and substantially overlap at least over part of their length as illustrated by way of non-limitative example in
The actuators V1, V2, V3 are intended to cooperate thrustingly, in some cases, with the top support members O1, O3 in order to camber the working cylinders 3; 3′; 4; 4′ in a first direction and with regard to the remainder with the bottom support members O2, O4 in order camber the working cylinders 3; 3′; 4; 4′ in the other direction. According to an embodiment illustrated in
Likewise, the hydraulic actuators of the means 10 for applying vertical camber forces to the intermediate cylinders 5, 6 are actuators disposed in the first and second interspaces of the chocks E2 of the intermediate cylinders.
The actuators V1′, V2′, V3′ disposed in the same interspace are parallel to each other and overlap at least over part of their length as illustrated by way of non-limitative example in
The actuators V1′, V2′, V3′ are intended to cooperate thrustingly in some cases with the top support members O1′, O3′ in order to camber the intermediate cylinder in a first direction and with regard to the remainder with the bottom support members O2′, O4′ in order to camber the intermediate cylinder in the other direction.
The actuators V1, V2, V3 and/or V1′, V2′, V3′ may be single-acting actuators. Working only thrustingly in one cambering direction or the other, they create no discontinuity when the camber direction is reversed. Moreover, the actuators V1, V2, V3 and/or V1′, V2′, V3′ act directly on the chocks E1 or E2, and control of the camber forces is facilitated thereby.
According to an embodiment illustrated in
The chocks E1 of the working cylinders 3, 4; 3′, 4′ have sliding faces, on either side of the chock E1, parallel to each other, intended to cooperate with guide faces, preferably provided on the uprights of the cage.
Likewise the chocks E2 of the intermediate cylinders 5, 6 have sliding faces, on either side of the chock E2, parallel to each other, intended to cooperate with guide faces, preferably provided on the uprights of the cage. Preferably, and as illustrated in
According to this embodiment, the sliding faces S may comprise shoes, substantially parallel to each other and to the gripping plane, fixed at the ends of the support members O1, O2, O3, O4; O1′, O2′, O3′, O4′.
Alternatively, the guidance between the cage 2 and the chocks E1, E2 may be obtained by providing the sliding faces, laterally to the body of the chocks, at each interspace.
According to an essential feature of the invention, the chocks E1 of the working cylinders 3, 4; 3′, 4′ and the chocks E2 of the intermediate cylinders 5, 6 are asymmetric chocks so as to enable the rolling mill to pass from a first configuration of the range of diameters of working cylinders 3, 4 (see
Preferably the same intermediate cylinders 5, 6 are kept from the first configuration C1 to the second configuration C2 of the rolling mill. It is however possible, according to another alternative, to change intermediate cylinder diameters from the first configuration C1 to the second configuration C2.
Asymmetric means the fact that the support members O1, O2, O3, O4; O1′, O2′, O3′, O4′ of the chocks E1 or E2 are not distributed, in the direction of the uprights, at equal distances from the support axis of the cylinder of the chock E1 or E2.
By turning over the chocks E1 or E2 and making them engage with the same actuators V1, V2, V3 or V l′, V2′, V3′, it is then possible to offset the position of the axis of the cylinder, without modifying the position of the actuators.
According to an embodiment given by way of non-limitative example, the first configuration C1 of the rolling mill 1 may make it possible to mount working cylinders with a diameter of between 800 mm and 500 mm, preferably 670 mm and 520 mm, for example between 620 mm and 570 mm, and the second configuration C2 of the rolling mill makes it possible to mount working cylinders with a diameter of between 500 mm and 250 mm, preferably between 500 mm and 350 mm, for example between 450 mm and 400 mm.
Advantageously, the change in configuration of the rolling mill is obtained by keeping the chocks E1, E2, turning over the chocks E1 of the working cylinders and turning over the chocks E2 of the intermediate cylinders, keeping the same cage 2, the same means for applying a clamping force between the chocks of the support cylinders, the same means 9 for applying vertical camber forces to the working cylinders, the same means 10 for applying vertical camber forces to the intermediate cylinders, and the same type of support cylinder 7, 8, and optionally the same intermediate cylinders 5, 6.
During this change of configuration, the cage 2, the means for applying a clamping force between the chocks of the support cylinders, the means 9 for applying vertical camber forces to the working cylinders, the means 10 for applying vertical camber forces to the intermediate cylinders, and the support cylinders 7, 8, are not removed from the rolling mill.
On the other hand, the working cylinders 3, 4 (and respectively 3′, 4′) are removed with their chocks E1. Once separated from the cylinders, the chocks E1 are assembled on the working cylinders 3′, 4′ (and respectively 3, 4) with different diameters, in the turned-over position. The new working cylinders with their turned-over chocks are mounted in the cage 2.
Likewise, the intermediate cylinders 5, 6 are removed with their chocks E2. In the case where the intermediate cylinders 5, 6 are kept, the chocks E2 are simply turned over out of the cage 2, before being mounted once again in the cage 2. In the case of a change of intermediate cylinders, with different diameters, the chocks E2 are separated from the cylinders and are assembled on the intermediate cylinders with different diameters. The new intermediate cylinders with their turned-over chocks are then mounted in the cage 2. Preferably identical chocks E1 are used for the working cylinders, top and bottom, and identical chocks E2 for the intermediate cylinders, top and bottom. The chocks E1 and/or E2 of the top cylinders are simply reversed with respect to the chocks E1 and/or E2 of the bottom cylinders.
Preferably, said rolling mill 1 comprises means for adjusting the axial movement of the intermediate cylinders. Advantageously, these means comprise supports 11, 12, 13, 14 mounted so as to slide with respect to the cage, in a direction parallel to the axis of the intermediate cylinder, the supports, 11, 12, 13, 14 taking the hydraulic actuators V1′, V2′, V3′ of said means 10 for applying vertical camber forces to the intermediate cylinders 5, 6.
The axial adjustment of the intermediate cylinders 5, 6, in particular in order to adapt the rolling force only over the width of the strip to be rolled, is thus obtained without relative movement between the chocks E2 of the intermediate cylinders and said corresponding hydraulic actuators V1′, V2′, V3′. Such a design allows high axial adjustment travels greater than ±160 mm, such as for example ±250 mm, and thus allows the user of traditional intermediate cylinders having a cylindrical length section following by a conical section, or cylinders with variable profiles with different shapes since they are more progressive.
The rolling mill according to the invention and the configuration change method finds an application in lines comprising an annealing operation, such as for example galvanisation lines or continuous annealing lines, or in rolling mills outside a line, such as for example reversible rolling mills or discontinuous rolling mills.
Naturally other embodiments could have been envisaged without departing from the scope of the invention as defined by the following claims.
List of Parts
| Number | Date | Country | Kind |
|---|---|---|---|
| 13 54824 | May 2013 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2014/051232 | 5/27/2014 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2014/191671 | 12/4/2014 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4311030 | Kitashima et al. | Jan 1982 | A |
| 4543810 | Stoy et al. | Oct 1985 | A |
| 7302820 | Le Viavant | Dec 2007 | B2 |
| 9120134 | Guo | Sep 2015 | B2 |
| 20060196243 | Le Viavant | Sep 2006 | A1 |
| 20130104617 | Guo et al. | May 2013 | A1 |
| Number | Date | Country |
|---|---|---|
| 0 059 417 | Sep 1982 | EP |
| 0 543 014 | May 1993 | EP |
| 2 851 942 | Sep 2004 | FR |
| S60-206508 | Oct 1985 | JP |
| H02-280910 | Nov 1990 | JP |
| Entry |
|---|
| International Search Report, dated Sep. 19, 2014, from corresponding PCT Application. |
| Number | Date | Country | |
|---|---|---|---|
| 20160107212 A1 | Apr 2016 | US |
