Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B13/00—Metal-rolling stands, i.e. an assembly composed of a stand frame, rolls, and accessories
  • B21B13/001—Convertible or tiltable stands, e.g. from duo to universal stands, from horizontal to vertical stands
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
  • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
  • B21B1/24—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process
  • B21B1/28—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a continuous or semi-continuous process by cold-rolling, e.g. Steckel cold mill
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B13/00—Metal-rolling stands, i.e. an assembly composed of a stand frame, rolls, and accessories
  • B21B13/14—Metal-rolling stands, i.e. an assembly composed of a stand frame, rolls, and accessories having counter-pressure devices acting on rolls to inhibit deflection of same under load; Back-up rolls
  • B21B13/145—Lateral support devices for rolls acting mainly in a direction parallel to the movement of the product
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
  • B21B37/16—Control of thickness, width, diameter or other transverse dimensions
  • B21B37/24—Automatic variation of thickness according to a predetermined programme
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B13/00—Metal-rolling stands, i.e. an assembly composed of a stand frame, rolls, and accessories
  • B21B13/02—Metal-rolling stands, i.e. an assembly composed of a stand frame, rolls, and accessories with axes of rolls arranged horizontally
  • B21B2013/025—Quarto, four-high stands
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B13/00—Metal-rolling stands, i.e. an assembly composed of a stand frame, rolls, and accessories
  • B21B13/02—Metal-rolling stands, i.e. an assembly composed of a stand frame, rolls, and accessories with axes of rolls arranged horizontally
  • B21B2013/028—Sixto, six-high stands

Definitions

• the subject of the invention is a method for widening the production range of a cold rolling installation for metal products in the form of a strip and also covers installations provided with means for implementing the process in order to widen their range of production.
• Cold rolling is normally carried out in several successive passes, either in two opposite directions on a reversible train, or on several rolling mill stands operating in tandem.
• the working rolls tend to move away from each other and the air gap between the facing generators must therefore be maintained by applying, between the rolls, a clamping force often called rolling force or effort.
• the rolling force to be applied to obtain a certain reduction rate in thickness depends, in particular, on the diameter of the working rolls which determines the length of the reduction zone as well as on mechanical and metallurgical characteristics, such as its elastic limit, its composition, for example, common low carbon low alloy steel, stainless steel, alloy steel, etc.
• a tandem cold rolling mill comprises a succession of cages arranged one after the other on the path of the strip, in order to ensure a progressive reduction in the thickness of the latter.
• Each rolling mill stand comprises, conventionally, two support columns spaced apart and connected by crosspieces, between which is mounted a set of superimposed rolls having parallel axes and placed substantially in the same clamping plane substantially perpendicular to the direction of movement of the product.
• Rolling mills of different types can be produced.
• the product to be rolled passes between two working rolls which define the rolling plane; these cylinders are generally of relatively small diameter with regard to the forces to which they are subjected; they therefore bear, respectively, on at least two support rolls between which the rolling force is applied.
• the rolling stands used in the metallurgical industry can have several types of configuration depending on the nature of the product to be treated.
• the most common rolling mills are of the “quarto” type comprising two working rolls each associated with a support cylinder of larger diameter, or of the “sexto” type, in which intermediate rolls are interposed between each working cylinder and the corresponding support cylinder.
• This arrangement allows the use of small diameter cylinders which can be associated with lateral support rollers, in a so-called "Z.HIGH" configuration.
• cylinders comprising a greater or lesser number of cylinders
• the cylinders bear on each other along substantially parallel support lines, and directed along a generator whose profile, normally rectilinear, depends on the applied forces and the resistance of the cylinders.
• the clamping force is applied by screws or jacks interposed between the cage and the ends of the shaft of a support cylinder, the other support cylinder bearing by these ends directly on the cage, or by by means of a wedging or height adjustment device intended to compensate for the variations in diameters of all of the cylinders which gradually wear out.
• chocks which are slidably mounted vertically inside windows formed in the two columns of the cage, and each provided with two chock guide faces, parallel to the clamping plane.
• the support cylinders have a large diameter, the corresponding guide faces are generally formed directly on the two uprights of the corresponding column of the cage.
• the working rolls having a smaller diameter, their chocks are smaller and the corresponding guide faces, which are more tightened, are provided, generally, on two massive pieces fixed on the two uprights framing the window and s' extending inwardly projecting therefrom.
• the clamping forces are normally applied between the two ends of the two support cylinders. Since the laminated product, of variable width does not entirely cover the length of the working rolls, each roll can bend under the action of the applied forces and this results in a variation in thickness of the passage space of the strip between the working rolls, which generates defects in profile and flatness. To try to correct these profile defects across the rolled product, it was first proposed to compensate for the deformation of the rolls due to the rolling force, by bulging their surface obtained by machining according to a particular profile.
• the lack of thickness on the cross section of the rolled product is complex because it is the result of all the deformations of all of the cylinders, which are of different diameters, and of the deformation of all the constituent parts of the rolling stand under stress.
• intermediate rolls makes it possible to use working rolls of smaller diameter and, thus, to reduce the rolling force necessary for the same thickness reduction. It is also possible to perform axial displacement, in opposite directions, of the working rolls in the quarto rolling mills, and / or of intermediate cylinders in the sexto rolling mills, in order to better control the distribution of the stresses over the width of the product.
• rolling determines, by work hardening, a progressive increase in the hardness of the product and, consequently, in the rolling force to be applied for the same reduction in thickness, d 'one cage to the next.
• the means of applying the clamping force may saturate in power if the hardness of the starting product is too high.
• very large capacity installations for example exceeding 1 million tonnes per year, have only been carried out for two families of steel, on the one hand steels for body sheets and, on the other hand , steels for packaging.
• user needs are constantly evolving in the direction of a diversification of the qualities demanded and a change, sometimes abrupt, in the quantities to be supplied.
• TRIP Transaction Induced Plasticity
• TRIP steels have a breaking limit which can reach twice the value of the elastic limit. The work hardening curve from which the scheme of the rolling passes is determined is therefore completely different.
• such steels are generally characterized by the value of their breaking limit and not, as previously, by that of their elastic limit.
• the steel industry is therefore subject to contradictory imperatives.
• the rolling facilities must be equipped with expensive devices, specially adapted to the characteristics of the products to be laminated to obtain the desired qualities and, on the other hand, the quantities requested by customers are often insufficient to make such equipment profitable.
• the object of the invention is to solve all of these problems by means of a process making it possible to widen the production range of a rolling installation by having the possibility of treating thereon, steels having dimensional characteristics, mechanical and metallurgical very diverse, while maintaining sufficient productivity for all grades of metal and benefiting, however, from all the means necessary to guarantee, optimally, the qualities of thickness, flatness and surface condition desired for the rolled product.
• the invention thus provides a production tool easily adaptable to changing needs, both in the quality of the rolled product and in the quantities to be supplied.
• the invention therefore applies, in general, to a cold rolling installation for metal products in the form of a strip, comprising at least two rolling stands operating in tandem for a progressive reduction in the thickness of the product, each cage being associated with means for applying a rolling force between two working rolls, allowing, for a given configuration of the cage, to achieve a certain rate of reduction in thickness, taking into account the mechanical and metallurgical characteristics of the product, said characteristics being included in a determined production range.
• At least one of the rolling cages is equipped with transformation means making it possible to change the configuration of the cage thus transformable, while retaining the same means for applying the rolling force, so as to have at least two configurations each adapted to a production range and, for the rolling of a product, the configuration of the transformable cage is chosen according to the characteristics of said product so that these enter the corresponding production range to the chosen configuration.
• the configuration of the transformable cage can be chosen as a function of the hardness of the material constituting the product to be laminated.
• the production range can thus include products whose rupture limit, after hot production can range from less than 160 MPa to at least 1000 MPa.
• the rolling stands each being associated with means for controlling at least one of the quality factors such as the regularity of thickness, the flatness and / or the surface condition, changes the configuration of at least one of the rolling stands according to the dimensional, mechanical and metallurgical characteristics of the product, so as to maintain the same quality over the overall production range of the installation.
• the quality factors such as the regularity of thickness, the flatness and / or the surface condition
• At least one transformable cage of a quarto configuration is passed, comprising two working cylinders supported on two support cylinders, to a configuration sexto comprising two working cylinders supported by intermediate cylinders on the same support cylinders, and vice versa.
• At least one transformable cage of a sexto configuration is passed, comprising two working rolls supported respectively, by a pair of first intermediate rolls, on a pair of support cylinders, in an “octo” type configuration comprising two working cylinders supported respectively, by a pair of second intermediate cylinders, on the same first intermediate cylinders and the same support cylinders, and vice versa.
• At least one transformable cage with removable means for lateral support of the working rolls, in order to allow, in an additional configuration, the use of very small working rolls diameter.
• the configuration is changed, at least, of the first stand of the rolling mill, in order to give it a sexting configuration for rolling strips having, at the entrance to the rolling mill, a breaking limit equal to or greater than 600 MPa and a quarto configuration for rolling strips with a lower breaking limit.
• the invention also covers a rolling installation for implementing the method comprising at least two rolling cages operating in tandem, in which at least one of the cages is equipped with means for rapid replacement of a first pair of cylinders working by two assemblies mounted in cassettes each comprising a working cylinder of smaller diameter, associated with an intermediate cylinder, said transformable cage thus having two possible configurations, respectively a first configuration with at least four cylinders, adapted to a first range of production, and a second configuration with at least six cylinders, adapted to a second production range, retaining in the two configurations, at least, the same support cylinders and the same means of applying the rolling force.
• At least one of the cages, in particular the first cage can pass from a quarto configuration to a sexto configuration, and vice versa.
• At least one of the cages in particular an intermediate cage can pass from a sexto configuration to an octo configuration, with possibly removable means for lateral support of the working rolls.
• the transformable cage is equipped with means for cambering the cylinders which are the same in the two configurations and cooperate with the support parts of the chocks of the working rolls in a first configuration and with the support parts of the chocks of the intermediate rolls in a second configuration and the support parts are placed, in each of the configurations, substantially at the same level with respect to the rolling plane, on each side thereof.
• Figure 1 is a partial schematic view, in elevation, of an installation according to the invention comprising four rolling stands in quarto configuration.
• Figure 2 is a schematic view, in elevation of the installation according to the invention, after transformation of the first and the last cage.
• FIG. 3 schematically represents, in elevation, a rolling stand according to the invention in quarto configuration.
• Figure 4 is an enlarged view of the central part of the cage of Figure 3, after transformation into sexto configuration.
• FIG. 5 represents, in elevation, another embodiment of a transformable cage, in sexto configuration.
• FIG. 6 represents, in elevation, the central part of the cage of FIG. 5, after transformation into an octo configuration with lateral supports.
• Figure 7 shows the octo cage of Figure 6, in the cassette disassembly position.
• Figure 8 shows the octo cage of Figure 6, in the disassembly position of the side supports.
• Figure 9 is a partial elevational view showing a variant of the lateral support device.
• FIG. 10 is a top view, partially broken away, of the end of a cassette for the octo configuration of FIG. 8.
• Figure 11 is a sectional view along line I, I of Figure 9.
• Figure 1 shows schematically a tandem rolling installation with four cages operating continuously, that is to say without band engagement, the rolling mill being fed by coils welded end to end. Schematically, such an installation comprises, in a direction of travel of the strip, an inlet section E, a rolling section L and an outlet section S.
• the laminating section L comprises, in the example shown, four cages operating in tandem, that is to say effecting, at the same time, each a reduction in thickness on the product and controlled so as to maintain between them a level of traction, generally high, compatible with the resistance of the product and allowing, as is known, to achieve a greater thickness reduction in each cage.
• the inlet section E comprises devices, not shown, for tensioning the strip, placed just in front of the first stand and a guide device G.
• the outlet section S generally comprises a fractionation shears C to constitute reels and, for example, two winders B, B 'each having a guide and deflection device D, D'. It does not seem necessary to describe in more detail such a continuous rolling installation, the characteristics and advantages of which have been indicated, for example, in an article entitled “coupled stripping-tandem from Sainte Agathe to Sollac Florange” published in La Revue de la Métallurgie, de Mars 1998. In particular, such an installation may include a greater or lesser number of cages operating in tandem and, depending on the nature and destination of the product, various sections for processing the metal strip, whether or not arranged in a continuous line.
• An essential parameter is obviously the diameter of the working rolls on which the metal flow conditions in the rolling right-of-way depend.
• the smaller diameters make it possible, with equal reduction, to reduce the rolling effort required, but the wear range is reduced and the life of the rolls shorter, which leads to an increase in the cost of production.
• the contact arc being smaller, the stability of the cage is more difficult to maintain, in particular in the case of tandem rolling mills which, as is known, allow to exert strong pulls upstream and downstream of each rolling stand.
• ⁇ is the coefficient of friction
• F the rolling force
• T e and T s the tensile forces at the outlet and the inlet of the rolling stand
• D the diameter of the working rolls.
• an essential quality demanded of a rolling plant is to provide a product having a thickness and surface qualities as constant as possible.
• it is therefore necessary to constantly adjust the factors involved in the thickness reduction process, in order to maintain, throughout the production, the stability of the thickness reduction and the qualities of flatness and surface condition. required.
• the tensile forces which can be applied to the strip, respectively at the inlet and at the outlet of the installation depend on the devices placed respectively upstream and downstream thereof and are lower than the forces generated. by a cage of the tandem rolling mill on those which frame it.
• the surface appearance is important and the downstream treatments of the strip (galvanization, painting, etc.) impose a precise and constant roughness of the surface and this roughness is given by that of the working rolls of the last stand of the tandem rolling mill.
• the impression of the roughness of the cylinders on the strip is all the easier the larger the diameter. It is therefore another factor of choice for a large diameter of the working rolls, even in the last cage.
• a hot strip having a thickness of at least 3 mm and a fairly thin thickness must be obtained at the outlet of the installation. , of the order of 0.7 to 0.8 mm.
• the diameter can, without disadvantage, being located in a range substantially from 530 mm to 620 mm, the real range of use being of the order of 58 mm to 80 mm, which is economical with respect to the life of the cylinders .
• the breaking limit can go, for example up to 600 MPa. Above this breaking limit, there is a saturation of the mechanical means for driving the cylinders, the power of which is limited and the rolling force necessary cannot be exerted to obtain the desired thickness reduction. As a result, a tandem rolling installation can normally only be used for a relatively limited range of products for which the characteristics of the various members have been determined and, until now, it seemed necessary to have available specialized installations for the rolling of other grades of steel, in particular those with a breaking strength greater than 600 MPa, such as TRIP steels.
• the invention makes it possible to solve this problem simply, quickly and economically, by simply changing the configuration of at least one of the stands of the rolling mill, so as to modify the diameter of the working rolls and, thus, the range of products that can be processed in the rolling mill.
• the installation of the conventional type presented diagrammatically in FIG. 1, comprising four rolling stands operating in tandem and each equipped in a quarto configuration is adapted, as we have seen, to production with a large capacity, of usual quality sheets, for example for the automotive industry.
• Each cage L1, L2, L3, L4 is of the quarto type shown diagrammatically in FIG. 1 and therefore comprises, inside a cage comprising two spaced apart columns 10, a pair of working cylinders 2, 2 ′ resting on support cylinders 3, 3 ′ and limiting a gap for the passage of the product M which passes, in a rolling plane P substantially horizontal, in a direction orthogonal to the axes of the two working rolls, the axes of the different cylinders being placed substantially in a vertical clamping plane Pi.
• each cylinder is mounted to rotate about its axis, on anti-friction bearings housed in chocks mounted slidingly, parallel to the clamping plane P-i, in windows of each column 10 of the cage.
• the working rolls 2, 2 ' which have a smaller diameter than the support rollers 3, 3', are carried by two chocks 20, 20 'mounted to slide along vertical guide faces 12a, 12b formed at the ends of two parts 13a, 13b which protrude inside the window 11 while the guide faces of the chocks 30, 30 ′ of the support cylinders 3, 3 ′ are formed along vertical sides 11a, 11b of each window 11 of the cage.
• each column 10 of the cage In the lower part of each column 10 of the cage, is arranged a hydraulic clamping device 15 which, in the embodiment of FIG. 3, is equipped with a piston making it possible to apply the rolling force and to control the thickness regulation by resting on the chock 30 'of the lower support cylinder 3'.
• a screw wedging device 16 which makes it possible to keep the stacking of the cylinders tight while compensating for the variations in height, due to the wear of the cylinders.
• This device 16 can comprise, for example, a screw driven by a geared motor and bearing on the corresponding chock 30 of the upper support cylinder 3.
• the windows 11 and the means 15, 16 for clamping and wedging the cylinders are dimensioned to allow adjustment over a large amplitude of the spacing between the support cylinders 3, 3 ".
• each stand of the rolling mill is also equipped with devices for controlling the flatness of the product by bending (or bending) the working rolls.
• these bending devices consist, for each chock, of two sets of jacks 5, 5 ′ bearing, on each side of the window 11, on the two uprights of each column 10, the latter being provided, in addition , of guide faces between which the two chocks 20, 20 ′ are slidably mounted parallel to the vertical clamping plane Pi in which the axes of the cylinders are placed substantially.
• these lateral guide faces 12a, 12b are formed at the ends of two projecting parts 13a, 13b integral with the two uprights of each column 10 and on which generally bear the camber cylinders 4, 4 '.
• camber cylinders must act on the ends of the working rolls or of the intermediate rolls in sexto configuration, either in a positive direction of spacing of the rolling plane, to compensate for an excessive thinning of the edges of the rolled product, either in a negative direction of approach towards the rolling plane. It is therefore possible to use either double-acting cylinders fixed on the chock or on an intermediate piece, or two pairs of jacks acting in opposite directions on the support parts of each chock, on each side thereof.
• Figures 3 and 4 show a first embodiment according to the invention of a transformable cage, in quarto or sexto configuration.
• the means for bending the cylinders are mounted, with their hydraulic supply circuits, in massive pieces 4a, 4b called “hydraulic blocks” and fixed on the two uprights of each column 10 of the cage, in the central part of it.
• Each hydraulic block 4a, 4b carries, at the rolling plane P, a part 13a, 13b which projects inwards from the inside of the window and carries, at its internal end, a vertical face 12a, 12b for guiding chocks 20, 20 ′ of the working rolls 2, 2 ′ which are provided with support parts 21 called “ears”, which project outwards, on either side of the vertical clamping plane P1.
• each assembly 5 comprises at least one pair of opposite jacks 51, 52 placed on either side of the lug 21 and bearing on it, respectively in the positive direction d spacing of the rolling plane and in the negative direction of approach.
• each hydraulic unit 4a, 4b carrying two sets of jacks, respectively upper 5 and lower 5'.
• the camber cylinders respectively positive 51a and negative 52a, placed on the same side of the clamping plane Pt, are housed in a support piece 40a slidably mounted, parallel to the axes of the cylinders, on the corresponding hydraulic block 4a fixed in the central part of the column 10 and it is the same on the other side of the clamping plane Pi.
• each working cylinder for example the upper cylinder 2 is associated with two support parts 40a, 40b mounted to slide axially on the two hydraulic blocks 4a, 4b and on which the positive camber cylinders 51a bear, respectively, 51b and the negative camber cylinders 52a, 52b.
• the two support parts 40a, 40b are associated with means not shown, such as hydraulic cylinders, bearing on the cage to control the axial movement of the assembly formed by the working cylinder 2 and its two chocks 20 with the associated support pieces 40a, 40b carrying the sets of bending cylinders 5a, 5b.
• the projecting parts 13a, 13b serve only for guiding the chocks 20, 20 ′ of the two cylinders, between their opposite ends 12a, 12b.
• each projecting part 13 also carries two sets of jacks, respectively upper 50 and lower 50 'provided for the bending of the working rolls in the sexto configuration shown in FIG. 4.
• the cage includes the same support cylinders 3, 3 ′ but these have been separated so as to replace each working cylinder 2 of the quarto configuration by a set of two superimposed cylinders, respectively a new one.
• working cylinder 22 of smaller diameter and an intermediate cylinder 32.
• the windows 11 and the clamping means 15, 16 are dimensioned to give a sufficient amplitude of adjustment to the support cylinders 3, 3 '.
• each chock 23 of a working cylinder 22 of small diameter has the same width as a chock 20 of a working cylinder 2 in quarto configuration and is therefore guided vertically between the ends 12a, 12b of the two projecting parts 13a, 13b.
• each chock 23 is provided, substantially at the level of the axis of the cylinder 22, with lateral projecting parts forming ears which engage in notches formed in the guide faces 12a, 12b of the two projecting parts 13a. , 13b so as to cooperate with the sets of camber cylinders 50 housed in each projecting part 13a, 13b and which each comprise a pair of opposite jacks, 55 respectively of positive cambering and 56 of negative cambering.
• the chocks 33, 33 'of the intermediate cylinders 32, 32' are slidably mounted vertically, on guide faces 41, 41 'parallel to the clamping plane and formed on the opposite faces of the pieces of sliding support 40, 40 ′ each carrying the two sets of cambering cylinders, respectively positive 51, 51 ′ and negative 52, 52 ′ described previously in the quarto configuration of FIG. 3.
• the change of configuration can therefore be made while preserving not only all the means 15, 16, 3, 3 ′ for applying the rolling force but also the means for adjusting the transmission conditions of this force such as the cambering means 5, 5 'or axial displacement 40, 40'.
• the same sliding support pieces 40, 40 ′ can be kept with the same sets of camber cylinders 5, 5 ′ and simultaneously, on the one hand, positive or negative bending of the corresponding cylinders and , on the other hand, an axial displacement, in opposite directions, either of the two working cylinders 2, 2 'in the quarto configuration, or of the two intermediate cylinders 32, 32' in the sexto configuration.
• each small-diameter working cylinder 22 associated with an intermediate cylinder 32 forms, with their chocks, a set mounted in a cassette which can be moved axially to be removed from the cage or else be introduced therein, said assembly being able to be carried by the support parts 40a, 40b which slide axially.
• the support parts 40a, 40b which slide axially.
• FIG. 2 shows, by way of example, the installation shown in FIG. 1 after transformation of the first (L1) and the last (L4) cages in sexto configuration, the intermediate cages L2, L3 remaining in quarto configuration.
• this first cage L1 is therefore of the transformable type shown in FIGS. 3 and 4 allowing rapid switching from the quarto configuration provided for usual steels to a sexto configuration, which makes it possible to ensure from the first pass, a significant reduction and, therefore, achieve thickness reductions of up to 70% on the whole tandem rolling mill for this type of steel.
• the diameter of the working rolls can be chosen in a range which can go from 360 mm to 485 mm depending on the range of wear selected and the width of the rolling mill.
• the horizontal deviation of the roll can become significant and be detrimental to the flatness of the strip and to the stability of the rolling stand. This deviation is all the more important as the support points of the working cylinder are distant, that is to say that the rolling mill is wide.
• a wear range of 360 mm to 405 mm can be used for a 66 "rolling mill and a range of 425 mm and 485 mm for a rolling mill with a width of 80".
• FIG. 2 it has been observed that it would be advantageous to also use working rolls of smaller diameter on the last stand L4 because, at the outlet of the tandem rolling mill 1, the metal of the strip is at its maximum hardness. It is therefore preferable that the last L4 cage is also transformable in order to configure it in sexto mode for the manufacture of steels with very high elastic limit and particularly those of the “TRIP” type.
• the rolling mill in order to maintain the quality of the product over this extended range of characteristics, for the rolling mill to be equipped with the same means for regulating thickness and correcting flatness defects such as bending and displacement devices.
• axial of the cylinders as described above with reference to FIGS. 3 and 4.
• the first cage L1 For example, from the installation shown in FIG. 1, which is adapted to the usual qualities of metal, with working cylinders of the order of 530 to 620 mm, it is possible to transform the first cage L1 to give it a “sexto” configuration with working cylinders having a diameter chosen in a range which can go from 360 mm to 485 mm, which allows, without other modification of the installation, to treat, for example, steels with high elastic limit in the first cage L1 which achieves most of the thickness reduction.
• the two intermediate cages L2 and L3 which usually carry out a smaller thickness reduction, can remain in “quarto” mode with large cylinders.
• this transformation of the rolling stands is done by means of a rapid cylinder change device which, in any case, is necessary for the replacement of the worn rolls.
• the arrangements according to the invention therefore make it possible to adapt, with great flexibility, to a change in the mechanical and dimensional characteristics of the products to be laminated and, thus, to considerably expand the production range of the installation. Because the means for applying the rolling force and the means for adjusting the transmission conditions thereof are retained, the same installation can be adapted very quickly to a change in product characteristics while maintaining the same performance of final quality on the product, in particular the regularity of thickness, the flatness and the quality of surface.
• the Pinsert chassis can be provided with lateral support parts placed substantially at the same level as the support ears of the chocks of the working rolls 2, 2 'so as to adapt to the same bending devices.
• each cage being able to be equipped with working rolls having a wide range of diameters.
• the rolling mill therefore comprises at least one transformable cage of the type shown in FIGS. 5 to 12, which can have working rolls of fairly large diameter in a sexto configuration (FIG. 5) and very small diameter cylinders with lateral supports, in an eight-cylinder configuration (Figure 6).
• FIGS. 5 to 7 show a variant in which each chock is provided, on each side of the clamping plane, with two support parts spaced apart from one other on either side of the horizontal plane passing through the axis of the cylinder and passing, respectively, above and below a projecting part integral with the column of the cage and in which the camber cylinders are housed .
• each chock 23 of a working cylinder 22 is provided, on each side of the clamping plane Pi, with two support parts 24, 25 passing respectively above and below a piece 42 fixed on the block hydraulic 4 and extending projecting towards the inside of the window up to a vertical face 43 for lateral guide of the chock 23.
• Each projecting part 42 carries at least one pair of jacks, not shown, acting in opposite directions , respectively on an upper support part 24 of the chock 23 for the positive bending of the cylinder 22 and on a lower part 25 for the negative bending.
• the two working chocks 20, 20 ′ were guided, on each side, by the same projecting part 13a, 13b centered on the rolling plane P
• the working chocks 23, 23 ′ are guided, laterally by two separate pieces 42, 42 ′ arranged on either side of the rolling plane P.
• the chocks 33, 33 'of the intermediate cylinders 32, 32' are slidably mounted between vertical guide faces 41, 41 'formed at the ends of two support pieces 40, 40' which, as before, are slidably mounted on the hydraulic blocks 4a , 4b parallel to the axes of the cylinders.
• the positive and negative camber cylinders of the working chocks 23, 23 ' are mounted on the second projecting parts 42, 42' and not on the sliding parts 40, 40 'as in the case of FIGS. 3 and 4.
• Figure 5 allows the replacement of a fairly large working cylinder 22 by an assembly 6 mounted in cassette comprising a small diameter working cylinder 61 associated with an intermediate cylinder 62.
• the sum of the diameters of the two cylinders 61, 62 being of the same order as the diameter of the working cylinder 22 of the sexto arrangement shown in FIG. 5, of so that the intermediate cylinders 32, 32 'remain substantially at the same level.
• the two cylinders 61, 62 of each cassette 6 are rotatably mounted, at their ends, on two chassis 7 having a shape similar to that of the chocks 23 of the working cylinders 22 of the sexto configuration and consequently comprising support parts 71, 72 spaced vertically by the same distance as the support parts 24, 25 of a working chock 23 and therefore passing, respectively, above and below projecting parts 42a, 42b, the ends 43 of which form vertical guide faces of the chassis 7 in the form of chocks.
• each cassette 6 of an octo configuration has the same profile as the chocks 23 of the working cylinder 22 of the sexto configuration
• a rapid replacement system can be used by displacement parallel to the axes of the cylinders, the chocks 23 or the chassis 7 bearing, by means of rollers 26, 73, on rails 46 formed on the projecting parts 42a, 42b.
• the rollers 26 are mounted on the upper support parts 24 of the upper chock 22 or 71 of the chassis 7 of Pinsert octo.
• rollers 26 ', 73' are fixed to the lower support parts 24 'of the chocks 22' or 71 'of the chassis.
• the projecting parts 42, 42 ′ carry sets of camber cylinders which remain in place during the change of configuration and act, in the positive or negative direction, either on the working rolls
• FIGS. 10 and 11 show in detail the mounting of the chassis of an octo insert comprising a working cylinder 61 of small diameter and a second intermediate cylinder 62.
• Each second intermediate cylinder 62 is provided, at each end, with a journal carried by a bearing 74 whose external cage is fixed to the chassis 7 which thus behaves like a chock for the cylinder 62.
• the associated working cylinder 61 is simply rotatably mounted, at each end, on an axial thrust bearing 75 but the latter is mounted, with a possibility of transverse play, in a retaining member 76 fixed on the internal face of the chassis 7 and comprising a spring device 77 which permanently applies the working cylinder 61 to the intermediate cylinder 62, so as to take account of a variation, by wear, of the diameters of the cylinders, as shown in FIG. 11.
• the first intermediate cylinders rotate in the same direction as the small-diameter working cylinders. It is therefore not necessary to use motors with two directions of rotation, the drive torque being able to be applied, by means of extensions, either to the working cylinders of fairly large diameter in the sexto configuration, or on the first intermediate cylinders, in the octo configuration.
• the arrangements according to the invention therefore make it possible to quickly switch from a sexto configuration equipped with working cylinders having a diameter in a high range, for example 495 mm to 515 mm, to an eight-cylinder configuration having working cylinders of small diameter, for example in the range 140mm / 160mm associated with intermediate cylinders 62 in the range 330mm / 355mm.
• working rolls of this small diameter are liable to bend during rolling and must therefore preferably be associated with lateral support rollers in an X-shaped arrangement, shown, for example, in the figure. 6.
• Each working cylinder of small diameter, respectively upper 61 and lower 61 ', is therefore held laterally by two sets of rollers 8a, 8b each mounted on a support frame 81 which can slide, in a direction inclined relative to the rolling plane P, on guides 82 fixed on the corresponding upright of the column of the cage, the sliding of the support 81 being controlled by a jack 83.
• each set of rollers 8 can be easily disassembled with its support frame 81, so as to clear the central space of the cage in the sexto configuration shown in FIG. 5, the four slides 82 and the jacks 83 remaining alone fixed on the columns 10 of the cage.
• roller assemblies 8 When it is desired to switch from the octo configuration to the sexto configuration, the roller assemblies 8 are moved back inside the slides 82 in order to clear the entire central space of the rolling mill, as indicated in FIG. 7. It is then possible to remove the inserts 6 with their support frame 7 from the cage to replace them by the two large diameter working cylinders 22, 22 'carried by their chocks 23, 23' which roll on the rails 46, 46 ', so as to restore the sexto configuration shown in FIG. 5.
• One or more side support assemblies 8, 8 ' can also be easily removed from the cage for maintenance or replacement.
• a dismounting easel 85 is brought into the central space of the cage, resting, by rollers, on the upper rails 46 and carrying two orthogonal walls forming a cross. 86 which limits four quadrants into which the four sets of rollers 8 pushed by the jacks 83 can be introduced.
• the chassis 81 for supporting the rollers are then disconnected from the jacks and the easel 85 can be removed from the cage, by axial displacement, carrying the four sets of rollers 8, 8 '.
• the invention is not limited to the details of the embodiments which have just been described, variants which can be imagined without departing from the protective framework of the invention.
• two types of chocks have been shown in the figures, the invention being able to be applied to other types and other bending means which can remain on site, in all configurations, as soon as the support parts of the chocks of the working rolls or of the intermediate rolls are placed substantially at the same level.
• the device for axial displacement of the cylinders could be used in combination with working cylinders having a curvilinear profile of the 'CVC' type in order to produce a curved variation, or alternatively, it could be used, in known manner, with cylinders of work presenting a part of their table machined to carry out a control of the thinning of the edges of the laminated strips.
• each actuator 83 for controlling the sliding of a set of rollers 8 is articulated on the column 10 around an axis spaced from the rolling plane and controls the rotation a bent lever 87 connected to the chassis 81 for supporting the support rollers 8 by a connecting rod 88 articulated at its ends.
• tandem rolling mill to which the invention applies can be of any known type and could include a greater or lesser number of cages.
• the invention has been described in its application to the production of sheets for the automotive industry but can be applied to any other type of product for which it is advantageous to widen the production range of an installation. , for example aluminum.

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