EP0665069A1 - Process and equipment for straightening a thin metal band - Google Patents

Abstract

A process is claimed for planishing a thin metal strip (1) under traction in an installation comprising a planishing machine (3) incorporating at least one bending unit (30) with two planishing units (31,32) staggered in height and a dressing assembly of multi-rollers (5) on upper and lower frames (6,6') each carrying a row of rollers (51,51') that are parallel and staggered longitudinal and by height. Some means are provided to regulate the overlapping of the planishing units (31,32) and the dressing assembly (5) and two tensioning blocks (2,2') to determine the elongation imposed on the strip. Flatness are corrected in the planishing machine (3) by regulating the speed of defilement and the overlapping of the planishing units (31,32) and longitudinal camber defects are corrected in the multi-roller dressing assembly (5). The installation used is also claimed.

Description

The subject of the invention is a method and an installation for leveling under tension a thin metal strip.

The thin and hard steel sheets such as the white irons used in particular for the manufacture of packaging, are produced by rolling in the form of thin metal strips of great length which, then, are treated, cut and formed according to the intended use.

In general, a thin metal strip must have a certain number of qualities such as an excellent flatness, a drawing ability, a surface condition and mechanical properties conforming to the standards corresponding to the desired applications.

To obtain these qualities, the metal strip undergoes a certain number of treatments and, in particular, it is subjected to a leveling often carried out by traction-bending and under imposed elongation.

Generally, a leveling machine comprises one or two bending units each consisting of a pair of small diameter cylinders placed on either side of the strip and offset in height so as to determine, by their nesting, an angled path of the strip producing alternating flexions on the two cylinders.

The strip is subjected to traction between two tensioning blocks placed on either side of the machine and each consisting of several nested rollers on which the strip is wound. The rollers of the two tensioning blocks are rotated at slightly different speeds so that the speed of movement of the strip in the downstream tensioning block is a little higher than the speed of movement in the upstream block.

This results in a permanent elongation of the strip, the value of which can be determined by adjusting the difference in running speeds between upstream and downstream.

Leveling is carried out by subjecting the tensioned strip to at least two alternating flexions on small diameter cylinders. It is known that, during each bending, the taut external part of the strip can be in the field of plastic deformations, even if the applied tensile stress is much lower than the elastic limit. It is thus possible, without subjecting the strip to excessive stress, to determine, between the two tensioning blocks, an elongation sufficient to exceed the length of the longest fiber so as to achieve leveling of the strip by equalizing the lengths of all of its longitudinal fibers.

The permanent elongations obtained for a given product are all the greater when the radii of curvature are small and the tensile stresses high, the latter however always remaining below the elastic limit.

It is thus possible to obtain flat strips but these operations induce internal stresses in the thickness of the strip. These are balanced, but however lead to a deformation of the profile of the strip, which generally has a camber in the transverse direction, and often also, in the longitudinal direction.

The transverse camber, generally called "tile", can be fairly easily corrected on a device called anti-tile, placed downstream of the leveler and comprising a cylinder bearing on the strip on the side opposite to that of the last cylinder of the leveler and associated with two larger diameter rollers.

The defect in longitudinal camber, also called a "hanger", can be corrected on a scouring cylinder but, for very thin and hard bands, the correction is difficult to perform, in particular because of the very high sensitivity of the devices used. Indeed, for very thin strips, the faults are very fleeting and fluctuating for the same machine setting.

However, a residual longitudinal camber can hinder the introduction of the strip into the following treatment plants and, moreover, can lead to deformations when the strip is cut into strips, depending on the dimensions of the products to be manufactured.

It is possible to act manually on the machine settings but, the strip moving at very high speed, it is thus only possible to correct detectable faults and, necessarily, with a certain time delay. In addition, during the unwinding of another reel, it may be necessary to repeat all the settings.

The subject of the invention is a method for satisfactorily correcting the defects induced by leveling, and in particular the longitudinal camber. The method according to the invention gives very great operating flexibility and allows, after having made a first choice, to immediately adapt the settings to the properties of the strip, if necessary, during running.

In general, the object of the invention is essentially to obtain products having weak, fairly homogeneous longitudinal camber, and, in any case, to maintain them, when necessary, in the same direction when it is impossible to obtain a more satisfactory result.

The method according to the invention applies to an installation comprising a traction-flexion leveler comprising at least one flexion unit consisting of a pair of cylinders offset in height and a multi-roller dressing assembly comprising two frames, respectively lower and upper, each carrying a row of parallel rollers, offset longitudinally and in height, so as to determine, by nesting of the rollers, a corrugated path of the strip with flexions alternating, means for adjusting the nesting of the cylinders of each bending unit, means for adjusting the nesting of the rollers of the straightening assembly and two tensioning blocks placed respectively upstream and downstream of the installation on the path of the strip to apply on it a tensile stress capable of determining an elongation of the strip, the value of which is imposed by adjusting the running speeds in said blocks.

According to the invention, the flatness defects in the leveler are corrected by adjusting the running speeds and the nesting of the leveling crews so that the elongation imposed for leveling is practically carried out as soon as it leaves the leveler and at least the longitudinal camber defects due to passage through the leveler are corrected in the multi-roller assembly by determining decreasing overlaps of the rollers between the entry and the exit of the multi-roller assembly by tilting a row with respect to the other, so as to cause gradually decreasing alternating flexion effects which determine a relaxation of the stresses, the number and the intensities of the alternating flexions being determined by adjusting the overlaps respectively at the input and at the output of the multi-roller assembly so as to correct the camber defect without significantly increasing the elongation already carried out in the traction-flexion leveler.

The tile correction can be performed, at the same time as the longitudinal camber correction, in the multi-roller assembly, but an anti-tile device can also be placed between the leveler and the multi-roller assembly to correct at least partially the tile before entering the multi-roller assembly.

According to another particularly advantageous characteristic of the invention, the nestings are adjusted in the flexion units of the leveler taking into account the dimensional and structural characteristics of the strip so as to achieve in the leveler the elongation imposed for the flatness correction while generally maintaining the tensile stress applied to the strip below about 60% of the elastic limit of the metal and the nests are adjusted, respectively at the inlet and at the outlet of the multi-roller assembly, to correct the camber defects by limiting the increase in the traction of such that the additional elongation achieved in the multi-roller assembly does not normally exceed 0.2%.

According to another preferred characteristic, the nestings of the leveler and of the multi-roller assembly are adjusted for each reel and / or determined permanently during the running of the strip by an automatic system taking into account all the dimensional characteristics. , structural and qualitative of the product, the known diameters of the active cylinders, the tensions applied to the strip and the interactions between the various components of the installation.

In a particularly advantageous manner, the automation system is associated with a mathematical model on which are displayed, before processing a coil, all the characteristics specific to the product to be treated and specific to the installation, said mathematical model developing the instructions for nesting the different organs from programmed equations and taking into account the indications obtained by measurement or by observation of the residual defects in flatness and in longitudinal and transverse camber during the processing of a strip of nature and dimensions analogues.

However, in a simplified embodiment, the automation system determines the nesting of the various organs from established tables, for each type of product, taking into account the characteristics specific to the machine and the indications obtained previously by measurement or by observation of the residual defects of flatness and longitudinal camber and transverse during the treatment of a strip of similar nature and dimensions.

According to another extremely advantageous characteristic, the operator can at any time manually correct each of the adjustments controlled by the automation system as a function of measurements or observations made on the product during and / or after the treatment.

Preferably, the manual corrections thus made are recorded, classified and possibly optimized in a self-adaptation system which memorizes them and, after unlocking by the operator, introduces the necessary modifications in the automation system so that, by thereafter, the nesting instructions thus corrected are imposed on the various members during the course of the strip and for the following strips of the same type.

The invention therefore makes it possible, when the process for leveling a strip of determined characteristics has been perfected, to automatically apply the same process to all strips having the same characteristics and, in particular, coming from the same origin. , the flatness defects resulting, among other things, from the entire history of the strip and its process of development from liquid steel to its final form and repeating, generally, on strips of the same origin.

Furthermore, after verification by a competent authority, the corrections recorded in the self-adaptation system can be validated and entered in the mathematical model which is readjusted so that the instructions developed correspond to the nests previously corrected.

However, the invention also provides the means of very quickly obtaining the right settings even for coils of a product whose characteristics do not correspond to those of one of the coils already processed. In this case, in fact, one can choose from these one or more reference types which are closest to the new coil and the parameters corresponding to a very similar type are displayed on the automation system, either interpolated or extrapolated parameters, so as to determine, as a function of the reference type (s), the tension and nesting setpoints of the various members, for the new coil. The unwinding of the reel is then controlled and the operator manually corrects the instructions determined by the automation system as a function of the effects obtained on the strip during unwinding.

The corrections thus made to the instructions given by the mathematical model are recorded in the self-adaptation system which can be unlocked by the operator, if the corrections made are judicious, so that the corrected instructions are used for the rest of the process. of the coil and for similar coils.

After approval and validation by a competent authority, the corrected instructions can be stored in the mathematical model to constitute a new model usable, thereafter, for all analogous coils.

However, the invention will be better understood from the following description of a particular embodiment, given by way of example and shown in the accompanying drawings.

Figure 1 shows schematically, in section longitudinal, the whole of a leveling installation for implementing the method according to the invention.

Figure 2 is a block diagram of the entire installation control system.

Figure 3 is a block diagram, on an enlarged scale, showing the passage of the strip in the multi-roller assembly.

In FIG. 1, there is shown in longitudinal section, the whole of a planing installation for a metal strip 1 which, in the Figure, scrolls from right to left passing successively through an upstream tensioning block 2, a leveler 3 comprising, in the example shown, two bending units 31, 32, an anti-tile device 4, a dressing assembly with multi-rollers 5 and a downstream tensioning block 2 '.

All these devices are arranged in a frame 10 in the form of a cage associated with means not shown for the maintenance or replacement of the various members.

The two tensioning blocks 2, 2 ', each consist, in the usual way, of several rolls of fairly large diameter on which the strip 1 is wound to obtain the necessary traction and which are driven in rotation by a mechanism not shown. , so that the winding speed on the downstream block 2 'is a little higher than that of the upstream block 2, the speed difference being adjustable to determine the desired elongation.

The leveler 3 is of conventional type and, in particular, each bending unit 30 comprises two leveling units 31, 32, placed, respectively, above and below the strip.

Each leveling unit 31 (32) comprises an active cylinder 33 (33 ') of small diameter which bears, on the side opposite the strip, on support rollers 34 (34'), the assembly being placed on a frame 35 (35 ') who can slide vertically with respect to the cage 10 and whose vertical position can be adjusted by one or more hydraulic or mechanical actuators 36 (36 ').

Generally, the upper assembly 31 can move, under the action of jacks 36, between a high standby position, spaced from the strip, and a low working position, in contact with the strip. Mechanical screw jacks 36 make it possible to vary the level of the lower assembly 32 in order to adjust the nesting of the active cylinders 33, 33 ′.

The second bending unit 30a can be adjusted in the same way. In addition, it is possible, as shown in Figure 1, to completely separate the active cylinders from the strip, which allows, depending on the case, to use either a single bending unit or of them.

The anti-tile device 4, which is of a conventional type, comprises an active cylinder 41 placed between two rollers 45, 45 'of larger diameter and also resting on a set of support rollers 42 carried by a sliding frame 43 of which the position can be adjusted by a jack 44. This makes it possible to adjust the pressure applied to the strip by the anti-tile cylinder 41 which fits between the two rollers 45, 45 '.

Note that the anti-tile device is not always essential and can be eliminated in the simplest installations. However, it may be preferable to provide on the frame 10 of the installation a location 46 provided for the anti-tile device which, in this way, can be added to the machine if necessary. Similarly, the anti-tile cylinder 41 can be simply moved away from the strip or put into service according to the qualities of the sheets.

The multi-roller assembly 5, which is placed downstream of the anti-tile device 4 and before the downstream tensioning block 2 ', comprises two sets of rollers, respectively a upper assembly 50 and a lower assembly 50 ′ disposed respectively on either side of the running plane of the strip 1.

Each assembly 50 (50 ') is carried by a chassis, respectively upper 6 and lower 6', and comprises a row of parallel rollers 51 bearing, on the side opposite to the strip 1, on one or two rows of support rollers 52.

The two rows of rollers 51, 51 'are offset longitudinally and can thus overlap one another by adjusting the relative levels of the frames 6, 6'. so as to define a zigzag path. Generally, the lower row 51 ′ has one more roll than the upper row 51, but this arrangement depends on the circumstances, and in particular on the nature of the strip 1 and the distribution of the stresses.
The frame 6 carrying the upper assembly 50 is mounted to slide vertically in two windows 61 of the cage 10 can be placed, by means of one or two jacks 62, either in the low working position, or in the waiting position separated from the band.

Similarly, the chassis 6 'of the lower assembly 50' is mounted on a box-shaped frame 63 which can slide vertically in windows 61 'of the cage 10 and whose position can be adjusted by a jack 64 thus allowing the vertical displacement, parallel to itself, of the lower row of rollers 51 '.

However, the lower chassis 6 'forms a cradle which rests on two circular tracks 65 formed on the frame 63 and forming a circular raceway centered on a horizontal axis parallel to the axes of the rollers 51' and placed substantially at the plane tangent to these latter.

The cradle 6 ′ can thus tilt relative to the frame 63 by turning around the axis of the raceway 65 under the action of a screw jack 66 mounted on the frame 55 and supported by an articulated link system , on an arm 67 secured to the cradle 6 ', the latter being kept applied to the raceway 65 by a jack 68 fixed on the frame 63 and allowing the play to be made up.

Other tilting systems could obviously be used for this purpose.

The screw jack 66 therefore makes it possible to give the row of lower rollers 51 ′ an adjustable inclination relative to the top row 51 while the screw jacks 64 allow the overall spacing between the two rows to be increased or decreased. rollers 51, 51 '.

It is thus possible, by acting separately or simultaneously on the screw jacks 64 and 66, to adjust the nestings of the rollers at the inlet and at the outlet of the multi-roller assembly 5 in order to determine a gradually decreasing nesting of the rollers in the direction of travel of the strip, as shown in FIG. 3.

Of course, other equivalent means, for example hydraulic cylinders or other actuators, can be used to modify the nestings and the relative orientations of the two sets of rollers.

In general, it is possible, by acting in combination on the adjustment cylinders 64 and 66, to adjust the centers A1 at the entry and A2 at the exit of the leveler, to modify the intensity and, possibly , the number of inverted flexions, as shown in Figure 3.

• sur les vérins 36, 36a, pour le réglage des imbrications P1, P2, respectivement des deux unités de flexion 30, 30a,
• sur le vérin 44 pour le réglage de l'effet T du dispositif anti-tuile 4,
• sur les vérins à vis 64 et 66, pour le réglage des entraxes A1 à l'entrée et A2 à la sortie de l'ensemble multi-rouleaux 5.

To this end, the installation is advantageously associated with an adjustment system 7, shown diagrammatically in FIG. 2, and comprising positioning means 71 to 75 acting respectively:

• on the jacks 36, 36a, for adjusting the nestings P1, P2, respectively of the two bending units 30, 30a,
• on the jack 44 for adjusting the effect T of the anti-tile device 4,
• on screw jacks 64 and 66, for adjusting the center distances A1 at the inlet and A2 at the outlet of the multi-roller assembly 5.

Each positioning means 71 to 75 comprises a regulator receiving, on a first input 71a to 75a, a positioning command supplied by an automation system 8 and, on a second input 71b to 75b, a signal supplied by a device measurement M1 to M5 indicating, at each instant, the respective positions of the corresponding organs, so as to immediately order the correction necessary to adapt the effect of the organ considered to the order given, at the same instant, by the system of automation 8.

In addition, pairs of push buttons B1 to B5, acting in opposite directions, allow the operator to intervene, if necessary, on each positioning means 71 to 75 to bring, in one direction or in the 'other, a correction to the position of the organ considered ordered by the automation system 8, taking into account information of all kinds which reach it, for example by observing the cut product.

• de la nature du produit, du code Qualité et du code Défaut,
• de l'épaisseur et de la largeur,
• de la destination.

The automation system 8 develops the position setpoint, at each instant, of each of the positioning means 71 to 75, from a set of tables and / or a mathematical model 80 programmed so as to take into account the different characteristics of the installation and the product to be leveled and, in particular:

• the nature of the product, the Quality code and the Fault code,
• thickness and width,
• of the destination.

We can indeed establish, in a known manner, tables and equations which make it possible to define the actions to be exerted on the product by each of the organs of the machine taking into account the mechanical characteristics of the machine, the known diameter of the cylinders and rollers, their number and their overlaps, as well as the constraints applied to the product and the interactions between the various organs.

These tables and these equations are programmed in the mathematical model 80 in which the operator can introduce, by an input 80a, all of the parameters (p) specific to the product and, in particular, those which have been indicated above, and by an input 80b the parameters (m) specific to the machine, such as the diameters of the cylinders and rollers of each of the members of the machine, which can be measured continuously or checked during stops. These parameters are introduced by the operator, by means of a console 81, on the arrival of a new coil or of a series of coils of a certain type.

On another input 80c of the mathematical model 80, the elongation A is displayed which must be imposed on the strip in order to correct the flatness defect detected upstream of the installation, for example by a flatness measuring roller of known type.

This imposed elongation is determined in the usual way taking into account the characteristics of the product and of the machine and remaining within the ranges of predetermined tension stresses.

From all of these parameters and the programmed equations, the mathematical model 80 develops, on the one hand, an elongation instruction and, on the other hand, nesting instructions for the various organs.

The elongation instruction is displayed at the input 76a of a device 76 for adjusting the drive mechanism 21 of the tensioning blocks 2, 2 ′, such a mechanism making it possible, in known manner, to maintain between the upstream and downstream blocks the speed difference corresponding to the imposed elongation.

However, the elongation setpoint A depends on the diameters of the tensioning rollers in the upstream 2 and downstream 2 ′ blocks and can therefore be corrected by a device 83 to take account of possible wear thereof.

The voltages Te and Ts applied to the strip, respectively at the inlet and at the outlet of the installation, are a consequence of the process and do not normally intervene in the set point determination system. However, these tensions must obviously be limited for safety reasons and, in any case, must always remain below the elastic limit of the product and, preferably, between 20 and 60%, approximately, of this, the most strong pulls referring to the thinnest bands and with the strongest elastic limit.

To this end, the installation is equipped with devices 22, 23, for measuring the voltages respectively Te at the input and Ts at the output, and the measured voltages are displayed at the input 82a of a device 82 for correcting the instructions. In the event of an overshoot compared to predetermined values, the automation system can thus react, either by simple alarm, or by direct action on all or part of the setpoints that it develops.

The nesting instructions P1, P2 ... P5 developed by the mathematical model 80 and thus corrected, are displayed, respectively, on the positioning means 71 to 75. As indicated, the mathematical model takes account of the interactions between the different members to work out the nesting instructions so that the elongation imposed for the correction of flatness is carried out practically entirely in the leveler 3 by means of the two bending units 30, 30a, or one of between them only, as the case may be.

However, the traction-bending effect applied to the product depends on the diameters of the cylinders and rollers and this is why, before being displayed on each of the positioning means 71 to 75, the corresponding setpoint is corrected in a device 84 associated with each positioning means to correct the setpoint according to the actual diameters of the cylinders or rollers of the member under consideration, which can be measured, for example, at each stop of the machine.

Furthermore, the operator can also, as indicated, intervene in the settings of the various components of the machine by means of push buttons B1 to B5.

Of course, such corrections can only be made by an authorized operator.

Thanks to these provisions, the adjustment system can operate entirely automatically, but with the possibility of correcting the instructions upon operator intervention for adjusting the nestings.

In fact, measuring devices M1 to M5 are associated with each member and each supply a signal representative of the actual position, at the instant considered, of the cylinders or rollers of the corresponding member. These signals are displayed on the input 85a of a self-adaptation system 85 which, on the operator's order, can intervene on the automation system to automatically correct the nesting instructions so that they correspond to the measured positions and that the corrections made by the operator are maintained until the end of the reel unwinding as well as for the following reels of the same type.

On the other hand, after validation by a competent authority on an input 85c of the self-adaptation system 85, the latter can intervene on the mathematical model 80 to correct certain values contained in the tables and readjust the mathematical model, according to the setting values actually used.

Similarly, the elongation actually carried out is measured and displayed on the input 85b of the self-adaptation system which can thus correct, as a function of the effects observed, the elongation instruction previously displayed on the mathematical model 80.

The self-adaptation system 85 is a classification and management computer system which records all the adjustments, classifies the results and makes it possible to choose the optimal values for the strip being processed.

However, all these settings are simply kept in reserve in the self-adaptation system, which is locked by a device 87, the installation remaining controlled by the mathematical model with the possibility of manual intervention by the operator.

The latter, if he judges the corrections correct, can, from the console 81, unlock the self-adaptation system by means of a link 86 of man / machine dialogue to introduce into the automation system the corrected instructions. which will thus be used for the continuation of the unwinding of the reel and for the following reels of the same type.

All the corrections made remain in memory in the self-adaptation system until verification by a competent authority which, by an command 85c, can order the validation of certain corrections and the corresponding registration of the mathematical model 80.

In this way, the mathematical model established from equations and theoretical considerations can be adapted to the effects measured or observed on the product.

In addition, the self-adaptation system 85 makes it possible, from a mathematical model established for certain products, to find almost immediately the right settings for new products or else to adapt the system to new, more efficient instructions.

In practice, when a new coil is introduced into the installation, the operator knows a certain number of parameters specific to the product such as its different mechanical and dimensional characteristics, thickness, width, hardness, composition, etc ... as well as her destination and introduces these parameters, using the console 81, into the mathematical model 80.

The operator can also know the flatness defects to be corrected, for example if they are common to a type of product. But it can also measure them by means of a device placed upstream of the installation. From tables or charts, or according to instructions given by a calculation system, the operator determines the elongation that should be imposed in the leveler 3 to correct these defects. This elongation is displayed on the input 80c of the mathematical model 80 which, from the programmed equations, determines the tension imposed by the tensioning blocks 2, 2 ', and the theoretical positions of the leveling crews 30, 30a, making it possible to carry out the lengthening imposed for leveling. The mathematical model also calculates the effects of transverse and longitudinal camber theoretically resulting from the actions carried out for leveling and chooses a combination between the tensions and the flexions in the leveler making it possible to minimize the camber. However, the residual effects are calculated and corrected in the multi-roller assembly 5 and, optionally, the anti-tile device 4, the overlaps of which are determined by the mathematical model taking into account all the interactions between the elements of the installation and in such a way that the additional elongation produced in the multi-roller assembly does not exceed 0.2%, the tension stress there being hardly increased.

The leveling result can be verified by tests carried out on the strip leaving the installation and possibly cut into strips. Measurements of the longitudinal or transverse camber could, possibly, be carried out during the running of the strip. Finally, the operator can also, by direct observation, observe imperfections and residual tape defects.

He can thus decide to correct some of the nesting instructions developed by the mathematical model and correct himself some of the calculated nestings, using pushbuttons B1 to B5.

These corrections being made during the running of the strip, the operator preferably acts on the least sensitive actuators which give greater latitude for adjustment. In particular, it can first of all vary the nesting A2 at the outlet of the multi-roller assembly to increase or decrease the number and the intensity of the degressive flexions and, if necessary, act on the nesting A1 at the input, this setting being more sensitive.

Thanks to the wide adjustment possibilities given by the multi-roller assembly, this manual operator action is essential for eliminating the longitudinal camber.

However, the operator can also intervene on the levelers 30, 30a, and, optionally, the anti-tile device 4, by means of push buttons B1 to B3, so as to take account of the interactions between the two parts of the installation. and perfect the leveling according to the real characteristics and properties of the strip being unwound.

As indicated, the corrections made are recorded and optimized in the self-adaptation system 85.

If the competent authority considers, after verification, that the adjustments made are valid for all the bands of the type in progress, for example for all the bands of the same thickness and classified in the same category, these adjustments are validated by the command 85c and, after unlocking the self-adaptation system 85, the corrections previously made and judged to be optimal are introduced into the memory of the mathematical model so that, thereafter, the corrected setpoints are imposed on the other bands of the same category.

Similarly, corrections can be made, after validation, to the values found in the self-adaptation system 85.

Similarly, if a new coil does not correspond to a known type, one can, according to certain parameters such as its dimensions, the nature of the metal and its hardness, choose, from the known types, one or more types as close as possible to the new coil and display on the mathematical model either the parameters corresponding to a very similar type, or parameters obtained by intrapolation or extrapolation.

The mathematical model 80 adjusts the voltages and the nests as a function of the parameters displayed and the unwinding of the coil is then controlled.

During the course of the process, the operator can determine, by measurement or by observation and from his own experience, the corrections that should be made to the overlaps determined by the mathematical model. If the result is satisfactory, these corrections are validated by the competent authority and stored in the mathematical model which thus constitutes a new model applicable thereafter to all coils of the same type.

Of course, the invention is not limited to the details of the embodiment which has just been described by way of simple example and which could be the subject of variants without departing from the scope of the claims.

In particular, a complete machine has been described but, in certain cases, certain members could be useless.

We have already indicated, for example, that the leveler could have a single leveling crew 30. The second crew can be placed on the machine and, simply, put out of service when it is unnecessary. But it is also possible, for certain types of products, to use a machine with only one crew.

Similarly, the multi-roller assembly can correct the tile defect and, in certain cases, the anti-tile device 4 could therefore be eliminated.

In this regard, it should be noted that the respective arrangements of the leveling crews 30, 30a and of the anti-fatigue device 4 with respect to the strip 1, as they have been represented in FIGS. 1 and 2, correspond to the most common case , but could possibly be reversed, the antitile cylinder 41 then being located above the strip 1.

Generally, in fact, the arrangement of the various members as well as the order and the number of active rollers of the multi-roller assembly 5 will be determined as a function of the characteristics, in particular the thickness and the hardness, of the range of products to be treated, normally, in the installation.

In particular, the upper row of rollers 51 generally has one roll less than the lower row 51 ', as shown in FIGS. 1 and 2, and the first active roller, on which the strip is completely stretched, is often the second of the series, but this arrangement could be modified according to the targeted deformations. For example, the two rows could have the same number of rollers, as in the case of Figure 3, or the longest row could be the top row.

The deflector roller 45 located just after the anti-drug can also be interchangeable and / or of smaller diameter, and adjustable in height so as to make it more or less active compared to a simple deflector.

It is obvious, on the other hand, that the configuration shown can be modified, some deflectors can be removed or, on the contrary, added to other places in the installation.

Furthermore, a particularly sophisticated installation has been described in which all the settings are developed from tables and a mathematical model. In some simple cases, however, only tables established for different types of product could be used, based on operations previously carried out on the same machine for similar products.

If the necessary equipment is available, the installation can also be completed by a set 9 of measuring means placed downstream of the output tensioning block 2 ′ and comprising, for example, a device 91 for measuring residual flatness defects , for example from the voltage constraints, a device 92 for measuring tiles, for example by laser, and a device 93 for measuring the defect in longitudinal camber or "hanger", the measurements carried out being displayed on the auto system -adaptation 85 which determines possible correction instructions. For example, the flatness measurement carried out at 91 can determine a correction on the imposed elongation. The detection of tile or longitudinal camber faults can lead to a correction of the nests, in priority on the nesting A2 downstream of the multi-roller assembly 5 and, if necessary, on the nesting A1 to l 'entry or on the nesting of the anti-tile device 4 when it is used.

The tension of the strip can also be measured outside the installation by tensiometers 94, 95, placed respectively upstream of the input tensioning block 2 and downstream of the output block 2 '. From these measurements of the external voltages, the automatic system 8 can modify the elongation instructions if the multiplying coefficients of the tensioning blocks become too large. Actions on external traction can also be considered in the system, depending on production contingencies and the ability to regulate parameters outside the installation. A possible measurement of the intermediate tension, for example at 96, upstream of the multi-roller assembly 5, can possibly be used to correct the overlaps of the leveling equipments 30, 30a.

The reference signs, inserted after the technical characteristics mentioned in the claims, have the sole purpose of facilitating the understanding of the latter and in no way limit their scope.

Claims (17)

Method for planing under tension of a thin metal strip (1) in an installation comprising a planer (3) by traction-bending comprising at least one bending unit (30) with two planing units (31, 32) offset in height and a multi-roller dressing assembly (5) comprising two frames, respectively upper (6) and lower (6 '), each carrying a row of rollers (51, 51') parallel and offset longitudinally and in height so as to determining, by nesting of the rollers, an undulating path of the strip with alternating flexions, means for adjusting the nesting of the leveling equipments (31, 32), means for adjusting the nesting of the rollers (51, 51 ' ) of the straightening assembly and two tensioning blocks (2, 2 ′) placed respectively upstream and downstream of the installation on the path of the strip (1) in order to apply a tensile stress thereon capable of determining an elongation of the strip whose is imposed on them by adjusting the scrolling speeds in said blocks (2, 2 ′),
characterized by the fact that the flatness defects in the leveler (3) are corrected by adjusting the running speeds and the nesting of the leveling crews (31, 32) so that the elongation imposed for leveling is, practically, produced as soon as it leaves the leveler and which at least the longitudinal camber defects due to the passage in the leveler (3) are corrected in the multi-roller assembly (5), by determining decreasing overlaps of the rollers between the entry and exit of the multi-roller assembly (5) by tilting one row (51 ') relative to the other (51), so as to cause progressively decreasing alternating bending effects which determine a stress relaxation, the center-to-center distances at the entry and exit of the multi-roller assembly (5) being adjusted so as to vary the number and the intensities of the alternate flexions to correct the defect in camber without substantially increasing the elongation already achieved in the leveler (3) by traction-flexion. Leveling method according to claim 1, characterized in that the tile correction can be carried out, at the same time as the longitudinal camber correction, in the multi-roller assembly (5). Leveling method according to claim 1, characterized in that the tile correction is carried out, at least partially, in an anti-tile device (4) placed between the leveler (3) and the multi-roller assembly (5) to at least partially correct the tile before entering the multi-roller assembly (5). Leveling method according to one of claims 1, 2, 3, characterized in that the centers of the leveling equipment (31, 32) are adjusted taking into account the dimensional and structural characteristics of the strip (1) of so as to achieve in the leveler (3) the elongation imposed for the flatness correction while maintaining the tensile stress applied to the strip below approximately 60% of the elastic limit of the metal. Leveling method according to claim 4, characterized in that the overlaps are adjusted, respectively at the inlet and at the outlet of the multi-roller assembly (5) to correct the camber defects by limiting the increase traction so that the additional elongation achieved in the multi-roller assembly (5) does not exceed 0.2%. Leveling method according to one of the preceding claims, characterized in that the overlaps of the leveler (3) and the multi-roller assembly (5) are adjusted for each reel and permanently adjusted to the during the running of the strip by an automatic system (8) taking into account the main dimensional, structural and qualitative characteristics of the product (1), the known diameters of the active cylinders, the tensions applied to the strip to obtain the elongation imposed and the interactions between the different organs of the installation. Leveling method according to claim 6, characterized in that the automation system (8) is associated with tables and a mathematical model (80) on which are displayed, before processing a coil, the assembly characteristics specific to the product (1) to be treated and specific to the installation, said mathematical model (80) elaborating the instructions for nesting of the various organs on the basis of programmed equations and taking into account the indications obtained by measurement or by observation residual flatness and longitudinal and transverse camber defects during the processing of a strip of similar nature and dimensions. Leveling method according to claim 6, characterized in that the automation system (8) determines the nestings of the various members from tables established, for each type of product, taking into account the characteristics specific to the machine and the indications obtained previously by measuring or observing residual defects in flatness and longitudinal and transverse camber during the processing of a strip of similar nature and dimensions. Leveling method according to one of the preceding claims, characterized in that the operator can at any time manually correct each of the adjustments controlled by the automation system (8) according to measurements or observations made on the product (1) during and / or after treatment. Leveling method according to claim 9, characterized in that the manual corrections thus carried out are recorded, classified and optimized in a self-adaptation system (85) which stores them and, after unlocking by the operator, introduces the modifications necessary in the automation system (8) so that, thereafter, the nesting instructions thus corrected are imposed on the various members during the unwinding of the strip and for the following strips of the same type when the same conditions occur. represent. Leveling method according to claim 10, characterized in that, after verification by a competent authority, at least some of the corrections recorded in the self-adaptation system (85) can be validated and introduced into the mathematical model (80) which is readjusted so that the instructions developed correspond to the nests previously corrected. Leveling method according to one of claims 10 and 11, characterized in that, for the treatment of a coil whose characteristics do not correspond to those of one of the coils already treated, one chooses from these a or several types of reference closest to the new coil and the parameters corresponding to the closest type are displayed on the automation system, or parameters interpolated or extrapolated so as to determine, depending on the or reference types, the tension and nesting instructions for the various components for the new coil, then the unwinding of the coil is controlled and the operator manually corrects the instructions determined by the automation system (8) by based on the effects obtained on the tape during the course of the tape, the corrections thus made being recorded in the self-adaptation system (85) and introduced, on the operator's order, into the automation system (8), so as to correct the instructions developed for the continuation of the unwinding of the reel and for similar reels. Leveling method according to claim 12, characterized in that at least some of the corrections made manually are validated by a competent authority and introduced into the mathematical model to readjust it and constitute a new model suitable for all similar coils. Installation for implementing the method according to one of the preceding claims, comprising a pull-bending leveler (3) comprising at least one bending unit (30) with two leveling units (31, 32) offset in height and a multi-roller dressing assembly (5) comprising two sets of rollers, respectively upper (50) and lower (50 '), each carrying a row of rollers (51, 51') parallel and offset longitudinally and in height so to determine, by nesting of the rollers, a corrugated path of the strip with alternating flexions, means (36 ') for adjusting the nesting of the leveling crews (31, 32), means (6, 62, 63, 64 ) for adjusting the relative levels of the two rows of rollers (51, 51 ') of the dressing assembly (5) and two tensioning blocks (2, 2') placed respectively upstream and downstream of the installation on the path of the strip (1) and associated with means (21) for adjusting the speed its scrolling in said blocks (2, 2 ′) making it possible to apply to the strip (1) a pulling stress capable of determining an imposed elongation of the latter,
characterized in that at least one (51 ') of the two rows of rollers is carried by a cradle (6') mounted tilting about a horizontal axis parallel to the axes of the rollers and associated with means (63, 64) of vertical displacement and (66) tilting of the cradle (6 ') for adjusting the nestings of the rollers of the two rows (51, 51'), by modifying the centers, respectively A1 at the inlet and A2 at the outlet of the multi-roller assembly (5), and that said means (36 ′, 63, 64, 66) for adjusting the nests, respectively, of the planing equipments (31, 32) and of the multi-roller assembly (5), are associated, respectively, with positioning means (71 to 75) controlled by an automation system (8) comprising means (80) for determining the overlaps to be imposed on the various members, taking into account all of the proper parameters to the product and to the installation, and means (71 to 75) for positioning the various members as a function of the nesting instructions developed by said determination means (80). Leveling installation according to claim 14, characterized in that the automation system (8) is associated with a mathematical model (80) on which the respective parameters can be displayed, by means of a console (81) to the machine and specific to the product to be treated as well as the prescribed elongation set, said mathematical model (80) developing nesting instructions for each of the positioning means (71 to 75), the latter each constituting a means of regulation on which is displayed the actual position of the member considered and which controls the means (36 ′, 63, 64, 66) for adjusting the nests to adapt the measured position to the corresponding nesting instruction. Leveling installation according to one of claims 14 and 15, characterized in that the means (21) for adjusting the running speeds of the tensioning blocks (2, 2 ') are associated with an adjustment device (76) which determines the speed difference between said tensioning blocks corresponding to an elongation setpoint developed by the mathematical model (80), said setpoint being able to be corrected as a function of the known diameter of the rollers of the tensioning blocks (2, 2 ′). Leveling installation according to one of claims 14 to 16, characterized in that it comprises means (B1 to B5) for manual adjustment of the nestings of the various members (30, 4, 5) and a self-locking system. adaptation (85) capable of classifying and memorizing the corrections carried out manually, said self-adaptation system (85) being connected to the mathematical model (80) by a link provided with a locking system (87) and the unlocking of which can be controlled by a man / machine link (86) so as to introduce and, after possible validation, to memorize in the mathematical model (80) the corrections corresponding to a type of product and optimized by the self-adaptation system ( 85).

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