CN102548681A - Method and device for continuous stretch-bend-leveling of metal strips - Google Patents

Abstract

The invention relates to a method and a device for the continuous stretching-bending-levelling of a metal strip, a metal strip under tensile stress below the elastic limit, around at least four leveling rollers in plastic or elastic- Alternately bend in the plastic range and at the same time undergo plastic stretching. In this case, the bending radii on all four straightening rollers can each be adjusted individually and independently of one another, whereby the respective straightening rollers are adjusted in a position-controlled manner.

Description

Method and apparatus for continuously stretching-bending-levelling metal strips

technical field

The present invention relates to a method and apparatus for stretching-bending-levelling of a metal strip under tensile stress below the elastic limit or yield point around at least four leveling rollers in the plastic range or elastic-plastic Alternately bent over a range and subjected to plastic stretching. These smoothing rolls, which act plastically or elasto-plastically, can also be referred to as stretching rolls. The degree to which the metal strip (total) is plastically stretched and thus elongated is called the degree of stretch.

With this stretching-bending-leveling method, uneven metal strips can be leveled so that their unevenness can be eliminated. Unevenness means, for example, metal strip corrugations and/or metal strip crescent-shaped defects, which are caused by length differences of the metal strip fibers in the plane of the metal strip. However, this unevenness also refers to a warping of the metal strip in the longitudinal and/or transverse direction, which is caused by bending moments in the metal strip, for example when the metal strip is elastically-plastically bent on guide rollers Warpage caused by the metal strip, or warpage caused by elastic-plastic deformation when the metal strip is wound. Longitudinal warping is also called coil set, and transverse warping is also called cross bow. During stretching-bending-levelling, the uneven metal strip is passed around rollers of sufficiently small diameter (alternately) under tensile stress below the elastic limit R _E or the technical elastic limit R _P0.01 of the metal strip material It is bent so that an elastic/plastic deformation is produced in the metal strip by superposition of tensile stress and bending. The metal strip is plastically elongated, wherein the height of the plastic elongation is referred to as the degree of stretch. During plastic elongation, the originally short metal strip fibers are elongated relatively strongly. Ideally, all strip fibers after leveling have the same length, so in principle, an ideally leveled strip should be free of corrugations or crescents.

Background technique

According to the stretching-bending-leveling method known from practice, in principle by alternating bending in the elastic-plastic range, after leveling it is still possible to leave residual bending moments in the metal strip, which It can be observed as transverse ridges on metal strip processing lines, which can lead to plastic residual warpage in the longitudinal and/or transverse direction on cut-out metal sheets. Residual bending moments arise when the individual bending strengths are not optimally coordinated with one another. The bending radius depends on the strip data (thickness, modulus of elasticity, strength state of cycle, transverse shrinkage coefficient), strip tensile stress, roll diameter and geometry of the strip around the roll. To a first approximation, this geometry can be described by the wrapping angle of the metal strip around the roller. At a sufficiently large wrapping angle or under sufficient tensile stress, the metal strip has the radius of a roller. The curvature of the metal strip then reaches its maximum value and remains constant at further increasing wrapping angles or increasing tensile stresses. Usually, however, the wrapping angle is set in such a way that the metal strip no longer follows the roll radius at least with respect to the last rolls on the stretching-bending-leveling frame. Even with an optimal setting of a given stretch-bending-leveling frame, residual bending moments can occur due to process parameter fluctuations. Since in practice both the tensile stress of the metal strip and the degree of elongation associated therewith, as well as the strength values and strip thickness of the metal strip are basically subject to certain fluctuations. The stretch-bend-levelling methods known from practice are more or less sensitive to such fluctuations. This means that, according to conventional stretch-bend-levelling methods, such fluctuations have a more or less strong influence on the retained or generated residual curvature. This phenomenon also applies to those stretch-bending-levelling methods, ie those in which the metal strip is deformed elastically-plastically around four leveling rollers.

It is known that in the case of a stretch-bending-levelling stand with four leveling rollers, the geometry of the stretching-bending-levelling stand has to be adjusted in order to obtain the best possible leveling results configuration. Thus, for example, from DE 696 08 937 T2 (or EP 0 767 014 B1) a stretching-bending-leveling frame is known which is equipped with four leveling rollers. Both the leveling rollers and the underlying leveling rollers can be adjusted for their position. While the lower leveling rollers can be adjusted via a mechanical worm drive to achieve improved leveling results with a certain degree of precision, the upper leveling rollers are hydraulically operated. In this way a desired roll overlap can be set.

For comparison, reference may also be made to the stretching-bending-levelling racks disclosed in DE 695 14 010 T2 (or EP 0 665 069 B1) and DE 38 85 019 T2 (or EP 0 298 852 B1).

Similarly, the professional paper "Benefits of a New Leveling Process for Packaging Steel Products": Multi-Roll Stretch-Leveling Apparatus (Emmanuel Decassey, Irsid, Arcelor Group, METEC Congress, June 2003) introduces a Stretch-bending-leveling unit with four leveling rollers. Here, both the overlap of the first leveling unit (the first roller and the second roller) and the overlap of the second leveling unit (the third roller and the fourth roller) are adjustable.

DE 69 101 995 T2 (or EP 0 446 130 B1 ) also addresses the possibility of adjusting the position of all four leveling rollers. This of course applies above all to the changeover between the maintenance position and the working position. Because when adopting a kind of stretching-bending-leveling frame, generally need to open and close this frame again immediately, to reach the purpose of passing a connecting position between two metal wires or metal strips. In practice, however, it has turned out that the known stretch-bend-levelling stands or stretch-bend-levelling methods are relatively sensitive to fluctuations in the process parameters, so that the residual curvature cannot be satisfactorily reduced to a minimum .

In principle, so-called multi-roller levelers, also known as multi-roller leveling devices, have a relatively small reaction to process parameters. In the case of multi-roll levelers, the metal strip is bent several times around leveling rolls with small diameters. By using a plurality of rollers, a metal strip with a small residual curvature can be produced. A disadvantage thereof is the fact that multiple rollers involve high maintenance and replacement costs. Furthermore, the lower roller and the upper roller are frictionally connected to each other via a backup roller or an intermediate roller and a backup roller, such as a 1:1 transmission gearbox, respectively. Because the metal belt is plastically elongated when passing through the multi-roller frame, the speed of the metal belt can also be increased under the same size condition. The metal belt also advances synchronously only on one roller, and slippage occurs between other rollers and the metal belt. The rolls are usually run at high speeds on high speed - metal strip handling lines. This slippage causes the rollers to vibrate, which creates chatter marks on the surface of the metal strip. In practice this situation is unacceptable for many purposes. For the above reasons, conventional stretch-bending-levelling stands are also combined with multi-roller leveling units (cf. EP 0 665 069 B1 and DE 695 14010 T2).

Furthermore, DE 27 50 752 also describes a method for leveling and improving the quality characteristics of metal strips, in particular for electrical purposes, according to which the treated metal strip is bent without backpressure and subjected to a Plastic alternating bends. In this case, the metal strip is bent in a flat position while maintaining its plastically bent state, the deflection of the metal strip adjoining the last bend then taking place entirely in the elastic or substantially elastic range. This is thus achieved here only with two bending rollers without counterpressure connected in between or followed by one or more deflection rollers. However, several bending rollers are also provided. However, the possible result is that the final bending is performed with a plastic bending deformation as high as possible, and then the metal strip can only be bent elastically or mainly elastically.

Contents of the invention

Starting from the known background technology, the technical problem to be solved by the present invention is to provide a stretching-bending-leveling method, which can obtain the best flatness results under the premise of a small technical complexity of the equipment , and is particularly insensitive to fluctuations in process parameters (tensile stress, metal strip strength and metal strip thickness). Furthermore, a device is proposed which is characterized by a simple construction, which is cost-effective to manufacture and which achieves the desired results.

To solve the above-mentioned object, the invention proposes a method of the type mentioned at the outset for the continuous stretching-bending-levelling of metal strips, so that the bending radii can be individually and independently of each other on all four leveling rollers be adjusted. To this end, the invention proposes that all four bending rollers be adjusted in a position-controlled manner. If the metal strip is bent alternately around more than four straightening rollers, the invention proposes that the bending radii of the last four straightening rollers be adjusted individually and independently of each other, at least with respect to the direction of travel of the metal strip, so that It is achieved that preferably at least the last four leveling rollers are adjusted individually in a position-controlled manner.

The tests were carried out using a calculation model that takes into account the stresses in the longitudinal and transverse directions, the calculation model taking into account the thickness of the metal strip, elastic modulus, transverse shrinkage coefficient, cyclic strength condition, metal strip tensile stress, roll radius and metal With the geometry around the course of the roll as calculation parameter, these experiments have led to convincing conclusions that the method provides outstanding residual curvature results and is in particular relatively insensitive to fluctuations in the process parameters. It is particularly important here that the four elastically-plastically acting bending rollers can be adjusted or adjusted independently of one another with sufficient precision in a position-controlled manner. The position of the leveling rollers is then set with an accuracy and adjustment accuracy of ±0.05° or less, preferably ±0.02° or less, with respect to the wrapping angle of the metal strip around the leveling rollers. The wrapping angle of the metal strip around one or more leveling rolls, preferably around all leveling rolls, can be 0.5° to 60°, preferably 1° to 35°. The (total) elongation is, for example, 0.1% to 1.5%, preferably 0.2% to 0.6%. The tensile stress of the metal strip is preferably 10% to 90%, preferably 30% to 60%, of the elastic limit of the metal strip or the material of the metal strip.

Simulation calculations demonstrate that a two-roller design is generally not achievable in the stretch-bend-levelling process because the longitudinal and transverse bending moment curves as a function of the strip curvature are not negative mirror images of each other as in pure bending , but move relative to each other due to tensile stress. Therefore, in order to correct the curvature of the plastic metal strip produced on the first roller in the longitudinal and transverse directions, it is not sufficient to have another roller, since then either only the longitudinal bending moment or only the transverse bending moment can be balanced. Thus, for given process parameters, the minimum number of rolls required to produce a metal strip with ideally no residual curvature is three. However, calculations have shown that the resulting residual bending moment, or the response of the removal of this residual bending moment, is quite sensitive to fluctuations in the process parameters when using a stretching-bending stand with three rollers. The same conclusion applies to a four-roll stand, on which the individual rollers cannot be adjusted individually or independently of one another with the required precision. The remedy here is provided by the method proposed by the invention, according to which all four rollers can be adjusted individually and independently of each other in a position-controlled manner.

Furthermore, the invention proposes that, with respect to the direction of travel of the metal strip, the distance between at least two (directly) successively arranged leveling rollers is at least 15% of the (maximum) width of the metal strip, for example at least (maximum 30% of the width of the metal strip, particularly advantageously at least 50% of the (maximum) width of the metal strip. In this case, it is expedient if the above-mentioned distance also exists between two respectively paired (directly) successively arranged straightening rollers for all four straightening rollers. Thus, the distance between two such leveling rollers can be, for example, at least 150 mm, preferably at least 300 mm. Model-based experiments have led to convincing results here: by advantageously selecting the distance between the elastic-plastically acting leveling rollers, it is also possible to adjust the length of the metal strip width due to the process conditions. The stretch difference is minimized or eliminated. It turns out that generally larger horizontal distances have an advantageous effect. Under the condition of a given maximum structural length of the stretching-bending stand, it is advantageous to design at least one distance between the elastically-plastically acting leveling rollers to be at least 30% of the maximum metal strip width, however designed as At least 500mm. What matters here is the spacing of the leveling rollers in the direction of travel of the metal strip, which corresponds to the horizontal spacing in a horizontally constructed stretching-bending-leveling frame. In principle, this can also refer to the distance in the oblique direction or in the vertical direction, depending on which direction the metal strip is guided.

With regard to the application of the product being leveled, different leveling roller spacings are ideal, so that when these spacings are designed to be variable or adjustable, the leveling results can be further improved for waviness defects. Therefore, according to a further proposal of the invention, it is provided in an independent sense that the distance between at least two leveling rollers in the direction of travel of the metal strip is adjustable or adjustable. Therefore, the ideal spacing can be predetermined for a certain metal strip according to the model test.

Furthermore, the invention proposes that the desired value for the position of the leveling roller and/or the desired value for the wrapping angle of the metal strip around the leveling roller is determined using a calculation model which takes at least Stresses in the longitudinal and transverse directions, dealing with strip thickness, modulus of elasticity, transverse shrinkage, cyclic strength condition of the strip, tensile stress of the strip, roll radius and geometry of the strip running around the roll as calculation parameters, for The nominal values used for the thickness and strength of the metal strip, for example for the tensile limit, are calculated such that the residual longitudinal warpage and residual transverse warpage are zero or at least negligible. Therefore, it is ideal to produce metal strips with very little residual curvature. Of course, there is another possibility, which is to use a standard calculation model to determine those rated values, so that both a small or negligible residual transverse warpage value can be obtained, and the residual longitudinal warpage can have a definite value. The invention considers here that there will always be applications in which, although a residual transverse warpage must be completely avoided, a certain residual longitudinal warpage can be tolerated if this residual longitudinal warpage exists only in a certain direction And therefore have only one definite sign of words.

Furthermore, the invention proposes to measure the cross-sectional crowning of the metal strip across the width of the metal strip after one or more leveling rollers, for example after the last leveling roller, in particular after each leveling roller. The measured cross-sectional crowning can then be fed to a control device, which corrects the wrapping angle or the roll position on the basis of the measured values such that a metal strip with sufficiently low residual longitudinal and transverse warpage can be produced.

Accordingly, the invention firstly includes embodiments in which setpoint values for the bending radius and thus for the roller position and/or for the wrapping angle are determined using a mathematical model, and then the setpoint values are used to operate the plant . Simulation tests have shown that such a treatment leads to excellent results even with certain fluctuations in the process parameters. There is also the possibility that those nominal values can be corrected during the commissioning of the plant or even during the operation of the plant, and also on the basis of the results obtained through tests. This correction can be performed "off-line". As mentioned, there is also the possibility to carry out "online" corrections in a controlled or regulated manner, taking into account the measured values. This adjustment can also be based on a calculation model that takes into account at least the stresses in the longitudinal and transverse directions, dealing with as calculation parameters the thickness of the metal strip, the modulus of elasticity, the modulus shrinkage coefficient, the cyclic strength condition of the metal strip, the metal The strip tensile stress, the roll radius and the geometry of the strip travel around the roll correlate a certain cross-sectional camber to the residual longitudinal warpage of the metal strip or the residual transverse warpage of the metal strip.

The calculation model described can be based on a finite element method which also takes into account stresses and elongations over the width of the metal strip. Based on the maximum expected or measured unevenness of the metal strip before leveling, the optimum stretching and/or the optimum horizontal spacing of the elastic-plastically acting rollers can be calculated according to the finite element method to obtain Minimal remaining unevenness, here specifically referring to corrugations and crescents of the metal strip.

The subject matter of the invention also relates to a device for the continuous stretching-bending-levelling of a metal strip with a method of the type described. The device has at least four bending rollers, around which a metal strip under a tensile stress below the elastic limit is alternately bent in the plastic or elasto-plastic range. Furthermore, the device has at least one control and/or regulation device. The invention proposes that the bending radii on all four leveling rollers can be adjusted individually and independently of one another. The invention also preferably provides that all four leveling rollers are connected to the adjustment device and can be adjusted in a position-controlled manner. For this purpose, each individual leveling roller is assigned one or more finely adjustable actuators, preferably screw jacks. The diameter of one or more or preferably all four leveling rollers is, for example, 15 mm to 150 mm, preferably 25 mm to 80 mm. As already mentioned, it is particularly advisable to work with a larger distance between the leveling rollers. It is particularly advantageous to design the device such that the distances are adjustable, for example in that the position of at least one leveling roller is variably adjustable in the direction of travel of the metal strip.

A further requirement for the leveling process was that, in addition to no residual curvature, the metal strip corrugation/metal strip crescent defects be reduced to a minimum. Corrugations existing on the strip prior to leveling must be eliminated, and the leveling process itself must not create new corrugations. During the stretching-bending-levelling process, the problem arises that the metal strip resting on the roller is elastically-plastically deformed and thus plastically elongated. With the plastic longitudinal elongation of the metal strip, there is also a plastic reduction in the width of the metal strip. This means that the section of the metal strip lying directly in front of the roller is wider than the section of metal strip lying directly behind the roller. However, since the metal strip cannot change its width suddenly, a shear stress is formed in the plane of the metal strip, and this shear stress varies in both the width and the length of the metal strip. These shear stresses in turn lead to an overall inhomogeneous plastic deformation of the metal strip across the width of the metal strip, resulting in different plastic longitudinal elongations across the width of the metal strip and thus to corrugations caused by the leveling process. defect. These corrugations are generally moderate corrugations that intensify with increasing stretch. Model-based experiments have led to surprising results here: These differences in stretching in the width of the metal strip due to process conditions can be made possible by an advantageous selection of the spacing between elastically-plastically acting rollers Minimized or eliminated. It has been proven that generally larger horizontal distances have an advantageous effect. Depending on the application of the product to be leveled, different roller distances are optimal, so that the leveling result can be further improved in the case of corrugations if at least one leveling roll is designed to be horizontally adjustable.

Given the large horizontal spacing of the elastically-plastically acting smoothing rollers, the sinking depth of the smoothing rollers is considerable for a given wrapping angle. In order to pass through a connection point of two coils, for example a punched connection point or a welded seam, the stretch-bending stand usually has to be opened, ie the rollers are moved out of the way. Here, this process has to last for a long time if the return distance is large. If the strip continues to travel in an "on-line" condition during this time, the corollary is that the length of the unleveled strip around the junction becomes greater. This situation is in principle undesirable. Therefore the present invention proposes a kind of alternative scheme: in the front of at least one elastic-plastic acting leveling roller, arrange an adjacent guide roller and/or configure an adjacent guide roller behind it, this kind of phase Adjacent guide rollers preferably have a diameter at least three times greater than the diameter of the leveling rollers, particularly advantageously at least ten times the diameter of the leveling rollers. In this way, the adjustment stroke and thus the unlevelled metal strip section can be considerably shortened. In this case, the deflection roller has such a large diameter that only a purely elastic deformation of the metal strip occurs for at least part of the thickness range of the leveled metal strip. It is advantageous if at least the last two leveling rollers are not equipped with intermediate guide rollers in order to achieve the highest possible accuracy when setting the wrapping angle.

It is also possible for at least one of the adjacent deflection rollers to have a concave or convex roller profile. Furthermore, one or also both adjacent guide rollers are designed to have a roller curvature in the horizontal direction and/or in the vertical direction. In front of the first elastically-plastically acting leveling roller, a tensioning roller or guide roller with a variable contour can be arranged with a wrap angle of at least 120°. Take this measure and just can reach following object: On at least one elastic-plastically acting leveling roller, adjust a definite distribution of tensile stress along the width of the metal strip, thereby being able to influence the tension along the width of the metal strip in this way. The degree of stretching is distributed such that after leveling the metal strip has as few remaining corrugations as possible. The increase in tensile stress especially on the edges of the strip suppresses moderate waviness.

Furthermore, the elastically-plastically acting leveling rollers can be supported against deflection by support rollers. For example, segmented backup rolls can be used. In this way, the elastically-plastically acting leveling rollers can be supported against deflection by two rows of segmented backup rollers or two intermediate rollers and three rows of segmented backup rollers.

Description of drawings

The invention will be described in detail below with reference to the accompanying drawings which show only one embodiment.

The accompanying drawings indicate:

Fig. 1 is a simplified schematic diagram of a device for stretching-bending-levelling proposed by the present invention;

The embodiment of the change of the device shown in Fig. 2 Fig. 1;

Figure 3 Calculated residual longitudinal warpage for a metal strip leveled using the apparatus shown in Figure 1; and

Figure 4 Residual longitudinal warpage obtained using a conventional three-roll stand with individual adjustments.

Detailed ways

A device for continuous stretching-bending-levelling of a metal strip 1 is shown in the drawing. In the exemplary embodiments, the device has four smoothing rollers 2 around which a metal strip 1 under tensile stress below the elastic limit is bent alternately in the plastic or elastic-plastic range. Each of these leveling rollers 2 is supported here by at least two support rollers 3 in a known manner. The metal strip 1 is under tensile stress below the elastic limit. In addition, tension rollers, not shown in the figures, are provided, for example a set of braking rollers at the inlet end and a set of sliding rollers at the outlet end.

According to the invention, the bending radii on all four leveling rollers can be adjusted individually or independently of one another. For this purpose, all four leveling rollers 2 can be adjusted in a position-controlled manner by means of an adjusting device not shown in the drawing and by means of actuators not shown in the drawing, such as screw jacks , which is of course carried out in a direction V perpendicular to the direction R of travel of the metal strip. This is indicated in the drawing by the functional position of the leveling roller 2 indicated by dashed lines. The parameters and especially the roller radius and the tensile stress of the metal strip are adjusted in such a way that the metal strip does not (still) follow the roller radius on all four leveling rollers. By adjusting the adjustment depth and thus by adjusting the position and by setting the wrapping angle associated therewith, a change of the respective bending radius can thus be effected.

In the exemplary embodiment shown in FIG. 1 , no other rollers are arranged between the four leveling rollers 2 . Only guide rollers 4 are arranged before and after the entire leveling roller arrangement.

In contrast, FIG. 2 shows a modified embodiment in which a guide roller 4 a is arranged in front of each leveling roller 2 and a guide roller 4 b is arranged behind each leveling roller. Even with this embodiment, the position of all four leveling rollers 2 can be changed in a position-controlled manner perpendicular to the direction R of travel of the metal strip.

Although in principle the embodiment shown in FIG. 1 is preferred because it has no other (purely elastically acting) rolls besides the elastically acting roll line rolls at the inlet and outlet, but The embodiment shown in FIG. 2 may also be advantageous. Combinations of the two embodiments are also possible. With respect to purely elastically acting guide rollers, it should be noted that these only act purely elastically in the case of thin and/or relatively high-strength metal strips, e.g. for strip thicknesses of less than one millimeter range of aluminum strip cases. Furthermore, even if they have only small elasto-plastic effects, they can influence the leveling result with respect to the residual curvature. If a stretching-bending-leveling machine frame is to cover a relatively large range of metal strip thicknesses, then it can be particularly preferred to dispense with guide rollers.

For the start-up of such a device, the exact setpoint positions of all four leveling rollers 2 must be determined using a mathematical model. It is possible here to first determine the nominal wrapping angle using a calculation model which takes into account at least the stresses in the longitudinal and transverse The strip tensile stress, the roll radius and the geometry of the strip's course around the roll are treated as calculation parameters; the setpoint values for the thickness and strength of the strip, for example for the tensile limit, are calculated in such a way that the remaining Longitudinal warpage and residual transverse warpage are zero or nearly zero. In this way the position of the leveling roller 2 can be precisely adjusted. Calibration of these positions can then be performed "off-line" based on experimental results.

Of particular importance here is the fact that a precisely executed adjustment ensures that the residual curvature conditions are extremely insensitive to fluctuations in process parameters such as in particular tensile stress and strength values of the metal strip and fluctuations in strip thickness. Since in practice the metal strip of the coil is usually subject to certain strength and thickness fluctuations, and the tensile stress cannot always remain perfectly constant, the residual curvature obtained with the hitherto known methods is also subject to large fluctuations. This is avoided within the scope of the present invention. The method proposed by the invention shows a particularly satisfactory residual curvature profile. Reference is made to the comparative observations shown in FIGS. 3 and 4 for this purpose.

FIG. 3 shows the residual longitudinal warpage kL (in 1/m) as a function of the degree of stretch S (in %) of an aluminum strip which has been leveled with a device shown in FIG. 1 . This involves using a mathematical model to find the value. In the present example, a yield point of 250 MPa with fluctuations of ±10 MPa and a metal strip thickness of 0.28 mm with ±0.05 mm were used. The permissible limit values for the residual longitudinal warpage of ±0.5 m ⁻¹ are also shown in the figure. It can be seen from the figure that the residual longitudinal warpage within the given tolerance range is in a relatively wide range of about 0.31-0.59% stretch. Furthermore, it is worth noting the fact that the residual longitudinal warpage within a range of ±0.05% elongation only fluctuates by ±0.15m ^-1 . The remaining transverse warpage, not shown in the figures, is then always smaller than the remaining longitudinal warpage. Furthermore, the residual longitudinal warpage within an elongation range of 0.36-0.52% is limited to a negative range with little fluctuation. By adapting the wrapping angle on the last roller, the remaining curvature in the diagram can be shifted upwards or downwards. Thus, a positive residual longitudinal warp can also be set.

In contrast, FIG. 4 shows a corresponding simulation with a three-roll stand, in which the individual rolls are also adjustable in a position-controlled manner. It can be seen from the figure that the residual longitudinal warpage fluctuates within a significantly larger range in the case of fluctuating degrees of elongation. Limit values are only kept within a range of 0.33-0.36% for the degree of elongation. In practice, this is difficult to ensure, for example, in the acceleration phase and the delay phase.

In addition, it is worth noting in general the fact that the stated results can be achieved with relatively few smoothing rollers, so that the device proposed according to the invention is generally characterized by a simple construction and cost-effective production.

If work is carried out by a variant device equipped with more than four leveling rollers, the wrapping angles of at least the last four leveling rollers can be individually adjusted according to the invention in order to obtain a similarly satisfactory a state of residual curvature. According to the method proposed by the invention, with an advantageous selection of the wrapping angle, the value of the residual transverse warpage is significantly smaller than the residual longitudinal warpage. The remaining longitudinal warpage of a cut-out metal sheet after leveling then corresponds approximately to the cross-sectional arching of a metal strip measured on a tension-bending-leveling machine under the tension of the metal strip. It is therefore also possible to propose the following: to measure the arching of the section at least at the outlet end, to deduce the remaining longitudinal warpage from this measured value, and to adjust the wrapping angle and thus also the position in the event of deviations from the desired value, until a section arch corresponding to the desired residual longitudinal warpage is set.

A simple way to do this is to adjust the wrap angle on the last elasto-plastic active roll, thereby shifting the residual curvature trend shown in Figure 3 upwards or downwards. A closed control loop is also conceivable here. In addition, it may also be beneficial to measure section arching after each elasto-plastic bending so that all wrap angle settings can be optimized and adjusted using computational models. For this purpose, corresponding measuring devices can be provided which are connected to a control and regulating device. This situation is not shown in the drawings. Using a finite-element model it is possible, for example, to predict the theoretically optimal cross-sectional crowning behind each roller. The individual rollers can then be adjusted in such a way that the measured and calculated results agree as well as possible. It can then be assumed that the actual leveling process differs only slightly from the theoretically calculated results and also agrees well with the leveling results.

As already mentioned, the position-controlled adjustment of the leveling rollers (transversely to the direction of travel of the metal strip) is preferably carried out with a finely adjustable screw jack. Such fine adjustment elements typically work with an adjustment speed of 2-3 mm/sec. In order to pass through a connection point (for example a punched connection point or a welded seam) of two reels, it may be advantageous to open the stretching-bending stand, ie to remove the rollers. This process with finely adjustable screw jacks can take a long time if the return stroke is large in this case. Therefore, in the embodiment shown in FIG. 2, a front guide roller 4a and a rear guide roller 4b are arranged. In this way, the adjustment stroke can be shortened considerably.

Alternatively or additionally, there is the possibility to provide a quick adjustment in addition to the fine adjustment (for example via a screw jack). This possibility is particularly suitable for the embodiment shown in FIG. 1 , but in principle also applies to the embodiment shown in FIG. 2 . The leveling rollers are then additionally equipped with a quick adjustment, for example a hydraulic or pneumatic cylinder adjustment. It can be advantageous here to assign a common adjustment mechanism to several leveling rollers. Therefore, for example, according to the embodiment shown in FIG. 1, it is preferable to arrange the first leveling roller and the third leveling roller on a common upper frame, which can be adjusted by means of one or more cylinder-type adjustment mechanisms. adjust. Accordingly, the second leveling roller and the fourth leveling roller can be mounted on a lower frame, which can likewise be adjusted by means of one or more cylinder-type adjustment mechanisms. The quick adjustment can be performed, for example, between two end stops for opening and closing the stretch-bending-leveling frame. None of these possibilities are shown in the figure.

Claims (31)

1. the method that is used for continuously elongated-bending-smoothing metal tape; Wherein, A metal tape that is under the tension that is lower than elastic limit is alternately in addition crooked and meanwhile stand plastic elongation in plasticity or elastic-plastic scope around at least four straightener rolls, and it is characterized in that: the bending radius on four all straightener rolls can individually and independently of one another be regulated respectively.

2. by the described method of claim 1, it is characterized in that: four all straightener roll opsition dependent controlled way are adjusted, so that regulate bending radius.

3. by claim 1 or 2 described methods; Wherein, Metal tape is in addition crooked around straightener roll more than four; It is characterized in that: the bending radius on (with regard to the metal tape direct of travel) last four straightener rolls can be distinguished individually and independently of one another and regulates at least, and this realizes that so promptly preferably said at least last four straightener rolls individually opsition dependent controlled way are adjusted.

4. by each described method in the claim 1 to 3; It is characterized in that: the position of straightener roll can enough a kind of precision, for example degree of regulation is set up, and this precision is ± 0.05 ° or littler, preferred ± 0.02 ° or littler with regard to metal tape around holding with regard to the angle of straightener roll

5. by each described method in the claim 1 to 4, it is characterized in that: metal tape around one or more, preferably the angle that holds around all four straightener rolls is 0.5 °-60 °, is preferably 1 °-35 °.

6. by each described method in the claim 1 to 5, it is characterized in that: degree of drawing is 0.1% to 1.5%, for example is 0.2% to 0.6%.

7. by each described method in the claim 1 to 6, it is characterized in that: the metal tape tension is 10% to 90% of elastic limit metal tape or strip material, is preferably 30% to 60%.

8. by each described method in the claim 1 to 7; It is characterized in that: the spacing between the straightener roll that with regard to the metal tape direct of travel, is provided with in succession successively at least two (directly) is at least 15% of (maximum) metal tape width; Preferably be at least 30% of (maximum) metal tape width, be preferably 50% of (maximum) metal tape width especially.

9. by each described method in the claim 1 to 8, it is characterized in that: two (directly) successively in succession the spacing between the straightener roll of setting be at least 150mm, preferably be at least 300mm.

10. by claim 8 and 9 described methods, it is characterized in that: for all four straightener rolls, between the straightener roll of setting said spacing is set in succession successively in per two (directly).

11. be used for the method for continuously elongated-bending-smoothing metal tape; Particularly by each described method in the claim 1 to 10; Wherein, A metal tape that is under the tension that is lower than elastic limit is alternately in addition crooked and meanwhile stand plastic elongation in plasticity or elastic-plastic scope around a plurality of straightener rolls, and it is characterized in that: the spacing on the metal tape direct of travel between at least two straightener rolls is set at variable.

12. by each described method in the claim 1 to 11; It is characterized in that: utilize a kind of computation model confirm to be used for straightener roll the position rated value and/or be used for the rated value that hold angle of metal tape around straightener roll; This computation model is considered the stress on the vertical and horizontal at least, with metal tape thickness, metal tape elastic modelling quantity, cross-direction shrinkage coefficient, cycle strength condition, metal tape tension, roller radius and/or metal tape around the rated value of the rated value of the geometrical configuration of the trend of roller and/or metal tape thickness and/or intensity for example the rated value of limit of stretch handle as calculating parameter.

13. by the described method of claim 12, it is characterized in that: each rated value is to utilize computation model to confirm with such standard, promptly remaining lonitudinal warping is zero with residue cupping (roughly).

14. by the described method of claim 12, it is characterized in that: each rated value is to utilize computation model to confirm with such standard, promptly remaining cupping (roughly) is zero, and residue lonitudinal warping is a definite value.

15., it is characterized in that: after one or more straightener rolls, for example in the end after straightener roll, preferably after each straightener roll, on the metal tape width, measure the cross section of metal tape and arch upward by each described method in the claim 1 to 14.

16. by the described method of claim 15, it is characterized in that: the adjusting of arching upward and realize the position under the situation of measured value or hold angle in the cross section that obtains considering.

17. by the described method of claim 16; It is characterized in that: adjusting is the basis with a kind of computation model; This computation model is considered the stress on the vertical and horizontal at least; Processing is as metal tape thickness, the elastic modelling quantity of metal tape, cross-direction shrinkage coefficient, the cycle strength condition of calculating parameter; Metal tape tension, roller radius and metal tape be around the geometrical configuration of the trend of roller, and the cross section of confirming arched upward be associated with metal tape residue lonitudinal warping or metal tape residue cupping.

18. by each described method in the claim 1 to 17; It is characterized in that: one or more said computation models all are the basis with the FInite Element; Wherein, Preferably with reference to greatest expected or before smoothing measured metal tape unevenness, calculate the optimum stretch degree and/or calculated the optimum level spacing of each straightener roll of elasticity/plasticity effect according to FInite Element, said optimum stretch degree and/or optimum level spacing cause the least residue unevenness.

19. be used for coming the device of continuously elongated-bending-smoothing metal tape (1) by each described method of claim 1 to 18; This device comprises at least four straightener rolls (2); A metal tape (1) that is under the tension that is lower than elastic limit is alternately in addition crooked in plasticity or elastic-plastic scope around these straightener rolls; And this device comprises at least one control and/or adjusting device, it is characterized in that: the bending radius on all four straightener rolls (2) can individually and independently of one another be regulated respectively.

20. by the described device of claim 19, it is characterized in that: all four straightener rolls (2) all link to each other with an adjusting device and can the opsition dependent controlled way regulate.

21. by claim 19 or 20 described devices, it is characterized in that: diameters one or more, preferably all four straightener rolls (2) are 15mm-150mm, for example are 25mm-80mm.

22. by each described device in the claim 19 to 21; It is characterized in that: latter two straightener roll (2) at least in said four straightener rolls (2), preferred last three straightener rolls (2) directly are provided with successively in succession, and other roller is not set between them.

23. by the described device of claim 22, it is characterized in that: four straightener rolls (2) all are directly one after the other to settle successively, and other roller is not set between them.

24. be used for coming the device of continuously elongated-bending-smoothing metal tape, particularly by each described device in the claim 19 to 23 by each described method of claim 1 to 18; This device comprises a plurality of straightener rolls (2); A metal tape (1) that is under the tension that is lower than elastic limit is alternately in addition crooked in plasticity or elastic-plastic scope around these straightener rolls, and it is characterized in that: the spacing between at least two straightener rolls (2) can be set to variable on metal tape direct of travel (R).

25. by the described device of claim 24, it is characterized in that: the position of at least one straightener roll (2), preferably the position of all straightener rolls (2) can be conditioned along metal tape direct of travel (R).

26. by each described device in the claim 19 to 25; It is characterized in that: settled an adjacent guide roller (4 in the front and/or the back of a straightener roll (2) at least; 4a, 4b), this guide roller or these guide rollers (4; 4a, the diameter that 4b) is had preferably are three times of diameter of straightener roll at least, are preferably at least ten times of diameter of straightener roll especially.

27. by the described device of claim 26, it is characterized in that: preposition guide roller (4,4a) and/or rearmounted guide roller (4,4b) have recessed or protruding roller profile.

28. by claim 26 or 28 described devices, it is characterized in that: preposition guide roller (4,4a) and/or rearmounted guide roller (4,4b) be furnished with along roller turning mechanism horizontal direction and/or vertically.

29. by each described device in the claim 19 to 28; It is characterized in that: the idler roller or the guide roller of an idler roller or guide roller, preferred variable contour are set in the front of first straightener roll (2), and said idler roller or guide roller are for example held with at least 120 ° angle by metal tape.

30. by each described device in the claim 19 to 29, it is characterized in that: straightener roll (2) can be adjusted by means of actuator, for example screw jack.

31. by each described device in the claim 19 to 30, it is characterized in that: the straightener roll of each adjustable positions (2) or a plurality of straightener roll (2) of distinguishing adjusting position also jointly attach and are provided with a fast adjuster.

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