EP1955786B1 - Method for levelling metal strips - Google Patents

Description

The invention relates to a method for leveling metal strips, in particular thin metal strips, in the course of rolling, straightening and / or stretching according to the preamble of claim 1. A device for carrying out such a method has at least one tensioning roller set with at least two tensioning rollers. Thin bands means in the context of the invention, in particular metal strips of a thickness of 0.05 mm to 1 mm, preferably 0.1 mm to 0.5 mm. Metal bands means especially bands of aluminum alloys.

Metal strips and in particular thin metal strips must meet today's standard ever higher demands on the strip flatness with the highest quality of the strip surface. In this connection, various methods for leveling metal strips, z. B. rolling (in particular temper rolling), the straightening (in particular stretch bending straightening) and the stretching. The devices used for this purpose often have a Einlaufspannrollensatz for Zugaufbau and a Auslaufspannrollensatz to Zugabbau on. This applies in particular to the stretch bending and drawing as well as for the tempering in the case of in-line skin-pass coating. In temper rolling, the temper rolling stand is then arranged between these sets of tension rollers, while the stretch bending unit can be provided in the case of stretch bending levels between these sets of tension rollers. In a drafting device, at least one further set of tensioning rollers is usually provided between the infeed tensioning roller set and the outfeed tensioning roller set as the tensioning roller set.

With the known method for leveling metal strips by rolling, straightening and / or stretching, in particular ripples (edge waves and center waves) or band saws as well as unbalanced to the band center can be Barely completely eliminate flatness profiles, so that ideal flatness is rarely achieved. To further improve the flatness, it is known to eliminate ripples and tape sacks, z. B. during temper rolling a variable over the bandwidth temperature profile to influence the tensile stress distribution to generate, so that the degree of leveling can be adjusted by changing the tensile stress distribution (see. DE 199 33 610 A1 ).

In addition, it has been proposed for reducing edge waves or center bowls in the course of leveling metal strips, in a tensioning roller set an adjustable contour with z. B. convex outer curvature and / or concave inner curvature provide (see. EP 0 587 995 A1 ).

Furthermore, there is known a device for bending of metal strip with parallel arranged guide rollers and arranged in the gusset of two guide rollers straightening roller, in which the tape looped around the straightening roller between two lines of contact along which the guide rollers are in indirect contact with the straightening roller over the tape , In order to change the immersion depth and thus also determined by the straightening radii or the contact lines wrap depending on the strip thickness and the strength of the strip material, the support rollers, the guide roller and the straightening roller are mounted on a common console, which is a pivot point can pivot (cf. DE 197 08 488 A1 ). As a result of these measures, the tensile stress distribution over the bandwidth is not varied so that the degree of grading can not be varied over the bandwidth.

From the JP 62084828 (Patent Abstracts of Japan), a device for straightening metal strips is known, wherein a straightening device is positioned between an inlet tensioning roller set and an outlet tensioning roller set is. The last roll of the Einlaufspannrollenensatzes and the first role of the Auslaufspannrollensatzes can be pivoted in the strip running plane.

The invention has the object of providing a method for leveling metal bands of the type described above in such a way that the flatness of the band can be improved in a simple yet cost-effective manner. In particular, edge waves, center waves and / or band saber are to be almost completely suppressed.

To solve this problem, the invention teaches in a generic method of the type described above that is set by pivoting at least one tensioning roller of the tensioning roller set in the strip running plane and / or transverse or perpendicular to the strip running plane over the bandwidth variable planing. Such a tensioner is usually rotatably mounted on both sides in bearings. In this case, the invention proposes that the position of a bearing or both bearings and thus the position of an axle or shaft end or both axis or shaft ends of a tension roller in the belt running plane and / or is set transversely to the belt running plane. In a rolling mill, z. B. Dressieranlage may be one or more roles of the Einlaufspannrollensatzes and / or the Auslaufspannrollensatzes. The same applies to a straightening device, for. B. stretch bender. In the case of a Zugreckanlage, in which between the Einlaufspannrollenensatz and the Auslaufspannrollensatz usually one or more other sets of tension rollers are provided to form stretching zones, it is expedient if one or more of these tension rollers of Zugreckrollensatzes be adjusted according to the invention.

The invention is based on the recognition that the degree of leveling is due to the adjustable misalignment or inclined position of a tensioning roller or to set a variable leveling over the bandwidth. So can be z. B. when rolling or tempering or straightening or stretch bending between the tension roller sets affect the tensile stress distribution within the metal strip and set a variable over the bandwidth tensile stress distribution. If, for example, a misalignment occurs within the strip running plane, this results in one side of the strip becoming "tighter" and the other side becoming "looser", ie the strip tension increases at one of the strip edges, and decreases at the other edge of the strip. Since the processes described (esp. Rolling and straightening) sensitive to the tensile stress distribution or strip tension depend, can be adjusted by adjustable inclination within the strip running plane in particular unilateral flatness errors such. B. single-sided edge waves, band saber or the center of the band unbalanced flatness profiles eliminate. In the context of the invention, however, not only is it possible to pivot the respective tensioning roller in the strip running plane, but alternatively or additionally, the tensioning roller can also be pivoted transversely to the strip running plane or perpendicular to the strip running plane. The strip running plane always means the strip running plane in the respective deformation zone. By pivoting a tension roller perpendicular to the strip plane, the tape tension distribution is also affected because the tape edges are tighter compared to the center of the tape, ie in the middle of the band increases the tape tension against the two band edges. Such an adjustment can therefore be used to compensate for center ripples. When rolling and straightening, in which the band tension between the sets of tension rollers is usually below the yield strength, the tension distribution and thus the degree of planing are influenced by the described skewing or angle adjustment. But even when drawing, in which the strip tension in the stretching zone in the yield point, the degree of planing is due to the misalignment or angular adjustment of one or more rollers influenced. Thus, the tensile stress distribution, assuming ideal plastic conditions in the stretching zone, is not influenced by the skewing. Nevertheless, the degree of planing during the drawing process also depends on the angular position of the roller, since it directly influences the plastic strain distribution and thus the plastic belt extension over the belt width variably.

The invention includes embodiments in which only one roller of a tensioning roller set is adjusted or pivoted. But it is also within the scope of the invention that multiple roles within a tensioner roller set, z. B. be adjusted both roles of an S-roll pair.

According to a further proposal of the invention it is provided that the metal strip is guided around the pivotable tensioning roller with a wrap angle of at least 45 °, since from a wrap angle of 45 ° (or more) the desired effect, namely the influence of the degree of planing by pivoting the roller clearly stands out. Preferably, a wrapping angle of at least 90 ° or more than 90 ° is selected. According to a particularly preferred embodiment, the wrap angle in the region of the pivotable roller is at least 180 °.

According to a further proposal of the invention it is provided that a device is used which has at least one flatness measuring device, the z. B. may be arranged downstream of the tension roller set. Such a flatness measuring device according to the invention is connected to a control and / or regulating device, which in turn interacts with the adjustable tensioning roller. By a subsequent measurement of the tension distribution in the belt after rolling or after straightening or after drawing a closed planarity control loop can be realized.

To set the skew or inclined position or for positioning of the two bearing points of such a tensioner can be assigned to the two bearings each have a separate or several separate actuators. These actuators may be hydraulic (or pneumatic) cylinder piston assemblies, electric motor actuators or the like. It is expedient if these actuators are controlled by the described control and / or regulating unit, possibly taking into account the flatness measurement results.

The invention therefore relates to a method for leveling metal strips in the course of rolling, straightening and / or stretching. Such a method is carried out with a device of the type described, wherein the metal strip under strip tension is at least partially plastically deformed. In this case, the invention proposes that by means of pivoting at least one tensioning roller, a planing degree variable over the bandwidth is set. In the case of rolling (eg temper rolling) or straightening (eg stretch bending), the pivoting affects the tensile stress distribution across the belt width and thus the degree of planing. In the case of drafting, the pivoting directly influences the plastic strip extension or the plastic strain distribution. The tensioner is z. B. in the tape running plane and / or transversely or perpendicular to the tape plane and thus tilted or tilted. The tensioning roller is pivoted about a pivot axis which is (substantially) perpendicular to the axis of rotation of the tensioning roller. The tensioning roller (or its axis) can be pivoted to set the tension distribution by an angle of 0 to 5 °, preferably 0 to 3 ° become. For this purpose, the tensioning roller in the area of a bearing point or in the region of both bearing points by a distance of 0 to 2 mm, z. B. 0 to 1 mm can be adjusted. Preferably (after the leveling of the belt) the flatness of the belt is determined, for. B. with a flatness measuring roller or the like and the adjustment of the tension roller is then controlled and / or regulated in dependence on the determined flatness.

Fig. 1

eine Vorrichtung zum Planieren von Metallbändern im Wege des Walzens in einer schematischen Seitenansicht,

Fig. 2

eine vereinfachte Draufsicht mit angedeuteter Zugspannungsverteilung,

Fig. 3

eine abgewandelte Ausführungsform des Gegenstandes nach Fig. 1,

Fig. 4

die Zugspannungsverteilung über die Bandbreite b beim Gegenstand nach Fig. 3 und

Fig. 5

eine Vorrichtung zum Planieren von Metallbändern durch Zugrecken in einer schematischen Seitenansicht.

In the following the invention will be explained in more detail with reference to drawings showing merely exemplary embodiments. Show it

Fig. 1

a device for leveling metal strips by means of rolling in a schematic side view,

Fig. 2

a simplified plan view with indicated tensile stress distribution,

Fig. 3

a modified embodiment of the article according to Fig. 1 .

Fig. 4

the tensile stress distribution over the bandwidth b of the object after Fig. 3 and

Fig. 5

a device for leveling metal strips by stretching in a schematic side view.

In the figures, a device for leveling metal strips 1, in particular thin metal strips of aluminum alloys, is shown in various embodiments. Such a device has at least one tensioning roller set 2 designed as an inlet tensioning roller set and at least one tensioning roller set 3 designed as an outlet tensioning roller set, wherein the inlet tensioning roller set 2 corresponds to the tension construction and the outlet tensioning roller set 3 serves the train dismantling. Between the inlet tensioning roller set 2 and the outlet tensioning roller set 3, a belt treatment device, for. B. a rolling mill 4 ( Fig. 1 to 4 ) and / or a pull-out unit 5 ( Fig. 5 ) can be arranged. The drafting unit 5 according to Fig. 5 has a further tensioning roller set 6, which is designed as Zugreckrollensatz.

According to the invention, it is now provided that at least one of the tensioning rollers 7, 8 of at least one tensioning roller set 2, 3, 6 in the belt running plane B and / or transversely to the belt running plane B is pivotable. Taking into account the fact that such a tension roller 8 is rotatably supported on both sides in bearings 9, it is provided that the position of one of these bearings 9 or both bearings 9 in the belt running plane B and / or transverse to the belt running plane B is adjustable. For this purpose, 9 position drives or actuators may be connected to the bearings, which are not shown in the figures.

In the following, the invention will be explained by way of example with reference to rolling (cf. Fig. 1 to 4 ). Between the Einlaufspannrollenensatz 2 and the Auslaufspannrollensatz 3 is according to Fig. 1 and 3 a rolling mill 4 is arranged. According to Fig. 1 can be the rolling stand 4 directly upstream or downstream tensioning roller 8 of a tensioning roller set 2 within the belt running plane B pivot and consequently skew. In this way, the strip tension concentrates on one side, ie in the region of one edge of the strip, the strip tension increases while it decreases on the other edge of the strip. The inclination of the roller 8 within the belt running plane B is in Fig. 2 (heavily oversubscribed). The pivot angle α in the strip running plane is usually only 0 to 2 °, preferably only 0 to 1 °. The resulting tensile stress distribution Z is in Fig. 2 also indicated. In the manner shown can be z. B. a band saber correct. In the illustrated embodiment, the relevant roller 8 need not be driven. In the context of the invention, however, both (rotating) driven and non-driven tensioning rollers are always included. Incidentally, in Fig. 1 recognizable that it is expedient if the wrap angle is about 180 ° or more. The misalignment of the roller 8 and the adjustment angle α is - as explained - relatively small, so that a displacement of a bearing 9 of less than one millimeter can be sufficient. Surprisingly enough such small adjustments, so that at the same time problems with an impermissible belt run are avoided. In order to expand the overall flatness adjustment range, it is possible to combine the illustrated roller 8 with the other flatness actuators of a rolling mill 4.

While in the embodiment according to Fig. 1 the tension roller 8 is pivoted in the strip running plane B, shows Fig. 3 an embodiment in which the roll stand 4 directly upstream or downstream roller 8 is pivoted perpendicular to the strip plane B. Fig. 4 makes it clear that in this way the tensile stresses Z in the band 1 concentrate on the band edges or margins, consequently a higher band tensile stress is present in the region of the band edges than in the area of the band center. As a consequence, the rolling reduction at the edges or, in the case of temper rolling stands, the degree of temper rolling increases and there is a tendency for edge waviness, so that suitable waviness can be compensated for by suitable process control. Also in this embodiment, it is expedient to tune the adjustment of the imbalance with the other flatness actuators of the rolling mill in order to expand the Gesamtplanheitsstellbereich.

In a similar manner as in the rolling according to Fig. 1 to 4 the effect according to the invention can also be achieved in the case of stretch bending. Such Embodiment is not shown in the figures. At the point in the band, where there is a higher tension than at the other points, the band is stretched more plastically and thus lengthened.

Fig. 5 shows a drafting device. This also has a Einlaufspannrollensatz 2 for train construction and a Auslaufspannrollensatz 3 for train reduction. Between the Einlaufspannrollensatz and the Auslaufspannrollensatz another set of tension rollers 6 is arranged, which is designed as Zugreckrollensatz with two Zugreckrollen 7, 8. Between these two access rollers 7, 8, the stretching zone R is formed, within which the plastic deformation takes place to influence the band flatness. According to the invention it is now provided that at least one of these Zugreckrollen 7, 8, z. B. the outlet side Zugreckrolle 8, in the strip running plane B and / or transverse to the strip plane B is pivotable. Belt running plane B also here means the strip running plane B in the region of the deformation zone and consequently in the region of the stretching zone R. In the Fig. 5 only one adjustment is indicated transversely or perpendicular to the tape plane B. When drawing the tensile stress in the stretching zone in the order of the yield strength. In ideal plastic conditions where no strain hardening occurs, it is believed that pivoting does not affect the tensile stress distribution in the belt in the stretch zone. However, the pivoting directly influences the degree of planing, since the plastic strain behavior of the strip in the stretching zone depends on the angular position of the roll. The adjustable roller 8 works as it were as another flatness actuator.

It is always expedient if a flatness measuring device 10 is integrated in the systems described. This may be a flatness measuring roll 10 or even a planarity measuring device of another kind, for. B. a non-contact flatness measuring device act. In Fig. 5 is implied that it is expedient to arrange this flatness measuring device 10 behind the outlet tensioning roller set 3. By a subsequent measurement of the tension distribution in the belt after rolling or straightening or stretching, the adjustment of the tensioning roller 8 described can be controlled and / or regulated. Possibly. a closed flatness control loop can be set up. The invention can also be used with other planarity actuators such. B. combine a contour variable role.

Claims (7)

1. A method for flattening metal strips (1), particularly thin metal strips, e.g. of aluminum alloys, in the course of rolling, leveling and/or tensile straightening,
   with a device that features at least one tension bridle (2, 3, 6) with at least two tensioning rollers (7, 8,), wherein the metal strip (1) that is subjected to front tension is at least sectionally deformed in a plastic fashion, characterized in that a variable flattening level is adjusted over the strip width by pivoting at least one tensioning roller (7, 8) in the strip running plane (B) and/or transverse to the strip running plane (B).
2. The method according to Claim 1, characterized in that the tensioning roller (7, 8) for adjusting the flattening level is pivoted in the strip plane (B) and/or transverse to the strip plane (B) by an angle α = 0° to 5°, preferably 0° to 3°.
3. The method according to Claim 1 or 2, characterized in that the tensioning roller (7, 8) is rotatably supported in bearings (9) on both sides and adjusted in the strip plane and/or transverse to the strip plane by 0 to 2 mm, e.g. 0 to 1 mm, in the region of one bearing (9) or in the region of both bearings (9) in order to adjust the flattening level.
4. The method according to one of Claims 1 to 3, characterized in that the planarity of the strip (1) is determined and the tensioning roller (7, 8) is controlled and/or adjusted in dependence on the determined planarity.
5. The method according to one of Claims 1 to 4, wherein at least one tension bridle in the form of a run-in tension bridle (2) for building up the tension and at least one tension bridle in the form of a run-out tension bridle (3) for reducing the tension are used, wherein at least one roll stand (4), one leveling device and/or one tensile straightening device (5) with at least one tension bridle in the form of a set of tensile straightening rollers (6) is arranged between the run-in tension bridle (2) and the run-out tension bridle (3), and wherein at least one of the tensioning rollers (7, 8) of at least one of the tension bridles (2, 3, 6) is pivoted in the strip running plane (B) and/or transverse to the strip running plane (B).
6. The method according to one of Claims 3 to 5, characterized in that the position of one bearing (9) or both bearings (9) is adjusted by means of one or more positioning actuators.
7. The method according to one of Claims 1 to 6, characterized in that the metal strip (1) is guided around the pivotable tensioning roller (8) with a wrap angle of at least 45°, preferably at least 90°, particularly at least 180°.

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