Strip press for a rolling mill and method for generating tensile stress in a metal strip in a rolling mill

Abstract

The invention relates to a strip press (1) for a rolling mill, with press elements adjustable above and below a strip plane, which are designed as upper and lower press punches (13, 14) arranged vertically and transversely to a strip travel direction in a press frame (10), characterized in that at least some of the upper and / or lower press punches (13, 14) can be individually adjusted against a metal strip. The invention further relates to a method for generating tensile stress in a metal strip in a rolling mill by means of a strip press (1) with press elements adjustable above and below a strip plane in the form of vertically adjustable upper and lower press punches (13, 14), wherein at least some of the press punches (13, 14) can be individually adjusted against the metal strip.

Description

[0001] The invention relates to a belt press for a rolling mill with press elements which are each adjustably arranged above and below a belt plane and which are designed as upper and lower press rams which are adjustably arranged vertically and transversely to a belt running direction in a press frame.

[0002] The invention further relates to a method for generating a tensile stress in a metal strip in a rolling mill by means of a strip press with press elements in the form of vertically adjustable upper and lower press rams, each adjustably arranged above and below a strip plane.

[0003] In the current state of the art, strip presses are typically used in cold rolling mills, particularly in reversing mills. Their purpose is to maintain the strip tension in the strip end for as long as possible during the unwinding of the first rolling pass, when the strip has almost been unwound from the uncoiler or has already left the uncoiler. This is achieved by applying force to the strip end, simulating tensile stress in the uncoiler. The tension maintained by the strip press makes it possible to create stable rolling conditions in the roll gap of the rolling stand, which still allow the strip to be formed after the strip end has already left the coiler. This makes it possible to roll a longer strip segment, thus reducing the amount of scrap.

[0004] A belt press and a method of the type mentioned above are known, for example, from DE 442605A. The belt press for cold rolling mills described therein is characterized in that the braking means acting on the workpiece in the form of pressure plates and the like are arranged and designed in such a way that, to prevent the strip from running, they can selectively act on one side with greater pressure on the side of the workpiece's center axis in the direction of the outward-running side of the strip, while simultaneously reducing the braking on the side of the strip facing away from the running side. The belt press is arranged on a console of the roll stand of the rolling stand and comprises a pressure spindle for adjusting an upper brake plate. The strip is pressed between two wooden blocks, one of which is attached to the console, the other to the upper brake plate.By means of an angle lever, the pivot point of which is located on the upper brake plate, one side of the upper brake plate can be lowered and the other side raised at the same time, thereby influencing the straight running of the belt.

[0005] Another belt press is known from DE2112753 C3. This belt press comprises pressure bars arranged in groups above and below the belt level, each of which can be lifted off from one another. These pressure bars can be moved symmetrically to a vertical center plane of the belt press via threaded spindles. The belt press comprises a vertically adjustable press frame on which the upper press rams are arranged for laterally adjustment relative to the center plane of the belt and for vertical adjustment with the entire press frame.

[0006] In conventional belt presses, wooden strips or blocks, or wood-plastic composite materials, are provided on the press rams, which act as wear parts or wear blocks, respectively, which engage with the metal strip. These conventional belt presses suffer from the disadvantage that, particularly if the wooden strips or blocks wear unevenly, they lead to imprecise strip guidance. This is particularly aggravated when only a small number of supports are provided for wide sheet metal strips. Uneven wear of the wear blocks can lead to significant local deviations in the tensile stress distribution, which can disrupt the stability of the rolling conditions.

[0007] If the belt press has integrated side guides, as is the case with DE 2112753C3, for example, the dimensions of the crossbeams are so large that access to the belt press for maintenance purposes is difficult. Visibility of the roll gap of the rolling stand located behind it is also impaired by the side guides.

[0008] The invention is therefore based on the object of providing a press of the type mentioned at the outset, as well as a method for generating a tensile stress in a metal strip, which are intended to ensure a uniform tension on the metal strip, wherein in particular the tension build-up is intended to take place independently of the wear state of the wear elements or wear bodies of the press rams.

[0009] In particular, a wedge shape of the belt should be easily compensated for during unthreading, i.e., it should be possible to reliably prevent the belt from running off relative to a central longitudinal axis by appropriate tension control.

[0010] The object is achieved by providing a belt press having the features of claim 1 and by providing a method having the features of claim 8.

[0011] Advantageous embodiments of the invention emerge from the subclaims.

[0012] According to one aspect of the invention, a belt press for a rolling mill is provided with press elements which are each adjustably arranged above and below a strip plane and which are designed as upper and lower press punches which are adjustably arranged vertically, transversely to a strip running direction in a press frame, wherein the belt press according to the invention is characterized in particular in that at least some of the upper and / or lower press punches are designed to be individually adjustable or pressed against the metal strip.

[0013] The belt press according to the invention is designed in particular as a belt press for use in a cold rolling tandem plant.

[0014] In terms of terminology and function, the strip press according to the invention is to be distinguished from a strip clamp in cold rolling tandem rolling mills. The latter serves only to temporarily secure the strip completely. The strip press according to the invention, on the other hand, is designed to maintain the strip tension in the strip end during the unwinding of the first rolling pass when the strip has almost been unwound from the uncoiler or has already left the uncoiler. The strip press according to the invention acts as a tension brake and is equipped with press rams, which preferably have wear elements for frictional contact with the moving metal strip.

[0015] In particular, because at least some of the upper and / or lower press rams are designed to be individually adjustable against the metal strip, the belt press according to the invention enables individual distribution of the support / pressing points and press rams across the strip width, thereby enabling a targeted and controlled build-up of tension and preventing premature wear of the wear bodies or wear elements. This means that at least two upper and / or lower press rams can be adjusted or controlled independently of one another.

[0016] In an expedient variant of the belt press according to the invention, an odd number of upper press rams and an odd number of lower press rams are preferably provided, wherein at least some of the press rams can be arranged in groups so as to be adjustable together.

[0017] For example, it can be provided that the upper press dies are adjustable in groups and that the lower press dies are adjustable individually. Although the lower press dies can also be designed to be adjustable together and the upper press dies individually, the first variant has the advantage that the upper press dies can first be lowered together to the fitting line, and then the lower press dies make contact with the metal strip or rolled stock when the end of the strip is almost unwound, thus avoiding premature contact with the rolled stock and preventing any wear elements from leaving marks on the metal strip or rolled stock. Preferably, only those press dies that have full coverage with the strip width are raised and brought into engagement with the metal strip. This also prevents uneven wear within the contact surfaces of individual wear elements.

[0018] Particularly preferably, at least some of the press rams, preferably individually, are designed to be hydraulically adjustable.

[0019] In a particularly preferred embodiment of the belt press according to the invention, some of the press rams are designed to be hydraulically adjustable in a force-controlled manner, preferably the lower press rams. This force-controlled adjustment makes it particularly easy to compensate for any belt drift or wedge-shaped belt formation during unthreading.

[0020] The contact force of individual press rams can be individually controlled. This has the particular advantage that the pressing force or support force can be adjusted and maintained across the entire range, regardless of wear on the wear elements.

[0021] In each cylinder, for example, the contact pressure of the press rams can be individually controlled via pressure sensors in the hydraulic system.

[0022] In a practical embodiment of the belt press according to the invention, the upper press rams are arranged so that they can be adjusted together on a cross member that is vertically adjustable and mounted in the press frame. The vertical adjustability of the cross member can be ensured, for example, by means of several hydraulic cylinders, by means of which the upper press rams can be lowered together and simultaneously to the fitting line.

[0023] In principle, within the scope of the invention, an arrangement comprising the belt press with one or more of the features described above and a device for laterally guiding the metal belt can be provided, the adjustability of which is decoupled from the adjustability of the press rams according to the invention. The device for laterally guiding the metal belt is preferably mechanically and functionally separated from the belt press, thus providing a modular design of the belt press according to the invention and eliminating the need for large, space-consuming crossbeams.

[0024] Particularly preferably, the press frame comprises a chassis by means of which the belt press can be pulled out of the stand inlet of the rolling stand as a unit transversely to the strip running direction for maintenance purposes.

[0025] A further aspect of the invention relates to a method for generating a tensile stress in a metal strip in a rolling mill by means of a strip press with press elements in the form of vertically adjustable upper and lower press dies, each adjustably arranged above and below a strip plane, wherein the method according to the invention is characterized in particular in that at least some of the press dies are designed to be individually adjustable against the metal strip, preferably hydraulically.

[0026] Advantageously, the tensile stress of the metal strip is adjusted by regulating the adjustment movement of at least some of the press dies.

[0027] Particularly preferably, a force-controlled or force-guided control of the adjusting movement of at least some of the press rams is provided.

[0028] The control can, for example, be based on a detected misalignment of the metal strip, preferably in such a way that an asymmetrical distribution of the pressing pressure on the metal strip is provided on both sides of a center line of the metal strip. Individual pressing rams can be engaged and disengaged from the metal strip on either side of a center line of the strip path, depending on the width of the metal strip, or can optionally act on one side with greater pressure on the side of the center axis of the metal strip in the direction of the outward-facing side of the strip.

[0029] Preferably, it can be provided that the lower press rams are each brought into contact with the metal strip individually by means of hydraulic cylinders, wherein preferably only those press rams are raised which have full coverage with the strip width.

[0030] In the method according to the invention, it can be provided that the upper press punches are first lowered simultaneously and evenly onto the pass line of the rolling mill, wherein contact with the metal strip is only made when the coil is almost completely or completely unwound from the uncoiler.

[0031] According to the invention, a lateral guide is provided which is functionally and mechanically separated from the belt press.

[0032] The invention is explained below with reference to an embodiment shown in the drawings.

[0033] They show: Figure 1 is a schematic representation of a cold rolling mill with a belt press according to the invention, Figure 2 is a perspective view of the belt press according to the invention, Figure 3 is a perspective view of the belt press according to the invention with a device arranged in front of it for laterally guiding the metal strip, and Figure 4 is a front view of the lateral guide, which is not an essential component of the belt press according to the invention.

[0034] The Figure 1schematically shows a cold rolling mill 100 with a strip press 1 according to the invention. The cold rolling mill comprises a decoiler 2, a first reversing coiler 3, a first rolling stand 4, a second rolling stand 5, and a second reversing coiler 6. A metal strip 8 wound into a coil 7 is rewound from the decoiler 2 via the first rolling stand 4 and the second rolling stand, reducing in thickness during a first rolling pass, onto the second reversing coiler 6. The rolling direction of the first rolling pass is indicated in the drawing by an arrow in the strip travel direction. Cold rolling mills designed as reversing systems are known as such, so the cold rolling mill will not be discussed in detail below.

[0035] Immediately before the inlet of the first rolling stand 4, the belt press 1 according to the invention is arranged, which in the Figures 2 and 3shown in detail. The belt press 1 has the task of maintaining the tension of the metal strip 8 when the coil 7 is almost completely or completely unwound from the decoiler 2, so that the strip length between the decoiler 7 and the belt press 1 remains available for rolling. To this end, the belt press 1 keeps the metal strip 8 under tension until the end of the strip has reached or left the belt press 1.

[0036] As is particularly evident from Figure 3 As can be seen, the belt press 1 is detachably fastened on one side to a roll stand 9 on the inlet side of the first roll stand 4.

[0037] The belt press 1 comprises a press frame 10 ( Figure 2 ), which is arranged on a chassis 11 with rollers 12. This allows the belt press 1 to be moved in and out of a rolling mill 100 transversely to the direction of belt travel for maintenance purposes.

[0038] Upper press rams 13 and lower press rams 14 are arranged within the press frame 10. In the described embodiment, a total of seven upper press rams 13 and seven lower press rams 14 are provided, with the upper press rams 13 being fastened to a cross member 15, with which the upper press rams 13 can be vertically adjusted together and simultaneously. The cross member 15 is guided in a vertically adjustable manner in lateral frame legs 16 of the press frame 10. For this purpose, the cross member 15 has a guide rail 17 on each of its end faces, which is guided vertically in a guide slot 18 in a manner that prevents rotation and tilting.

[0039] The cross member 15 is vertically displaceable via three upper piston-cylinder assemblies 19, each of which is attached to an upper cross member 20 as an abutment. The ends of the upper piston-cylinder assemblies 19 pointing downward toward the top of the metal strip 8 are each attached to the cross member 15, to which the upper press rams 13 are in turn attached. The upper press rams 13 are fixed relative to the cross member 15 and can only be displaced together with the cross member 15.

[0040] The lower press rams 14 can each be individually displaced vertically via lower piston-cylinder assemblies 21 and can be adjusted against an underside of the metal strip 8, wherein a total of seven lower piston-cylinder assemblies 21 are provided, corresponding to the number of lower press rams 14, which are fastened on one side to a lower cross member 22 of the press frame 10.

[0041] Both the upper press dies 13 and the lower press dies 14 comprise mutually facing wear bodies 23, which are designed as a plastic-wood composite material arranged on the end faces of the press dies 13, 14.

[0042] During a first rolling pass of the rolling mill 100, the metal strip 8 is unwound under tensile stress from the coil 7 arranged on the decoiler 2 and wound onto the second reversing coiler 6. The metal strip 8 is guided under tensile stress through the strip press 1 and through the first and second rolling stands 4, 5. During this time, the crossbeam 15 of the strip press 1 is lowered such that the upper press rams 13 are located approximately on the pass line of the rolling mill, although they do not yet have to be in engagement with the metal strip 8. Immediately before the metal strip 8 has been completely unwound from the decoiler 2, the lower press rams 14 are hydraulically adjusted against the underside of the metal strip 8, applying a force that maintains the required tensile force in the metal strip 8.In this way, it is possible to keep the released end of the metal strip 8 under tension until it reaches the strip press 1. As can be seen from the . Figures 2 and 3 As can be seen, the belt press 1 is arranged directly in front of or on the inlet side of the first rolling stand 4 and is supported against it.

[0043] Any misalignment of the metal strip 8 is corrected by the lower press rams 14 being individually adjusted in a force-controlled manner against the underside of the metal strip 8 in such a way that, on the one hand, only those lower press rams 14 which have full coverage with the metal strip 8 are brought into engagement with the metal strip 8, and on the other hand, the lower piston-cylinder assemblies 21 are force-controlled and are adjusted in a force-controlled manner against the underside of the metal strip 8 so that different braking forces can be applied on either side of a center line of the metal strip 8, on the one hand to adjust the tensile stress on either side of the center line so that the metal strip 8 runs straight, and on the other hand to compensate for any wear of the wear bodies 23.

[0044] As from Figure 3As can be seen, a lateral guide 24 is arranged upstream of the belt press 1, which is located directly in front of the belt press 1. The lateral guide 24 is functionally and mechanically decoupled from the belt press 1 and comprises two pairs of guide rods 25 arranged below the metal belt 8, on each of which guide profile supports 26 are arranged so as to be horizontally displaceable by means of a drive 27. The drive 27 comprises a rack 28 and a hydraulic cylinder 29 which interacts with the rack and acts on the rack 28 with a piston rod 32. On the side facing the metal belt 8, angular guide profiles 30 are arranged on the guide profile supports 26, which interact with the side edges of the metal belt 8 as lateral guides 24. These also act as a safeguard to prevent lateral deflection of the free end of the metal belt 8.

[0045] The side guides 24 are each attached to an inlet guide for the metal strip 8. In the event of maintenance, the belt press 1 can be moved out of the rolling line on a guideway 31 by means of the chassis 11 and the rollers 12 arranged thereon, whereas the side guide 24 remains in the rolling line. List of reference symbols

[0046] 100Rolling Mill 1Strip Press 2Decoiler 3First Reversing Coil 4First Rolling Stand 5Second Rolling Stand 6Second Reversing Coil 7Coil 8Metal Strip 9Roll Housing 10Press Frame 11Chassis 12Rollers 13Upper Press Rams 14Lower Press Rams 15Cross Beam 16Frame Legs 17Guide Rails 18Guide Slot 19Upper Piston-Cylinder Arrangements 20Upper Crossbeam 21Lower Piston-Cylinder Arrangements 22Lower Crossbeam 23Wear Body 24Side Guide 25Guide Rod Pairs 26Guide Profile Support 27Drive 28Tooth Rack 29Hydraulic Cylinder 30Guide Profiles 31Guide Track 32Piston Rod

Claims

1. Belt press (1) for a rolling mill with press elements which are each adjustably arranged above and below a belt plane and which are designed as upper and lower press rams (13, 14) which are adjustably arranged vertically, transversely to a belt running direction in a press frame (10), characterized in that at least some of the upper and / or lower press rams (13, 14) are designed to be individually adjustable against a metal strip (8).

2. Belt press (1) according to claim 1, characterized in that at least some of the pressing rams (13,14) are adjustable together in groups.

3. Belt press (1) according to one of claims 1 or 2, characterized in that the upper pressing rams (13) are adjustable together and that the lower pressing rams (14) are adjustable individually.

4. Belt press (1) according to one of claims 1 to 3, characterized in that at least some of the pressing rams (13, 14), preferably individually, are designed to be hydraulically adjustable.

5. Belt press (1) according to one of claims 1 to 4, characterized in that at least some of the pressing rams (13,14) are designed to be hydraulically force-controlled adjustable.

6. Belt press (1) according to one of claims 1 to 5, characterized in that the upper press rams (13) are arranged so as to be jointly adjustable on a cross member (15) which is mounted so as to be vertically adjustable in the press frame (10).

7. Belt press (1) according to one of claims 1 to 6, characterized in that the press frame (10) has a chassis (11) which is designed to move the press frame (10) in and out of a rolling line transversely to the strip running direction for maintenance purposes.

8. Method for generating a tensile stress in a metal strip (8) in a rolling mill by means of a strip press (1) with press elements in the form of vertically adjustable upper and lower press rams (13, 14) arranged above and below a strip plane, characterized in thatat least some of the pressing punches (13, 14) are designed to be individually adjustable against the metal strip (8).

9. Method according to claim 8, characterized in that the tensile stress of the metal strip (8) is adjusted by regulating the adjusting movement of at least some of the pressing rams (13,14).

10. Method according to one of claims 8 or 9, characterized in that a force-controlled regulation of the adjusting movement of at least some of the press rams (13,14) is provided.

11. Method according to one of claims 9 or 10, characterized in that the adjustment movement is controlled as a function of a detected misalignment of the metal strip (8), preferably in such a way that an asymmetrical distribution of the pressing pressure on the metal strip (8) is provided on both sides of a center line of the metal strip (8).

12. Method according to one of claims 8 to 11, characterized in thatindividual press stamps (13,14) on both sides of a center line of the strip path are brought into and out of engagement with the metal strip (8) depending on the width of the metal strip (8).

13. Method according to one of claims 8 to 12, characterized by the use of a belt press (1) having the features of claims 1 to 7.

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