Guide device for chocks of working rolls in a roll stand

Abstract

The invention relates to a device (2) for guiding chocks (12) which are designed to support two working rolls (10) of a roll stand (1), said working rolls forming a rolling gap, and to a roll stand. The device (2) has: two bending blocks (20) for receiving a respective chock (12); at least one guide (15) on which the bending blocks (20) are guided such that the bending blocks (20) can be moved relative to one another along the guide (15); and multiple bending actuators (30) which are designed to move the bending blocks (20) along the guide (15) relative to one another.

Description

[0001] Guide device for chocks of work rolls in a rolling stand

[0002] Technical area

[0003] The invention relates to a device for guiding chocks which are designed to support work rolls forming a roll gap of a rolling stand, as well as to a rolling stand for rolling a strip-shaped rolled product, preferably for rolling a cold strip in a cold rolling mill.

[0004] Background of the invention

[0005] In the production of flat-rolled metal products, slabs or strips are passed through one or more rolling stands. A rolling stand has at least two parallel work rolls that form a roll gap through which the strip passes for thickness reduction. In addition to the work rolls, the rolling stand usually has backup and / or intermediate rolls that interact with the work rolls for various reasons, such as stabilizing the work rolls, transmitting force, etc.

[0006] The work rolls can bend under load, causing the rolled metal strip to have a non-constant thickness across the strip width. Various measures are known to improve the flatness of the rolled product or generally influence its cross-sectional profile, such as crowning, axial displacement, or bending of the work rolls by applying forces to the roll neck.

[0007] Systems for bending work rolls are described, for example, in DE 39 06 618 C2 and WO 2008 / 080476 A1. The systems are designed in a cassette configuration, comprising bending blocks guided on rods that hold and guide chocks for supporting the work rolls. To bend the work rolls, they are usually clamped against the respective backup rolls by means of piston-cylinder units. In conjunction with a suitable backup roll profile, the work rolls undergo the desired positive bending, i.e., convex bending with respect to the rolling surface of the rolled product.

[0008] In special cases, however, a negative bending of the work rolls—that is, a concave bend relative to the rolling surface of the rolled product—is desired, for example, in skin-pass rolling with low rolling forces. However, such negative bending concepts are not possible with existing cassette-type devices, or are limited to very low negative bending forces. This applies particularly to systems with small roll diameters.

[0009] Description of the invention

[0010] An object of the invention is to provide an improved device for guiding chocks which are designed to support work rolls of a rolling stand forming a roll gap, as well as an improved rolling stand for rolling a strip-shaped rolled product, in particular to increase the range of applications of the rolling stand.

[0011] The object is achieved by a device having the features of claim 1 and a rolling stand having the features of claim 11. Advantageous further developments follow from the subclaims, the following presentation of the invention and the description of preferred embodiments.

[0012] The device according to the invention, also referred to herein as a "guide device," serves to guide chocks for work rolls in a rolling stand. The rolling stand is designed for rolling a strip-shaped rolled product, preferably for rolling a cold strip in a cold rolling mill. The rolled product is preferably a steel sheet; however, other metals and alloys are also suitable, for example, aluminum, copper, and magnesium.

[0013] The device comprises two bending blocks, each for receiving a chock, and at least one guide on which the bending blocks are guided, so that the bending blocks can be displaced relative to one another along the guide. The device further comprises a plurality of bending actuators configured to displace the bending blocks relative to one another along the guide.

[0014] In other words, the bending actuators are designed to apply bending forces to the work rolls when installed between the two bending blocks. These can be positive bending forces, whereby the bending blocks are moved apart along the guide(s), whereby the work rolls, in cooperation with any backup rolls, tend to be bent convexly, as seen in relation to the rolling surfaces of the rolled product. Alternatively, negative bending forces can be achieved, whereby the bending blocks are moved towards each other. Rolling under negative bending forces can take place under a lifted upper backup roll, i.e. with exclusively the negative bending force as the rolling force, for example in skin-pass operation.

[0015] The guide device with multiple bending actuators enables rolling with comparatively high negative bending forces for special rolling tasks. Furthermore, common rolling applications with positive and low negative bending forces can be carried out, thus expanding the application spectrum of a rolling stand equipped with one or more guide devices with only minimal additional structural effort, i.e., without the need for special adjusting cylinders or similar systems. The bending system is also particularly low-friction. Preferably, exactly three bending actuators are provided per guide device, thus maximizing the application spectrum with only minimal structural modifications and while retaining conventional equipment.

[0016] Preferably, the bending actuators are each constructed as a piston-cylinder unit, each comprising a bending cylinder and a bending piston movably mounted therein. The bending cylinder is arranged or inserted in one of the two bending blocks, while the associated bending piston is attached to the other bending block via a bending piston rod. The actuation of the piston-cylinder units is preferably hydraulic. The use of piston-cylinder units installed in this way allows for a cassette design in which the bending actuators act vertically on the positively guided bending blocks, which in turn accommodate the chocks. The cassette design saves space and allows for a flexible and modular construction.

[0017] Preferably, three piston-cylinder units are arranged in the axial direction of the work rolls in such a way that the arrangement has two outer piston-cylinder units and one middle piston-cylinder unit, wherein the middle piston-cylinder unit is preferably installed inversely to the outer piston-cylinder units, whereby the force effect when applying bending forces can be increased and furthermore a particularly space-saving installation of the piston-cylinder units is possible.

[0018] The piston-cylinder units can be used either jointly or selectively. In particular, in the case of three piston-cylinder units, only the outer piston-cylinder units or only the inner piston-cylinder unit can be used. The piston ring side of the piston-cylinder units can also be used for power transmission. This means that, for example, in the case of three piston-cylinder units, the negative bending force can be achieved from the piston surface of the middle piston-cylinder unit and the piston ring surface of the outer piston-cylinder units, or alternatively only from the piston surface of the middle piston-cylinder unit. The reverse applies for positive bending.

[0019] Preferably, the two bending blocks are arranged vertically in their installed position, i.e., one above the other as seen in the direction of gravity, defining an upper bending block and a lower bending block. Thus, in the installed state, the bending blocks are correspondingly assigned to an upper work roll and a lower work roll. The bending cylinders of the outer piston-cylinder units are preferably arranged in the lower bending block, while the bending cylinder of the middle piston-cylinder unit is arranged in the upper bending block.

[0020] It should be noted that terms for spatial relationships such as “above”, “below”, “one above the other”, “above”, “below”, “horizontal”, “vertical”, etc. are clearly defined by the intended installation position of the guide device in the rolling stand.

[0021] Preferably, the bending blocks each have at least one guide bushing which is in sliding contact with the guide, whereby a reliable guidance of the bending blocks is realized in a structurally simple manner.

[0022] Preferably, the one or more guides are designed as round guides, i.e., rod-shaped or cylindrical bodies. The use of round guides ensures clear guide relationships without the risk of over-determination that occurs with any nested flat guides, ensures problem-free lubrication, and requires only minimal mechanical engineering effort to seal the guide device. The round guides can be manufactured cost-effectively with minimal design effort and are easy to install and maintain.

[0023] The above-mentioned object is further achieved by a rolling stand for rolling a strip-shaped rolled product, preferably for rolling a cold strip in a cold rolling mill, wherein the rolling stand has at least one guide device, preferably two guide devices, according to one of the embodiments set out above.

[0024] The features, technical effects, advantages and embodiments described with regard to the guide device apply analogously to the rolling stand.

[0025] Particularly preferably, the rolling stand comprises two chocks, corresponding to two work rolls mounted therein, which form a roll gap in which the rolled product, which can be transported in a conveying direction, can be formed, and two guide devices. In other words, the work rolls are held and guided on both sides by guide devices via the associated chocks.

[0026] Preferably, the rolling stand further comprises two backup rolls that can be brought into contact with the work rolls to support the work rolls. The rolling stand is thus preferably designed as a four-high rolling stand. However, the guide device(s) can also be used in the same way in a six-high rolling stand.

[0027] Preferably, the rolling stand comprises two roll stands, each defining a stand window. Holding pieces are attached to each of the roll stands on both sides of the stand window or are formed integrally with it. The holding pieces hold the one or more guides. The roll stands function as a framework or frame for fastening the guide device(s) via corresponding holding pieces.

[0028] The rolling stand is preferably configured for skin-pass rolling, with at least one of the work rolls having a textured rolling surface. A special type of use of the rolling stand is skin-passing with low rolling forces. While rolling forces currently range between 11,000 kN and 35,000 kN in reduction mode, rolling forces of only approximately 400 kN may be required in skin-pass mode. These can be achieved using the new bending blocks described above with three piston-cylinder units. The actual roll adjustment is then not used for this purpose. In skin-pass mode, the upper backup roll can be lifted off, and the rolled product can be formed using only the negative bending force as the rolling force.

[0029] Preferably, the chocks each comprise two guide surfaces, each of which is in substantially complete contact with a corresponding bending block. Thus, when installed, the chocks always rest on their entire guide surface.

[0030] Further advantages and features of the present invention will become apparent from the following description of preferred embodiments. The features described therein can be implemented alone or in combination with one or more of the above-mentioned features, provided the features do not contradict each other. The following description of the preferred embodiments is made with reference to the accompanying drawings.

[0031] Brief Description of the Figures Preferred further embodiments of the invention are explained in more detail by the following description of the figures. They show:

[0032] Figure 1 is a sectional side view of a rolling stand with bending blocks for bending the work rolls;

[0033] Figure 2 is a perspective view of a device for guiding chocks, comprising a combination of an upper and a lower bending block which are adjustable relative to each other; and

[0034] Figure 3 is a perspective, sectional view of the device according to the embodiment of Figure 2.

[0035] Detailed description of preferred embodiments

[0036] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements are provided with identical reference numerals in the figures, and a repetitive description of these elements is partially omitted to avoid redundancy.

[0037] Figure 1 shows a rolling stand 1 in the form of a stepped section. The rolling stand 1 serves for rolling a strip-shaped rolled product that can be transported in a conveying direction (horizontal direction of Figure 1), in particular for rolling a cold strip in a cold rolling mill. The rolled product is preferably a steel sheet; however, other metals and alloys are also possible, for example, aluminum, copper, and magnesium.

[0038] According to the exemplary embodiment, the rolling stand 1 is designed as a four-roll stand (four-high rolling stand), comprising two parallel, opposite work rolls 10 which form a roll gap, as well as two associated support rolls 11 which are in contact with the work rolls 10 in order to support the work rolls 10.

[0039] The work rolls 10 can have a flat rolling surface or be structured, i.e. their rolling surfaces can include a texture that is transferred to the rolled product by rolling. During skin pass rolling, the rolled product generally undergoes only slight reduction and elongation. Skin pass rolling can change the mechanical properties of the rolled product, for example, by improving the formability (deep-drawing and / or stretch-forming properties) of the product. In this way, any strip non-flatness, for example caused during an annealing process or rolling, can be eliminated. Skin pass rolling also allows the desired roughness and surface structure of the rolled product to be set by using appropriately structured work rolls 10.

[0040] The work rolls 10 are held and rotatably supported by chocks 12. The chocks 12 are, on the one hand, adapted to the work rolls 10 and, on the other hand, compatible for use with the bending blocks 20 described in detail below, so that the rolling stand 1 can be used modularly for work rolls 10 of different diameters, shapes, and properties. In this sense, the chocks 12 form an installation interface between the work rolls 10 and the bending blocks 20.

[0041] The rolling stand 1 has two roll housings 13 (only one roll housing 13 is shown in the section in Figure 1), which functions as a scaffold or frame for fastening the various components and defines a housing window. In the housing window, holding pieces 14 are fastened to both sides of the roll housing 13 or are connected to it as one piece. The holding pieces 14 each hold one or more guides 15, which are preferably designed as round guides, i.e. rod-shaped or cylindrical bodies. The bending blocks 20 for the chocks 12 are guided on the guides 15. The bending blocks 20 accordingly have guide bushings 21 which are in sliding contact with the guides 15. Each bending block 20 preferably has an anti-twist device on the back of the bending block 20, for example in the form of slide strips.

[0042] A distinction is made here between an upper chock 12, which is designed to support the upper work roll 10, and a lower chock 12, which is designed to support the lower work roll 10. Similarly, two lower and two upper bending blocks 20 are provided, which hold the corresponding chocks on both sides and guide them vertically along the guides 15.

[0043] Figures 2 and 3 show, in perspective, a device 2, also referred to herein as a "guide device," for guiding chocks 12. The guide device 2 comprises a combination of an upper bending block 20 and a lower bending block 20, which are adjustable relative to each other along the guide(s) 15. Figure 3 is a sectional, perspective view to show in detail the configuration of bending actuators 30 for adjusting or displacing the bending blocks 20.

[0044] From Figures 2 and 3 it can be seen that for each device 2, ie for each combination of an upper and lower bending block 20, several bending actuators 30 - in the present preferred embodiment exactly three - are installed.

[0045] The bending actuators 30 are designed to move the upper bending block 20 and the lower bending block 20 relative to one another along the guides 15, i.e., to apply bending forces between the two bending blocks 20 in the installed state. These can be positive bending forces, in which the bending blocks 20 are moved apart along the guides 15, as a result of which the work rolls 10, in cooperation with the backup rolls 11, tend to be bent convexly, as seen relative to the rolling surfaces of the rolled product. Alternatively, negative bending forces can be applied, in which the bending blocks 20 are moved towards one another. Rolling under negative bending forces can take place under a lifted upper backup roll 12 (shown on the left in Figure 1), i.e., exclusively with the negative bending force as the rolling force and thus usually with comparatively low rolling forces, for example in skin-pass operation.

[0046] The bending actuators 30 are preferably implemented as piston-cylinder units, each comprising a bending cylinder 31 in which a bending piston 32 is displaceably mounted. The bending cylinders 31 are each mounted or arranged in a corresponding bending block 20, while the associated bending piston 32 is attached to the corresponding bending block 20 via a bending piston rod 33. The piston-cylinder units are preferably actuated hydraulically. However, the bending actuators 30 can also be constructed differently, for example, electromotive, magnetic, or pneumatic.

[0047] In the cassette design presented herein, the bending actuators 30 act vertically on positively guided bending blocks 20, which in turn accommodate the chocks 12. In the installed state, the chocks 12 preferably rest on their entire guide surface 12a, i.e., they are each in contact with the corresponding bending block 20 with substantially the entire guide surface 12a, as shown in Figure 1. Any axial displacement of the work roll 10 occurs in the bending blocks 20, i.e., the bending system does not need to be displaced.

[0048] In the present embodiment, exactly three bending actuators 30 are installed per combination of an upper and lower bending block 20, which allows the negative bending forces to be significantly increased. The bending actuators 30 are preferably arranged on the guide surface side and are located on a line parallel to the axial direction of the work rolls 10.

[0049] In the case of three piston-cylinder units, the middle piston-cylinder unit is preferably installed inverted relative to the outer piston-cylinder units, which increases the force effect when applying bending forces and also allows for a particularly space-saving installation of the piston-cylinder units. Furthermore, it is possible to use only the outer piston-cylinder units or only the inner piston-cylinder unit.

[0050] The piston ring side of the piston-cylinder assemblies can also be used for power transmission. This means that the negative bending force can be achieved from the piston surface of the middle piston-cylinder assemblies and the piston ring surface of the outer piston-cylinder assemblies, or alternatively only from the piston surface of the middle piston-cylinder assemblies. The reverse applies to the positive bending.

[0051] Preferably, the bending cylinders 31 of the outer piston-cylinder units are located in the lower bending block 20, while the bending cylinder 31 of the middle piston-cylinder unit is installed in the upper bending block 20.

[0052] The roll stand 1 described herein enables rolling with comparatively high negative bending forces for special rolling tasks. Furthermore, common rolling applications with positive and negative bending forces can be carried out, thereby increasing the application flexibility of the roll stand with only minimal additional structural effort, i.e., without special adjustment cylinders or similar systems. The bending system is also particularly low-friction.

[0053] A special type of use of the rolling stand 1 is for skin-passing with low rolling forces, for example, 400 kN to 500 kN. During skin-passing operation with these low rolling forces, the upper support roll 11 is lifted, and the rolled product is skin-passed using only the negative bending force as the rolling force. For this purpose, a position measuring system (not shown in the figures) is preferably installed on the bending blocks 20, which allows for skin-passing force control without separate adjusting cylinders.

[0054] Where applicable, all individual features presented in the embodiments may be combined and / or exchanged without departing from the scope of the invention.

[0055] List of reference symbols

[0056] 1 rolling stand

[0057] 2 Device for guiding chocks 10 Working roll

[0058] 11 Support roller

[0059] 12 chock

[0060] 12a Guide surface

[0061] 13 Roller stand 14 Holding piece

[0062] 15 Guide

[0063] 20 bending blocks

[0064] 21 Guide bushing

[0065] 30 bending actuator 31 bending cylinder

[0066] 32 bending pistons

[0067] 33 Bending piston rod

Claims

Patent claims 1. Device (2) for guiding mounting blocks (12) which are configured for supporting work rolls (10) forming a roll gap of a rolling stand (1), wherein the device (2) comprises: two bending blocks (20) for receiving one mounting block (12) each; at least one guide (15) on which the bending blocks (20) are guided so that the bending blocks (20) are displaceable along the guide (15) relative to each other; and several bending actuators (30) which are configured to displace the bending blocks (20) along the guide (15) relative to each other.

2. Device (2) according to claim 1 , characterized in that exactly three bending actuators (30) are provided.

3. Device (2) according to claim 1 or 2, characterized in that the bending actuators (30) are each constructed as a piston-cylinder assembly, comprising a bending cylinder (31) and a bending piston (32) slidably mounted therein, wherein the bending cylinder (31) is provided in one of the two bending blocks (20), while the associated bending piston (32) is attached to the other bending block (20) via a bending piston rod (33).

4. Device (2) according to claims 2 and 3, characterized in that the three piston-cylinder assemblies (30) are arranged in the axial direction of the work rollers (10) such that the arrangement comprises two outer piston-cylinder assemblies (30) and one central piston-cylinder assembly (30) has the middle piston-cylinder assembly (30) installed in reverse to the outer piston-cylinder assemblies (30).

5. Device (2) according to claim 4, characterized in that the two bending blocks (20) are arranged vertically one above the other in their installation position, so that an upper bending block (20) and a lower bending block (20) are defined, wherein the bending cylinders (31) of the outer piston-cylinder assemblies (30) are arranged in the lower bending block (20), while the bending cylinder (31 ) of the middle piston-cylinder assembly (30) is arranged in the upper bending block (20).

6. Device (2) according to one of the preceding claims, characterized in that the bending blocks (20) each have at least one guide bushing (21), preferably two guide bushings (21), which are in sliding contact with the corresponding guides (15).

7. Device (2) according to one of the preceding claims, characterized in that at least two guides (15) are provided.

8. Device (2) according to one of the preceding claims, characterized in that the one or more guides (15) are designed as round guides.

9. Rolling stand (1 ) for rolling a strip-shaped rolled product, preferably for rolling a cold strip in a cold rolling plant, wherein the rolling stand (1 ) has at least one device (2) according to one of the preceding claims.

10. Rolling stand (1 ) according to claim 9, characterized in that the rolling stand has two installation pieces (12), two work rolls (10) mounted therein, which form a roll gap in which the material is conveyed in a conveying direction a transportable rolled product is formable, and has two devices (2) according to any one of claims 1 to 10, wherein the rolling stand (1) preferably further comprises two backup rolls (11) which can be brought into contact with the work rolls (10). Rolling stand (1) according to claim 9 or 10, characterized in that the rolling stand has two roll stands (13), each defining a stand window, wherein retaining elements (14) are attached to the roll stand (13) on both sides in the stand window or are formed integrally with it, and the retaining elements (14) hold one or more guides (15). Rolling stand (1) according to any one of claims 9 to 11, characterized in that the rolling stand is configured for skin rolling, wherein preferably at least one of the work rolls (10) has a structured rolling surface.Rolling stand (1) according to one of claims 9 to 12, characterized in that the installation pieces (12) each have two guide surfaces (12a) which are each substantially completely in contact with a corresponding bending block (20).

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