EP0049798B1 - Rolling mill - Google Patents

Abstract

A rolling stand has a conventional housing defining a pair of parallel and spaced axes defining a plane. Respective rolls have roll ends journaled in the housing at the axes and roll bodies axially symmetrical about the respective axes and having centered on the respective axes complementary roll-body surfaces of noncylindrical shape and each formed by rotation of a continuously curved generatrix about the respective axis. One of these contoured rolls is displaceable axially relative to the other roll from an end position to another position, and the roll-body surfaces form at the plane in the other position a uniform nip and in the end position a nonuniform nip. This system is set up to be able to displace one of the rolls axially relative to the other of the rolls between the end position and the other position. These contoured rolls may themselves define the nip, or may engage and deform other rolls that define it.

Description

The invention relates to a rolling mill with work rolls, which are optionally supported on back-up rolls or back-up rolls and intermediate rolls, the work rolls and / or back-up rolls and / or intermediate rolls being axially displaceable relative to each other and each roll of at least one of these pairs of rolls running towards a bale end , curved contour is provided, which extends on the two rollers on opposite sides in each case over part of the width of the rolling stock.

Rolling mills of this type are already part of the prior art through US-A-2776586 and DE-A1-2919105. They are designed in such a way that, in rolling operation, the shape of the roll gap and thus the profile of the rolled strip can be influenced by the axial displacement of the rolls having the curved contour and a bending stress acting on them at the same time.

A disadvantage of such a known rolling mill is that, in addition to the device for the axial displacement, additional rolls bending devices must be assigned to the rolls having a curved contour over part of their bale length. On the one hand, roll bending devices are required in order to be able to bend the ends of the rolls provided with the curved contour away from the roll gap or from the rolling strip (positive bending), and on the other hand, roll bending devices are also required which allow the ends of the rolls provided with the curved contour to be bent guaranteed against the roll gap or the rolled strip (negative bending). In one case this reduces the rolling pressure on the strip edges, while in the other case an increase in the rolling pressure in the area of the strip edges can be achieved.

A change in the roll gap contour is only possible to a limited extent in the known rolling mill without roll bending devices and only in the sense of a concave strip shape.

It is obvious that a rolling mill designed in this way not only requires a high level of investment in the plant, but also that the correct setting of the roll gap or rolled strip contour is difficult because the axial adjustment of the rolls having the curved contour and their bending deformation are coordinated with one another have to.

In addition, it has proven disadvantageous in the case of the known type of scaffolding that even with a positive work roll bend, the strip edge pressure is still relatively high.

The present invention aims to overcome these drawbacks. It is therefore her aim to create a rolling mill of the generic type in which the shape of the roll gap and thus the rolled strip cross section can be influenced practically exclusively by the axial displacement of the rolls provided with the curved contour and, if necessary, the strip edge pressure can be reduced without any effort.

This object can be achieved in a simple manner in that the curved contour extends over the entire bale length of both rollers and has a shape in which the two bale contours complement each other exclusively in a certain relative axial position of these rollers.

It is particularly advantageous that the measures according to the present invention can also be implemented in duo rolling mills, that is to say they are not restricted to rolling mills with backup rolls or backup and intermediate rolls, as is the case according to D E-A 1-2919 105.

Furthermore, the advantage has been shown that the shape of the roll gap and thus the cross-sectional shape of the rolled strip can be influenced even by small displacement paths of the rollers having the curved contour and that no direct adjustment of the position of the displaceable rollers to the width of the rolling stock has to take place, as is the case, for example, with is the case with another known rolling mill according to DE-A-2 260 256.

The effective crowning of the roller set to the rolling force and the width of the rolling stock can be set quickly and specifically due to the small displacement paths, whereby rectangular, concave and convex rolling stock cross-sections can be achieved depending on the displacement direction and degree. A particularly simple construction of a rolling mill according to the invention can be achieved by the features of claim 2. The design of the rollers specified in claim 3 has proven particularly useful.

On the other hand, however, it is also possible according to the invention to equip a rolling mill with rolls which have the features specified in claims 4, 5 and 6.

A particularly simple construction of a rolling mill according to the invention is achieved by using the identification features specified in claim 7. Irrespective of or simultaneously with this configuration, the features of claim 8 can also be used in practice.

The shape of the roll gap and thus the roll strip cross section can also be influenced by the measures that are set out in claims 9 and 10.

It is advantageous in a rolling mill according to the invention that the shape of the rollers having the curved contour can be freely selected, so that the effective crowning can be adapted to the respective requirements. The axial displacement of these rollers can, if necessary, be carried out in the same or in opposite directions. Here the axial displacement paths of both rollers can be the same or different.

Finally, it is also no problem to use the inventive design of a rolling mill in cooperation with conventional methods of influencing the strip profile, for example to work with strip thickness and inclined position adjustment and also with thermal measures.

Although the invention shows a way to change the roll gap contour within wide limits without using a roll bend, it is nevertheless not excluded to implement the invention on a roll mill with roll bending devices.

• Fig. 1 in Walzrichtung gesehen ein Duo-Walzwerk nach der Erfindung,
• Fig. 2 eine der Fig. 1 entsprechende Darstellung eines Quarto-Walzwerks,
• Fig. 3 ebenfalls in Walzrichtung gesehen ein erfindungsgemässes Sexto-Walzwerk,
• Fig. 4 eine bevorzugte Ausführungsform für die Walzenkontur bei einem erfindungsgemässen Walzwerk,
• Fig. 5 eine mögliche Einstellung des Walzenpaares nach Fig. 4 für einen sich nach den Bandkanten hin verengenden Walzspalt,
• Fig. 6 eine Einstellung des Walzenpaares nach
• Fig. 4 für einen sich nach den Bandkanten hin erweiternden Walzspalt und
• Fig. 7 eine andere mögliche Konturgestaltung für ein Walzenpaar eines erfindungsgemässen Walzwerks.

Further features and advantages of rolling mills according to the invention are explained in detail below using exemplary embodiments shown in the drawing. Show here

• 1 seen in the rolling direction, a duo rolling mill according to the invention,
• 2 a representation corresponding to FIG. 1 of a four-high rolling mill,
• 3 also seen in the rolling direction an inventive six-high rolling mill,
• 4 shows a preferred embodiment for the roll contour in a rolling mill according to the invention,
• 5 shows a possible adjustment of the pair of rollers according to FIG. 4 for a roll gap narrowing towards the strip edges,
• Fig. 6 shows an adjustment of the pair of rollers
• Fig. 4 for a widening after the strip edges and
• 7 shows another possible contour design for a pair of rolls of a rolling mill according to the invention.

1 shows a duo rolling mill 1, in the roll stands 2 of which a pair of work rolls 3, 4 are each guided by means of chocks 5, 6. Using conventional adjusting devices 7, the pair of work rolls 3, 4 can be set against the rolling strip 9 running through the roll gap 8.

Both work rolls of the pair of work rolls 3, 4 are mounted axially displaceably in the chocks 5, 6 via their pins 10, 11, the devices for axial adjustment 'each engaging a roll neck 10 or 11.

From Fig. 1 it can be seen that the roll bales 12 of both work rolls 3 and 4 of the work roll pair 3, 4 have a curved contour over their entire length, for example in such a way that this contour in the case of the upper work roll 3 over the the left half of the roll barrel 12 is convex and concave over the right half thereof, while in the lower work roll 4 it is concave over the left half of the roll barrel 12 and convex over the right half of the same. Both sections of the rolled bales 12 are determined by the same curvature curves.

From Fig. 1 it is readily apparent that both work rolls 3 and 4 of the work roll pair 3, 4 have an identical - here bottle-like - shape of the roll barrel 12 and are provided in the roll stand of the duo rolling mill 1 relative to each other in an installed position turned through 180 °.

In Fig. 1 the average axial setting of both work rolls 3 and 4 of the work roll pair 3, 4 is shown, and it can be seen that with this axial setting the roll gap 8 at least over the width of the roll belt 9, but preferably over the entire bale length, a constant Cross-sectional height, although it runs slightly S-shaped.

2 shows a four-high rolling mill 21 according to the invention, in which the two support rolls 23 and 24 of a pair of support rolls 23, 24 are guided in the roll stands 22 via chocks 25, 26.

Between the support roller pair 23, 24, as is usual in a four-high rolling mill, a work roller pair 23 ', 24' is provided, which delimits the roll gap 28 for the rolled strip 29. The adjustment of the work rolls 23 'and 24' to determine the height of the roll gap 28 is carried out by adjusting devices 27 which act on the chocks 25 and 26 of the support rolls 23 and 24.

In the four-high rolling mill 21 according to FIG. 2, both support rollers 23 and 24 of the support roller pair 23, 24 are held axially displaceably in the chocks 25 and 26 via their roller journals 30 and 31, respectively, with the devices not shown on each of the roller journals 30 and 31 attack for axial adjustment.

From Fig. 2 it can be seen that in the four-high rolling mill 21, the roll bales 32 of the two support rolls 23 and 24 have the curved contour over their entire length, in the same way as the work rolls 3 and 4 in the work roll pair 3, 4 of the duo rolling mill 1 1. The left half of the roll barrel 32 of the upper support roller 23 thus has the convexly curved contour, while the right half of the same is provided with the concave curved contour. Conversely, the left half of the roll barrel 32 of the lower support roller 24 has the concavely curved contour and the right half thereof has the convexly curved contour. Here, too, both bale sections are determined by the same curvature curves.

It can also be seen from FIG. 2 that the roll bales of the work rolls 23 'and 24' are cylindrical in themselves, but are given a slightly S-shaped bend due to the interaction with the support rolls, so that the roll gap 28, which the roll band 29 passes through, receives a correspondingly slightly S-shaped cross-sectional shape.

3 shows a six-high rolling mill 41 in which, in the roll stands 42, in addition to the two support rolls 43 and 44 of the support roll pairs 43, 44 and the two work rolls 43 'and 44' of the work roll pair 43 ', 44', two intermediate rolls 43 " and 44 "of an intermediate roll Paares 43 ", 44" are arranged. The support rollers 43 and 44 of the support roller pair 43, 44 are guided by chocks 45 and 46 in the roller stands 42, while the intermediate rollers 43 "and 44" of the intermediate roller pair 43 ", 44" in turn in chocks 45 "and 46", respectively be guided in the chocks 45 and 46 for the support rollers 43 and 44.

In the six-high rolling mill 41, only the intermediate rolls 43 "and 44" are arranged axially displaceably, while the support rolls 43 and 44 of the support roll pair 43, 44 and the work rolls 43 'and 44' of the work roll pair 43 ', 44' are immovably mounted. For this purpose, corresponding adjusting devices (not shown) act on a roll neck of the intermediate rolls 43 ″ and 44 ″.

Both the support rolls 43 and 44 of the support roll pair 43, 44 and the work rolls 43 ', 44' of the work roll pair 43 ', 44' have cylindrical rolls. On the other hand, the intermediate rolls 43 "and 44" of the pair of intermediate rolls 43 ", 44" are equipped with roll bales which have a curved contour over the entire length of the bale. The bale contour of the intermediate rolls 43 "and 44" can basically correspond to that of the two work rolls 3 and 4 of the duo rolling mill 1 according to FIG. 1 or that of the backup rolls 23 and 24 of the four-high rolling mill 21 according to FIG. 2. However, it can be limited by curvature curves with larger radii, because the intermediate rolls 43 "and 44" are each supported on the cylindrical roll balls of the support rolls 43 and 44. As a result, the intermediate rolls 43 ″ and 44 ″ are subjected to a deformation, which results in a greater curvature of the bale contour in the direction of the work rolls 43 ′ and 44 ′. With the help of the intermediate rolls 43 "and 44", a slightly S-shaped curvature is then forced onto the cylindrical roll bales of the work rolls 43 'and 44', which in turn determines the shape of the roll gap 48 for the rolled strip 49.

1, the shape of the roll gap 8 is determined directly by axial displacement of one or both work rolls 3 and 4. In the four-high rolling mill 21 according to FIG. 2, however, a corresponding axial displacement of one or both support rolls 23 and 24 takes place to change the shape of the roll gap 28. In the six-high rolling mill 41 according to FIG. 3, the shape of the roll gap 48 is finally influenced solely by the axial displacement of one or both intermediate rolls 43 "and 44".

4-6, the method of operation of a rolling mill according to the invention will now be explained, regardless of whether it is a duo rolling mill 1 according to FIG. 1, a four-high rolling mill 21 according to FIG. 2 or a sexto rolling mill 41 according to FIG. 3. For the mode of operation it is only a matter of the pair of rollers which has a curved contour over the entire length of the bale, in such a way that the two bale contours complement each other exclusively in a specific, relative axial position of the rollers.

For the sake of simplicity, it should be assumed in connection with FIGS. 4 to 6 that the pair of rolls having the curved bale contour are the work rolls 3 and 4 of the duo rolling mill 1 according to FIG. 1.

FIG. 4 shows the mean axial sliding position for both rollers 3 and 4 of the pair of rollers 3, 4, which corresponds to that of FIG. 1. Here, the roll gap 8 between the two rolls 3 and 4 has a constant height over the entire bale length, so that the roll strip 9 is rolled out over its entire width with a uniform thickness, although the roll gap 8 has a slightly S-shaped curvature.

4, then the height of the roll gap 8 between the two curved contoured bales 12 of the work rolls 3 and 4 results as

If one or both rollers 3 and 4 are moved in the axial direction by the amounts _VI and v ₂ (FIG. 6), then the shape of the roll gap 8 changes accordingly

It is therefore possible to continuously influence the shape of the roll gap 8 in such a way that the roll pressure on the longitudinal edges of the roll strip 9 is increased, for example, in the setting according to FIG. 5. On the other hand, the setting of the two rolls 3 and 4 according to FIG. 6 results in a reduction in the rolling pressure on the longitudinal edges of the rolled strip 9.

The particular advantage of the design of the roller set 3, 4 shown in FIGS. 4 to 6 is that both rollers 3 and 4 are designed completely identically and their shape can be freely selected so that the effective crowning optimally meets the respective requirements can be adjusted.

The axial displacement of the two rollers 3 and 4 of the pair of rollers 3, 4 can take place in the same direction or in opposite directions, as required, and the axial displacement paths can also be the same or different.

It is easiest to determine the contour, which is curved over the entire length of the bale, on the rollers 3 and 4 mechanically, in particular by grinding. However, it is also possible to support the curved contour by thermally influencing the roll bale, namely by partially heating or cooling the same. The shape of the roll gap 8 can, of course, also be additionally influenced by the fact that the axes of the cooperating pair of rolls 3, 4 are installed in the roll plane in a mutually inclined manner. An additional influence on the shape of the roll gap 8 leaves but can also be achieved if the axes of the cooperating pair of rollers are set inclined to one another transversely to the roller plane. It is essential, however, that the shape of the roll gap 8 can be determined mainly by axially displacing the two rolls of the roll pair, the roll balls of which have the curved contour over their entire length.

7 is intended to illustrate that the invention is not fundamentally limited to the bottle-like curved contour of the rolled bales shown in FIGS. 4 to 6, in which the course of curvature is convex over one half of the bale and concave over the other half of the bale, but also it is possible to use a pair of rollers 3, 4 in which the bales of both rollers 3 and 4 have different shapes, but also here in such a way that the two bale contours complement each other exclusively in a certain relative axial position of the rollers 3 and 4.

4 to 6, it is possible, for example, to contour the roll bale 12 'of the one roll 3 in multiple alternation convex-concave-convex and the roll bale 12 "of the other roll 4 in a correspondingly inverted concave-convex-concave manner, such as 7. It is also conceivable to contour the roller bale 12 of one roller 3 convexly over its entire length and the roller bale 12 of the other roller 4 concavely curved over its entire length.

The method of operation according to the invention for determining the shape of the roll gap has the considerable advantage that it can be used in two- and multi-roll stands as well as in cold and hot rolling. Furthermore, it can be used just as well for one-way scaffolding and reversing scaffolding as for tandem streets and reversing streets.

Claims (10)

1. Rolling mill with working rolls (3, 4; 23', 24'; 43', 44'), which in a given case bear against support rolls (23, 24) or support rolls (43, 44) and intermediate rolls (43", 44"), wherein the working rolls and/or support rolls and/or intermediate rolls are axially displaceable one relative to the other and each roll of at least one of these roll pairs is provided with a curved outline which extends in direction towards one barrel end and over a part of the width of the rolled stock towards each of opposite sides at both rolls, characterised thereby, that the curved outline extends over the entire barrel length of both rolls (3, 4, or 23, 24 or 43", 44") and has a structure, for which both the barrel outlines complementarily augment each other exclusively in a certain relative axial setting (for example Fig. 4) of these rolls (3, 4 or 23,24 or 43", 44").

2. Rolling mill according to claim 1, characterised thereby, that both rolls (3 and 4; 23 and 24; 43" and 44") of the roll pair (3, 4; 23, 24; 43", 44") have identical shapes and are arranged in their installed position turned through 180° each relative to the other (Figs. 1, and 3).

3. Rolling mill according to claim 1 or 2, characterised thereby, that the roll barrels (12, 23', 24', 43', 44' or 32, 43, 44 or 43", 44") display a convexly curved outline over the one half of the barrel length and a concavely curved outline over the other half of the barrel length and both barrel portions are in that case determined by equal curvatures (Figs. 4to 6).

4. Rolling mill according to claim 1, characterised thereby, that both rolls of the roll pair have different shape (12', 12"; Fig. 7).

5. Rolling mill according to claim 1 or 4, characterised thereby, that the roll barrel (12') of the one roll (3) has a convexly curved outline over its entire length and the roll barrel (12") of the other roll (4) has a concavely curved outline over its entire length.

6. Rolling mill according to claim 1 or 4, characterised thereby, that the roll barrel (12') of the one roll (3) has a convexly-concavely-convexly curved outline in multiple change and the roll barrel (12") of the other roll (4) has a correspondingly converse concavely-convexly-concavely curved outline (Fig. 7).

7. Rolling mill according to at least one of the claims 1 to 6, characterised thereby, that the outline of the roll barrels (12; 12', 12"; 32) is determined mechanically, for example by profile grinding.

8. Rolling mill according to at least one of the claims 1 to 7, characterised thereby, that the outline of the roll barrels (12; 12', 12"; 32) is influenced thermally, for example through heating and/or cooling.

9. Rolling mill according to at least one of the claims 1 to 8, characterised thereby, that the axes of the roll pair (3, 4; 23', 24' ; 43', 44') determining the roll gap (8; 28; 48) are pivotable one relative to the other in the roll plane.

10. Rolling mill according to at least one of the claims 1 to 9, characterised thereby, that the axes of the rolls of the roll pair (3, 4; 23, 24; 43", 44") displaying the curved barrel outline are settable in inclination one relative to the other transversely to the roll plane.

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