阅读说明：本技术 用轧制机架的灵活的配置进行热轧 (Hot rolling with flexible configuration of rolling stands ) 是由 S·布拉金 M·哈克尔 K·克里姆佩尔斯塔特 B·林泽尔 E·奥皮茨 A·塞林格 于 2020-04-28 设计创作，主要内容包括：热轧机组具有至少一个第一轧制机架和最后的轧制机架(1a、1d)。在所述热轧机组中必须相继地对第一金属带和第二金属带(2、5)进行轧制。所述金属带(2、5)的区段分别首先穿过所述热轧机组的第一轧制机架并且而后才穿过所述热轧机组的最后的轧制机架(1a、1d)。所述最后的轧制机架(1d)在所述第一金属带(2)的轧制与所述第二金属带(5)的轧制之间从四辊式机架改装为六辊式机架或者相反地改装,从而使得所述最后的轧制机架(1d)在轧制所述第一金属带(2)期间被配置为具有工作辊(3)和支承辊(4)的四辊式机架并且在轧制所述第二金属带(5)期间被配置为具有工作辊(6)、中间辊(7)和支承辊(4)的六辊式机架。(The hot rolling train has at least one first and one last rolling stand (1 a, 1 d). The first and second metal strips (2, 5) must be rolled successively in the hot-rolling mill train. The sections of the metal strip (2, 5) are each passed first through a first rolling stand of the hot-rolling mill train and only then through a last rolling stand (1 a, 1 d) of the hot-rolling mill train. The last rolling stand (1 d) is converted between the rolling of the first metal strip (2) and the rolling of the second metal strip (5) from a four-roll stand to a six-roll stand or vice versa, such that the last rolling stand (1 d) is configured during the rolling of the first metal strip (2) as a four-roll stand with working rolls (3) and back-up rolls (4) and during the rolling of the second metal strip (5) as a six-roll stand with working rolls (6), intermediate rolls (7) and back-up rolls (4).)

1. Method for operating a hot-rolling train having at least one first and one last rolling stand (1 a, 1 d),

-wherein a first and a second metal strip (2, 5) are rolled one after the other in the hot rolling mill train,

-wherein the sections of the metal strip (2, 5) are each passed first through a first rolling stand of the hot-rolling mill train and only then through a last rolling stand (1 a, 1 d) of the hot-rolling mill train,

it is characterized in that the preparation method is characterized in that,

the last rolling stand (1 d) is converted between the rolling of the first metal strip (2) and the rolling of the second metal strip (5) from a four-roll stand to a six-roll stand or vice versa, such that the last rolling stand (1 d) is configured during the rolling of the first metal strip (2) as a four-roll stand with working rolls (3) and back-up rolls (4) and during the rolling of the second metal strip (5) as a six-roll stand with working rolls (6), intermediate rolls (7) and back-up rolls (4).

2. The method of operation according to claim 1,

it is characterized in that the preparation method is characterized in that,

the sum of the diameters (D ', D') of the working rolls (6) and intermediate rolls (7) of the last rolling stand (1D) configured as a six-high stand corresponds at least approximately to the diameter (D) of the working rolls (3) of the last rolling stand (1D) configured as a four-high stand.

3. The operating method according to claim 1 or 2,

it is characterized in that the preparation method is characterized in that,

when the last rolling stand (1 d) is converted from a four-high stand to a six-high stand or vice versa, the working rolls (6) and the intermediate rolls (7) of the last rolling stand (1 d) configured as a six-high stand are inserted or removed as a unit.

4. The operating method according to claim 1, 2 or 3,

it is characterized in that the preparation method is characterized in that,

the first rolling stand (1 a) is configured as a four-roll stand not only during rolling of the first metal strip (2) but also during rolling of the second metal strip (5).

5. The operating method according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

casting the metal strip (2, 5) in a continuous casting plant (9) arranged upstream of the first rolling stand (1 a) before rolling in the hot rolling train, and feeding the metal strip (2, 5) out of the casting heat to the first rolling stand (1 a).

6. The method of operation according to claim 5,

it is characterized in that the preparation method is characterized in that,

the hot rolling train is operated in a continuous operation.

7. The operating method according to one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

-the hot rolling train has a number of further rolling stands (1 b, 1 c) between the first and the last rolling stand (1 a, 1 d),

-the further rolling stands (1 b, 1 c) are configured as four-high stands during rolling of the first metal strip (2),

-the further rolling stands (1 b, 1 c) are configured either as four-roll stands or as six-roll stands during rolling of the second metal strip (5), and

-only one single transition from rolling in a four-high stand to rolling in a six-high stand is made during rolling of the second metal strip (5) seen in the sequence of rolling stands (1 a to 1 d).

8. A hot-rolling train having at least one first and one last rolling stand (1 a, 1 d) such that a section of a metal strip (2, 5) rolled in the hot-rolling train passes through the first and only the last rolling stand (1 a, 1 d) in each case, wherein the first rolling stand (1 a) is configured as a four-high stand with working rolls (3) and back-up rolls (4),

it is characterized in that the preparation method is characterized in that,

the last rolling stand (1 d) is configured as a six-roll stand with work rolls (6), intermediate rolls (7) and back-up rolls (4).

9. The hot rolling mill train of claim 8,

it is characterized in that the preparation method is characterized in that,

the working rolls (6) and the intermediate rolls (7) of the last rolling stand (1 d) configured as a six-roll stand are arranged in a roll cassette (8) that can be inserted and removed as a unit.

10. The hot rolling mill train according to claim 8 or 9,

it is characterized in that the preparation method is characterized in that,

a continuous casting installation (9) is arranged upstream of the first rolling stand (1 a), in which continuous casting installation the metal strip (2, 5) is cast before rolling in the hot-rolling mill train, so that the metal strip (2, 5) can be fed to the first rolling stand (1 a) out of the casting heat.

11. The hot rolling mill train of claim 10,

it is characterized in that the preparation method is characterized in that,

the hot-rolling train can be operated in a continuous mode of operation.

12. The hot rolling mill train of any one of claims 8 to 11,

it is characterized in that the preparation method is characterized in that,

-the hot rolling train has a number of further rolling stands (1 b, 1 c) between the first and last rolling stands (1 a, 1 d),

-the further rolling stands (1 b, 1 c) are configured as four-high stands or as six-high stands, and

-performing only one change from a four-high stand to a six-high stand seen in the sequence of rolling stands (1 a to 1 d).

Technical Field

The invention relates to a method for operating a hot-rolling mill train having at least one first and one last rolling stand,

-wherein a first metal strip and a second metal strip are rolled one after the other in the hot rolling mill train,

-wherein the sections of the metal strip are each passed first through a first rolling stand of the hot rolling mill train and only then through a last rolling stand of the hot rolling mill train,

-wherein the last rolling stand is retrofitted between the rolling of the first metal strip and the rolling of the second metal strip.

The invention further relates to a hot rolling train having at least one first and one last rolling stand, such that a section of the metal strip rolled in the hot rolling train passes through the first rolling stand and only then through the last rolling stand, wherein the first rolling stand is configured as a four-high stand with working and back-up rolls.

Background

The above-mentioned subject matter is generally known. In particular, finishing mill groups for rolling metal strips (in particular made of steel) are usually operated in this way and method, and finishing mill groups for rolling metal strips (in particular made of steel) are usually constructed in this way. The last rolling stand (and usually also the other rolling stands of the finishing train) is modified in order to replace worn working rolls and, if necessary, also worn back-up rolls. Here, the arrangement of the rolling stands is not changed. Only 1: 1, replacement.

The rolling stands of a hot rolling mill train are usually equipped with so-called four-high stands. A four-high stand is a rolling stand which, in addition to the working rolls, also has back-up rolls at which the working rolls are supported. In the English language region, such a rolling stand is often also referred to as 4-high.

In hot rolling, in particular also for materials with high strength, there is a tendency toward smaller and smaller final thicknesses. For example, in modern casting roll installations, strip thicknesses of significantly less than 1 mm, in part even only 0.6 mm, can already be produced for soft quality. Such a final thickness cannot be achieved for harder materials. Since for this purpose in practice work rolls with a very small diameter are required. However, due to the diameter of the work rolls used today, the final thickness is limited. In particular, as the diameter of the work rolls decreases, the torque that can be transmitted also decreases. Furthermore, it must be possible to apply the cooling medium to the work rolls within a sufficient range in order to be able to operate the hot-rolling train in a continuous operation.

In general, the problem is solved by: work rolls having as small a diameter as possible are used. The smaller the diameter of the work roll, the less torque that can be used to drive the work roll without risking breakage of the roll neck. For harder materials, the torque is higher. The problem that arises is that, on the one hand, the diameter of the working rolls should be as small as possible in order to be able to achieve the smallest possible final thickness, but, on the other hand, it should not be too small, since otherwise the necessary torque cannot be transmitted.

The problem is solved in cold rolling by a rolling stand with a plurality of rolls, for example a so-called 12-roll rolling stand or a 20-roll rolling stand. Such rolling stands cannot be used in hot rolling because they occupy an excessive number of positions and do not allow sufficient cooling of the rolls, in particular the work rolls.

It is known from US 2006/0010952 a1 to design the individual roll stands in a cold-rolling mill train in a retrofittable manner, so that they can be configured as four-roll stands or as six-roll stands, as required. A six-high rolling stand is a rolling stand which, in addition to the working rolls and the back-up rolls, also has intermediate rolls, wherein the working rolls are supported at the intermediate rolls and the intermediate rolls are supported at the back-up rolls. In the English language region, such a rolling stand is often also referred to as 6-high.

It is also known from US 2006/0196243 a1 to design a rolling stand so as to be retrofittable, so that it can be configured as a four-roll stand or as a six-roll stand, as required. The rolling stand of US 2006/0196243 a1 appears to be a cold rolling stand as well.

It is known from JP 63013603 a to design a rolling stand in a retrofittable manner, so that it can be configured as a four-roll stand or as a six-roll stand, as required.

Disclosure of Invention

The object of the invention is to provide a possibility to produce a material with a higher strength and a smaller final thickness also in a hot-rolling mill train.

This object is achieved by an operating method for a hot-rolling mill train having the features of claim 1. Advantageous embodiments of the operating method are the subject matter of the dependent claims 2 to 7.

According to the invention, an operating method of the type mentioned at the outset is designed in such a way that: in the context of retrofitting a last rolling stand, the last rolling stand is retrofitted from a four-roll stand to a six-roll stand between the rolling of a first metal strip and the rolling of a second metal strip or vice versa, so that the last rolling stand is configured during the rolling of the first metal strip as a four-roll stand with working rolls and back-up rolls and during the rolling of the second metal strip as a six-roll stand with working rolls, intermediate rolls and back-up rolls.

By means of such a retrofitting, it is possible to roll a metal strip made of a softer material or to roll a metal strip to a greater final thickness, while the last rolling stand is also configured as a four-high stand, as in the prior art. However, it is of course possible to adapt the last rolling stand to a six-roll stand according to the invention when a metal strip made of a harder material is to be rolled to a small final thickness.

The rolling plan (that is to say the sequence of the metal strips to be rolled one after the other) can be set up in such a way that the retrofitting of the last rolling stand takes place at a point in time at which the working rolls currently in the last rolling stand would have to be dismantled due to wear of the working rolls. This approach results in an optimized production rate. In principle, however, the retrofitting can also be carried out independently of the state of wear of the working rolls and therefore independently of the replacement of the working rolls (in the case of a four-roll stand) or of the working rolls and optionally also of the support rolls (in the case of a six-roll stand) by wear.

Preferably, the sum of the diameters of the working rolls and of the intermediate rolls of the last rolling stand configured as a six-high stand corresponds at least approximately, typically to an accuracy of 20%, more preferably to an accuracy of 10%, to the diameter of the working rolls of the last rolling stand configured as a four-high stand. The adjustment range of the last rolling stand can thus be used optimally not only in the configuration as a four-high stand but also in the configuration as a six-high stand.

Preferably, the working rolls and the intermediate rolls of the last rolling stand configured as a six-roll stand are installed or removed as a unit when the last rolling stand is converted from a four-roll stand to a six-roll stand or vice versa. This makes it possible to carry out the retrofitting particularly quickly.

The first rolling stand is preferably configured as a four-high stand both during rolling of the first metal strip and during rolling of the second metal strip. The structure of the first rolling stand is thereby kept simple.

Preferably, the metal strip is cast before rolling in the hot rolling train in a continuous casting plant arranged upstream of the first rolling stand and is conveyed out of the casting heat to the first rolling stand. The operation of the hot-rolling train can thereby be optimized in terms of energy.

Preferably, the hot-rolling train is operated in continuous operation. Thereby, the productivity of the hot rolling mill train can be maximized.

In a minimum design, the hot-rolling mill train has only the first and the last rolling stand, i.e. a total of two rolling stands. However, the hot rolling mill train usually has a number of further rolling stands, for example two further rolling stands, three further rolling stands or four further rolling stands, between the first and the last rolling stand, so that there are a total of four, five or six rolling stands including the first and the last rolling stand. During rolling of the first metal strip, the further rolling stand is configured as a four-high stand. During rolling of the second metal strip, the further rolling stand can be configured either as a four-roll stand or as a six-roll stand. However, it is preferred that only one change from rolling in the four-high stand to rolling in the six-high stand is made in the sequence of the rolling stands, i.e. from the first rolling stand to the second rolling stand, further to the third rolling stand, etc. up to the last rolling stand. When that is to say that a particular one of the further rolling stands is configured as a four-high stand, then all further rolling stands arranged between this rolling stand and the first rolling stand are also configured as four-high stands. When, conversely, a particular one of the further rolling stands is configured as a six-high stand, then all further rolling stands arranged between this rolling stand and the last rolling stand are configured as four-high stands.

The object is also achieved by a hot rolling mill having the features of claim 8. Advantageous embodiments of the hot-rolling mill train are the subject matter of the dependent claims 9 to 12.

According to the invention, a hot-rolling mill train of the type mentioned at the outset is designed in such a way that the last rolling stand is configured at least temporarily as a six-roll stand with work rolls, intermediate rolls and back-up rolls.

Preferably, the working rolls and the intermediate rolls of the last rolling stand configured as a six-roll stand are arranged in a roll cassette that can be inserted and removed as a unit. As a result, not only can the change of the working rolls and the intermediate rolls due to wear be carried out particularly quickly, but also the conversion from a four-roll stand to a six-roll stand or vice versa can be carried out particularly quickly.

Preferably, a continuous casting installation is arranged upstream of the first rolling stand, in which the metal strip is cast before rolling in the hot rolling train, so that the metal strip can be conveyed out of the casting heat to the first rolling stand. The operation of the hot-rolling train can thereby be optimized in terms of energy.

Preferably, the hot-rolling train can be operated in a continuous operation. Thereby, the productivity of the hot rolling mill train can be maximized.

Usually, the hot rolling mill train has a certain number of further rolling stands between the first and the last rolling stand. The further rolling stand can be configured as a four-high stand or as a six-high stand. However, the changeover from the four-high stand to the six-high stand is preferably only made once, seen in the sequence of the rolling stands, i.e. from the first rolling stand to the second rolling stand, etc.

Drawings

The above features, characteristics and advantages of the present invention and the manner and method of how to achieve them will become more apparent in conjunction with the following description of embodiments, which are explained in detail in conjunction with the accompanying drawings. Here, in the schematic view:

fig. 1 shows a hot rolling train during rolling of a first metal strip;

FIG. 2 shows the hot rolling train of FIG. 1 during rolling of a second metal strip;

FIG. 3 shows the removal of the work rolls from the last roll stand of the hot rolling mill train;

FIG. 4 shows the loading of the work rolls and the intermediate rolls into the last roll stand of the hot rolling mill train;

figure 5 shows the last rolling stand of the hot rolling mill train in two different configurations; and is

Fig. 6 shows a modification of the hot rolling train of fig. 1.

Detailed Description

According to fig. 1, the hot rolling train has a plurality of rolling stands 1a to 1 d. The hot-rolling train can be designed in particular as a finishing train.

According to fig. 1, there are four rolling stands 1a to 1 d. However, the number of rolling stands 1a to 1d can also be greater, for example five, six or seven. Alternatively, the number can also be smaller, for example two or three. But at least two rolling stands 1a to 1d are present. If there are more than two rolling stands 1a to 1d, a certain number of further rolling stands 1b, 1c are arranged between the first 1a and the last rolling stand 1 d.

The first metal strip 2 is hot rolled at a specific point in time in the hot rolling train. The first metal strip 2 can be a steel strip in particular. The first metal strip 2 passes through the hot-rolling train along the conveying direction x without stopping and without reversing direction. Thus, the individual sections of the first metal strip 2 first pass through the first rolling stand 1a, then through the second rolling stand 1b, then through the third rolling stand 1c and finally through the last rolling stand 1 d. Before rolling in the first rolling stand 1a, the first metal strip 2 can be heated, for example, in a furnace (not shown) to the necessary rolling temperature. The rolling temperature is mostly between 900 ℃ and 1200 ℃ for steel strips. After rolling in the last rolling stand 1a, the first metal strip 2 can be rolled, for example, into a coil (not shown).

In the state shown in fig. 1, i.e. during the rolling of the first metal strip 2, all rolling stands 1a to 1d of the hot-rolling mill train are configured as four-high stands. The rolling stands 1a to 1d thus each have a work roll 3 and a back-up roll 4, but no further rolls. This also applies in particular to the first and last rolling stands 1a, 1d of the hot-rolling mill train.

Fig. 2 shows the same hot rolling train with the same rolling stands 1a to 1d during rolling of the second metal strip 5. According to the illustration in fig. 2, the first rolling stand 1a continues to be configured as a four-high stand at this point in time, i.e. during the rolling of the second metal strip 5. However, at least the last rolling stand 1d is configured as a six-roll stand. The last rolling stand therefore has, in addition to the back-up rolls 4, also work rolls 6 and intermediate rolls 7. The intermediate roll 7 is arranged between the backing roll 4 and the working roll 6.

The further rolling stands 1b, 1c can be configured either as four-high stands or as six-high stands during the rolling of the second metal strip 5 according to the illustration in fig. 2. However, the changeover from a four-high stand to a six-high stand is only made once, as seen in the sequence of the rolling stands 1a to 1d, without depending on which of the further rolling stands 1b, 1c are configured as four-high stands and which of the further rolling stands 1b, 1c are configured as six-high stands. In the specific embodiment of the rolling mill train corresponding to the illustration in fig. 1 and 2, having a total of four rolling stands 1a to 1d, it is therefore possible for the two further rolling stands 1b, 1c to be configured as four-high stands. It is also possible that the two further rolling stands 1b, 1c are configured as six-roll stands. However, if one of the two further rolling stands 1b, 1c is configured as a four-high stand and the other of the two further rolling stands 1b, 1c is configured as a six-high stand, then the further rolling stand 1b, i.e. the rolling stand adjacent to the first rolling stand 1a, is configured as a four-high stand and the further rolling stand 1c, i.e. the rolling stand adjacent to the last rolling stand 1d, is configured as a six-high stand.

In the case of a four-high frame, the working rolls 3 are usually driven. In the case of a six-roll stand, the working rolls 6 are usually driven in the same way. However, in addition or as an alternative, usually as an alternative, the intermediate rolls 7 can also be driven in the case of a six-roll stand. In the case of a corresponding configuration, these statements also apply to the last rolling stand 1d of the hot-rolling mill train.

It is assumed next that the first metal strip 2 is first rolled and only the second metal strip 5 is subsequently rolled in the hot-rolling mill train. In principle, however, the opposite procedure is also possible.

In order to be able to roll both the first metal strip 2 and the second metal strip 5 in the same hot-rolling mill train, at least the last rolling stand 1d (and optionally also at least one of the further rolling stands 1b, 1 c) is converted from a four-roll stand to a six-roll stand between the rolling of the first metal strip 2 and the rolling of the second metal strip 5. Thus, according to the illustration in fig. 3, starting from the arrangement of the last rolling stand 1d as a four-high stand, the working rolls 3 of the four-high stand are disassembled. As is generally customary and indicated by the arrow a in fig. 3, the removal takes place in the axial direction of the work roll 3 through a window of the machine stand on the operating side. The detached work rolls 3 are shown together in fig. 3 with broken lines.

After the removal of the working rolls 3, the working rolls 6 and the intermediate rolls 7 of the six-roll stand are inserted according to the illustration in fig. 4. As is generally conventional from the prior art and is indicated in fig. 4 by the arrow B, the insertion takes place in the axial direction of the working rolls 6 and of the intermediate rolls 7 through the window of the machine stand on the operating side.

As a result, the last rolling stand 1d is therefore configured either as a four-high stand, see the left side of fig. 5, or as a six-high stand, see the right side of fig. 5, as required.

The back-up rolls 4 are not switched together when retrofitting the last rolling stand 1 d. The back-up rolls 4 are therefore identical back-up rolls 4 not only in the configuration of the last roll stand 1d as a four-roll stand but also in the configuration of the last roll stand 1d as a six-roll stand.

Preferably, the working rolls 6 and the intermediate rolls 7 of the six-roll stand are arranged in a roll box 8 according to the illustration in fig. 4. It is thereby possible to insert the roll cassette 8 itself, i.e. as a unit. The working rolls 6 and the intermediate rolls 7 of the six-roll stand can therefore also be inserted as a unit, that is to say in particular at the same time.

In order to keep the adjustment region, i.e. the roll gap, of the last rolling stand 1D, which can be formed between the working rolls 3 and between the working rolls 6, as large as possible both in the configuration as a four-high stand and also in the configuration as a six-high stand, the diameters D, D 'and D ″ of the working rolls 3, 6 and 7 should preferably be matched to one another in such a way that the sum of the diameters D', D ″ of the working rolls 6 and 7 of the six-high stand at least approximately corresponds to the diameter of the working rolls 3 of the four-high stand. However, minor deviations of maximum 20%, better maximum 10%, can be tolerated.

Furthermore, in the configuration of the last rolling stand 1D as a six-high stand, the diameters D', D ″ of the work rolls 6 and intermediate rolls 7 should be determined taking into account: whether the working rolls 6 or the intermediate rolls 7 are driven. In the first-mentioned case, the diameter D' of the working roll 6 can be as large as the diameter D ″ of the intermediate roll 7, and if necessary can even be larger than the diameter D ″ of the intermediate roll 7. In the last-mentioned case, the diameter D' of the working roll 6 is preferably significantly smaller than the diameter D ″ of the intermediate roll 7. For example, the diameter D' of the working roll 6 can be between 50% and 70% of the diameter D ″ of the intermediate roll 7.

The conversion of the last rolling stand 1d from the configuration as a four-roll stand to the configuration as a six-roll stand is explained above. However, the opposite procedure, i.e. a conversion from a six-roll stand to a four-roll stand, is likewise possible. The opposite approach only has to be taken. Furthermore, the explanations with respect to fig. 3 to 5 also apply to each further rolling stand 1b, 1c, which should be adapted from a configuration as a four-high stand to a configuration as a six-high stand.

According to the illustration in fig. 6, the hot-rolling mill train can have a continuous casting installation 9. The continuous casting installation 9 is arranged before the first rolling stand 1 a. In the continuous casting installation, the metal strips 2, 5 are cast before rolling in the hot rolling train. The metal strip 2, 5 can thus be transported out of the casting heat to the first rolling stand 1 a. The hot-rolling train is therefore extended in this case to a cast-rolling complex installation. Due to the presence of the continuous casting installation 9, the hot-rolling train can be operated in particular in a continuous mode of operation. However, as an alternative, a batch operation is also possible. Furthermore, it is possible for the hot-rolling train to have a furnace (not shown in the figures) as an alternative or supplement to the continuous casting installation 9. The furnace, if present, is arranged before the first rolling stand 1 a. If necessary, a rolling stand 10 upstream of the first rolling stand 1a, in particular a roughing stand of a roughing train, can also be upstream. The preceding rolling stand 10, if present, is arranged after the continuous casting installation 9 and/or furnace.

Fig. 6 shows a state in which all of the rolling stands 1a to 1d are configured as four-high stands. However, if the last rolling stand 1d and, if appropriate, at least one of the further rolling stands 1b, 1c are also configured as a six-roll stand, then the continuous casting installation 9 and, if appropriate, the preceding rolling stand 10 are also present.

Other embodiments of the rolling stands 1a to 1d can be implemented as desired. In particular, the working rolls 3, 6 can be moved axially, both in the configuration as a four-roll stand and also in the configuration as a six-roll stand. In the configuration as a six-roll stand, the intermediate rolls 7 can also be moved as an alternative or in addition to the working rolls 6. The bending of the working rolls 3, 6 and, if necessary, the bending of the intermediate roll 7 can also be as in the prior art. Furthermore, the work rolls 3 can be arranged slightly offset with respect to the back-up rolls 4 in the configuration of the rolling stands 1a to 1d as four-high stands, viewed in the conveying direction x of the metal strip 2, 5. In the configuration of the last rolling stand 1d as a six-roll stand, the working rolls 6 can be arranged slightly offset with respect to the intermediate rolls 7, as seen in the conveying direction x of the metal strip 2, 5. Likewise, the intermediate rolls 7 can be arranged slightly offset with respect to the back-up rolls 4 in the configuration of the last rolling stand 1d as a six-roll stand, seen in the conveying direction x of the metal strip 2, 5. The offset of the working roller 6 relative to the intermediate roller 7 and the offset of the intermediate roller 7 relative to the backing roller 4 are preferably oriented identically. Possible thrusts can be trapped by the support rollers, as long as necessary. The support rollers, if present, are arranged on the inlet side and/or outlet side of the work roll 6. However, such an abutment roller should be dispensed with according to a possible solution.

In the arrangement as a four-high stand as well as in the arrangement as a six-high stand, the working rolls 3, 6 are usually cooled in the last rolling stand 1 d. For cooling, corresponding cooling racks are present. In order to cool the working rolls 6 in the configuration as a six-roll stand, the cooling stand can be arranged on the inlet side and/or on the outlet side, if appropriate, at the roll box 8. Alternatively, the cooling stand can be an integral part of the last rolling stand 1d itself, so that it cannot be installed and removed together when retrofitting the configuration of the last rolling stand 1 d.

The present invention has many advantages. Due to the smaller diameter D' of the work rolls 6 relative to the diameter D of the work rolls 3, it is thus possible, for example, to roll both metal strips 2, 5 made of softer material and metal strips 2, 5 made of harder material to a small final thickness. Subsequent cold rolling can be eliminated or started with a thinner inlet product, whereby the cold rolled outlet product can then have a smaller thickness. Nevertheless, the range of products that can be manufactured is not affected, and often even extended. In particular for larger final thicknesses, the necessary bending stiffness during rolling can be achieved by configuring the last rolling stand 1d as a four-high stand. The amount of pass reduction in the last rolling stand 1d can be maximized in the configuration as a six-roll stand, wherein the rolling forces and rolling moments necessary for this can nevertheless be reduced. At the same time, improved material properties of the second metal strip 5 can thereby also be achieved. In particular, the microstructure of the second metal strip 5 can be homogenized and so-called shear bands can be prevented. Finally, ferrite rolling can be carried out in the hot-rolling mill train. This makes it possible to positively influence the so-called r value, which characterizes the planar anisotropy and is important for the deep drawability of the rolled metal strip 2, 5. In the prior art, cold rolling with subsequent annealing is required for this purpose. By the invention, cold rolling and annealing can be omitted.

Although the invention has been illustrated and described in detail by means of preferred embodiments, the invention is not limited by the disclosed examples and other variants can be derived therefrom by the person skilled in the art without departing from the scope of protection of the invention.

List of reference numerals:

1a to 1d Rolling Mill Stand

2. 5 Metal strip

3. 6 working roll

4 support roller

7 intermediate roll

8-roller box

9 continuous casting equipment

10 arranged at the front of a rolling stand

A. Arrow B

D. D 'and D' diameter

x transport direction.