EP3658305B1 - Scaffold cooler for cooling a steel strip in a rolling stand - Google Patents

Description

field of technology

The present invention relates to rolling mill technology, in particular to the hot rolling and cooling of a metal strip, such as steel strip, or sheet metal in a rolling train. The rolling mill can be, for example, a finishing mill for strip production or a hot rolling mill for sheet metal production.

On the one hand, the invention relates to a roll stand with a roll stand on the operator side and a roll stand on the drive side, with no work rolls and no chocks for the work rolls being arranged in the roll stand.

On the other hand, the invention relates to a method for installing a stand cooler for cooling a steel strip in a roll stand, and a method for removing such a stand cooler from a roll stand.

For reasons of clarity, a roll stand with removed chocks and removed work rolls is also referred to as a roll stand in this document. This nomenclature is self-evident for the person skilled in the art and increases clarity.

State of the art

As is well known, during hot rolling the hot rolling stock is plastically deformed in a roll gap by so-called work rolls, as a result of which, for example, the thickness of the rolling stock is reduced. After hot rolling, the rolled stock is typically cooled in a cooling line and then removed from the rolling line, for example as a coil or sheet.

The material properties of a hot-rolled strip not only depend on its chemical composition, but also depend very much on the chronological sequence of the processing steps in the hot-rolling mill. In a combined casting and rolling plant, e.g. an Arvedi ESP plant, the chronological sequence of continuous casting, rough rolling, intermediate heating, finish rolling, cooling and coiling is essential. When setting the microstructure or the phase components of the rolled strip (the hot-rolled strip after finish rolling is referred to as the finished strip), the time interval between the last rolling pass in a roll stand of the rolling train and the start of cooling of the strip is also decisive. In many cases, this period of time should be as short as possible.

Hot rolling mills have a fixed number of roll stands, so that due to the high technical complexity of these machines it is not possible to remove one or more roll stands of the rolling mill when producing thick strips and to add back removed roll stands when producing thin strips. Thus, in general, a rolling mill must be capable of producing both thick and thin strips.

It is known that thick strips are transported more slowly in a rolling mill and are reduced in thickness less than thin strips. This means that, for example, a thick strip is often rolled to its final thickness before the last rolling stand, e.g. in the second rolling stand, whereas a thin strip in the same rolling mill is only rolled to its final thickness in the last, e.g. fifth, rolling stand. In the former case, therefore, the roll stands 3, 4 and 5 are raised so that the thick strip runs through these roll stands without being rolled there. Due to the relatively slow transport speed of thick strips and the fact that the last forming takes place in one of the first roll stands, there is a relatively long period of time until the finished strip reaches the cooling section behind the last roll stand and is cooled there with a certain intensity. This long period of time can mean that thick strips can no longer achieve certain material properties, which limits the product mix of the rolling mill.

This problem is exacerbated in the continuous operation of combined casting and rolling plants, since the transport speed of the strip is indirectly proportional to the strip thickness. In addition, the continuous operation means that the intermediate or finished strip cannot be accelerated on the roller table, since it is coupled to the continuous casting plant. As a result, the transport speed of a thick strip in an ESP plant can be in the range of 0.5 m/s or less and is therefore significantly slower than in other hot rolling mills that are not operated endlessly, which transport the rolled stock before, during or after the rolling mill. can accelerate after passing through the rolling train.

However, even if a hot rolling mill is not operated endlessly (e.g. in batch or semi-endless operation), the underlying problem cannot be solved satisfactorily, since a change in strip speed is always accompanied by a change in temperature during the last rolling pass in the finishing train. In addition, the breaking of the endless coupling between the aggregates of a hot rolling mill leads to many well-known problems, such as the threading in and out of the strip from the rolling stands and the cooling line, the shocks caused by the strip head and strip foot, the different temperatures of the strip head and strip foot, etc. Thus, this possible solution is either ruled out completely or at least cannot be implemented satisfactorily.

From the US 2017/0 056 944 A1 a cooling arrangement is known which can be arranged in front of or behind a roll stand. This cooling arrangement has a configuration as is known from the approach in conventional cooling sections. she However, at just a few meters, it is shorter than conventional cooling sections.

From the DE 37 04 599 A1 interstand cooling for cooling a steel strip behind a roll stand is known. The interstand cooling comprises a lower and an upper water box, the water boxes each having a connection for a coolant and a plurality of cooling nozzles or cooling tubes arranged in the depth direction of the stand cooler. The water tanks can be supplied with coolant via the connections. This allows the underside and the top of the steel strip to be cooled by the cooling nozzles or cooling tubes of the water boxes.

From the DE 22 35 063 A1 is also known an interstand cooling. The interstand cooling comprises a lower and an upper water tank, the water tanks each having a connection for a coolant and a cooling slot extending in the depth direction. The water tanks can be supplied with coolant via the connections. This allows the bottom and top of the steel strip to be cooled down through the cooling slots in the water tanks.

The prior art does not reveal how the problem of the long period of time in the case of thick strips between the last rolling pass and the start of cooling in hot rolling mills, in particular in continuous cast-rolling compound plants, can be overcome.

Summary of the Invention

The object of the invention is to change the existing state of the art with an innovative solution for a hot rolling mill, in particular a casting-rolling compound system and here especially for an endlessly operated casting-rolling compound system, so that the period of time between the last Roll pass during hot rolling and the start of strip cooling can be reduced without having to remove one or more roll stands from the hot rolling mill before the production of thick strips or without having to reinstall removed roll stands before the subsequent production of thin strips. The solution is intended to expand the product mix of the hot rolling mill and enable a wide range of high-quality steel strip to be produced.

The device aspect of this object is achieved by a rolling mill having the features of claim 1. Advantageous embodiments are the subject matter of claims 2 to 8 dependent on claim 1.

• wobei in dem Walzgerüst keine Arbeitswalzen und keine Einbaustücke für die Arbeitswalzen angeordnet sind, das Walzgerüst jedoch einen Gerüstkühler zum Abkühlen eines Stahlbands aufweist,
• wobei der Gerüstkühler derart dimensioniert ist, dass er durch den bedienseitigen Walzenständer des Walzgerüsts anstelle von Einbaustücken und der oberen und unteren Arbeitswalzen in das Walzgerüst eingebaut werden kann,
• wobei der Gerüstkühler einen unteren Wasserkasten und einen oberen Wasserkasten umfasst,

wobei der untere Wasserkasten und der obere Wasserkasten jeweils einen Anschluss für ein Kühlmittel und mehrere in der Tiefenrichtung des Gerüstkühlers angeordnete Kühldüsen oder Kühlrohre oder zumindest einen in der Tiefenrichtung des Gerüstkühlers verlaufenden Kühlschlitz aufweisen, so dass der untere und der obere Wasserkasten durch den jeweiligen Anschluss mit Kühlmittel versorgt werden können und die Unterseite des Stahlbands durch die Kühldüsen oder Kühlrohre oder den Kühlschlitz des unteren Wasserkastens und die Oberseite des Stahlbands durch die Kühldüsen oder Kühlrohre oder den Kühlschlitz des oberen Wasserkastens abgekühlt werden können.Specifically, the solution is a roll stand with a roll stand on the operator side and a roll stand on the drive side,

• wherein no work rolls and no chocks for the work rolls are arranged in the roll stand, but the roll stand has a stand cooler for cooling a steel strip,
• wherein the stand cooler is dimensioned such that it can be installed in the roll stand through the operator-side roll stand of the roll stand instead of chocks and the upper and lower work rolls,
• the scaffold cooler comprising a lower header and an upper header,

wherein the lower water box and the upper water box each have a connection for a coolant and a plurality of cooling nozzles or cooling pipes arranged in the depth direction of the frame cooler or at least one cooling slot running in the depth direction of the frame cooler, so that the lower and the upper water box through the respective connection with Coolant can be supplied and the bottom of the steel strip can be cooled through the cooling nozzles or cooling tubes or the cooling slot of the lower water box and the top of the steel strip can be cooled through the cooling nozzles or cooling tubes or the cooling slot of the upper water box.

The term "stand cooler" refers to a cooling device that cools a steel strip with adjustable intensity and can be installed in a rolling stand in place of chocks and work rolls. The designation explicitly does not refer to a cooling device that cools the rolls of a roll stand!

The framework cooler can also have a combination of several cooling nozzles or cooling tubes and one or more cooling slots.

The stand cooler can be installed in the rolling mill instead of chocks and upper and lower work rolls, so that the rolling mill with the stand cooler can cool the top and bottom of a steel strip with a given intensity. This means a cooling that is comparable to the cooling in a cooling section downstream of the rolling train.

It is known to use interstand cooling between the roll stands of a hot rolling train in order to dissipate the heat generated in the material during deformation and to keep the strip temperature within permissible limits. This cooling is usually not dimensioned to achieve cooling of the strip in the sense of this invention. To expand the cooled area, a combination of a stand cooler with interstand cooling (which only cools the strip between the roll stands) is possible and advantageous for certain requirements.

• mehrere in der Tiefenrichtung des Gerüstkühlers angeordnete Kühldüsen oder Kühlrohre oder
• zumindest einen in der Tiefenrichtung des Gerüstkühlers verlaufenden Kühlschlitz

aufweist. Durch den jeweiligen Anschluss bzw. die jeweiligen Anschlüsse werden der untere und der obere Wasserkasten mit Kühlmittel versorgt. Die Abkühlung der Unter- und Oberseite des Stahlbands erfolgt durch Kühldüsen oder Kühlrohre bzw. einen oder mehrere Kühlschlitze.For cooling, the scaffold cooler has an upper and a lower water tank, each of which has at least one connection for a coolant and

• a plurality of cooling nozzles or cooling pipes arranged in the depth direction of the skeleton cooler, or
• at least one cooling slot running in the depth direction of the stand cooler

having. The lower and upper water tanks are supplied with coolant through the respective connection or connections. The upper and lower sides of the steel strip are cooled by cooling nozzles or cooling tubes or one or more cooling slots.

For easy installation and removal of the stand cooler, it is advantageous if the stand cooler has at least two guide surfaces, the guide surfaces being connected to the lower or upper water tank, so that the stand cooler is introduced into the roll stand in the width direction of the roll stand or the steel strip (e.g. pushed in) and preferably the frame cooler rests on the guide surfaces when installed.

The at least two guide surfaces, which are connected to the upper and/or the lower water box, allow the stand cooler to be introduced into the roll stand in a simple manner in the width direction of the roll stand, e.g. on rails. After retracting the scaffold cooler, it can remain on the rails or, for example, be supported by the bending block. When installed, the framework cooler preferably rests on the guide surfaces.

By replacing the chocks and the upper and lower work roll with the stand cooler, the time between the finish rolling (i.e. the last rolling pass in the hot rolling mill) and the beginning of the strip cooling can be drastically reduced, so that, for example, even thick hot strip has the necessary metallurgical properties (e.g. structure ) and can be produced with high quality. In addition, the section between the last rolling roll stand and the cooling section is already being used for cooling.

If the stand cooler is installed or removed mainly during an interruption in rolling operation (eg when changing the work rolls of other roll stands), it is advantageous if the stand cooler is designed in one piece, with preferably the lower and the upper water box are connected to each other by uprights. In this embodiment, the framework cooler can be installed and removed as a unit.

If the stand cooler is also to be able to be installed or removed during rolling operation, it is advantageous if the stand cooler is designed in at least two pieces, with the lower and the upper water box each having two guide surfaces. This allows the upper part of the stand cooler with the upper water box to be installed in the mill stand independently of the lower part of the stand cooler with the lower water box, thereby facilitating the installation during the continuous rolling operation.

As an alternative to the two-piece design, a one-piece design would also be possible, e.g. with a "C" shape of the framework cooler.

With the two-piece design of the stand cooler, the lower water box can be brought into the roll stand, e.g can be. As a result, the gap between the outlet openings of the water tanks and the steel strip can be adjusted during operation.

Simple guidance of the framework cooler is ensured if the lower water tank and/or the upper water tank each has two lateral support straps, each of the two support straps having a guide surface.

Since it is often necessary to cool the edge areas and the central area of the steel strip to different extents, viewed in the width direction of the steel strip, it is advantageous if the lower water tank and the upper water tank have at least two connections. As a result, for example, the cooling nozzles assigned to the edge areas are supplied with a lower pressure than the cooling nozzles assigned to the central area.

As a rule, the roll stand has (at least) back-up rolls. In this case, the stand cooler is arranged between the back-up rolls of the roll stand when installed in the roll stand.

In normal operation of each roll stand, the stand cooler is not present, but work rolls and chocks for the work rolls. The stand cooler of the present invention is installed in the rolling stand as an alternative to the work rolls and the chocks for the work rolls. The roll stand therefore preferably also has the work rolls and chocks mentioned for the work rolls. Here, the work rolls and the chocks for the work rolls—as in the prior art—are dimensioned such that after the stand cooler has been removed from the roll stand, they can be installed in the roll stand through the operator-side roll stand of the roll stand.

• Entfernen von Einbaustücken und einer oberen und einer unteren Arbeitswalze aus dem Walzgerüst;
• Einbau des Gerüstkühlers anstelle von Einbaustücken und der oberen und unteren Arbeitswalzen in das Walzgerüst, wobei der Gerüstkühler horizontal in Breitenrichtung des Walzgerüsts bzw. des Stahlbands durch einen bedienseitigen Walzenständer eingebracht wird; und
• Verbinden der Anschlüsse des oberen und unteren Wasserkastens mit einer Kühlmittelversorgung, sodass die Unter- und die Oberseite des Stahlbands über die Kühldüsen oder Kühlrohre oder den Kühlschlitz des unteren Wasserkastens und des oberen Wasserkastens durch ein Kühlmittel abgekühlt werden können.

A procedural aspect of the invention, relating to the installation of a stand cooler for cooling a steel strip in a roll stand of a rolling train, is achieved according to claim 9 by the following process steps:

• removing chocks and an upper and a lower work roll from the mill stand;
• installing the stand cooler in place of chocks and the upper and lower work rolls in the rolling stand, the stand cooler being introduced horizontally in the width direction of the rolling stand or the steel strip through an operator-side stand; and
• Connecting the ports of the upper and lower water box with a coolant supply, so that the lower and the upper side of the steel strip can be cooled by a coolant via the cooling nozzles or cooling tubes or the cooling slot of the lower water box and the upper water box.

The connections can be connected e.g. by flange connections, by manually operated lever arm couplings with hose connection or by automatic coupling when the scaffold cooler is pushed in.

In the case of a rolling mill that is not operated continuously, it is expedient to install the stand cooler during a break in operation of the rolling train.

Particularly in the case of continuously operated compound casting/rolling systems, e.g. of the Arvedi ESP type, it is advantageous if the stand cooler is installed while the rolling train, in particular a finishing train, is in operation.

According to one embodiment, a port is supplied by a coolant under a pressure of 2 to 5 bar.

According to a further embodiment, a connection is supplied by a coolant under a pressure of 0.1 to 0.8 bar.

In the operation of a scaffold cooler, it is advantageous to supply the connection or connections of the lower water box with a higher pressure than the connection or connections of the upper water box. This can be done by separate pressure controls for the top and bottom ports. Alternatively, this can be done by flow controls so that the flow rate to the lower plenum is higher than to the upper plenum (e.g. 60% of the total water flow goes to the lower plenum and 40% to the upper plenum).

The aforementioned pressure ranges are not mutually exclusive, since, for example, the edge area of the steel strip can be cooled through a first connection with a coolant under a pressure of 0.1 to 0.8 bar, whereas the center area can be cooled through a second connection with a coolant can be cooled under a pressure of 2 to 5 bar.

Advantageously, the production of steel strips is carried out according to claim 13, wherein first a first steel strip is rolled in at least two roll stands of a hot rolling train, the first steel strip is then cooled in a cooling section and the cooled first steel strip is then conveyed out - for example as a plate or coil. Then, a stand cooler (as described above) is installed in a roll stand of the rolling mill. After the stand cooler has been installed in the rolling stand, a second steel strip is rolled in at least one rolling stand of the rolling train, the second steel strip is cooled in at least one rolling stand of the rolling train using the stand cooler, the cooled second steel strip is cooled in the cooling section, and the cooled second steel strip is conveyed out.

• Trennen der Anschlüsse des oberen und unteren Wasserkastens von einer Kühlmittelversorgung;
• Ausbau des Gerüstkühlers aus dem Walzgerüst, wobei der Gerüstkühler horizontal in Breitenrichtung des Walzgerüsts aus einem bedienseitigen Walzenständer ausgebracht (z.B ausgezogen) wird; und
• Einbau von Einbaustücken und einer oberen und einer unteren Arbeitswalze anstelle des Gerüstkühlers in das Walzgerüst.

The procedural aspect of the invention, relating to the removal of a stand cooler from a roll stand, is solved in claim 14 by the following process steps:

• disconnecting the upper and lower water box connections from a coolant supply;
• Removal of the stand cooler from the roll stand, the stand cooler being removed (eg pulled out) horizontally in the width direction of the roll stand from a roll stand on the operator's side; and
• Installation of chocks and an upper and a lower work roll in the roll stand instead of the stand cooler.

The connections can in turn be separated, for example, by means of flange connections, manually operated lever arm couplings with hose connections or by automatic coupling when the frame cooler is pushed out.

Depending on the type of rolling mill or its mode of operation (continuous or non-continuous), the stand cooler can be removed take place during ongoing operation or during a break in operation of a rolling train.

It is advantageous to set the cooling capacity of the stand cooler in a model-controlled manner depending on the material (in particular the chemical composition), the rolling parameters (thickness and speed of the steel strip) and the steel quality to be achieved. Depending on the above-mentioned values, a cooling model supplies online, i.e. during ongoing operation of the hot rolling mill, a quantity of cooling water and, if necessary, a width-dependent cooling water distribution for the upper and lower side of the steel strip. The pressure and/or the flow rate of the cooling medium through the stand cooler are set in a controlled or regulated manner so that the steel strip achieves the desired properties in the best possible way after passing through the roll stands with the built-in stand coolers and cooling in the cooling section.

Brief description of the drawings

Other advantages and features of the present invention emerge from the description of non-limiting exemplary embodiments. The following shown schematically

Fig 1

zwei Ansichten eines Walzgerüsts mit eingebauten Einbaustücken und Arbeitswalzen nach dem Stand der Technik,

Fig 2

zwei Ansichten von Einbaustücken und Arbeitswalzen nach dem Stand der Technik,

Fig 3

eine Seitenansicht eines Walzgerüsts vor einer Kühlstrecke nach dem Stand der Technik,

Fig 4

eine Seitenansicht einer Fertigwalzstraße mit fünf Walzgerüsten vor einer Kühlstrecke nach dem Stand der Technik,

Fig 5

eine Seitenansicht einer Fertigwalzstraße mit fünf Walzgerüsten, wobei in die letzten drei Walzgerüste je ein erfindungsgemäßer Gerüstkühler eingebaut ist,

Fig 6

zwei Ansichten eines Gerüstkühlers,

Fig 7

eine weitere Ansicht des Gerüstkühlers aus Fig 6,

Fig 8

zwei Ansichten eines Walzgerüsts mit einem eingebauten Gerüstkühler,

Fig 9a und 9b

je eine Ansicht eines Gerüstkühlers mit einem Kühlschlitz,

Fig 10

eine schematische Darstellung der Wasserwirtschaft für ein Walzgerüst mit einem eingebauten Gerüstkühler,

Fig 11

ein Schnitt in Breitenrichtung durch ein Walzgerüst mit einem eingebauten Gerüstkühler,

Fig 12

eine Ansicht eines Gerüstkühlers mit Kühlrohren anstelle von Kühldüsen,

Fig 13

eine Vorderansicht eines Gerüstkühlers mit eingebautem Gerüstkühler und Abweiseblechen, und

Fig 14

eine Ansicht eines einstückigen Gerüstkühlers in C-Form.

Figures show:

figure 1

two views of a roll stand with installed chocks and work rolls according to the prior art,

figure 2

two views of prior art chocks and work rolls,

figure 3

a side view of a roll stand in front of a cooling section according to the prior art,

figure 4

a side view of a finishing train with five rolling stands in front of a cooling section according to the prior art,

figure 5

a side view of a finishing train with five roll stands, with a stand cooler according to the invention being installed in each of the last three roll stands,

figure 6

two views of a scaffold cooler,

figure 7

another view of the scaffold cooler figure 6 ,

figure 8

two views of a roll stand with a built-in stand cooler,

Figures 9a and 9b

one view each of a frame cooler with a cooling slot,

figure 10

a schematic representation of the water management for a roll stand with a built-in stand cooler,

figure 11

a widthwise section through a roll stand with a built-in stand cooler,

figure 12

a view of a scaffold cooler with cooling tubes instead of cooling nozzles,

figure 13

a front view of a scaffold cooler with built-in scaffold cooler and deflectors, and

figure 14

a view of a one-piece C-shape scaffold cooler.

Description of the embodiments

the figure 1 shows on the left a side view of a roll stand 11 with built-in chocks 4a, 4b for an upper and lower one Backup roll 4 and built-in chocks 5a, 5b for an upper and lower work roll 5. The right representation of figure 1 shows the roll stand 11 in a schematic sectional view without chocks 4a, 4b, 5a, 5b. A hot strip, not shown, here a steel strip, is rolled in the roll stand 11 by the work rolls 5, with the work rolls 5 being supported on the back-up rolls 4 located behind them. A bending block 6 can bend the work rolls 5 and thus adjust the profile or flatness of the rolled hot strip. The chocks 4a, 4b, 5a, 5b, the so-called AGC (short for Automatic Gap Control) cylinder 3 and the bending block 6 are installed in the two stand windows 2 of the roll stand 1. Only the roller stand 1 on the operator side can be seen in FIG. The roller stand on the drive side is covered by the roller stand 1 on the operator side. only in figure 11 it can be seen, but is not identified there with a reference number.

The hot strip is guided on a rolling table 10 and brought to the work rolls 5 . In order to limit the temperature of the work rolls 5, at least one (here two) upper cooling head 8a and at least one (here two) lower cooling head 8b of the work roll cooling system are provided before and after the work rolls 5. In addition, an upper cooling head of the interstand cooling system 7a is installed before the roll stand 11, and a lower cooling head of the interstand cooling system 7b is installed after the rolling stand 11. Of course, an upper and a lower cooling head of the interstand cooling 7a, 7b can also be arranged before and after the roll stand 11. A swiveling looper roller 9 can adjust the tension in the hot strip. Thus, the temperature of the hot strip can be changed before and after rolling. Since roll stands 11 with so-called stand fixtures are known, a more detailed description of the prior art is omitted.

In figure 2 Fig. 12 is a left side view and right is a front view of a chock 5a having an upper work roll 5 and a chock 5b having a lower work roll 5 shown. The work rolls 5 are displaceably mounted in the roll stand 11 by the chocks 5a, 5b.

the figure 3 shows the roll stand 11 figure 1 in a rolling mill. A steel strip, not shown, is fed to the roll stand 11 on a roller table 12 in the transport direction TR and rolled in the roll gap between the two work rolls 5 . After the hot rolling, the rolled strip is again guided on the following roller table 12 to a cooling section 45 with a plurality of cooling distributors 13 and cooled there with an adjustable intensity.

the figure 4 shows a possible situation when rolling a thick hot strip in a rolling train 40 designed as a finishing train with five roll stands 11. Since it is a thick hot strip, the last rolling pass takes place in the third (ie in the middle) roll stand 11. The thickness of the hot strip is reduced - for example - from 45 mm to 20 mm. After rolling, the finished rolled strip leaves the central roll stand 11 at a speed of, for example, 0.4 m/s. In the areas marked C, the finished strip can be cooled by the upper and lower cooling heads of the interstand cooling system 7a, 7b. The finished strip cannot be cooled in the roll stands 11 themselves. The uncooled areas are marked with NC. Since the horizontal distance between the center line of the third roll stand 11 and the beginning of the cooling section 45 with the cooling distributors 13 (with two roll stands 11 not used for rolling the strip 50 and typical distances between the roll stands 11) is approx. 20 m, the rolled Hot strip according to the above example 50 s until it reaches the cooling section 45. This time is already too long for certain types of steel, so that the steel strip can no longer achieve the desired microstructure or phase properties. The interstand cooling (marked C in the figure) with the upper and lower cooling heads 7a, 7b (see figure 1 ) does not change anything because the cooling capacity is too low and the rolled Hot strip on the way to the cooling section 45 is mostly not cooled.

the figure 5 shows the situation during hot rolling of a thick steel strip in a rolling train 40 designed as a finishing train with originally five roll stands 11. In the last three roll stands, the chocks 5a, 5b and the work rolls 5 (see figure 1 ) removed and instead a scaffolding cooler 20 each (details in the Figures 6 to 11 ) installed 1 per roller stand. The last roll pass takes place in the second roll stand 11 from the left; the finished strip is intensively cooled in each of the three subsequent roll stands 1 by a stand cooler 20 . By cooling the steel strip by means of the stand cooler 20, the finished strip is already cooled from the middle roll stand 1. This makes it possible to produce thick strips of special steel grades (eg demanding tube grades) that could not be produced without stand cooler 20 .

In figure 6 two views of a frame cooler 20 are shown, namely in a side view on the left and in a sectional view on the right. The skeleton cooler 20 has an upper header tank 21a and a lower header tank 21b. The underside of the upper water tank 21a and the upper side of the lower water tank 21b are equipped with cooling nozzles 23 so that a hot strip, not shown here, can be cooled in the width direction B. In order to further increase the cooling effect, seven cooling nozzles are arranged one behind the other in the transport direction (see Fig figure 6 to the right). The water tanks 21a, 21b have lateral support straps 25, the support straps 25 of the lower water tank 21b each having a guide surface 26. On these guide surfaces 26, the stand cooler 20 can be moved into a rolling stand (not shown here) in the width direction B of the hot strip. The frame cooler 20 shown is designed in one piece, with the upper and lower water tanks 21a, 21b being connected to one another by uprights 27. The cooling nozzles 23 are supplied with coolant through a total of four connections 22, two connections 22 supplying the upper and the lower water box 21a, 21b.

In figure 7 12 is a front view of the scaffold cooler of FIG figure 6 shown. The cooling nozzles 23 are typically supplied with an overpressure of 2 to 5 bar. The cooling intensity depends on the pressure and can be adjusted via the overpressure of the cooling medium.

In figure 8 a roll stand 1 with a stand cooler 20 is shown in a side view on the left and a sectional view on the right. The framework cooler 20 from the Figures 6 and 7 When installed, it rests on the two guide surfaces 26 of the lower support straps 25 on guide rails in the roll stand 1 or on the counter-guides of the chock 4b of the lower support roll and can be installed and removed on these. As can be seen, the stand cooler 20 is arranged between the back-up rolls 4, i.e. in a line with the back-up rolls 4.

the Figures 9a and 9b show one to the Figures 6 and 7 alternative framework cooler 20, which has cooling slots 24 instead of cooling nozzles. Since the steel strip 50 is not cooled differently in its width direction B or in the depth direction T of the framework cooler 20, it is sufficient if the upper and lower water tanks 21a, 21b each have only one connection 22. The uprights 7 and the straps 25 are as in the Figures 6 and 7 executed.

In figure 10 a water line plan for the coolant supply of a roll stand 11 with a built-in stand cooler 20 is shown. A pump 30 fed from a tank 31 represents the coolant supply. The pressure of the cooling medium water is reduced from 13 bar to 4 bar by the pressure control valve 28 and after passing the open switching valve 29 and the flow control valve 32 via connections to the upper and lower water tank 21a, 21b. The top and bottom of a hot strip, not shown here, are cooled by cooling nozzles 23 . In built State of the stand cooler 20 in the roll stand 11, the switching valves 29 for the supply of the cooling medium to the cooling heads for cooling the work rolls are closed. From an energy point of view, it would be more favorable to feed the frame cooler 20 through a separate cooling circuit without pressure reduction through pressure control valves 28, for example directly with a pressure between 0.1 and 5 bar. These are typical pressures of existing low-pressure cooling systems. Alternatively, it would also be possible to connect the stand cooler 20 directly to the existing coolant supply of the roll stand without reducing the pressure.

In figure 11 the installation of a stand cooler 20 in the roll stand 1 of a roll stand 11 is shown schematically. After the AGC cylinders 3 and the chocks 4a for the upper backup roll 4 have been started up, the chocks 5a, 5b for the work rolls 5 and the work rolls 5 are removed. The stand cooler 20 is then pushed in horizontally in the width direction B of the roll stand 11 through the roll stand 1 on the operator side (shown on the right here). Finally, the connections 22 of the stand cooler 20 are connected to a coolant supply, so that an upper side and an underside of a hot strip, not shown, are cooled by the cooling nozzles 23 .

the figure 12 shows a schematic section through a stand cooler 20 with cooling tubes 23a instead of cooling nozzles 23 (see figure 6 to the right). Cooling tubes 23a are typically operated with an overpressure of between 0.1 and 1 bar, so that they can easily implement what is known as laminar cooling.

The removal of a stand cooler 20 from a roll stand 1 is not shown separately, since the steps for installation are simply carried out in reverse order.

In the figure 13 is the covering of the edge areas of a steel strip 50, engl. edge masking, shown. In this case, at least one edge region of the steel strip 50, in the figure it is four edge areas, by inserting a deflector plate 33 or a channel between the cooling nozzles 23, cooling tubes 23a (see figure 12 ) or the cooling slot 24 (see Figure 9b ) of the stand cooler 20 and the surface of the steel strip 50 are covered so that the edge portion is not cooled. The cooling water from the cooling nozzles 23 or cooling tubes is discharged to the outside in the direction of the width of the steel strip 50 . The position of the deflector plate 33 or the chute can be finely adjusted manually or automatically (e.g. by an actuator, not shown, which displaces the deflector plate 33 in the direction of the arrow), so that overcooling of the edge areas is reliably prevented.

In figure 14 is an alternative scaffold cooler 20 to the scaffold cooler of FIG figure 7 shown in C shape. Since the C-shaped stand cooler 20 is open at one end in the width direction B, the stand cooler 20 can be easily mounted on and removed from a rolling mill stand during ongoing operation of the rolling mill. The connections 22 of the upper and lower water box 21a, 21b, the cooling nozzles 23 and the guide surfaces 26 are identical to figure 7 . As an alternative to the guide surfaces, the frame cooler 20 could also have wheels for guiding on a rail. The uprights 27 are only arranged at one end of the stand cooler, for example the operator end.

Although the invention has been illustrated and described in detail by the preferred embodiments, the invention is not limited by the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention as defined by the claims.

Reference List

1

roller stand

2

stand window

3

AGC cylinder

4

backup roll

4a

Chock for the upper backup roll

4b

Chock for the lower backup roll

5

stripper

5a

Chock for the upper work roll

5b

Chock for the lower work roll

6

bending block

7a

Upper cooling head of the interstand cooling

7b

Lower cooling head of the interstand cooling

8a

Upper cooling head of the work roll cooling

8b

Work roll cooling lower cooling head

9

looper roll

10

rolling table

11

mill stand

12

roller table

13

Cooling distributor of a cooling section

20

scaffold cooler

21a

Upper Water Box

21b

Lower water box

22

connection

23

cooling nozzle

23a

cooling tube

24

cooling slot

25

carrying straps

26

guide surface

27

stayers

28

pressure control valve

29

switching valve

30

pump

31

tank

32

flow control valve

33

deflector plate

40

rolling mill

45

cooling line

50

steel strap

B

Width direction of the roll stand

C

Chilled area

LC

Cooled area of the cooling line

NC

Uncooled area

T

Depth direction of scaffold cooler

TR

transport direction of the steel strip

Claims (15)

1. Roll stand (11) having an operator-side roller housing (1) and a drive-side roller housing,

   - wherein no working rollers (5) and no chocks (5a, 5b) for the working rollers (5) are disposed in the roll stand (11), but the roll stand (11) however has a stand cooler (20) for cooling a steel strip (50);

   - wherein the stand cooler (20) is dimensioned in such a manner that said stand cooler (20), instead of chocks (5a, 5b) and the upper and lower working rollers (5), can be installed in the roll stand (11) through the operator-side roller housing (1) of the roll stand (11);

   - wherein the stand cooler (20) comprises a lower water tank (21b) and an upper water tank (21a), wherein the lower water tank (21b) and the upper water tank (21a) have in each case one connector (22) for a coolant, and a plurality of cooling nozzles (23) or cooling pipes (23a) that are disposed in the depth direction (T) of the stand cooler (20), or at least one cooling slot (24) that runs in the depth direction (T) of the stand cooler (20), such that the lower and the upper water tank (21b, 21a) can be supplied with coolant by way of the respective connector (22), and the lower side of the steel strip (50) can be cooled by way of the cooling nozzles (23) or cooling pipes (23a) or the cooling slot (24) of the lower water tank (21b) and the upper side of the steel strip (50) can be cooled by way of the cooling nozzles (23) or cooling pipes (23a) or the cooling slot (24) of the upper water tank (21a) .
2. Roll stand (11) according to Claim 1, characterized in that the stand cooler (20) has at least two guide faces (26), wherein the guide faces (26) are connected to the lower water tank (21b) or the upper water tank (21a) such that the stand cooler (20) can be incorporated into the roll stand (11) in the width direction (B) of the roll stand (11).
3. Roll stand (11) according to either of Claims 1 or 2, characterized in that the stand cooler (20) is embodied so as to be in one piece, wherein the lower and the upper water tank (21b, 21a) are connected to one another by uprights (27).
4. Roll stand (11) according to either of Claims 1 or 2, characterized in that the stand cooler (20) is embodied so as to be in at least two pieces, wherein the lower and the upper water tank (21b, 21a) have in each case two guide faces (26).
5. Roll stand (11) according to one of Claims 1 to 4, characterized in that the lower water tank (21b) and/or the upper water tank (21a) have in each case two lateral support lugs (25), wherein the support lugs (25) have in each case one guide face (26).
6. Roll stand (11) according to one of Claims 1 to 4, characterized in that the lower water tank (21b) and the upper water tank (21a) have in each case one first and one second connector (22) such that the peripheral regions of the steel strip (50) by way of the respective first connector (22) and the central region of the steel strip (50) by way of the respective second connector (22) can be cooled to dissimilar degrees.
7. Roll stand (11) according to one of Claims 1 to 6, characterized in that the roll stand (11) has supporting rollers (4), and in that the stand cooler (20) in the state installed in the roll stand (11) is disposed between the supporting rollers (4) of the roll stand (11).
8. Roll stand (11) according to one of Claims 1 to 7, characterized in that said roll stand (11) has additional working rollers (5) and chocks (5a, 5b) for the working rollers (5), and in that the working rollers (5) and the chocks (5a, 5b) for the working rollers (5) are dimensioned in such a manner that said working rollers (5) and said chocks (5a, 5b) after the stand cooler (20) has been uninstalled from the roll stand (11) can be installed in the roll stand (11) through the operator-side roller housing (1) of the roll stand (11).
9. Method for installing a stand cooler (20) for cooling a steel strip (50) in a roll stand (11) of a rolling train, wherein the stand cooler (20) comprises a lower water tank (21b) and an upper water tank (21a), wherein the lower water tank (21b) and the upper water tank (21a) have in each case one connector (22) for a coolant, and a plurality of cooling nozzles (23) or cooling pipes (23a) that are disposed in the depth direction (T) of the stand cooler (20), or at least one cooling slot (24) that runs in the depth direction (T) of the stand cooler (20), said method comprising the following method steps:

   - removing chocks (5a, 5b) and an upper and a lower working roller (5) from the roll stand (11);

   - installing the stand cooler (20), instead of chocks (5a, 5b) and the upper and lower working rollers (5), in the roll stand (11), wherein the stand cooler (20) in the width direction (B) of the roll stand (11) is incorporated horizontally through an operator-side roller housing (1); and

   - connecting the connectors (22) of the upper and the lower water tank (21b, 21a) to a coolant supply such that the upper and the lower side of the steel strip (50) by way of the cooling nozzles (23) or cooling pipes (23a) or the cooling slot (24) of the lower water tank (21b) and of the upper water tank (21a) can be cooled by a coolant.
10. Method according to Claim 9, characterized in that the installation of the stand cooler (20) is performed during the ongoing operation of the rolling train (40) or during an interruption in the operation of the rolling train (40).
11. Method according to either of Claims 9 or 10, characterized in that the coolant supplies at least one connector (22) at a pressure of 2 to 5 bar.
12. Method according to one of Claims 9 to 11, characterized in that the coolant supplies at least one connector (22) at a pressure of 0.1 to 1 bar.
13. Method for rolling steel strips in a hot-rolling train (40) which has a plurality of roll stands (11), said method comprising the following method steps:

    - hot-rolling a first steel strip in at least two roll stands (11) of the rolling train (40);

    - cooling the first steel strip in a cooling section (45);

    - conveying away the cooled first steel strip;

    - installing a stand cooler (20), performed according to a method according to one of claims 9 to 12;

    - hot-rolling a second steel strip in at least one roll stand of the rolling train (40);

    - cooling the second steel strip in at least one roll stand (11) of the rolling train by means of the stand cooler (20);

    - cooling the cooled second steel strip in the cooling section (45) ;

    - conveying away the cooled second steel strip.
14. Method for uninstalling a stand cooler (20) for cooling a steel strip (50) from a roll stand (11) of a rolling train, wherein the stand cooler (20) comprises a lower water tank (21b) and an upper water tank (21a), wherein the lower water tank (21b) and the upper water tank (21a) have in each case one connector (22) for a coolant, and a plurality of cooling nozzles (23) or cooling pipes (23a) that are disposed in the depth direction (T) of the stand cooler (20), or at least one cooling slot (24) that runs in the depth direction (T) of the stand cooler (20), said method comprising the following method steps:

    - separating the connectors (22) of the upper and the lower water tank (21b, 21a) from a coolant supply;

    - uninstalling the stand cooler (20) from the roll stand (1), wherein the stand cooler (20) in the width direction (B) of the roll stand (11) is extracted horizontally from an operator-side roller housing (1);

    - installing chocks (5a, 5b) and an upper and a lower working roller (5), instead of the stand cooler (20), in the roll stand (11).
15. Method according to Claim 14, characterized in that uninstalling the stand cooler (20) is performed during the ongoing operation of a rolling train (40) or during an interruption in the operation of a rolling train (40).

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