EP3177412A1

EP3177412A1 - Adjusting a targeted temperature profile at the strip head and strip base prior to cross-cutting a metal strip

Info

Publication number: EP3177412A1
Application number: EP15738039.5A
Authority: EP
Inventors: Manfred Kuegel; Axel RIMNAC; Alois Seilinger
Original assignee: Primetals Technologies Austria GmbH
Current assignee: Primetals Technologies Austria GmbH
Priority date: 2014-08-06
Filing date: 2015-07-09
Publication date: 2017-06-14
Anticipated expiration: 2035-07-09
Also published as: CN106536074A; RU2017106342A3; RU2017106342A; WO2016020134A1; EP3177412B1; CN106536074B; MX2017001670A; US10870139B2; RU2679321C2; EP2982453A1; US20170209907A1

Abstract

The invention relates to the area of metallurgical systems, specifically a rolling mill with a cooling zone for cooling and scissors for cross-cutting metal strips, which are preferably made of steel. The aim of the invention is to provide a method and a device with which even metal strips with thicknesses > 4 mm and/or metal strips made of high-strength materials can be cross-cut by means of scissors arranged after a production line and a cooling zone. This is achieved by a method in which the metal strip (6) is cooled in the cooling zone (10) to a specified temperature profile in the longitudinal direction of the metal strip (6) such that the metal strip (6) has a higher temperature in the region of the strip head of the trailing metal strip portion (31) and the strip base of the leading metal strip portion (32) than in the upstream and downstream regions.

Description

description

Setting a targeted temperature profile at the tape head and band foot before cutting a metal band

Technical Field The present invention relates to the field of metallurgical ^¬ rule systems, specifically a rolling mill with a cooling zone for cooling and scissors for cutting of metal strips, preferably of steel. On the one hand, the invention relates to a method for Quertei ^¬ len a metal strip, preferably a steel strip, said method comprising the steps of:

- guiding the metal strip in a transport direction through a cooling zone;

- cooling the metal strip in the cooling zone; ^¬ at closing

- Cutting the metal strip on a pair of scissors, so that the metal strip in a leading Metallbandab ^¬ section with a band foot of the leading metal band section and a trailing metal band ^¬ section with a tape head of the trailing Me ^¬ tallbandabschnitts is divided and the band ^¬ head of the trailing metal band section in Transport direction immediately follows the band foot of the leading metal band section,

On the other hand, the invention relates to a device for cross-sectioning a metal strip for carrying out the erfindungsge ^¬ MAESSEN method, with a roller table for guiding the metal bands, with at least one cooling device, wherein the cooling ^¬ device is arranged in front of a pair of scissors for cutting the metal strip, so that the Metal strip (6) in a pre-run ^¬ the metal strip portion (28) with a band foot of the leading- the metal band portion (32) and a trailing metal ^¬ band portion (29) with a tape head of the trailing Me ^¬ tallbandabschnitts (31) is transversely divided and the tape head of the trailing metal band section (31) in the transport direction the belt foot of the leading metal band section (32) un ^¬ indirectly follows ,

^{PRIOR ART Hereinafter} , a pair of scissors, which can be made, for example, as pendulum scissors, is referred to as a separating device in front of the finishing train. An after the finishing train and in front of the reel ^¬ ordered scissors, which may be designed as a drum shears, for example, is hereinafter referred to as scissors.

The cutting of metal strips, especially of high-strength steel grades (yield stresses above 500 MPa) and / or thicknesses greater than 4 mm, according to the prior art requires some changes to the plant configuration. In order to be able to reliably separate high-strength and / or thick metal strips, some parts of the plant must be designed correspondingly larger. The scissors in front of the reel can not be made arbitrarily large for reasons of inertia and high cutting speed. Due to this limitation, the metal strip is often already cut on a separating device, which is located in front of the finishing train, and then the metal strip is finish rolled in batch mode. However, this has the consequence - to ensure a sufficient gap between the belt foot and the tape head ^¬ that the leading tape must be greatly accelerated. The sufficient gap is necessary so that no

Collisions between the tape head and the belt foot can occur in the following system parts - eg in front of the reel. Furthermore, it must be ensured that there are not two different metal bands on the same section of the outfeed roller table at the same time. The gap may also be necessary if a roll gap change - due to a change in thickness of the subsequent metal strip - is provided. The speed increase also means that the following ing parts such as the induction furnace, finishing train and the cooling zone are passed through faster. While going through the finishing train also occur because of the larger Ge ^¬ speed to temperature increases which itself negatively on the mechanical properties and the band

Surface quality affects. So that the mechanical properties ^¬ properties of the metal strip remain homogeneous over the length of the process parameters of the system components must be adjusted accordingly to avoid unfavorable temperature increases. The cooling pattern of the cooling zone must also be adjusted accordingly ^¬ speaking. Particularly disadvantageous is the separation on the shears before the finishing train in an ESP (Endless Strip Production) system, since the advantages of stable endless operation are thereby eliminated.

In WO / 59650 a system with a Strangußanlage, ei ^¬ ner roughing line, a separator, a furnace of a coiler, a Descaler, a finishing train, a cooling device, a pair of scissors and again a coiler is shown. An intermediate band is divided transversely at a separating device, wherein a leading metal band has a band foot and the trailing metal band has a band head. The already radially split tail of the strip and also already physika ^¬ cally existing tape head are disgusted then aufgewi- in a Induk ^¬ tion furnace overheated and by the coiler. Subsequently, the metal strip is again ^¬ wound from the reel and ^{finish-rolled} in a finishing train. Due to the overheated tape head and tape the foot of the metal band prop ^¬ net this investment particularly for rolling thin Me ^¬ tallblechen of> lmm. Overheating of the tape head and belt foot leads to comparable qualities as is the case with cold-rolled metal belts. After a cooling device is arranged a pair of scissors, which can cross-members on the tape length of the thin warmgewalz ^¬ th metal strip if required again.

In EP0730916 AI a hot rolling mill is shown, which has the following parts of the plant, a continuous casting, an oven, a rolling mill, a pair of scissors and a Haspelanla ^¬ ge. In the hot rolling mill you can during ongoing operation change the thickness of the metal strip to be rolled. By a tracking device, the change in the metal strip thickness can be detected and the scissors are controlled by this tracking device. Upon detection of a change in thickness - the metal strip - the scissors is activated for cutting. In the following coiler the metal strip is still wound from ^¬ closing.

Summary of the invention

The object of this invention is to provide a method and an apparatus of the type mentioned, with which metal strips with thicknesses greater than 4 mm and / or metal strips of high-strength grades (yield stresses above 500MPa) by a pair of scissors, after a finishing train and after a cooling section is arranged, can be divided transversely.

This object is achieved in the aforementioned method in that the metal strip is cooled in the cooling zone to a predetermined temperature profile in the longitudinal direction of the Metallban ^¬ , so that the metal strip in the region of the tape head of the trailing metal band section and Bandfu ^¬ ßes the leading metal band section a higher Tempe ^¬ ratur than in the upstream and downstream areas.

The metal strip is guided in the transport direction through a cooling zone. In the cooling zone, the metal strip is abge ^¬ cooled and then carried out a cross-cutting of Metallban ^¬ of the scissors, so that the transversely divided metal strip a tape head of the trailing metal band section and a

Has band foot of the leading metal band section. As a tape head, the beginning of a metal strip in transport ^{Rich ¬} tion is called. The band foot of the leading Metallbandab ^{¬ section} is the end of the leading metal band section after the transverse parts. Band head of the trailing metal band and band foot of the leading metal band are therefore identical to the transverse parts and only as an imaginary plane transverse to the transport direction available. Tape head of the trailing meter tallbandabschnitts and band foot of the leading Metallbandab ^{¬ section} are defined before entering the cooling device and not only after a successful cross cutting. Under metal band section is in each case that part of the metal strip understood that is wound into a coil. During production, many individual metal band ^{sections are produced} . The metal strip sections are part of the metal strip until they are cross-cut. After the cross-parts and finished winding of the leading metal band section, the to-be before subsequent metal strip section for the next Quertei ^¬ len for leading metal band section. In the region of the band head of the trailing metal band section and Bandfu ^¬ ßes the leading metal band section is set by the cooling zone, a temperature profile having a higher temperature than in the upstream and downstream areas.

The higher temperature in the area of the tape head of the trailing portion of the metal strip and the strip foot of the current before ^¬ metal band section, the yield stress is proposed preferably reduced by up to 50%. For high-strength Stahlsor ^¬ th the reduction of yield stress can be even> 50%. The expended for the cross-sectional portions of the belt Strengthens ^¬ te characterized reduced accordingly. The cross-cutting of the metal strip can be done easily with a common scissors used. Thus, it can be dispensed ^¬ who, the scissors interpreted larger - which is also possible due to the inertia anyway only in a limited context and is also associated with high costs. Furthermore, it is also not necessary to divide the metal strip with the separating device (ie before the finishing train) and to make the subsequent parts of the system larger or to place an additional second pair of scissors after the finishing line, which is designed for cutting the large thicknesses. This procedure ensures that the same equipment can also cut high-strength metal strips and / or metal strips with a thickness of> 4 mm - without having to accept any loss of quality in terms of strip properties and surface quality. In an advantageous embodiment of the method, the area of the band head of the trailing metal band section and band foot of the leading metal band section is tracked continuously (ie, in real time) at least from the beginning of the cooling zone to the scissors. The tape head of the trailing metal ^¬ band section and band foot of the leading Metallbandab ^{¬ section} are defined before entering the metal strip in the cooling zone. By tracking the Bandkop ^¬ fes the trailing metal band section and Bandfußes the leading metal band section of this area during the entire cycle - from at least the beginning of the cooling zone to scissors - constantly determined. As a result, it is possible to set a temperature profile in the desired range of the later tape head and tape foot.

The temperature profile that is set on the metal strip is advantageously a ramp profile. As a result, an optimized temperature profile can be set for each steel grade and / or thickness in order to minimize the cutting forces on the shears. But it can also be used different temperature profiles, such as a jump profile or a sinusoidal tempera ^¬ turprofil.

Advantageously, the temperature in the region of the band head of the trailing metal band section and band foot of the leading metal band section is at least 100 ° C. higher than that of the remaining metal band. From this temperature difference, a significant reduction in aufzu ^¬ wend forces during cross-cutting sets.

In a particularly preferred embodiment of the invention, the band foot of the leading metal band section and the band head of the trailing metal band section are uncooled. As a result, the forces to be expended when cutting are reduced the most.

The metal bands for which this method is particularly suitable ge ^¬ are those of high and ultra high-strength steel grades, especially tubular steels such as X70 or X80, hot strip multiphase steels such as dual phase steel DP600, DP800, DP1000 and others or fully martensitic steels. By this method it is possible that even hochfes ^¬ te metal strips with a thickness> 4mm can be divided transversely. The scissors do not have to be designed larger. With the method according to the invention can, for example, a metal strip of dual phases steel with the same system configuration, with a standard used shear, for example

DP1000 with a thickness of 8mm can be easily divided. Without inventive method would only max. 4 mm possible. Of course, it is also conceivable to use a smaller pair of scissors - with which e.g. Thicknesses of max. 2.5 mm could be divided. With the method according to the invention can - with the same scissors - metal strips of 5mm easily be divided.

In order to transmit the temperature profile to the metal strip, it is advantageous if this is done through the associated guide ^¬ te in the cooling zone quantity of cooling medium. The temperature profile is set in the cooling zone in the region of the tape head of the trailing portion of the metal strip and the strip foot of the leading Me ^¬ tallbandabschnitts by the cooling medium is not applied or into diesel sem area only to a reduced extent.

During the passage of the tape head of the trailing Metallbandab ^{¬ section} and the band foot of the leading Metallbandab ^{¬ section} through the cooling zone, the supply of the cooling medium is adjusted according to the desired temperature profile.

In a further advantageous embodiment, the adjustment of the amount of cooling medium is discrete. In a diskre ^¬ th adjustment of the amount be applied either 100% or 0% Kühlmedi- killed. This has the advantage that the cooling ^¬ zone can be easily performed without elaborate actuators ^¬ members - the need - for example, for setting the amount. An execution in a continuous manner is also conceivable. The adjustment then takes place via the quantity or the pressure.

This method is particularly advantageous if the metal strip is rolled before cooling in the cooling zone in a rolling train of a Gießnalzverbundanlage. This can be used Ver go ^¬ and existing plants without major alterations. This method can particularly preferably be used for ESP (Endless Strip Production) systems. This brings the clear advantages that during flexible ^¬ cher system configuration of the continuous operation can be extended to high-strength grades and greater thicknesses, without suffering adverse effects on the band characteristics.

A further advantageous embodiment of the method is that the metal strip after the cross-members is coiled onto a reel on ^¬. Due to the higher temperature of the tape head of the trailing metal band section threading the reel is facilitated - as well as the subsequent Anwickeln. At the same time damage such as impressions on the driver rollers are avoided. As a reel, the device is called, which winds the metal strip. A further advantageous embodiment is that the length ei ^¬ nes metal band section with increased temperature> a circumference of a coil, so that the coil is wrapped warm by the band foot of the front ^¬ running metal band section. He ^¬ creased temperature of the strip foot of the leading Metallbandab- section also has the positive effect that occurs ei ^¬ ner more uniform cooling of the metal strip. Since the outermost layer cools down more quickly - than the underlying - the cooling over the entire length of the winding up ^¬ th metal strip uniform, leading to see more homogeneous mechanical properties. The length of the warm belt foot should advantageously have at least the circumference of the coil. As a coil on the reel wound into a roll metal strip is called. For the cross-members of the metal strip is a partial explanatory front ^¬ particularly embodiment, that a blade gap of the shears is adjusted in dependence from ^¬ the thickness of the metal strip.

This allows the process of cross cutting, even during the

Operation, be further optimized and the cutting forces are further reduced depending on the thickness of the metal strip. It consists in first approximation, a linear dependence of the ide ^¬ alen knife gap on the thickness of the metal strip.

The inventive object is also achieved by the initially mentioned device ge ^¬ which comprises:

a tracking device for tracking the tape head of the trailing metal belt section and belt foot of the leading metal belt section to ^{¬ at} least from the beginning of the cooling device to scissors,

- A control device for controlling the cooling device and the scissors in dependence on the position of the tape head of the trailing metal band section and

Band foot of the leading metal band section.

With this device, it is possible to continuously track the position of the later tape head and tape foot of the metal strip from at least the beginning of the cooling device to scissors and to control the cooling device according to the position of the later tape head of the trailing metal band section and band foot of the leading metal band section.

In contrast, document EP0730916 shows a tracking device which detects a change in strip thickness. By this tracking device then a pair of scissors is controlled. However, a tracking device from the beginning of the cooling device to reaching the scissors is not shown in this document. Likewise, a control of the Kühlvor ^¬ direction is not shown by the position of the tape head and tape foot. Such a configuration can - without knowledge of the method described in claim 1 - not be derived from this document and is by no means obvious. An advantageous embodiment of the cooling device has at least three separate cooling sections, where ^¬ in the at least three cooling sections can be controlled or controlled separately. By at least 3 ge ^¬ separated cooling sections is ensured that the temperature can be turprofil reliably transmitted to the metal strip. If the region of the band head of the trailing metal band section and band foot of the leading Metallbandab ^{¬ section} - which is to have a greater temperature - reaches the cooling section, the first cooling section is turned off in the transport direction, while the remaining Kühlab ^¬ cuts remain turned on. When the area of the tape head of the trailing metal strip portion and Bandfu ^¬ SLI of the advancing metal strip section - is to have a larger temperature - Hert a second cooling section nä-, this is also turned off, and as soon as the loading ^¬ rich of the tape head of the trailing metal strip portion and band foot of leading metal band section - which ei ^¬ ne greater temperature to have - left the first cooling section, this is turned on again. When approaching the area of the tape head of the trailing Me ^¬ tallbandabschnitts and Bandfußes the leading metal band ^¬ section - which is to have a higher temperature - to a third cooling section, this is turned off and as soon as the area of the tape head of the trailing metal band section and Bandfußes the leading Metallbandabab ^{¬ section} - which should have a higher temperature - have left the second cooling section again, the second cooling section is turned on again. This is done for sämtli ^¬ che further cooling sections, which has the cooling device, analog. When exactly the respective cooling section on or off depends on which temperature ^¬ profile to the metal strip is to be transferred and how vie ^¬ le cooling sections having the cooler. Especially but of which area before the band foot of the leading metal band section and which area after the band head of the trailing metal band section should have a higher temperature.

To be able to ensure tracking of the position of the tape head of the trailing metal strip portion and tail of the strip of the leading Me ^¬ tallbandabschnitts particularly exact, it is particularly advantageous if the Nachverfolgungsein- direction ONS a computing device and at least one positive or comprises speed sensor, the front of the cross-members the metal belt controls the cooling device such that the desired temperature profile in the region of the tape head of the trailing metal band section and Bandfu- ßes the leading metal band section sets. The position or speed sensor can be a contacting (eg press-on of a roller or via the speed at the reel) or a non-contact (optically eg via a laser) design.

With respect to the embodiment of the cooling device, it is expedient to supply the cooling device as a water cooling section. In a particularly advantageous manner, the cooling apparatus is performed such that individually the flow rate of water nozzles of the cooling device in the transport direction or in sections, controlled by an actuator or Gere ^¬ gel may be, which is connected to the control device. The water nozzles are mounted on spray bars. Considering along the transport direction, the individual spray bars - which extend transversely to the transport direction over the entire width of the metal strip - so, each spray ^¬ beam itself is the smallest portion to this.

Sprühbalken may be, for example, tubes or nozzles over which the water exits. The sections can then be classified into any size depending on the requirements of each metal strip. So it can too several spray bars are controlled together. But it is also conceivable that each nozzle is controlled individually on each spray bar. The tracking of the region of the tape head of nachlau ^¬ fenden metal band section and the foot of the leading band metal band section is carried out in an advantageous Ausgestal ^¬ tung with a temperature measuring device. In order to detect the strip foot of the leading metal strip section and strip head of the trailing metal strip section, temperature measuring devices can also be used. The advantages that result are: To match the temperature profile with the specified, to determine the exact position of the tape head of the trailing metal band section and band foot of the leading metal band section and to match the calculated position. The temperature measuring devices can be arranged at various positions. Advantageous positions are in front of the cooling zone, in the middle of the cooling zone, after the cooling zone and before the scissors.

For the cross-members of the metal strip is a partial explanatory front ^¬ particularly embodiment, that the scissor comprises means for adjustment of the knife gap, wherein the device for adjusting the knife gap, the actual thickness of the Me ^¬ tallbands can be supplied. As a result, the process of cross-cutting can be further optimized and the cutting forces can be further reduced depending on the thickness of the metal strip. The knife gap is adjusted according to the thickness of the metal strip. It gets bigger, the larger the metal band is, which is split.

Further advantages and features of the present invention will become apparent from the following description of non-limiting embodiments, reference being made to the following figures, which show: Fig. 1 is a schematic representation of a casting-rolling compound plant according to the prior art.

FIG. 2 shows a schematic representation of a cast-rolled composite plant for the transverse cutting of metal strips according to the invention. FIG.

Fig. 3a and 3b shows the warm wrapping of a coil. Fig. 4 shows an inventive temperature profile of a Me ^¬ tallbandes.

FIGS. 5a and 5b show variant embodiments of a position sensor and a speed sensor.

Fig. 6 shows a graph of yield stress versus temperature from M. Spittel and T. Spittel Landolt-Börnstein Group VIII: Advanced Materials and Technologies, Volume 2, Springer Verlag, 2007, p. 11.

Fig. 7a and Fig. 7b temperature according to the invention show ^¬ profile of a metal strip just before and just after the Quertei ^¬ len

Fig.l shows a casting and rolling plant 1. In normal operation, a continuous casting system 2 generates a continuously cast-strangge ^¬ starting material 3 with slab cross-section, which is transported by means of a ^¬ roller table 4 to a roughing train. 5 After pre-rolling in the rough rolling mill 5, the metal strip 6 reaches the separating device 7. According to the prior art, here the transverse dividing of the metal strip 6 was effected by means of the separating device 7 - which in this case is a pendulum scissors. Thereafter, 4 driven gaps between the metal belts 6a-6d by driven rollers of the roller table. In the figure, then after the cross-members entste- rising band heads 31a-31d and the band feet 32a-32d also ersicht ^¬ Lich. After the passage of the induction furnace 8, 9 of the finishing train and the cooling zone 10 the winding of the Me ^¬ tallbandes occurs on the reel. 13 FIG. 2 shows an embodiment of the device according to the invention for cutting metal strips. The first steps up to Vorwalzstraße 5 carried out analogously to the prior art in Fig. 1. Thereafter, no cross-cutting, but the metal strip 6 passes undivided through the induction furnace 8, the finishing train 9 and then passes to the cooling zone 10 Be ^¬ before the metal strip 6 in When the cooling zone 10 enters, the actual temperature of the metal strip 6 is detected by means of a first temperature sensor 15 and sent to the control device 14. In the cooling zone 10, the desired temperature profile is applied to the metal strip 6 by the Wasserprühbal ^¬ kenabschnitte 20 or even individual spray bars 21 - the cooling device 19 - are controlled by the control device 14 accordingly. The tape head of the trailing Me ^¬ tallbandabschnitts 31 and band foot of the leading metal ^¬ band portion 32 of the metal strip 6 (see Fig. 4 below) are determined by the controller 14, using the position sensor 16 and the computing device 22, and determines their position continuously. The position sensor 16 may be a contacting (eg by the pressing of a roller or the speed at the reel) or a non-contact (op ^¬ table eg via a laser) execution. The position sensor 16 and computing device 22 form the Nachverfol- restriction device 23. The spray bar 21 can be according to the predetermined temperature profile over the entire run of the tape head of the trailing metal band portion 31 and strip foot of the advancing metal strip portion 32 is ^¬ represents. The metal strip 6, after passing through the cooling device 19 - in the area of the tape head of the trailing metal band portion 31 and band foot of -a before ^¬ running metal band portion 32 higher temperature than in the upstream and downstream areas. After complete passage of tape head of trailing Metallbandab- section 31 and band foot of the leading metal band section 32 through the cooling zone 10, the temperature profile is again detected by a second temperature sensor 17 and transmitted to the control device 14 to the actual profile with to match the target profile. When the tape head of the nachlau ^¬ fenden metal band section 31 and band foot of the leading metal band portion 32 has arrived at the scissors 12 he ^¬ holds this, by the control device 14, a signal and the metal strip 6 is transversely divided. The leading metal strip 28 is wound up by the reel 13 finished, then the tape head of the trailing metal band portion 31 is threaded at the reel 13 and the coiling process starts.

In Fig. 3a and Fig. 3b shows how the coil 30 is wrapped warm. In Fig. 3a, the wound coil 30 is shown, inside the tape head 31a, a metal band section with temperature To, a metal band section 33 of length L with temperature ΤΊ and the band foot 32a. The length L of the metal ^¬ bandteilstücks amounts to the length of the circumference of the coil 30. The temperature of the metal band section 33 has a higher temperature ΤΊ as the temperature To of ago ^¬ forthcoming part of the metal strip. In the diagram is the Tem ^¬ temperature T via the metal tape length x - this is about the extended length - shown.

In Fig. 3b is then seen that the warm metal band ^¬ piece 33 encloses the coil 30.

FIG. 4 shows a typical temperature profile according to the invention over the temperature profile length xp of a metal strip 6. In the area of strip foot of the advancing metal ^¬ tape 32 - xf on the Bandfußlänge - the temperature ΤΊ is higher than after, where a temperature To is adjusted until finally the area of the tape head of the trailing metal tallbandabschnitts 31 follows wherein also - via the Tape head length xk - again a temperature ΤΊ is set. The tape head length xk and the tape foot length xf need not be the same, as shown here. They can also have different lengths. The tape head 31a of the advancing metal strip 28 likewise has a temperature profile with the temperature ΤΊ. After the transverse cutting on the scissors, the metal strip 6 is inserted into a leading metal strip section 28 and a trailing metal strip section 29. Splits. But it is already before the cross-section - at least as soon as the two sections reach the cooling device - defined as a leading metal band section 28 and trailing Me ^¬ tallabschnitt 29.

In Fig. 5a, an embodiment of a position sensor 16 is shown nä ^¬ forth, the roller 41 is pressed onto the metal strip 6. By the movement of the metal strip, the pressed up roller rotates 41 and this is detected by an optical sensor 42 and the signal generated thereby is further processed in the STEU ^¬ ereinrichtung fourteenth By this signal and various other information such as the desired length of the metal strip, the position of the later band ^¬ head and band foot can be calculated at least in the range from the beginning of the cooling zone 10 to the scissors 12 of the controller 14. The Sprühbalkenabschnitte 20 or possibly the individual spray bars 21 in the cooling zone 10 are so driven that is established on the metal belt 6, a desired Tem ^¬ peraturprofil.

In Fig. 5b, a variant of a VELOCITY ^¬ keitssensors 18 is shown. Here, the position of the metal strip 6 is detected by the rotational speed of the reel 13 by an angle rotary encoder 43. By knowing the thickness of the metal strip 6, the diameter of the reel 13 and more

Information that is relevant for the production - such as the desired length of the metal strip - can here again the position of the tape head 31 and band foot 32 in the cooling ^¬ zone 10 are determined.

FIG. 6 shows the behavior of the yield stress a _F versus the temperature T of a steel H360LA. It can be seen from this that the yield stress decreases from 300 MPa at approx. 600 ° C to 150 MPa at approx. 800 ° C. Thus, by a temperature increase of the metal strip of about 200 ° C, the

Cutting forces on a pair of scissors are greatly reduced. In Fig. 7a, the metal strip 6, immediately before the Quertei len ^¬ , shown. The band foot of the leading Metallbandab ^{¬ section} 32 and the tape head of the trailing Metallbandab ^¬ section 31 are still identical before cross-cutting and only as an imaginary plane available. The leading Metallbandab ^¬ cut already know a tape head 31a on - which has originated from the previous cross parts. In Fig. 7b, the cross-cutting has already been done. This results in - in transport ^¬ direction 34 - thus a leading metal band portion 28, with the band foot of the leading metal band portion 32, and a trailing metal band portion 29 - with a tape head of the trailing metal band portion 31. The leading metal band portion has after the transverse parts a tape head 31 a and the Bandfuß the leading metal band section 32 on. The region of the band head of the trailing metal band ^¬ section 31 and the area of the band foot of the leading metal band portion 32 have the temperature profiles shown.

Reference sign list

1 cast roll composite plant

2 continuous casting plant

3 starting material

4 roller table

5 roughing line

6, 6a-6d metal band

7 separating device

8 induction furnace

9 finishing mill

10 cooling zone

12 scissors

13 reel

14 control device

15 First temperature sensor

16 position sensor

18 speed sensor

17 second temperature sensor

19 cooler

20 spray bar sections

21 spray bars

22 computing device

23 tracking device

28 leading metal band section

29 trailing metal band section

30 coil

31 tape head of the trailing metal section 31a-31d tape head

32 strip foot of the leading metal section

32a-32d band foot

33 metal band section

34 transport direction

41 role

42 Optical sensor

43 angle encoder

L Length of the metal band section _{Λ 0}

T temperature

xp temperature profile length xf tape foot length

xk tape head length

x metal band length

<3f yield stress

Claims

claims

Method for cutting a metal strip (6), preferably a steel strip, the method comprising the following steps:

- Guide the metal strip (6) in the transport direction through a cooling zone (10);

- cooling the metal strip (6) in the cooling zone (10); subsequently

- Crossing the metal strip (6) on a pair of scissors (12), so that the metal strip (6) in a leading ^¬ the metal strip portion (28) with a band foot of the leading metal band portion (32) and a trailing metal band portion (29) with a tape head of the trailing Metal strip section (31) is transversely divided and the tape head of the nachlau ^¬ fenden metal strip section (31) in Transportrich ^¬ tion (34) the strip foot of the leading metal strip section (32) immediately follows,

characterized in that the metal strip (6) in the cooling zone (10) to a predetermined temperature pro ^¬ fil in the longitudinal direction of the metal strip (6) is cooled so that the metal band (6) in the region of the tape ^¬ head of the trailing metal strip portion (31) and Bandfußes the leading metal band section (32) has a higher temperature than in the upstream and downstream areas.

A method according to claim 1, characterized in that the region of the tape head of the trailing metal ^¬ band section (31) and band foot of the leading Me ^¬ tallbandabschnitts (32) is at least from the beginning of the cooling ^¬ zone (10) to the scissors (12) constantly tracked ,

3. The method according to any one of the preceding claims,

characterized in that it is in the temperature ^¬ turprofil a ramp profile.

4. The method according to any one of the preceding claims, characterized in that the temperature in the region of the tape head of the trailing metal band section (31) and the band foot of the leading Metallbandab ^{¬ section} (32) by at least 100 ° C above that of the rest ^¬ union metal strip (6 ) lies.

5. The method according to claim 4, characterized in that the area of the tape head of the trailing metal band section (31) and the band foot of the leading metal band portion ^¬ (32) are uncooled.

6. The method according to any one of the preceding claims,

characterized in that the metal strip (6) consists of high and very high-strength grades, these are preferably tubular or hot strip multiphase steels or fully martensitic steels. 7. The method according to any one of the preceding claims,

characterized in that the metal strip (6) has a thickness> 4mm.

8. The method according to any one of the preceding claims,

characterized in that the temperature profile is adjusted by a the metal strip (6) in the cooling zone (10) supplied amount of cooling medium.

9. The method according to claim 8, characterized in that the supplied amount of cooling medium is adjusted discretely.

10. The method according to any one of the preceding claims,

characterized in that the metal strip (6) before cooling in the cooling zone (10) in a rolling mill of a

Cast roll composite system (1) is rolled.

11. The method according to any one of the preceding claims, characterized in that the metal strip (6) after the cross-cutting on a Hapsel (13) is reeled. 12. The method according to claim 11, characterized in that the length of a metal strip section (33) with He ^¬ heightened temperature> a circumference of a coil (30), so that the coil (30) by the band foot of the trailing metal band portion (32) wrapped warm becomes.

13. The method according to any one of the preceding claims,

characterized in that a knife gap of the scissors (12) in dependence of the thickness of the metal strip (6) is adjusted.

14. An apparatus for cross-sectioning a metal strip (6) for carrying out the method according to one of the preceding claims, comprising a roller table (4) for guiding the metal strip (6), with at least one cooling device, wherein the cooling device (19) in front of a pair of scissors (12 ) is arranged for cross-sectioning the metal strip, so that the metal strip (6) in a leading Metallbandab ^{¬ section} (28) with a band foot of the leading metal ^¬ band section (32) and a trailing metal band section (29) with a tape head of the trailing Me ^¬ tallbandabschnitts (31) is transversely divided and the band ^¬ head of the trailing metal band section (31) in the transport direction of the band foot of the leading metal band portion (32) immediately follows, characterized by,

- A tracking device (23) for tracking the position of the tape head of the trailing metal band portion (31) and the band foot of the vorlau ^¬ fenden metal band section (32) at least from the beginning of the cooling device (19) to the scissors (12), and

a control device (14) for controlling the cooling device and the scissors (12) as a function of the position of the strip head of the trailing metal strip Section (31) and tail of the strip of the leading ^¬ metal band portion (32)

15. The apparatus according to claim 14, characterized in that the cooling device has at least three separate cooling sections, wherein the at least three cooling sections can be controlled or regulated separately from each other.

6. Apparatus according to claim 14, characterized in that the tracking device (23) a calculating device (22) and a position (16) or speed sensor (18) for the metal strip (6) has ^¬.

7. Device according to one of claims 14 to 16, characterized in that it is at the cooling device (19) is a water cooling section. 18. Device according to one of claims 14 to 17, characterized in that the flow rate of the ^¬ serdüsen the cooling device (19) in the transport direction (34) can be controlled or regulated individually or in sections by an adjusting device, which with the control device (14 ) connected is.

19. The apparatus according to claim 14, characterized in that it is the tracking device (23) is a temperature measuring device.

20. Device according to one of claims 14 to 19, characterized in that the scissors (12) has a device for adjusting the blade gap, wherein the means for adjusting the blade gap, the aktu- current thickness of the metal strip (6) can be supplied.